Anesthesia for Cardiac Surgery

Which of the following are pulsatile VAD A. Abiomed BVS5000 B. Thoratec C. Centrifugal pumps D. Centrimag

A & B

Which of the following is released primarily from the ventricles in response to increased wall stress. A. ANP B. BNP C. Angiotensin i D. Renin

B. Heart Failure Heart failure is a complex pathophysiologic process that causes a clinical syndrome characterized by pulmonary congestion resulting from the heart's inability to fill with or eject blood in a sufficient quantity to meet tissue requirements.25 The heart was once thought of as simply the pump of the circulatory system, but it is now known that it evolves into an "endocrine organ" under stress, actively secreting neurohormonal factors in an attempt to meet the needs of the body. For example, atrial natriuretic peptide (ANP) is released from the atria in response to volume overload, and B-type natriuretic peptide (BNP) is released primarily from the ventricles in response to increased wall stress. These peptides help protect the myocardium by inducing physiologic effects such as diuresis, natriuresis, and vasodilation.28 In fact, BNP has been recognized as a powerful biomarker for diagnosis, determination of severity, and prognostication of heart failure.29 Heart failure is caused by an insult that alters perfusion and leads to a state of neurohumoral imbalance. Activation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system induces a host of pathologic responses. Many patients with heart failure will receive multimodal drug therapy aimed at interrupting the response and slowing disease progression4 (Fig. 26.5). β-Blockers, angiotensin-converting enzyme inhibitors (ACEIs), and aldosterone antagonists can have a synergistic effect when combined with anesthetics that leads to intraoperative hypotension. Nevertheless, it is recommended that medications used to control the patient's heart failure should be continued in the perioperative period, as their benefits are well-documented.25,28-30 If ACE inhibitors are withheld to prevent intraoperative hypotension, then they should b

Which of the folloiwng are nonpulsative VAD for long term support A. Heartmate XVE B. Thoratec C. Heartmate II D. CardioWest TAH

C.

Which of the following diagnostic tool is the most sensitive intraoperative monitor for detecting myocardial ischemia A. EKG B. TTE C. TEE D. Cardiac catheterization

C.

Which of the following should be decreased during Management of CABG A. Preload B. HR C. SVR D. PVR

A & B

Which of the following should be increased in the management of hypertrophic cardiomyopathy A. Preload B. Heart rate C. Contractility D. PVR

A.

Designed to last a lifetime. Requires the use of lifetime anticoagulation so lifestyle, childbearing, and compliance must be considered. Some make a clicking noise A. Valve Repair B. Mechanical valve replacement C. Bioprosthetic valve replacement D. Allograft replacement E. Ross procedure

B. Replacement With a Mechanical Valve

These are the most common pulmonary complications post CPB A. Hemothorax B. Pneumothorax C. Atelectasis D. Pleural effusion

C & D Lungs. Pulmonary complications after CPB can range from mild atelectasis that develops because the lungs are not ventilated on bypass to severe pulmonary dysfunction that was at one time known as pump lung, but is now known as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS), depending on the severity. Atelectasis and pleural effusions, which occur in 60% of cardiac surgery patients, are the most common injuries, but hemothorax, pneumothorax, and pulmonary edema may also occur.42 Patients with chronic obstructive pulmonary disease or any other preexisting respiratory disease are at increased risk for exacerbation of their existing pulmonary illness after CPB. Embolic insults, prolonged CPB, and the CPB-induced systemic inflammatory response, which causes an increase in pulmonary endothelial permeability, pose the biggest risk to the development of ALI and ARDS.60 Kidneys. Renal dysfunction manifesting as acute kidney injury is one of the major complications of cardiac surgery, and serves as a major predictor of morbidity and mortality for postoperative cardiac surgical patients. Bove et al.61 found 3.4% of 5,068 patients who underwent cardiac surgery with CPB developed acute renal failure (ARF; 100% creatinine increase), and 1.9% required renal replacement therapy. Hospital mortality was over 40% for patients with ARF, and increased to over 63% in patients who required renal replacement therapy. Optimizing cardiovascular volume status and CO, as well as limiting CPB time, are suggested to decrease the incidence of ARF. Gastrointestinal. Gastrointestinal system dysfunction is a relatively rare occurrence, but significantly increases the incidence of perioperative MI, renal failure, stroke, and even death.62 Gastrointestinal dysfunction seems to also be affected by hypoperfusion and/or embolic

In an aortic aneurysm repair, keeping the SPB lower than ____ mm Hg will minimize the chance of dissection. A. 90 B. 100 B. 110 C. 120

C. Anesthetic Management Anesthesia implications are similar to those of other cardiac surgeries involving a median sternotomy with CPB, but with several additional concerns. The anesthetist must prepare for the possibility of a difficult airway if the aneurysm is large and possibly causing a mass effect. Occasionally, a reinforced ETT must be used and advanced beyond the point of compression. Caution is advised if there is resistance to passing the TEE probe or OG tube, as the aneurysm may be compressing the esophagus. An epiaortic echocardiographic examination may be necessary. If AI is present, all the anesthetic management principles previously discussed regarding acute and chronic AI will apply. In general, maintenance of a relatively high heart rate and a low SVR will enhance forward flow. Keeping the SPB lower than 120 mm Hg will minimize the chance of dissection.273,274 Vasodilators are often utilized to control BP and lower the SVR. PACs are usually indicated because large shifts in volume can be reasonably anticipated, especially if the arch is involved. A large-bore multilumen PAC introducer allows volume to be rapidly infused. Alternatively, several large-bore PIVs can be used with a standard PAC introducer. Blood loss can be significant, so several units of red cells should be available. FFP and platelets are transfused as needed based on coagulation studies and nonsurgical bleeding. Antifibrinolytic therapy is also sometimes used. The best location for the A-line is determined by the plan for placement of the aortic cannula and aortic cross-clamp. For ascending aortic aneurysms, there is no consensus in the literature as to the best location for the A-line; the left brachial artery, as well as the left and right radial arteries, have been advocated. When the arch is involved, two A-lines are placed: one i

Three preoperative risk factors have been linked to bleeding and blood transfusion including the following except A. advanced age (70 years or older) B. Low red cell volume either from preoperative anemia C. Large body habitus D. urgent or complex surgery involving prolonged CPB times

C. Blood Conservation A review of over four million cardiac surgery patients between 1999 and 2010 showed that blood product utilization was increasing and peaked at 34% in 2010, despite publication of blood conservation guidelines by the Society of Thoracic Surgeons (STS) in 2007.45 Currently, 10% to 15% of the nation's blood supply is used for patients having cardiac surgery. The risks of transfusion are well-documented (see Chapter 22), and blood transfusions during cardiac surgery are associated with worse short-term and long-term survival,46,47 including a dose-related increase in the number of postoperative infections with the number of red blood cell (RBC) transfusion units.48 Additionally, the donor blood supply is either stable or decreasing.49,50 Blood is considered a finite, scarce, and expensive resource, and there is a national effort to limit its use. Three preoperative risk factors have been linked to bleeding and blood transfusion: (1) advanced age (70 years or older); (2) low red cell volume either from preoperative anemia and/or small body size; and (3) urgent or complex surgery involving prolonged CPB times.51 In 2011, the STS and the Society of Cardiovascular Anesthesiologists (SCA) published instructions for blood conservation in clinical practice guidelines.51 Practitioners of cardiac anesthesia are encouraged to review this important document; this chapter discusses only the highlights. The recommended techniques that promote the conservation of blood and blood products include the administration of antifibrinolytics, blood salvage, limiting the quantity of pump prime, ultrafiltration when appropriate, and the development of multidisciplinary blood management teams.

This is the most significant cause of perioperative ischemia A. Hypotension B. Hypertension C. Bradycardia D. Tachycardia

D.

These are used to assume the function of the failing ventricle as a bridge to recovery, a bridge to transplant, or as destination therapy. A. IABP B. ECMO C. VAD D. Impella

C. Ventricular Assist Devices General Considerations. Heart transplantation is the only definitive treatment for end-stage heart failure.82,254 It is estimated that close to 40,000 patients would benefit from a transplant; but because of the lack of donors, only 2804 heart transplants were performed in 2015. Additionally, the prevalence of heart failure increases with age, and patients over 65 years of age are not eligible transplant candidates.255,256 VADs are bringing new hope to this population. Today, VADs are used to assume the function of the failing ventricle as a bridge to recovery, a bridge to transplant, or as destination therapy. Heart failure patients considered for long-term VAD support typically have become refractory to standard medical therapy. They are often symptomatic at rest and are receiving IV inotropic support.8,82,257 It is not uncommon for these patients to develop end-organ dysfunction caused by decreased perfusion pressure and a low CO. Cardiogenic shock from an acute MI, viral cardiomyopathies, or post-CPB can all be indications for short-term VAD support (lasting days or weeks) and bridge to recovery.8,258 In this situation, the myocardium is granted time to rest while the VAD maintains circulation and decompresses the ventricle. Studies show that the decreased wall tension and myocardial O2 demand that occur as a result of the ventricular unloading allow remodeling and recovery of the ventricle.259,260 Careful patient selection and intervention timing are key to achieving a successful outcome with VAD placement.82 Contraindications to VAD insertion include active infection or sepsis, irreversible renal or hepatic dysfunction, severe PHTN unrelated to cardiac disease, metastatic cancer, and major coagulation disorders such as hemophilia and von Willebrand disease. Since the first successful

Used for aortic regurgitation, usually due to bicuspid valve. Preserves heart muscle strength and natural heart anatomy. Decreased risk of infection. Decreased requirement for life long anticoagulation A. Valve Repair B. Mechanical valve replacement C. Bioprosthetic valve replacement D. Allograft replacement E. Ross procedure

A. Aortic valve repair

The most ominous reason for significant persistent hypotension (MAP less than 30 mm Hg) is A. Aortic dissection B. Vasoplegia C. Sepsis D. Vagal response

A. Cardiopulmonary Bypass Period Initiation. Initiation of CPB can begin after the ACT is greater than 400 seconds. The venous clamp is first released, allowing blood to fill the venous reservoir; then the arterial clamp is removed, initiating CPB. Adequate venous drainage is necessary for the pump flow to be gradually increased to reach a calculated CI of 2.0 to 2.5 L/min per m2. Acceptable venous drainage usually correlates with a CVP of less than 5 mm Hg (and possibly a negative pressure, if VAVD is used). The heart should appear empty and not distended. Hypotension is common at the initiation of bypass, and is most likely related to the instantaneous hemodilution and reduced blood viscosity that occur, which can then result in a reduction of SVR. Phenylephrine boluses administered by the perfusionist are routinely necessary to augment the MAP during the initial phase of CPB. The most ominous reason for significant persistent hypotension (MAP less than 30 mm Hg) is an aortic dissection. The diagnosis can be confirmed by TEE, and the surgeon may note a hematoma on the wall of the aorta. If a dissection is suspected, CPB must be discontinued until the aorta can be recannulated distal to the dissection. Other causes of persistent hypotension while on CPB include vasoplegia and sepsis. When the CPB machine reaches full flow, there will no longer be a pulsatile trace visible on the PA-line, or A-line, indicating that blood is now bypassing the lungs. Consequently, mechanical ventilation is discontinued. During CPB, the anesthetist must ensure that adequate levels of anesthetic and muscle relaxant are maintained. Equipment integrity should be verified throughout the duration of CPB. If a volatile agent is to be used, the vaporizer must be properly seated on the oxygenator gas inlet of the CPB machine and turned on. An imp

Which cannula is removed first during the post bypass period A. Atrial B. Aortic

A. Postbypass Period Decannulation. Blood from the pump is transfused to the patient either at a slow but continuous rate or in 100-mL increments. Caution is taken to prevent overdistention and volume overload of either ventricle. Once major surgical bleeding is controlled and hemodynamic stability is satisfactory, preparation for decannulation can begin. The BP is usually lowered to 90 mm Hg systolic or a MAP of 70 mm Hg or less to reduce bleeding. The atrial (venous) cannula(e) are removed first, then the aortic cannula is removed, and the time is recorded. Blood that remains in the CPB reservoir and pump tubing is sent to the cell-saver device so that it can be washed and reinfused.

A normal CI value will be A. 1.9 B. 2.9 C. 3.9 D. 4.9

B & C

Anesthetic management for the management of hypertrophic cardiomyopathy include the following except A. Increase preload B. Increase Heart rate C. increase contractility D. increased in compliance

B & C Anesthetic Considerations and Surgical Options. Patients who remain symptomatic with gradients of 50 mm Hg despite optimal medical management are candidates for septal reduction therapy. Surgical septal myotomy via the aortic approach at an experienced surgery center is preferred over alcohol septal ablation.173 Approximately two-thirds of patients will also have structural malformations of the mitral valve. It is not uncommon to find that the mitral valve will need repair or replacement at the time of myectomy.82 Anesthetic management (Table 26.12) is directed at optimizing preload, avoiding increases in septal wall-anterior leaflet contact caused by increases in heart rate or contractility, and preventing sudden reductions in afterload. Excision of the hypertrophied basal septum may result in disruption of the conduction system of the heart, with new-onset heart block requiring pacing. After CPB is terminated, the outflow tract and mitral valve are examined using TEE. To determine the adequacy of surgical repair, the patient's heart rate and contractility are deliberately increased while the BP is simultaneously decreased, to mimic a physiologic hyperdynamic state such as exercise. An infusion of isoproterenol is ideal for achieving this goal, but at the time of this writing the use of isoproterenol is limited due to high cost and/or availability. Instead, dobutamine or rapid ventricular pacing (at a rate of 120 bpm), combined with an infusion of nitroglycerin, can be used. The echocardiographic examination will reveal whether obstruction, SAM, or MR develops with the tachycardia and hypotension. If more muscle needs to be excised, or the valve needs repair or replacement to prevent SAM, CPB will be resumed so the surgeon can make the necessary adjustments.

The final phase of the CPB circuit requires the blood to pass through a A. Heat exchanger B. Arterial Filter C. Oxygenator D. Main Pump E. Cardiotomy

B. The final phase of the CPB circuit requires the blood to pass through an arterial filter before returning to the arterial cannula and the rest of the body (see Fig. 26.8). The arterial filter has a pore size of 21 to 40 mcm, and acts as an air bubble trap and particulate filter, ideally preventing thrombi, fat globules, calcium, and tissue debris from entering the circulation. The arterial cannula is most often placed in the ascending aorta, but alternate sites include the femoral or the subclavian artery.

This is a mechanical circulatory assist device that can provide both pulmonary and systemic arterial perfusion support. A. IABP B. ECMO C. VAD D. Impella

b Extracorporeal Membrane Oxygenation. ECMO is a mechanical circulatory assist device that can provide both pulmonary and systemic arterial perfusion support. It is a temporary (used for days to weeks), closed-circuit device that allows the heart and/or the lungs to recover from injury or trauma while maintaining oxygenation and perfusion.82,248,249 The primary conditions that call for use of ECMO are cardiogenic shock, failure to wean from CPB, RHF, heart failure that cannot be treated with a VAD, and (as a last resort, but with increasing use) resuscitation of patients requiring cardiopulmonary resuscitation.248,250,251 ECMO is also used to support patients with severe respiratory failure and ARDS who have failed to respond to standard treatments and advanced modes of mechanical ventilation.248 There are two types of ECMO, and their goals and cannulae placement are somewhat different. Venovenous ECMO is the preferred method of treatment for respiratory failure (when the cardiac function is intact) and gas exchange is impaired.250-252 It supports the lungs by improving gas exchange and allowing lung-protective ventilation modes. In venovenous ECMO, the femoral and internal jugular veins are often selected as cannulation sites.253 Blood is drained from the SVC and IVC through a cannula in the right internal jugular and/or the femoral vein. The blood is oxygenated by the ECMO circuit and returned to the right atrium through the same vein or a different vein (separate drainage and return cannulae or a single double-lumen cannula). If left ventricular support is required in addition to pulmonary support, venoarterial ECMO is selected.251,252 In contrast to venovenous ECMO, venoarterial ECMO bypasses pulmonary circulation altogether, and a higher arterial oxygenation is achieved. Cannulation for venoarterial ECMO may be ce

. If the aortic root is dilated, a technically difficult valve-sparing operation known as a A. Modified David B. Bentall C. Cabrol

A. Ascending Aortic Aneurysms When the aortic aneurysm involves only the root and proximal aorta, standard aortic cannulation and CPB can be used because the distal aorta can be cannulated and a clamp placed between the cannula and the aneurysm. The femoral artery may be used as an alternate arterial cannulation site when the aortic cannula cannot be placed without jeopardizing flow to the head vessels. In this case, arterial flow is retrograde from the femoral artery to the great vessels. Additional approaches also include cannulation of the right axillary artery (or a graft sewn on the right axillary) or innominate artery.274 Usually a single, standard two-stage venous cannula suffices. A simple tube graft can be used to replace the aorta when the aortic root and valve are normal (Fig. 26.27). If the aortic annulus or sinuses of Valsalva (where the coronary arteries attach) are involved, the options become more complicated, and the selected technique may depend on the surgeon's expertise and preferences. When the sinuses of Valsalva are normal, the coronary arteries do not have to be reimplanted. The valve is repaired or replaced, the sinuses are spared, and a tube graft is used to repair the aneurysm. If the aortic root is dilated, a technically difficult valve-sparing operation known as a modified David or Svensson reimplantation procedure can be used (Fig. 26.28). A special instrument known as the Hegar dilator is placed in the LV outflow tract as the native AV (repaired if necessary) is sewn inside the graft used to repair the aneurysm. The dilator helps the surgeon correctly size the valve.275 The coronary arteries, which were removed along with a button of tissue from the native aorta, are then reimplanted into the graft. When the valve cannot be spared, an alternative procedure known as the Bentall (or modifie

Which of the following should be avoided in right ventricular failure A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide

B & D Right Ventricular Failure. Right heart failure (RHF) is most often secondary to left heart failure, but can also be caused by pulmonary hypertension (PHTN) or a right-sided MI. RHF causes systemic venous congestion, hepatomegaly, and peripheral edema.25,28 Management of RHF can be more difficult than that of left-sided failure because fewer options exist for unloading and supporting the right ventricle. The goal in managing RHF is to improve contractility while reducing right heart afterload. Therefore conditions or medications that increase right heart afterload, including those used to treat hypercarbia, hypoxemia, acidosis, and similar conditions, which can potentially increase pulmonary pressure and exacerbate PHTN, should be avoided. Nitrous oxide and desflurane can also increase pulmonary pressures, so they too should be avoided.28 Normally, the right heart is perfused throughout the cardiac cycle (see Fig. 26.3); however, when the right ventricle is distended, coronary perfusion occurs primarily during diastole, as it does in the LV.24

This is the only valve defect that causes the LV to be chronically underloaded. Volume management can be challenging because an adequate preload is needed to maintain flow across the stenotic valve, but too much volume can lead to pulmonary congestion. A. Mitral regurgitation B. Mitral stenosis C. Aortic stenosis D. Aortic regurgitation

B. Anesthetic Considerations and Surgical Options. Although avoiding tachycardia and treating AF help control the symptoms, MS mechanically obstructs ventricular filling. The three procedures used to relieve this obstruction are mitral balloon valvotomy, open commissurotomy of the mitral valve, and replacement with a mechanical or biologic valve. Closed commissurotomy is no longer recommended. Valvotomy or repair is generally preferred to replacement, but a left atrial thrombus, concurrent MR, or annular calcification may make replacement the treatment of choice.80 If the patient has a history of AF and the valve is approached through a full sternotomy, the surgeon will often elect to add a Maze procedure (see later) or pulmonary vein isolation to treat AF. The choice of radiofrequency (heat) or cryotherapy (cold) ablation is based primarily on surgeon preference. Anesthetic considerations for the Maze procedure and other options for atrial ablation are discussed after the valve section of this chapter. The left atrial appendage may also be excised to decrease the risk of emboli. Anesthetic considerations for MS are outlined in Table 26.14. Maintaining a low-normal heart rate is a priority so there is adequate time in diastole to fill the LV. If AF is present or develops, the ventricular rate must be controlled. Conditions or medications that can exacerbate PHTN should be avoided. These include hypercarbia, hypoxemia, nitrous oxide, desflurane and the Trendelenburg position. MS is the only valve defect that causes the LV to be chronically underloaded. Volume management can be challenging because an adequate preload is needed to maintain flow across the stenotic valve, but too much volume can lead to pulmonary congestion. The majority of patients have normal left ventricular function; however, the increase in ventricula

Patients with the following dissections usually present with sudden severe neck and chest pain, but symptoms mimicking a stroke, MI, or arterial embolization can also occur. A. Abdomina B. Descending C. Ascending D. Arch

C & D Aortic Dissection Acute ascending or aortic arch dissections are highly lethal, and timely surgical intervention correlates with survival. Descending dissections can usually be repaired on an elective basis, unless there are signs of organ ischemia. The dissection begins from an intimal tear that most often spreads antegrade, but can also dissect retrograde throughout the aorta, possibly encompassing the great vessels and/or the AV.8 Chapter 25 discusses in detail the pathophysiology of aortic dissection and the management of descending aneurysms. Patients with ascending or arch dissections usually present with sudden severe neck and chest pain, but symptoms mimicking a stroke, MI, or arterial embolization can also occur. Syncope is an ominous sign that cerebral or cardiac circulation is compromised. Diagnosis can be made with TEE, contrast-enhanced spiral CT scan, or MRI. Acute AI, tamponade, or limb ischemia can develop at any time.8,274 The initial priority is to obtain adequate vascular access for both monitoring BP and transfusing the patient. Control of the BP is critical. The A-line site should be carefully selected, avoiding ischemic limbs and locations that will be impacted by surgical cannulation. The aim of hemodynamic management is to decrease sheer forces, which can cause further dissection or rupture. The heart rate and BP are most often controlled using a β-blocker first to achieve a heart rate of approximately 60 bpm, followed by cautious vasodilation to achieve an SBP lower than 120 mm Hg. Vasodilator therapy should not be initiated prior to rate control, because the reflex tachycardia that may develop can increase aortic wall stress, causing harmful expansion of the dissection.276 Coexisting myocardial depression can make medication titration challenging. Some institutions have the patient prep

Which of the following inhalation anesthetics are contraindicated during cardiac surgery A. Sevoflurane B. Isoflurane C. Desflurane D. Nitrous Oxide

C & D Selection of Medications. An enormous body of information has accumulated regarding the cardiovascular effects of various anesthetic agents. The most significant considerations are highlighted. Traditionally, the choice of anesthetic has been based primarily on preexisting ventricular function and comorbidities, coupled with the desired length of action. However, the same anesthetic combination may cause different responses in patients with similar histories and hemodynamic profiles. Therefore the combination of medications selected for the anesthetic is far less important than the skill and judgment with which they are administered. Volatile Anesthetics. Volatile anesthetics can potentially cause myocardial depression, vasodilation, and hypotension. They lower the arrhythmogenic threshold to catecholamines, and do not provide pain relief in the postoperative period.108 In cardiac anesthesia, they are often combined with a narcotic in a balanced technique. Inhalation agents are now considered beneficial because of their preconditioning effect. A meta-analysis demonstrated that including halogenated anesthetics in the anesthetic regimen is associated with a better outcome after cardiac surgery than using a total IV technique.109 Most cardiac surgical patients will benefit from the myocardial protection of volatile agents; the exception may be those with severe LV dysfunction who cannot tolerate any further cardiac depression. Desflurane is a potential concern because sudden increases in inspired concentration can lead to tachycardia and hypertension, which can be detrimental in patients who have CAD, hypertrophic cardiomyopathy (HCM), or stenotic valvular lesions. Desflurane and nitrous oxide raise pulmonary vascular resistance, PA pressure, and wedge pressure.108,110 Nitrous oxide should be avoided just before, d

Which of the following is not a part of a setup in a cardiac operating room A. Large-bore PIV catheter B. Pulse oximetry C. Oral airways and appropriate endotracheal tubes D. Spinal drain pressure

D.

True or False Aneurysms that involve the arch are much more complicated than the ascending aorta

True Aortic Arch Aneurysms Aneurysms that involve the arch are much more complicated. Involvement of the cerebral vessels increases the risk of neurologic injury from both the threat of global ischemia and embolization of atherosclerotic debris. CPB is used with DHCA to protect the brain while the arch is replaced. DHCA was addressed earlier under the discussion of anesthetic management. If only the proximal aortic arch is involved, a hemiarch or partial arch replacement can be done. The origins of the arch vessels are usually dissected en bloc so that the three vessels lie on an island of native aortic tissue that can be anastomosed to the synthetic graft. The surgeon completes the distal anastomosis to the descending aorta first, and then sews on the island of tissue containing the arch vessels. Next, the aortic clamp is moved proximal to the arch vessels so that CPB flow can be reestablished and the cerebral vessels perfused. Finally, the proximal aortic graft anastomosis is completed (Fig. 26.29B). Aneurysms that involve the entire thoracic aorta are extremely complicated, and are often repaired in stages, combining both open and endovascular techniques. As shown in Fig. 26.29B, the distal graft is sutured circumferentially to the aorta just beyond the left subclavian artery, and the free end of the graft ("elephant trunk") is placed within the descending aneurysm. The aneurysm repair is completed in a second procedure (as shown in Fig. 26.29C) using an endovascular stent graft attached proximally to the elephant trunk, and the distal end is secured to a Dacron graft cuff.

When rewarming begins, it should be done gradually, maintaining a temperature gradient no greater than ___°C in the heat exchanger, and cerebral hyperthermia must be avoided. A. 10 B. 20 C. 30 D, 40

A. 10 Rewarming. Once systemic perfusion is reestablished using CPB, a period of hypothermic reperfusion is recommended. When rewarming begins, it should be done gradually, maintaining a temperature gradient no greater than 10°C in the heat exchanger, and cerebral hyperthermia must be avoided. Temperature gradients between the arterial outlet and venous inflow on the oxygenator during CPB cooling or rewarming should not exceed 10°C, to avoid generation of gaseous emboli.97 Even slight hyperthermia in patients with cerebral ischemia or infarction may exacerbate any damage.276 The STS recommendation is that surgical teams should limit arterial outlet blood temperature to less than 37°C to avoid cerebral hyperthermia.97 The optimal temperature for coming off bypass is a matter of debate. Some believe that a bladder temperature of 36.5°C should be achieved to decrease bleeding, whereas others hold that 35°C is cerebral-protective, and that bleeding is due to the procedure and to other causes.97

This approach shows to be more superior protection during Deep Hypothermic Circulatory Arrest A. Antegrade Cerebral Perfusion B. Retrograde Cerebral Perfusion

Antegrade Cerebral Perfusion. If DHCA is expected to last more than 30 minutes, selective ACP into the axillary, innominate, subclavian, or internal carotid artery is often used to extend the safe operative time. The perfusionist uses a roller pump to intermittently infuse blood cooled to 6°C to 12°C directly into the cerebral vessels at rates between 400 and 1000 mL/min. Many surgeons prefer to use right subclavian arterial cannulation if ACP is planned, and the BP is monitored using a right radial A-line during ACP, with the goal of maintaining the MAP between 30 and 70 mm Hg. However, the right A-line should not be used to control perfusion pressure during the cooling and rewarming period, as the pressure may be falsely elevated if the right subclavian is used for CPB arterial flow.7,82,274,277,279 NIRS is a relatively new, easily applied technology that measures frontal cerebral oxygenation through light transmittance. NIRS appears to be the most useful trend monitor during ascending aortic and arch surgery, particularly when ACP is employed. Significant reductions in left-sided sensor values compared with right-sided ones may indicate an incomplete circle of Willis. In this situation, ACP via the left carotid artery often restores the values.274 Retrograde Cerebral Perfusion. Retrograde cerebral perfusion (RCP) was popularized in past decades as a form of enhanced cerebral protection; however, ACP has been shown to provide superior protection. Clinical use of RCP is on the decline, but is still practiced.277,279 RCP requires the use of individual SVC and IVC venous cannulation. During the period of arrest, the A-line of the CPB circuit is connected to the SVC cannula, and cold oxygenated blood (between 8°C and 14°C) is infused at a rate of 220 to 600 mL/min. During RCP, the patient is kept in a slight Trendele

Close communication is imperative among all members of the transplant center's surgical/anesthetic team and the organ procurement team to avoid prolonged donor heart ischemic time, which should be less than __ hours. A. 2 B. 4 C. 6 D. 8

B. Anesthetic Management. The preoperative period has important time constraints. Close communication is imperative among all members of the transplant center's surgical/anesthetic team and the organ procurement team to avoid prolonged donor heart ischemic time, which should be less than 4 hours.270 The recipient will have had an extensive evaluation so that all information necessary for a quick assessment is readily available for review. Preoperative evaluation should follow an approach similar to that of any routine urgent preanesthetic evaluation, taking particular note of any recent deterioration. Chronic systemic hypoperfusion, venous congestion, hepatic dysfunction, and abnormal coagulation profiles are common. IABP settings and timing, VAD flow rates and settings, and all inotropic drug infusions should be noted. Patients with ICDs will need them deactivated before use of electrocautery. Because most heart transplantations are usually scheduled on short notice, most recipients will be considered full stomachs, and the last oral intake and the need for a rapid sequence or a modified rapid sequence induction should be assessed. Induction of anesthesia for a heart transplant recipient follows many of the same principles as those for any traditional cardiac surgery on a patient with poor left ventricular function, with some noted exceptions. All medications must be administered cautiously, because patients with severe heart failure are extremely sensitive to any alterations in myocardial preload and afterload. Obtaining rapid control of the airway to prevent aspiration during induction is often indicated. To prevent cardiovascular collapse on induction, it is imperative to maintain the patient's heart rate and intravascular volume, as well as to avoid decreases in SVR. This can often be achieved with a short-acting

This is the major cause of short-term morbidity after cardiac transplantation A. Left ventricular failure B. Right ventricular failure C. Heart block D. Afib

B. Cardiac Transplantation General Considerations. The first human heart transplant was performed in South Africa in 1967 by Christiaan Barnard, but it was not until the introduction of cyclosporine in the 1980s that there was significant long-term survival.268 Today, heart transplantation is the only definitive treatment for end-stage heart failure, and survival rates (adjusted for diagnosis, sex, race/ethnicity, and age) approach 85% at 1 year and 70% at 5 years.82 The United Network for Organ Sharing (UNOS) is the organization in the United States that is responsible for coordinating organ procurement and allocation. An extensive multidisciplinary evaluation is required to prioritize placement on the donor list, but generally candidates must have NYHA class IV heart failure, an EF less than 20%, and a diagnosis of end-stage heart disease that is terminal in 1 to 2 years if transplant does not occur.82 Once on the list, patients are assigned a priority status of 1A, 1B, or 2. Status 1A is the highest priority, and usually indicates that the patient is hemodynamically deteriorating, requiring vasopressor and/or mechanical circulatory assist support and mechanical ventilation.82 Ischemic or idiopathic cardiomyopathy is the most common diagnosis of heart transplant candidates, but failure can arise from many other causes.82 The donated organ comes from a relatively healthy patient who has been declared brain dead. The donor heart is extensively examined before being deemed suitable. Allocation of the heart is based on the UNOS priority status, ABO blood type compatibility match, weight ratio (within 20%), and distance from the donor site.82 The donor and recipient must be close enough geographically to ensure that the ischemic time of the heart is not prolonged. Right ventricular failure is the major cause of short-term

This is currently the most commonly used LVAD approved for intermediate- to long-term support or destination therapy in the United States A. HeartMate I B. HeartMate II C. HeartWare HVAD D. TandemHeart

B. Components, Types, and Heart Mate II. The VAD is a mechanical circulatory assist device that is attached to the heart through a cannula. An LVAD collects oxygenated blood that is returned to the left atrium from an inflow cannula, usually placed at the apex of the LV. From the inflow cannula, blood enters a pumping chamber. The pumping chamber then ejects blood into the systemic circulation through an outflow cannula that is usually attached to the aorta. A right ventricular assist device (RVAD) is similarly constructed, except that it receives deoxygenated blood from the right atrium and pumps blood into the pulmonary circulation. The RVAD inflow cannula is anastomosed to either the right atria or right ventricle, and the RVAD outflow cannula is anastomosed to the PA. VADs are categorized according to type of blood flow (continuous or pulsatile), length of time the device can be used for support (short, intermediate, or long-term), location of device (intra-, extra-, or paracorporeal), and their source of driving power (pneumatic or electric). Two generations of VADs are currently in clinical use, and more generations are under development. A complete discussion of VADs is beyond the scope of this chapter, but Tables 26.16 and 26.17 list some of the important characteristics of devices used for short-term and long-term support. HeartMate II is currently the most commonly used LVAD approved for intermediate- to long-term support or destination therapy in the United States (Fig. 26.25).82 There is currently a 79% rate of successful bridging to transplant with the HeartMate II.82 HeartMate II is an intracorporeal and nonpulsatile continuous flow device. An electrically powered axial-flow pump can generate up to 10 L/min of continuous blood flow. It can also operate at lower speeds, allowing the ventricle to assist wit

VAD patients are extremely dependent on A. Preload B. Afterload C. Contractility D. Heart Rate

D. Anesthetic Management. Anesthetic management of the LVAD candidate begins with preoperative assessment of the end-stage heart failure patient. Neurologic deficits, hepatic and renal dysfunction, and current cardiac function should be noted. Hepatic congestion from RHF, preoperative use of anticoagulation drugs, and exposure of the patient's blood to nonbiologic surfaces of the LVAD device can all contribute to potentially substantial blood loss, and coagulopathy that may develop after placement.254 Blood products (platelets, FFP, and RBCs) should be available, and large-bore central and peripheral IV access should be secured before incision, in case rapid transfusion becomes necessary. Antifibrinolytic agents such as aminocaproic acid may be administered perioperatively to minimize blood loss. Placement of a radial or brachial arterial catheter and PAC in addition to standard ASA monitors prior to induction is essential to assist the anesthesia provider in achieving hemodynamic stability during induction. Decreases in preload and increases in afterload are poorly tolerated in patients with end-stage heart failure.8 These patients are extremely dependent on heart rate and considered to have a relatively fixed CO, with an inability to increase SV. Rapid deterioration and cardiovascular collapse can occur on induction if the patient becomes bradycardic or loses sympathetic tone.8 Judicious use of etomidate and a neuromuscular blocker, or a high-dose narcotic with a neuromuscular blocker, may be selected to minimize hemodynamic instability.8 Because sepsis is the leading cause of mortality in LVAD recipients, attention should be given to the antibiotic regimen, and strict sterile technique should be maintained.255,266 A complete TEE examination assists with placement and detection of anatomic problems that can potential

Combining Deep Hypothermic Circulatory Arrest with cold antegrade cerebral perfusion (ACP) may prolong the safe period to as long as ___ minute A. 20 B. 40 C. 60 D. 80

D. Deep Hypothermic Circulatory Arrest Cerebral perfusion must be temporarily interrupted during repair of aneurysms involving the aortic arch. Deep hypothermia is the most important therapeutic intervention to prevent cerebral ischemia. The patient is cooled using CPB to maximally decrease the cerebral metabolic rate and O2 consumption, thereby extending the period that the brain can tolerate circulatory arrest. As cooling on CPB is initiated, most institutions cool the brain topically by placing ice bags around the head and/or use a cooling blanket. One study demonstrated a 50% improvement in metabolic function in patients who had their heads packed in ice versus those who did not.277 A barrier such as a towel should be placed between the ice bags and the skin to prevent thermal damage. Care should also be taken to protect the eyes, nose, and ears from pressure. A consensus statement that details "best practices" when using hypothermia for aortic arch surgery was published in 2013.278 The STS also published clinical practice guidelines for temperature management during CPB. To achieve deep hypothermia, the patient is cooled to a temperature of 14.1°C to 20°C. It is recommended that the oxygenator arterial outlet blood temperature be utilized as a surrogate for cerebral temperature measurement during CPB.97 Once the patient is cooled to the desired temperature and the EEG shows burst suppression, or the BIS reads 0, most of the blood volume is drained into the venous reservoir, and the CPB is turned off. Arrest periods of 20 to 30 minutes are considered safe during deep hypothermia.274,278 Combining DHCA with cold antegrade cerebral perfusion (ACP) may prolong the safe period to as long as 80 minutes.277,279 The traditional goal is to have a flat EEG. The BIS and cerebral oximeters have also been used to try to dete

Which of the following is not a contraindication to IABP placement A. Sepsis B. Descending aortic disease C. Severe PVD D. Severe Aortic stenosis

D. Devices and Procedures Developed to Manage Heart Failure Mechanical Circulatory Assist Devices Intraaortic Balloon Pump. An IABP is a mechanical circulatory assist device that uses synchronized counterpulsation to enhance myocardial perfusion by reducing afterload during systole and increasing coronary blood flow to the heart during diastole.8,240 The IABP was first introduced in 1968, and since then its role as a key component of left ventricular support has grown in both medical and surgical settings. Medical uses include the management of cardiogenic shock, MI, intractable angina, and arrhythmias.8,240 In the perioperative setting, it is most commonly used to stabilize patients preoperatively and/or to help wean a patient who is having difficulty separating from CPB.8,240 The IABP is also used to help support coronary perfusion to patients during OPCAB procedures.8,240 Sepsis, descending aortic disease, severe PVD, and severe AR are contraindications to IABP placement.8,240-243 The IABP consists of a flexible catheter that is attached at one end to a drive console, which contains computerized circuitry to determine proper timing for inflation and deflation. At the other end of the catheter is an inflatable, cylindrical, polyethylene balloon (containing helium) that comes in various sizes between 30 and 50 mL. It is most commonly placed percutaneously through the femoral artery via the Seldinger technique; however, alternative routes of access include the abdominal aorta and the axillary, subclavian, and iliac arteries.8,240,243,244 The catheter is then advanced so the tip of the balloon is situated at the junction of the aortic arch and the descending aorta (in the proximal segment of the descending aorta) and positioned 2 cm distal to the origin of the left subclavian artery.240,241,243,244 Proper sizing and pos

True or False The cause of aortic disease is usually acquired in younger patients

False Surgery on the Ascending Aorta and Aortic Arch General Considerations The cause of aortic disease is usually congenital (e.g., Marfan syndrome, Ehlers-Danlos syndrome, bicuspid AV disease) in patients who present at younger ages for surgery, but acquired (e.g., hypertension, inflammation) in older patients.8 A discussion of aortic disease, as well as the classification, etiology, diagnosis, and treatment of TAs, can be found in Chapter 25. This chapter focuses on anesthetic management for surgeries on the ascending aorta and arch. Care of patients having aortic surgery requires close communication between the surgeon, perfusionist, and anesthesia provider. Management will vary markedly, depending on what segment(s) of the aorta are involved and whether the AV can be preserved, repaired, or replaced. The plan for cannulation, invasive monitoring, and cerebral protection should be discussed prior to the surgery. Most TAs are asymptomatic, so they are often found coincidentally following an x-ray or other test performed for an unrelated problem. Large TAs can cause a mass effect that leads to a variety of symptoms, including cough, dysphasia, or hoarseness due to compression on the trachea, esophagus, or recurrent laryngeal nerve. Sometimes, SVC syndrome develops.8 Patients with a bicuspid AV or genetic mutation associated with aortic disease should be imaged and followed at regular intervals. Surgery is indicated for all symptomatic aneurysms, and is generally indicated for ascending TAs that are dilated to 5.0 cm for congenital lesions (4.5 cm if there is a family history of dissection) or 5.5 cm for acquired lesions. TAs usually grow slowly over a period of years, but an aneurysm that is growing at a rate exceeding 0.5 cm/year should also undergo surgical repair.273 TAs of the ascending aorta and arch are usually

Contraindications to the use of salvaged blood include A. Use of hemostasis agent B. Infection C. Malignancy D. Autoimmune disorder

A & B Blood Salvage. Blood that is suctioned from the surgical field while the patient is not on CPB, as well as the residual blood that remains in the CPB circuit at the end of bypass, should be directed into a centrifugal red cell salvage device. As previously discussed, the blood aspirated from the field during CPB can return to the pump cardiotomy or to the cell-salvage reservoir, depending on the surgeon's preference. The shed blood is stored in a reservoir until it reaches a quantity or weight specified by the device manufacturer. The blood is then "washed", a process that removes the serum, coagulation factors, and platelets. The red cells are preserved and placed in a bag that can then be infused into the patient. Cell-salvaged blood has a hematocrit of approximately 55% to 70%. Infusing large quantities of salvaged blood can contribute to a dilutional coagulopathy, because this blood is devoid of coagulation factors and platelets. Contraindications to the use of salvaged blood include infection and the use of topical hemostasis agents. Malignancy was previously considered a contraindication to salvage administration. However, the new guidelines state: "In high-risk patients with known malignancy who require CPB, blood salvage using centrifugation of salvaged blood from the operative field may be considered because substantial data supports benefit in patients without malignancy and new evidence suggests worsened outcome when allogeneic transfusion is required in patients with malignancy." Blood shed from mediastinal chest tubes can also be salvaged, washed, and reinfused.51Q,

Giving protamine over a period of 10 to 15 minutes will decrease the probability of which types of reactions A. type I (systemic vasodilation-histamine release) B. type II (anaphylactic reaction) C. type III (pulmonary vasoconstriction-delayed anaphylactoid)

A & C Protamine Administration. Protamine is used to reverse the anticoagulation caused by heparin. Protamine neutralizes heparin through electrostatic interaction, forming a heparin-protamine complex that renders heparin inactive. A test dose of 10 mg of protamine is routinely given to check for anaphylaxis because allergies or intolerance to protamine are relatively common. Protamine reactions can range from mild hypotension to anaphylaxis. Some surgeons prefer to give the test dose of protamine while the aortic cannula is in the aorta, in case anaphylaxis develops. Otherwise, the protamine is not administered until the patient is decannulated because clot formation in the CPB pump will have devastating consequences. Slow drug administration is the most effective strategy for avoiding hypotension, which is common when protamine is delivered rapidly. Giving protamine over a period of 10 to 15 minutes will decrease the probability of both type I (systemic vasodilation-histamine release) and type III (pulmonary vasoconstriction-delayed anaphylactoid) protamine reactions. However, an anaphylactic reaction (type II) can occur at any rate of administration.122 The normal dose of protamine is 1 mg of protamine to reverse every 100 units of heparin that was given. Therefore a normal heparin dose of 30,000 units would require 300 mg of protamine for reversal. An ACT is obtained at least 3 to 5 minutes after the entire protamine dose is given, to confirm that ACT has returned to baseline. Alternatively, an HDR assay can be used to determine the optimal protamine dose and check for residual heparin after protamine administration. Additional protamine doses of 50 to 100 mg are routinely administered to cover residual anticoagulation, if inadequate hemostasis is visualized in the surgical field.

Which of the following are phases of the prebypass period where there is intense stimulation A. Intubation B. Sternal split and spread C. Aortic cannulation D. Harvesting of conduit

A, B, C Precardiopulmonary Bypass Period. The precardiopulmonary bypass period begins when the patient arrives at the operating suite and ends when the patient is on CPB. A review of the patient's preoperative vital signs and cardiac function will help the anesthetist determine the "normal" range for that particular individual. The general goal is to maintain hemodynamic stability. Individual hemodynamic perturbations must be considered within the context of the patient's baseline status. For example, a patient with an acceptable heart rate, MAP, O2 saturation, and arterial pH does not need an inotropic agent if the CI is below the normal range. In this particular instance, general anesthesia reduces O2 demand, and the decreased CO is probably adequate to meet demand. Starting an inotrope to increase the CI within the normal range (higher than 2.2 L/min per m2) might paradoxically lead to ischemia by increasing myocardial O2 demand. The prebypass period is marked by periods of marked variable stimulation. The most intense stimulation occurs at intubation, incision, sternal split and spread, sympathetic nerve dissection, pericardial incision, and aortic cannulation. Hypertension and tachycardia that occur as a result of inadequate analgesia or sympathetic activation can lead to ischemia, dysrhythmias, or heart failure. The anesthetist must anticipate these events and consider a preemptive dose of narcotic and/or an increase in the concentration of the volatile agent. Hyperdynamic individuals may also need the addition of a short-acting β-antagonist such as esmolol (0.1-0.5 mg/kg) or an IV infusion of a titratable vasodilator such as nitroglycerin or sodium nitroprusside to treat the adrenergic response to these events. During the remainder of the prebypass period, including preincision and the harvesting of conduit, th

Which mitral leaflet increases the complexity of the repair and requires greater surgical expertise because the chords must often be shortened, transferred, or replaced. A. Anterior B. Posterior

A. Anesthetic Considerations and Surgical Options. The preload is elevated and must be judiciously maintained or gently reduced to enhance forward flow and minimize regurgitation. Inhalation agents and vasodilators are generally effective in reducing afterload and maintaining heart rate in the high-normal range (Table 26.15). Valve repair or replacement increases afterload and may unmask previously compensated LV dysfunction. An inotrope or inodilator may be needed after bypass. Occasionally, SAM develops after repair, especially if the anterior leaflet is long or has redundant tissue. TEE is used to diagnose this problem.8 Mitral valve repair is almost always recommended over replacement whenever possible, depending on the native valve pathology and on surgical expertise. The advantages of repair include improved postoperative LV function, increased long-term and short-term survival, improved quality of life, lower risk of complications, and less need for long-term anticoagulation.80 Over the past decade, as surgeons have gained experience with valve repair techniques, the number of mitral valve repairs performed and variety of approaches taken have risen dramatically. The mitral valve can be accessed through traditional sternotomy, partial upper sternotomy, right minithoracotomy, and robotically-assisted endoscopy. Another advancement involves endovascular placement of a clip (MitraClip, Abbott Vascular, Santa Clara, CA, USA) that grasps and coapts the mitral valve leaflets, resulting in fixed coaptation (approximation) of the mitral leaflets throughout the cardiac cycle. Transcather transapical mitral valve replacement is currently in development. These alternative approaches are discussed later in the chapter. Posterior leaflet problems are often repaired using a triangular or quadrangular resection with a complete

This is known to be five to ten times more potent as antifibrinolytic A. TXA B. Amicar

A. Antifibrinolytics. Antifibrinolytics are commonly administered to cardiac surgical patients requiring CPB. Use of antifibrinolytics reduces surgical bleeding and decreases the incidence of blood transfusion.51 Aminocaproic acid (Amicar) and tranexamic acid (Cyklokapron) are both lysine analogs that inhibit plasmin, the key enzyme in the fibrinolytic cascade. Both drugs form a reversible complex with plasmin that then inhibits fibrinolysis, or the natural breakdown of clots. Dosing regimens vary, but a common recommendation for aminocaproic acid is a 50 mg/kg bolus over 20 to 30 minutes, followed by an infusion of 25 mg/kg per hr into the immediate postoperative period. A standard dosing regimen of tranexamic acid is 10 mg/kg over 20 minutes, followed by 1 to 2 mg/kg per hr maintenance infusion into the immediate postoperative period. Dosing regimens vary among institutions. Tranexamic acid is known to be five to ten times more potent than aminocaproic acid, but also more expensive.

This is usually made of stainless steel tubes with heated or cooled water flowing through them. Blood flows around the tubes, and the temperature is adjusted to the desired level. A. Heat exchanger B. Arterial Filter C. Oxygenator D. Main Pump

A. Heat Exchanger. The blood enters a heat exchanger either separately or in combination with the oxygenator (see Fig. 26.8). The heat exchanger is usually made of stainless steel tubes with heated or cooled water flowing through them. Blood flows around the tubes, and the temperature is adjusted to the desired level. Traditionally, patients were cooled in an effort to protect the heart and other vital organs during CPB. Today, active cooling is less common, and the patient's temperature is allowed to naturally drop or drift while the surgery is performed. The patient is then actively rewarmed in preparation for the termination of CPB. For some procedures, the patient is actively cooled to decrease the metabolic rate. This process is discussed later in the chapter (see Surgery on the Ascending Aorta and Aortic Arch). As the patient is rewarmed, gas solubility decreases, and it is possible for air bubbles to form in the CPB circuit. Consequently, the oxygenated blood passes through a filter before it is returned to the patient.

This is the leading cause of sudden death in young people, but it can cause morbidity and death at any age. A. HCM B. DCM C. RCM D. Takutsuobo cardiomyopathy

A. Hypertrophic Cardiomyopathy HCM is the preferred contemporary nomenclature for this disease, but it was formerly known as idiopathic hypertrophic subaortic stenosis (IHSS) or HOCM. HCM is a common inherited disease that affects approximately 1 in 500 persons of all ages globally. It is a heterogeneous disease with diverse clinical presentations ranging from asymptomatic to life-threatening. When complications of HCM develop, they fall into three categories, which are not mutually exclusive: ventricular tachydysrhythmias, which can lead to sudden cardiac death (SCD), especially in young athletes; progressive DHF, despite normal LV systolic function; and AF, with a predisposition to stroke.173 HCM is the leading cause of sudden death in young people, but it can cause morbidity and death at any age.82 The American College of Cardiology Foundation (ACCF) and AHA recommend that diagnosis and treatment of HCM take place in a clinical center that specializes in management of this disease.173 Pathophysiology. Concentric LVH is the primary pathology in HCM, as opposed to AS, in which the LVH is secondary to stenosis. The pathophysiology of HCM is complex, and can include LVOT obstruction, MR, diastolic dysfunction, ischemia, and dysrhythmias. HCM can be either obstructive or nonobstructive, based on the degree of outflow tract obstruction and the presence or absence of mitral valve SAM (discussed later). Clinical management is guided by this finding. Echocardiography is used to determine the presence of obstruction and to document the gradient across the obstruction. A gradient of more than 30 mm Hg is considered significant, and a gradient of more than 50 mm Hg is the conventional threshold for surgical or percutaneous intervention if symptoms persist despite optimal medical management. Approximately one-third of patients m

Supply ischemia resulting from MI or chronic volume overload of the LV causes A. Eccentric hypertrophy B. Concentric hypertrophy

A. Left Ventricular Failure and Remodeling. In the face of sympathetic activation coupled with alterations in perfusion, pressure, and volume, the heart changes its size, shape, and function; that is, it remodels itself in an attempt to maintain cardiac output (CO). Supply ischemia causes an increase in ventricular compliance (dilation) and a decrease in contractility, whereas demand ischemia reduces compliance (stiffening) without initially impacting contractility.24,25 The primary characteristics of remodeling are: hypertrophy or dilation, myocyte death, and increased interstitial fibrosis. The clinical impact manifests as a change in systolic and diastolic function. Figs. 26.6 and 26.7 help summarize and visualize the process. Systolic Dysfunction. As demonstrated in Fig. 26.7A, supply ischemia resulting from MI or chronic volume overload of the LV causes eccentric hypertrophy or dilation. The chamber size increases in an attempt to preserve stroke volume (SV). In the dilated state, the heart loses its normal elliptical football shape and becomes more spherical, resembling a basketball.26 In this shape, the heart is unable to contract effectively (systolic dysfunction), and the mitral apparatus is stretched, potentially to a point that results in mitral regurgitation (MR). Of patients with heart failure, 35% to 50% will experience MR.32 The degree of systolic dysfunction is commonly expressed as an ejection fraction (EF). The EF is calculated as SV divided by end-diastolic volume (EDV). According to the American Society of Echocardiography's guidelines, a normal EF is 55% or greater. Dysfunction is graded as mild (45% to 54%), moderate (30% to 44%), and severe (less than 30%). When the SV is reduced, the body compensates by activating the SNS to raise the resting heart rate in an effort to maintain CO. Systolic hea

Ultrafiltration ________ the hematocrit A. increases B. decreases

A. Limiting Pump Prime. Traditionally, the addition of pump prime to the patient's blood volume at the initiation of CPB resulted in significant hemodilution. Several mechanisms have been devised that help limit the volume of pump prime. Minicircuits that require a smaller volume of pump prime are available, and should be considered for patients at high risk for anemia. VAVD in conjunction with these minicircuits has also proved helpful. Retrograde autologous priming (RAP) is a perfusion technique in which the CPB prime is displaced by passive exsanguination (back-bleeding) through the arterial and venous lines back into an empty bag that is out of the main circuit, prior to initiating CPB. This means that once the primed CPB circuit is attached to the arterial and venous cannulae, the blood is allowed to back up, filling the circuit, and the crystalloid prime fluid is discarded. A recent meta-analysis found that RAP significantly reduces allogenic blood transfusion for adult cardiac surgery patients who require CPB Ultrafiltration. Ultrafiltration is a process in which the perfusionist diverts the patient's blood to an ultrafilter made of hollow capillary fibers that act as a membrane to separate the aqueous portion of blood from the cellular and proteinaceous elements. The aqueous portion is then discarded, while the red cells and coagulation factors are hemoconcentrated. Ultrafiltration raises the hematocrit, so the technique is most often performed in an effort to prevent transfusing a patient who has a low hemoglobin (Hgb) level. An adequate pump volume is needed for ultrafiltration. When a patient is volume-overloaded preoperatively, there is excess volume in the pump, and ultrafiltration can be used to remove the excess volume.8 Of course, the most critical questions are what to transfuse, and when. Even the 20

This has the disadvantage of increased destruction of blood elements A. Roller pump B. Centrifugal pump C. Hand Crank

A. Main Pump. Blood is propelled through the CPB machine by an electrical pump (see Fig. 26.8). Two types of pumps are available. A roller pump produces flow by subtotally compressing large bore tubing against a tract and propelling the blood forward. Constant nonpulsatile flow is produced that is directly proportional to the number of revolutions per minute of the roller heads, regardless of arterial resistance in the circuit. A centrifugal pump uses a magnetically controlled impeller that rotates rapidly, creating a pressure drop that causes blood to be sucked into the housing and ejected. A major difference between the two pumps is that the flow from the centrifugal pump will vary with changes in preload and afterload. For this reason, a flowmeter must be attached to the arterial side of the pump. The roller pump is economical and simple to use. However, unlike the centrifugal pump, it has the disadvantage of increased destruction of blood elements. As a result, centrifugal pumps are replacing roller head pumps in contemporary practice. In the event of a power failure, a hand crank can be used to manually operate either pump.

The most popular alternative approach to sternotomy for single vessel coronary revascularization is A. MIDCAB B. TECAB C. PA-CAB D. TAVR

A. Minimally Invasive Myocardial Revascularization The quest to develop surgical techniques that are less invasive than the traditional median sternotomy for coronary revascularization has been in progress since the first minimally invasive coronary bypass revascularization was reported in 1967.143 In addition to improved cosmetic appearance, the goals driving development include the desire to lower sternal wound infection rates, decrease the risk of brachial plexus injury, decrease cost, promote early patient mobilization, and facilitate earlier hospital discharge.143,192,202-204 Several different minimally invasive techniques for single LAD bypass grafting have emerged over the last 40 years. These employ surgical methods already mentioned in this chapter. Minimally invasive direct coronary artery bypass (MIDCAB), total endoscopic coronary artery bypass (TECAB), and port-access coronary artery bypass (PA-CABG) are the most common approaches for minimally invasive coronary revascularization.205 The most popular alternative approach to sternotomy for single vessel coronary revascularization is the MIDCAB approach.82 Out of the three most common minimally invasive coronary revascularization approaches, MIDCAB has been found to be the most reliable surgical technique for isolated LAD grafting, and the most cost effective.205 As shown in Fig. 26.20, the MIDCAB is performed through a small (6-8 cm) left anterolateral thoracotomy incision that allows direct access for harvesting the IMA and grafting to the LAD artery.82,204 A MIDCAB may be performed with CPB and femoral cannulation, but is usually conducted off-pump, and anastomoses are hand-sewn.8,82,143 A right anterior thoracotomy may be performed for access to the RCA or PDA. Some institutions are beginning to utilize a hybrid approach combining the MIDCAB approach with

Which of the following is the safest site for an arterial line A. Radial B. Brachial C. Femoral D. Subclavian

A. Preparation for Surgery Operating Room Preparation. The surgical suite should be readied in preparation for the planned surgical procedure prior to the patient's arrival. Communication with the surgical, nursing, and perfusion teams is essential to ensure that all parties are ready to act appropriately if the patient should rapidly deteriorate requiring emergent surgical intervention and/or institution of CPB. The basic set-up and monitoring is similar to most major cases, with a few additions, as outlined in Table 26.6. Monitoring. Standard and extended monitors for cardiac surgery are listed in Table 26.6. ECG monitoring should include lead II for detection of dysrhythmias and lead V4 or V5 with automated ST analysis for detection of ischemia. Classically, data from London et al.11 identify V5 as the most sensitive single lead for detecting perioperative ischemia, but newer evidence from Landesberg et al.14,15 demonstrates that V4 has greater sensitivity. In practice, the V lead may need to be placed posteriorly at the 5th intercostal space, posterior to the axillary line to avoid the surgical field. The usefulness of the five ECG electrodes used during cardiac surgery is limited because much anterior and posterior wall ischemia cannot be detected. The TEE is more sensitive than the ECG for detection of ischemia.96 The 2015 STS guidelines recommend that core temperature be measured using a nasopharyngeal probe, or the pulmonary artery catheter (PAC). To avoid excessive nasopharyngeal bleeding, the probe should be placed at the beginning of the surgical procedure, before heparinization. It is recommended that the oxygenator arterial outlet blood temperature is used as a surrogate for cerebral temperature measurement during CPB.97 Many centers find a peripheral temperature monitor (bladder or rectal) is useful to c

This graft to the LAD artery has a 10-year patency rate of 85% to 99.1% A. Left internal thoracic artery B. Right internal thoracic artery C. Saphenous vein D. Radial artery

A. The left internal thoracic artery (LITA) is usually left in situ at its proximal origin from the left subclavian artery, dissected from the chest wall, and anastamosed to the left anterior descending (LAD) artery. A LITA graft to the LAD artery has a 10-year patency rate of 85% to 99.1%.149,150 The right internal thoracic artery is usually transected from its proximal origin to become a free graft with a proximal anastomosis originating from the aorta or another conduit. The surgical table is elevated and turned while the ITA is dissected. Lung volumes are reduced to improve the surgical view. The patient's arm should be well-padded because the axillary artery can be compressed by the chest wall retractor, lowering radial A-line pressures. A noninvasive cuff on the contralateral arm helps confirm the diagnosis. Heparin is usually administered before the LITA pedicle is clamped. The saphenous vein graft (SVG) and radial artery conduit can be harvested by open surgery or endoscopically. As with any endoscopic procedure, the respiratory rate may have to be increased to compensate for the addition of carbon dioxide. Most vein grafts are now removed endoscopically, but there are concerns that endovascular vein harvest (EVH) might decrease long-term graft patency.151,152 Some surgeons request that low-dose heparin (2500 units) be given intravenously during EVH to decrease these issues. The surgeon reverses the vein to avoid the valves. The distal anastomosis to the native coronary artery is usually completed first, and then the proximal portion is sewn to the aorta or bridged off another graft. Several surgical and technical complications can result in ischemia. In addition to the previously mentioned concerns about reoperations, patients who have undergone prior CABG surgery may have a patent LITA or other grafts lying d

Involvement of this mitral leaflet increases the complexity of the repair and requires greater surgical expertise because the chords must often be shortened, transferred, or replaced. A. Anterior B. Posterior

A. Volatile anesthetics should also comprise part of the anesthetic plan because of their preconditioning effect.109 Nitrous oxide should be avoided because of the possibility of expanding gaseous spaces. Patients considered for fast-track protocols, generally those with EFs above 35%, should receive a limited dose of narcotics. The highest risk patients may still require a primary narcotic technique to maintain hemodynamic stability. Conventional CABG surgery is performed through a median sternotomy with CPB. Different types of conduit can be used to bypass occluded areas of the patient's native coronary arteries to revascularize the myocardium distal to the occlusions (Fig. 26.11). The surgeon must take into consideration the viability of the myocardium, the quality of the target vessel, and the type and length of conduit needed to reach a point distal to the occlusions. The most commonly used conduits are the ITAs (formerly known as IMAs) and greater saphenous veins. The free radial artery graft is popular with some surgeons, whereas others question its long-term patency.148 Arterial grafts are generally reserved for high-grade lesions because flow in the native coronary can compete with flow in the arterial bypass graft. If there is not enough flow in the muscular artery, it will spasm and shut down. Topical (papaverine) and IV antispasmodic drugs such as calcium channel blockers or low-dose nitroglycerin infused intraoperatively are used to treat spasm.

AV block requiring permanent pacemaker placement has been a repeatedly reported complication following TAVR, and affects 10% to 50% of patients, with a higher incidence in which valve A. CoreValve B. Sapien XT valve C. JenaValve

A/ Anesthetic Considerations. Preoperative considerations for the high-risk AS patient who is undergoing a TAVR are similar to those mentioned earlier in the chapter that apply to patients with severe AS. The anesthetist must be aware of additional considerations that are inherent in a TAVR procedure to facilitate a safe and favorable surgical outcome. These considerations begin with understanding the details of the surgical procedure, the unique set-up of a hybrid OR, and the hemodynamic challenges that arise during the procedure. Fig. 26.22 shows an example of the hybrid OR setup. It must also be recognized that a TAVR procedure is a collaborative effort among many disciplines, including cardiology, anesthesia, and cardiothoracic surgery, and that all team members must clearly communicate with one another.219 Because fluoroscopy is used throughout a TAVR procedure, protective radiation safety equipment must be worn. Noninvasive and invasive monitoring for TAVR procedures are similar to those used for a standard cardiac case, including the use of a radial arterial catheter and PAC.219 All IV lines should have the appropriate amount of extension to facilitate safe use of any fluoroscopic device. Patients are positioned supine, with a slight tilt to the right for surgical exposure of the left chest, if the transapical approach is selected. Recent literature has reported the increasing use of local anesthesia with sedation in experienced institutions as an anesthetic technique for transfemoral catheter aortic implantation.82,214,230 Transthoracic echocardiography instead of TEE is utilized in these cases. Continuous neurologic assessment, avoidance of complications associated with general anesthesia in high-risk patients who have severe AS, and quicker recovery times are reported advantages of using local anesthesia with

Which of the following is not a part of an anesthesia checklist at the initiation of bypass A. Avoid heart distention B. Arteriovenous color difference should be absent C. CVP should be less than 5 mm Hg D. Pull back PAC 3-4 cm

B.

Which of the following is true regarding management of aortic stenosis A. Decrease preload B. Decrease HR C. Increase contractility D. Increase PVR

B.

Which of the following are major surgical risks according to EuroSCORE II A. Male B. Reoperation C. Urgency D. Age

B, C, D Comorbidities. For elective surgery, patient comorbidities should be optimized prior to the time of the operation. Multiple studies have correlated the following conditions with increased risk in the cardiac surgical population: diabetes mellitus, compromised renal function, depressed ventricular function, and heart failure.66,67 Diabetes mellitus and perioperative hyperglycemia are associated with increases in sternal wound infections, extended length of stay, recurrence of angina, postoperative mortality, and decreased long-term survival.68-71 In 2009, the STS developed evidence-based practice guidelines for blood glucose management in the perioperative period.72 Highlights of the STS recommendations are found in Box 26.1. Preoperative renal impairment is correlated with increases in morbidity and mortality. Despite research into reducing postoperative risk, thus far, only maintenance of normovolemia has proven effective in preventing further decline in renal function.73,74 Laboratory Studies. Laboratory studies that will assist in the perioperative period include a room-air arterial blood gas (ABG), electrolytes, serum blood urea nitrogen (BUN) and creatinine, fasting lipid profile, complete blood count, coagulation profile, Hgb A1c, and fasting blood glucose. Any serum biomarkers drawn to evaluate ischemia, infarction, or failure should be noted. Methicillin-resistant Staphylococcus aureus (MRSA) infection has a low prevalence but high mortality associated with cardiac surgery. Preoperatively, nasal swab cultures are taken, and those patients colonized with MRSA (≈ 3.9%) have vancomycin added to their antibiotic routine.75 Airway Assessment and Pulmonary Function. Airway assessment and pulmonary function deserve special attention. A plan must be developed to safely secure the airway and ventilate the pa

Which of the following is an anesthetic consideration for systolic dysfunction A. Volume will be needed to stretch noncompliant LV B. Avoid agents that cause further reductions. May need inotropic support C. Higher MAP needed to perfuse thick myocardium D. Slow normal to maximize diastolic time for coronary

B.

This is a catheter placed in the LV through the right superior pulmonary vein for the purpose of draining blood that has accumulated in the cavity A. Cardiotomy B. Left Ventricular Vent C. Cardioplegia pump D. Arterial Filter

B. - Left Ventricular Vent. The LV vent is a catheter placed in the LV through the right superior pulmonary vein for the purpose of draining blood that has accumulated in the cavity (see Fig. 26.8). Although the majority of blood is diverted from the heart during CPB, small amounts of blood may enter the LV from the bronchial arteries (which arise directly from the aorta or the intercostal arteries) or the Thebesian vessels (coronary veins that drain directly into the heart). Blood and cardioplegia can also fill the LV if the patient has aortic insufficiency (AI). This volume can cause the LV to distend, raise LVEDP, and compromise preservation by opposing the cardioplegia flow into the coronary arteries. Prior to inserting the vent, it is placed in a bowl of water to confirm that it is suctioning rather than blowing, because accidental blowing of the vent could lead to an air embolism. The vented blood returns to the cardiotomy portion of the venous reservoir. Cardioplegia Pump. The perfusionist controls the infusion of cardioplegia by means of an accessory roller pump (see Fig. 26.8). A separate heat exchanger is utilized to regulate temperature, rate, and pressure of cardioplegia administration. Cardioplegia is discussed later (see Myocardial Preservation).

This is the fluid used to fill the CPB circuit and components. It is composed of an isotonic balanced electrolyte solution, such as lactated Ringer's, Plasmalyte-A, or Normosol-R, that closely matches the principal ionic composition of blood. A. Cardioplegia B. Cannula C. Venous Reservoir D. Main pump

B. - Prime. Prime is the fluid used to fill the CPB circuit and components. It is composed of an isotonic balanced electrolyte solution, such as lactated Ringer's, Plasmalyte-A, or Normosol-R, that closely matches the principal ionic composition of blood. During setup, the perfusionist must take great care to de-air the circuit. Traditionally, the priming volume for the CPB is 1 to 2 L. However, the development of minimally invasive cardiac procedures necessitated the use of smaller cannulae and tubing to enable the surgeon to visualize the field. Medications and other solutions are often added to the prime for a variety of purposes: colloid to decrease postoperative edema, blood to treat anemia, mannitol to promote diuresis, heparin to ensure adequate anticoagulation, and bicarbonate to treat acidosis. Upon instituting CPB, the prime added to the circulating blood volume causes dilutional anemia, which will often result in a decrease in hematocrit (22% to 25%). The dilution offsets some of the increase in blood viscosity that occurs when the blood cools during CPB.

This can be administered in severe, uncontrolled bleeding situations when no surgical source of bleeding can be identified and replacement with red cells, plasma, platelets, and cryoprecipitate has been ineffective A. DDAVP B. Factor VII C. Amicar D. TXA

B. Additional Considerations. After the patient is decannulated, the surgeon may pack the chest to encourage hemostasis. Electrocautery is used routinely. During this period, the surgeon may need to lift the heart to inspect for bleeding on the posterior surface. Lifting and manipulating the heart and vasculature can cause significant dysrhythmias and hypotension. The surgeon should be informed if hypotension is severe or excessive in duration. As previously mentioned, electrocautery-induced suppression of the pacemaker can occur, so the pacemaker is often placed in an asynchronous mode. Synchronous pacing should be resumed as soon as the surgeon finishes using the electrocautery. Most patients require volume supplementation post-bypass. Often, a combination of crystalloid, colloid, and cell-saver blood is used. This combination usually results in a hematocrit of 25% to 30%. Persistent bleeding occasionally develops after CPB, especially if the surgery was complex and required a long pump run. The causes are multifactorial, but readily treatable problems should be addressed. Adequate reversal of heparin is confirmed via ACT or a heparin concentration assay, and additional doses of protamine are given, if needed. Hypothermia accentuates hemostatic defects, so the patient and the room are warmed to promote normothermia. Surgical causes of persistent bleeding are identified, as inadequate surgical hemostasis may develop and progress insidiously. If oozing persists, laboratory coagulation studies may reveal a deficiency in the coagulation cascade. Platelets, plasma, cryoprecipitate, and red cell transfusions may be required, depending on the underlying deficiency. If the patient has platelet dysfunction due to pre-existing pathology (e.g., uremia, liver disease), medications (e.g., ASA, thienopyridines), or even CPB, then

This may cause a downward spiral of decreasing coronary perfusion and ischemia to develop, which may ultimately end in cardiac arrest and sudden death in patients with Aortic stenosis A. Hypertension B. Hypotension C. Bradycardia D. Tachycardia

B. Anesthetic Considerations and Surgical Options. Valve replacement is a class I recommendation for symptomatic patients with severe AS, as well as for asymptomatic patients with a LV EF less than 50%, or those having cardiac surgery for another indication.80,82 Preoperatively, great caution is required in treating angina with nitrates because hypotension may cause a downward spiral of decreasing coronary perfusion and ischemia to develop, which may ultimately end in cardiac arrest and sudden death. Cardiac compressions can rarely generate enough pressure to provide adequate coronary perfusion to permit resuscitation. In patients with AS, hypotension should therefore be treated promptly with a vasoconstrictor like phenylephrine to prevent this hemodynamic decompensation.8 Anesthetic management follows directly from an understanding of cardiovascular pathophysiology. Table 26.10 outlines the anesthetic considerations. The anesthesia provider must be prepared for hemodynamic instability on induction and should choose the medications and speed of their administration accordingly. Patients often present with a significant degree of hypertension preoperatively. The BP may rise or fall abruptly during the procedure, depending on the level of stimulation. Hypertension is better tolerated than hypotension, but it must be kept in mind that hypertension can also be a source of increased myocardial O2 demand. Patients with severe AS have at least a 40 mm Hg mean (80 mm Hg systolic) pressure gradient between the LV and the aorta. Consequently, a systolic pressure of 180 mm Hg in the aorta correlates with a systolic pressure in the LV of at least 260 mm Hg.80,166 Tachycardia decreases the diastolic time needed for adequate coronary perfusion and ventricular filling, while increasing myocardial O2 demand at the same time. Hypotensi

When patients with CAD exercise or have increased stress, they develop A. Coronary ischemia B. Demand ischemia C. Supply ischemia D. Myocardial infarction

B. Anesthetic Considerations for Specific Cardiac Diseases and Surgical Procedures Coronary Artery Disease and Myocardial Revascularization Pathophysiology On-pump CABG surgery is the most frequently performed cardiac surgical procedure. Anesthetic management for these patients requires an understanding of coronary anatomy and physiology, as discussed in Chapter 25, as well as an understanding of the key physiologic principles covered at the beginning of this chapter. This section focuses on the considerations that pertain to CABG surgery. CAD is a complex disease state that involves narrowing of the coronary arteries. The pathogenesis of CAD is not definitively clear, but several theories have been proposed. Scientists believe the endothelium or innermost layer of the artery becomes injured. Over time, cholesterol components (such as low-density lipoproteins) and macrophages adhere to the endothelium and form plaques. The plaques continue to build and decrease the vessels' ability to distend. Because coronary O2 extraction is maximal at rest, the only way to increase O2 delivery to the tissues is to increase coronary flow. In normal coronaries, flow can increase 3 to 5 times over baseline when demand increases. However, this increase in flow, known as coronary reserve, is limited in patients with CAD. Thus, when patients with CAD increase demand by exercise or stress, they develop demand ischemia, which is symptomatically experienced as predictable, stable angina. General anesthetics protect against demand ischemia. ACSs and perioperative ischemia are usually caused by supply ischemia.15,137,138 Ischemia occurs when a piece of the plaque ruptures, causing a thrombus to form that significantly or totally occludes a segment of a coronary artery, leading to ischemia, dysrhythmias, and/or MI. The problem can be exacerbate

Which of the following is false regarding ICD during CPB A. Patients with an ICD should have defibrillation pads placed prior to induction so that a means for pacing and defibrillation is immediately available. B. The pads are positioned away from the generator to prevent damage to the device should defibrillation be necessary. C. A magnet must be available, and the magnet response identified. D. The magnet will usually deactivate ICD devices and place most modern pacemakers to off

B. Anesthetic Considerations in the Perioperative Period Preoperative Evaluation Because of the serious nature of the primary disease and the high prevalence of comorbidities, all patients undergoing cardiac surgery should have a thorough preoperative evaluation, including a history of the patient's medical condition and a complete physical examination. The preoperative assessment should focus on the cardiovascular system, but information must also be gathered and recorded about the airway, as well as pulmonary, neurologic, endocrine, renal, hepatic, and hematologic functions. Cardiovascular System. The medical record should be examined, and the results of all cardiovascular tests noted. Table 24.2 summarizes many of the common tests and findings that are used to identify cardiac pathology. Ventricular function and a history of heart failure are important considerations that affect anesthetic choice, hemodynamic management, and requirements for intraoperative pharmacologic support. The New York Heart Association (NYHA) functional class of heart failure has prognostic significance and predicts postoperative quality of life. The American Heart Association (AHA) and American College of Cardiology (ACC) stages of heart failure emphasize disease progression (Table 26.5). Patients with a history of severe heart failure are likely to have a cardiac electronic implantable device (CEID), including a pacemaker alone or in combination with an implantable cardioverter defibrillator (ICD). Many patients will have a biventricular pacemaker for cardiac resynchronization therapy (CRT). CRT improves CO, hemodynamics, heart failure symptoms, and quality of life.63 All implantable devices should be evaluated prior to cardiac surgery, and the results of the device interrogation should be readily available. CEIDs may need to be reprogramm

Open-cavity procedures, such as mitral, pulmonic, and tricuspid valve surgery, or procedures that repair defects such as atrial septal defects, patent foramen ovale (PFO) defects, or ventricular septal defects, all require a bloodless field uses what kind of cannulation A. One B. Two C. Three D. Four

B. Basic Circuit The CPB machine consists of five basic components: a venous reservoir, a main pump, an oxygenator, a heat exchanger, and an arterial filter (Fig. 26.8). The following is a simple explanation of full CPB: venous (deoxygenated) blood is drained from the right side of the heart via a cannula in the atrium and vena cava and carried by tubing to a reservoir; the main pump (centrifugal or roller) then propels the blood to an oxygenator and a heat exchanger; and the oxygenated blood passes through an arterial line filter before returning to the arterial circulation via a cannula in the ascending aorta to perfuse the rest of the body. The modern bypass machine also performs several other functions, including delivering cardioplegia by means of accessory pumps. The heart is vented, and blood is salvaged from the field, by means of suction devices. Cannulae. The CPB circuit includes cannulae and tubing made of medical grade polyvinyl chloride with a biocompatible coating to decrease the inflammatory response associated with CPB and to preserve blood components. One-, two-, or multi-stage (meaning more than one hole to drain the blood) venous cannulae are used to remove the deoxygenated blood from the heart. A large-bore two-stage or multistage venous cannula that drains blood from both the right atrium and the inferior vena cava (IVC) is used for CABG and aortic valve (AV) procedures in which the heart remains closed and small amounts of retained blood will not interfere with the surgery (Fig. 26.9). Open-cavity procedures, such as mitral, pulmonic, and tricuspid valve surgery, or procedures that repair defects such as atrial septal defects, patent foramen ovale (PFO) defects, or ventricular septal defects, all require a bloodless field. For such procedures, two separate single-stage venous cannulae are individ

The most appropriate MAP on bypass is no less than A. 40-50 mmHg B. 50-60 mmHg C. 60-70 mmHg D. 70-80 mmHg

B. Cardiopulmonary Bypass Principles Most cardiac surgeries must be accomplished with the aid of CPB. The machine is operated by a perfusionist, but it is imperative that the anesthetist have a clear understanding of the components and physiologic impact of CPB. The purpose of CPB is to provide a motionless, bloodless heart for the surgical procedure. This goal is achieved by temporarily diverting venous blood away from the heart to an extracorporeal circulation apparatus that adds O2 removes carbon dioxide (CO2) and then filters the blood before returning it to the body, most often via the ascending aorta. The CPB circuit is continuous with the systemic circulation and provides artificial ventilation, perfusion, and temperature regulation while diverting the blood from the surgical field. The technique results in stopping nearly all blood flow to the heart and lungs. To stop the heart's electrical activity and to protect it during the procedure, the heart is intermittently perfused and cooled with a chemical solution called cardioplegia. Although the goal is to provide near-physiologic hemodynamics and acid/base balance, the technique is nonphysiologic. A near-normal cardiac index (CI) is usually maintained with an arterial flow of 2.0 to 2.4 L/min per m2, but it is nonpulsatile. There is controversy over what is the most appropriate MAP on bypass, but most advocate no less than 50 to 60 mm Hg. Older patients, or those with known carotid disease, should have a higher MAP, closer to 60 to 70 mm Hg, to assure that there is adequate cerebral perfusion pressure.8 The patient's blood and blood components are exposed to the nonendothelial surfaces, which increase the incidence of platelet dysfunction and coagulopathy. CPB incites a host of inflammatory responses; these are outlined after the discussion of the circuit compon

Which of the following may require fluid administration post CPB A. good ventricular function usually have a BP, heart rate and rhythm, and CO within the normal range B. patient in diastolic heart failure C. patient in systolic heart failure D. patient experiencing vasoplegia syndrome

B. Hemodynamic Management. After CPB, most patients fall into one of four groups.123 The first group includes patients with good LV function preoperatively and few comorbidities; they usually separate from CPB easily and require little support. Patients with good ventricular function usually have a BP, heart rate and rhythm, and CO within the normal range. This group of patients may need some occasional adjustments of their volume or BP, but they are generally stable during the postbypass period. The second group consists of patients with significant concentric LVH and diastolic dysfunction. This group tends to be volume-dependent. The intravascular volume status should be continually reassessed using TEE, because the LVEDP may be elevated despite low ventricular volume due to decreased ventricular compliance. As volume is added from the pump, these patients may become hypertensive, even though their CO is still low, due to hypovolemia. In other words, this group of patients is prone to DHF. Judicious boluses of nitroglycerin will help the LV to relax and accept volume, as well as aid in controlling hypertension. As discussed at the beginning of the chapter, patients with concentric LVH require a high MAP and adequate diastolic time to fill the noncompliant ventricle (see Table 26.4). If the MAP decreases, they are prone to ischemia; therefore they may benefit from a low-dose vasoconstrictor such as norepinephrine if the BP is low after volume has been optimized. These patients are also very reliant on their atrial kick, which can contribute up to 40% of left ventricular EDV.82 If the patient's heart rate is slow or nodal, atrial or atrioventricular pacing can significantly improve hemodynamic function. Left ventricular outflow tract (LVOT) obstruction with possible systolic anterior motion (SAM) of the mitral valve ca

Which of the following is not a part of the STS guideline for perioperative glucose management A. Continue basal insulin dose B. Continuous infusion preferred if glucose 150 mg/dL or greater C. If patient in ICU more than 3 days, target should be 150 mg/dL or less D. Restart oral hypoglycemic if target achieved and no contraindications.

B. Highlights of STS Perioperative Glucose Management Recommendations Preoperative • Hold oral hypoglycemic for 24 hours prior to surgery. • Hold nutritional insulin after dinner the night before surgery. • Continue basal insulin dose (NPH dose may be cut by 1/3 to 1/2). • Check glucose level frequently day of surgery. • Maintaining glucose at 180 mg/dL or less is reasonable. Intraoperative • Intermittent bolus acceptable if nondiabetic and glucose less than 180 mg/dL. • Continuous infusion preferred if glucose 180 mg/dL or greater. • Continuous infusion preferred for diabetics, maintain postoperatively. • Adjust infusion per institutional protocol with a goal of maintaining glucose at 180 mg/dL or less. • Check glucose level every to 1 hour or more frequently. Postoperative in ICU • Consult endocrinology for diabetic patients. • If glucose persistently greater than 180 mg/dL, continue infusion. • If patient in ICU more than 3 days, target should be 150 mg/dL or less. • Before stopping infusion, transition to subcutaneous insulin. In Step-Down or Floor • Endocrinology to adjust basal and nutritional insulin doses • General goal is 180 mg/dL or less after meals and 110 mg/dL or less fasting. • Restart oral hypoglycemic if target achieved and no contraindications.

The highest rate of recall in cardiac surgery has been recorded during this period A. Pre-incision B. Incision to Bypass C. Cardiopulmonary bypass D. Rewarming

B. Incision to Bypass. The incision-to-bypass period begins with intensely stimulating events: incision, sternotomy, and sternal spread. The anesthetist should prepare for these events by deepening the anesthetic and administering additional muscle relaxant, if needed. The highest rate of recall in cardiac surgery has been recorded during this period; therefore an amnestic can be given if not previously administered.118 The lungs are deflated during sternotomy to decrease the risk of cardiac or pulmonary laceration. Repeat or redo sternotomy requires greater preparation and vigilance. Patients who have had a prior CABG may have an arterial or venous bypass graft lying directly beneath the sternum. Patients who have had prior chest radiation (often for breast cancer or lymphoma) can also have adherent scar tissue that is difficult to dissect. In these situations, the surgical team will examine the patient's lateral radiograph and possibly a magnetic resonance image (MRI) or computed tomography (CT) scan to determine the proximity of the cardiac structures to the sternum. If the heart appears to be adherent to the sternum, there are several management options for sternotomy and dissection. Some surgeons may expose the femoral vessels so they can quickly cannulate and institute CPB if arterial or cardiac trauma occurs at sternotomy. Other surgeons will cannulate the femoral vessels before sternotomy and institute CPB during dissection (the heart is not arrested and continues beating). An oscillating saw is often selected for slow, cautious sternotomy. Communication between the surgeon and anesthetist is crucial because the lungs may need to be deflated several times for short periods. In the rare event that a cardiac structure or great vessel is damaged and bleeding becomes uncontrollable, IV heparin (300-400 units/kg) is

The practice of clearly repeating back information when one team member makes a request of another, is imperative for safety A. Nonverbal communication B. Closed-loop communication C. Providing feedback D. Open-loop communication

B. Intraoperative Management This section focuses on management of general cardiac surgery from the time the patient enters the OR until his or her care is safely transitioned to the ICU team. What follows is a sequential description of events that occur during most cases, so that the anesthetist can gain an understanding of important perioperative milestones. The rationale for pharmacologic and hemodynamic management, as well as patient monitoring, was previously discussed. A discussion of management of specific cases and specialized equipment follows. The cardiothoracic OR is a fast-paced, high-intensity environment where up to a dozen practitioners must focus for extended periods. The patient population is high-risk because of the prevalence of multiple comorbidities in addition to the primary cardiac pathology. The surgical procedures can be quite complex, and manipulation of the heart and vasculature can profoundly impact hemodynamic function. The anesthetist is required to intently focus on both the surgical procedure and the patient's response to widely varying levels of stimulation. Problems must be anticipated, and interventions must be prompt. Throughout the process, communication between the anesthesia, surgical, nursing, and perfusion teams is critical. Failure to communicate can have devastating consequences. Closed-loop communication, the practice of clearly repeating back information when one team member makes a request of another, is imperative for safety.116

Advantages of the minimally invasive approaches to the mitral valve include the following except A. Decrease LOS B. Decrease patient recovery C. Decrease blood loss D. Decrease hospital cost

B. Minimally Invasive Mitral Valve Procedures Surgical Approaches. Minimally invasive mitral valve surgery involves repair or replacement of the mitral valve by a variety of less invasive surgical incisions and approaches than the traditional full median sternotomy. Minimally invasive mitral valve surgery has evolved extensively over the last 20 years; that is, since 1996, when Carpentier performed the first video-assisted mitral valve repair through a right minithoracotomy, and 1997, when Mohr performed the first robotic-assisted mitral valve repair.179,186 Minimally invasive surgical approaches for repair of the mitral valve today may include a lower hemisternotomy, right minithoracotomy, or total endoscopic approach through port chest incisions, with or without the use of video assistance or robotics (see Figs. 26.15 and 26.16).82,187 The minimally invasive mitral valve approach has shown successful surgical results and positive outcomes with regard to mortality and morbidity.82,187-189 Advantages of the minimally invasive approaches to the mitral valve include decreased hospital length of stay, faster patient recovery, decreased blood loss, decreased hospital cost, and improved cosmetic appearance compared to the traditional median sternotomy.187-189 Successful surgical outcomes are dependent on proper patient selection. Contraindications to a minimally invasive approach to mitral valve repair include inability to obtain TEE, severe AR, aortic and/or thoracic disease, Marfan syndrome, and previous aortic and/or thoracic surgery.190 Atherosclerosis of the descending aorta or femoral vessels precludes surgeries that require retrograde aortic cannulation through the femoral artery.

This is the least common left-sided valvular defect because it is caused primarily by RHD, which is now rare in developed countries A. Mitral regurgitation B. Mitral stenosis C. Aortic stenosis D. Aortic regurgitation

B. Mitral Stenosis MS is the least common left-sided valvular defect because it is caused primarily by RHD, which is now rare in developed countries.177,178 Although RHD affects men and women equally, MS is two to three times more prevalent in women. Occasionally, MS also develops as the result of severe mitral annular calcification caused by the atherosclerotic process. There are a host of other less common etiologies, including: carcinoid syndrome, left atrial myxoma, endocarditis, and collagen diseases.175 Clinically, significant stenosis takes decades to develop, and symptoms do not usually appear until the valve area, which is normally 4 to 5 cm2, is reduced to 2.5 cm2, and many patients remain asymptomatic until the valve area is 1 cm2.80,178 Pathophysiology. As the valve orifice narrows, diastolic filling of the LV is limited, and a pressure gradient develops across the mitral valve. Left atrial pressure (LAP) and volume increases, leading to atrial dilation and elevation in pulmonary pressures. Right ventricular failure can eventually develop if the PHTN is left uncorrected. Stenosis is considered severe when the valve area is less than 1.5 cm2, the mean gradient generally exceeds 5 to 10 mm Hg, and PA systolic pressures are greater than 30 mm Hg.80 The risk of surgery is 3% to 8% in most studies, but the presence of PHTN increases the risk to 12%.178 Flow across the valve will decrease in response to an increase in CO or a decrease in diastolic time. Hence, symptoms are usually first experienced during exercise or stress. Conditions such as pregnancy and sepsis may provoke AF in a previously asymptomatic patient, leading to decompensation. Approximately 33% of patients develop AF. The rapid heart rate is the primary cause of hemodynamic instability, rather than the loss of atrial kick.175 Patients with MS and

A catheter is blindly inserted into the right atrium or directly inserted after CPB and advanced into the coronary sinus, the largest venous drainage vessel of the heart. To place the catheter, the surgeon often lifts the heart to help locate the sinus and advance the catheter. A. Anterograde B. Retrograde

B. Myocardial Preservation Mild to moderate systemic hypothermia and cold cardioplegia are used for myocardial preservation. The patient can be actively cooled by the CPB circuit, or his or her temperature can be allowed to drift toward the ambient room temperature. Some surgeons cool the heart topically by packing icy slush around it. The goal is to achieve hypothermic diastolic circulatory arrest to decrease the metabolic rate, O2 consumption, and excitatory neurotransmitter release, and to preserve high-energy phosphate substrates.8 The brain also benefits from the hypothermia, and may be at least partially shielded from neurologic injury as a result. The cerebral metabolic rate decreases 6% to 7% for every degree Celsius decrease in brain temperature. A hyperkalemic crystalloid solution mixed with blood is the most commonly used cardioplegia solution today. The ratio of the mix varies, but is most often a 4 : 1 blood to crystalloid solution (i.e., Buckberg solution). The exact composition of cardioplegia solution is institution-driven, but the first dose (induction dose) is cold (2°C to 5°C), and contains 20 to 30 mEq/L of potassium. Maintenance doses are also cold, and contain 12 to 16 mEq/L of potassium. The goal is to maintain a myocardial temperature between 8°C and 10°C.42 An alternative, del Nido cardioplegia solution, which was historically used in pediatric heart surgery, is gaining popularity in the adult cardiac surgical arena. It consists of a 1 : 4 blood to a non-glucose-based crystalloid solution that is delivered as a single dose that lasts up to 180 minutes. It has been shown to be used effectively and safely in adult isolated valve surgery, and is associated with lower insulin requirements and potential time and cost savings.43 The amount of cardioplegia given in any single dose can be based on

This is a coated bundle of hollow microporous polypropylene fibers that are tightly wound to create a large surface area. A. Bubble Oxygenator B. Membrane Oxygenator

B. Oxygenator. The oxygenator performs the functions of oxygenating venous blood and removing CO2 (see Fig. 26.8). Historically, bubble oxygenators were used, but today only membrane oxygenators are in use. The membrane oxygenator is a coated bundle of hollow microporous polypropylene fibers that are tightly wound to create a large surface area. Blood flows around the tightly packed fibers, and gas flows through the fibers. The gas, consisting of O2 or a mixture of O2 and medical-grade air, diffuses passively across the membrane and into the blood. The O2 level in the blood can be controlled by changing the fraction of inspired O2 (FiO2), or O2 concentration. The amount of CO2 removed from the blood is controlled by changing the liter gas flow rate or "sweep" of gas through the oxygenator. Volatile anesthetic can also be added to the fresh gas inlet that enters the oxygenator to maintain appropriate blood concentration and depth of anesthesia while on CPB.

When the heart muscle experiences brief periods of ischemia lasting less than __ minutes, necrosis (or cell death) does not occur, but reversible contractile dysfunction, known as stunning, can develop and last for several hours. A. 10 B.. 20 C. 30 D. 40

B. Preconditioning, Stunning, and Hibernation When the heart muscle experiences brief periods of ischemia lasting less than 20 minutes, necrosis (or cell death) does not occur, but reversible contractile dysfunction, known as stunning, can develop and last for several hours.16-18 Many cardiac surgical patients require 12 to 24 hours of inotropic support after CPB, often as a result of stunning. Ischemic preconditioning refers to the phenomenon whereby a short period of ischemia improves the heart's ability to tolerate subsequently longer periods of ischemic insult.16,19 Multiple animal and clinical studies have demonstrated that volatile agents all produce this preconditioning effect, thereby protecting the myocardium from ischemic and reperfusion injury and reducing infarct size.20-23 Internationally, there is expert consensus support for the use of volatile agents in hemodynamically stable cardiac surgery patients as a means of reducing myocardial damage and death.21 Consequently, there has been a resurgence of inhalation anesthesia as a primary technique for cardiac surgery, especially in patients with near-normal ventricular function. The role of volatile agents in unstable patients and those with significant LV dysfunction is less clear, and large randomized controlled trials in cardiac surgery patients are still needed. When stable coronary plaques cause chronic reductions in coronary perfusion, steady-state ischemia occurs, which results in left ventricular perfusion-contraction matching, or hibernation. This phenomenon is considered a self-preservation mechanism whereby left ventricular contractile function is reduced to match the amount of O2 available.24,25 Unlike patients with stunned myocardium, patients with hibernating LVs often have significantly improved function after coronary artery bypass grafting (C

Which of the following is not approprate for the separation from bypass A. Rectal/bladder temperature ≥ 35°C, but ≤ 37°C B. Pump flow to maintain mixed venous saturation ≥ 50% C. Hct: 20% to 25% D. K+: 4-5 mEq/L

B. Preparation for Separation-From-Bypass Checklist 1. Air clearance maneuvers completed 2. Rewarming completed a. Nasopharyngeal temperature 36°C to 37°C b. Rectal/bladder temperature ≥ 35°C, but ≤ 37°C 3. Address issue of adequacy of anesthesia and muscle relaxation 4. Obtain stable cardiac rate and rhythm (use pacing if necessary) 5. Pump flow and systemic arterial pressure a. Pump flow to maintain mixed venous saturation ≥ 70% b. Systemic pressure restored to normothermic levels 6. Metabolic parameters a. Arterial pH, PO2, PCO2 within normal limits b. Hct: 20% to 25% c. K+: 4-5 mEq/L d. Ionized calcium 7. Ensuring all monitoring/access catheters functional? a. Transducers re-zeroed b. TEE (if used) out of freeze mode 8. Respiratory management a. Atelectasis cleared/lungs re-expanded b. Evidence of pneumothorax? c. Residual fluid in thoracic cavities drained d. Ventilation reinstituted 9. Intravenous fluids restarted 10. Inotropes/vasopressors/vasodilators prepared

Which valve placement is performed while ventilation is held (apnea) and a low CO state is induced by rapid ventricular pacing A. CoreValve B. Sapien XT valve C. JenaValve

B. Surgical Approach. The two most common valves in use in the United States today are the Edwards Sapien XT, which is a balloon-expandable bovine pericardial tissue valve (SAPIEN Transcatheter Heart Valve, Edwards Lifesciences, Irvine, CA, USA), and the Medtronic CoreValve (CoreValve, Medtronic Inc., Minneapolis, MN, USA), a self-expanding porcine pericardial valve.220,222 The Edwards Sapien valve may be used for several approaches, including the transfemoral, transapical, transaortic, and transsubclavian approaches.220,222 The CoreValve is used with the transfemoral approach, but may also be delivered in a retrograde fashion from the subclavian/axillary artery, the carotid artery, and (for direct aortic access) through either a ministernotomy or right anterior thoracotomy.220,222 The CoreValve and the Sapien XT valve have CE mark approval for valve-in-valve use in patients with severe AS, who are deemed to be a high surgical risk. Although not currently available in the United States, the JenaValve transapical TAVR system (JenaValve, Munich, Germany) received worldwide CE approval for treatment of AS in September of 2011 and for treatment for AI in September of 2013.223,224 The JenaValve is a porcine root valve that is sewn onto a Nitinol self-expanding stent.223,224 Before being sewn onto the stent, the root valve is fitted with an outer porcine pericardial patch.223,224 The JenaValve is fully repositionable and retrievable.223,224 Six other TAVR device systems (not including the valves described previously) have obtained CE mark approval in Europe for patients with severe AS who are considered high risk surgical candidates. The bioprosthetic valve is delivered over a catheter system into the diseased stenotic valve, most commonly via a transfemoral or transapical approach. Access is reached by an interventional car

Which atrial appendage releases a considerable amount of ANP A. Left B. Right

B. Surgical Therapy for Atrial Fibrillation Early in 1990, Cox et al. developed the Maze procedure, in which several incisions are made in a specified pattern around the atria to create a maze of scar tissue that blocks the reentry circuits that cause AF while still allowing conduction of an impulse from the sinus to the atrioventricular node.180,181 The original procedure has been improved, so that the Cox-Maze IV procedure is currently in use, replacing the original surgical incisions with a combination of bipolar radiofrequency ablation and cryoablation. This approach has achieved 90% freedom from AF at twelve months.182 The number of surgical and catheter-based techniques used to treat AF has expanded greatly as the understanding of causation has grown. Today, many catheter-based ablative procedures are available in the electrophysiology laboratory, but this discussion will be limited to procedures performed in the operating suite. Surgical procedures used to ablate AF are often carried out in conjunction with, and usually just prior to, other cardiac procedures, but they can also be performed independently. Traditionally, the Maze procedure requires CPB and includes the ligation or stapling of the left atrial appendage because it is considered a major source for emboli. The right atrial appendage is a significant source of ANP, so it is not removed. The procedure can be carried out through a traditional sternotomy or through a minimally invasive right anterior thoracotomy with femoral cannulation. Newer technology now allows surgeons to use a variety of alternate energy sources to quickly and simply make lesions that interrupt the reentry pathways.82 The pulmonary veins have been found to be a site of reentry, so they are now frequently isolated using ablative energy.183 Options for energy sources include radiofre

Vacuum-assisted venous drainage (VAVD) at a suction of −__ mm Hg causes less hemolysis A. 20 B. 40 C. 60 D. 80

B. Venous Reservoir. CPB is initiated when the perfusionist removes a clamp that occludes the tubing connecting the venous cannulae to the venous reservoir (see Fig. 26.8). The venous reservoir is typically hard-shelled and divided into two compartments, one for the venous drainage from the heart and the other for the blood suctioned or vented directly from the surgical field. This portion of the reservoir is known as the cardiotomy, and is discussed in detail later. Traditionally, blood drains from the patient to the reservoir by gravity. The rate of venous drainage is determined by the size and placement of the cannulae, the height of the bed, and the patient's intravascular volume status. With the introduction of minimally invasive techniques, gravity drainage proved to be inadequate due to the small size of the cannulae and tubing. Subsequently, the practice of vacuum-assisted venous drainage (VAVD) was established. A vacuum regulator is added to the venous reservoir with a piece of Y tubing, and a pressure of −40 mm Hg is applied. This Y tubing is used to turn on the suction or open the system to atmospheric pressure. Improved drainage can facilitate surgical exposure and decrease the necessity of adding more crystalloid and/or blood to the CPB circuit. The inherent risks include hemolysis of blood cells and air embolism. VAVD at a suction of −40 mm Hg causes less hemolysis than when the suction is increased to −80 mm Hg.35 It is critical that the fluid level in the venous reservoir be kept sufficiently high to prevent air entrainment from the main pump, which can result in an air embolism. An alarm is incorporated into the venous reservoir to alert the perfusionist if the fluid level drops below a specified level. The perfusionist may add fluid and medications to the venous reservoir.

Demand ischemia, resulting from chronic pressure overloading secondary to stenotic heart valves, obstructive cardiomyopathy, chronic hypertension, or obesity leads to A. Eccentric hypertrophy B. Concentric hypertrophy

B. - Diastolic Dysfunction. Diastolic dysfunction is a more difficult concept to explain, but one that is equally important. Pulmonary congestion and all the symptoms of heart failure can indeed develop with a normal EF. In fact, diastolic heart failure (DHF) is often called heart failure with preserved EF (greater than 40%) (see Fig. 26.6). Demand ischemia, resulting from chronic pressure overloading secondary to stenotic heart valves, obstructive cardiomyopathy, chronic hypertension, or obesity, causes the myocardium to thicken (concentric hypertrophy) and compliance to decrease (see Fig. 26.7).4 Pulmonary congestion develops because the fibrosed, nondistensible LV, with an increased LVEDP, is unable to fill adequately, despite near-normal systolic function. Diastolic failure is graded from class I to IV based on echocardiographic examination findings.33 The LV with concentric hypertrophy is prone to ischemia; therefore maintenance of a high MAP and slow normal heart rate is crucial.34 Hypotension should be treated promptly, usually with phenylephrine to avoid rapid decompensation, which can potentially lead to cardiac arrest. If the patient arrests, chest compressions rarely generate enough pressure to perfuse the hypertrophied, noncompliant LV. The mortality and hospitalization rates are similar in both systolic and diastolic failure.28,34 Table 26.3 compares the characteristics of patients with systolic and diastolic failure, and Table 26.4 outlines the anesthetic management strategies for systolic and diastolic dysfunction. Oftentimes, as DHF progresses, SHF will develop, and the two will coexist.28

Which of the following should not be observed when managing patients with aortic insufficiency A. Increase HR B. Increase SVR C. Increase Preload D. Increase contractility

B. & D Anesthetic Considerations and Surgical Options. Hemodynamic management of AI (Table 26.13) is focused on enhancing forward flow and minimizing the regurgitant volume. Regurgitation occurs during diastole, so a relatively high heart rate is used to minimize diastolic time. The patient's volume should be kept in the "high normal" range because the heart is dilated and compliance is increased. Judicious vasodilation lowers the SVR to enhance forward flow and reduce the regurgitant volume, while still maintaining adequate pressure to support coronary perfusion. The frequently quoted pneumonic that reflects this hemodynamic management strategy for regurgitant valvular lesions is "fast, full, and forward." During CPB, AI can lead to ventricular distention and pressure overload that directly opposes coronary perfusion and myocardial preservation. When CPB is initiated, a slow heart rate or ventricular fibrillation can lead to distension. After the aortic cross-clamp is applied, cardioplegia that is usually infused into the aortic root, intended to flow antegrade down the coronaries, can instead run into the LV secondary to the AV's incompetence. Even mild to moderate AI can cause LV distention; consequently, the presence of AI increases the risk of other cardiac surgical procedures. Achieving diastolic standstill in these situations often requires that cardioplegia be delivered directly into the coronary ostia and/or retrograde through the coronary sinus. An LV vent is placed to suction away fluid, thereby alleviating or preventing distension. A positive inotrope is often useful after CPB, especially if there was LV dysfunction prebypass or questionable preservation during bypass.82,175 Valve repair is sometimes possible, but is technically more challenging than mitral repair. Traditional replacement options are the sa

ABGs and ACTs are monitored every __ minutes during the maintenance of CPB A. 10 B. 20 C. 30 D. 40

C Maintenance. The flow rate on CPB is maintained at 50 to 60 mL/kg per min to reach a calculated CI of 2.0 to 2.5 L/min per m2. The ideal systemic pressure on CPB is 50 to 70 mm Hg, depending on the patient's age and comorbidities. The mixed venous O2 saturation should be monitored and maintained at 70%. Hypertension may indicate a light anesthetic level. This can be treated by increasing the inhalational agent or by administering a supplemental dose of narcotic or benzodiazepine. If hypertension persists, a vasodilator may be added. Hypotension is usually treated with bolus doses of phenylephrine by the perfusionist, but occasionally an infusion of a vasopressor may be needed. The train-of-four should be completely suppressed to prevent movement or shivering during CPB. Shivering may not be obvious, but it greatly increases O2 consumption, which may be manifested as low O2 on the venous gas sensor. ABGs and ACTs are monitored every 30 minutes. Acid/base imbalances are corrected as needed. Blood may be needed, depending on the patient's hematocrit and comorbidities, as well as on the complexity of the surgical procedure. Blood glucose usually increases to a level that requires treatment with an insulin infusion. Patients often develop some level of hyperkalemia related to the potassium in the cardioplegia solution. The insulin infusion counters this problem by driving potassium into the cell. Urine output is monitored: 1 mL/kg per hr is considered satisfactory. If urine output is low and the pump volume is adequate, the addition of a diuretic should be considered, especially if the patient was taking a diuretic preoperatively. If the hematocrit is low, hemoconcentration (ultrafiltration) through the CPB circuit can be considered as a blood conservation technique.

This has been considered to be the single best ECG lead for detecting myocardial ischemia. A. V1 B. V2 C. V3 D. V4 E. V5

C & D Ischemia Cascade - Myocardial ischemia leads to a cascade of events, as shown in Fig. 26.4.11,12 It is important to emphasize that diastolic dysfunction precedes systolic dysfunction, and that regional wall motion abnormalities occur on echocardiography before changes on the electrocardiogram (ECG). An imbalance between myocardial O2 supply and demand will initially induce diastolic dysfunction, making the ventricle stiff and less compliant. These abnormalities will manifest as an increase in the pulmonary artery end-diastolic pressure (PAEDP). However, multiple studies show that the PAEDP is not specific for ischemia.13 Systolic dysfunction causes regional wall motion abnormalities that can be readily detected on transesophageal echocardiography (TEE). TEE is the most sensitive intraoperative monitor for detecting myocardial ischemia.12 Traditionally, V5 has been considered to be the single best ECG lead for detecting myocardial ischemia.11 More recently in 2002, Landesberg showed that V4 and V3 were more sensitive than V5 in detecting perioperative ischemia (87%, 79%, and 66%, respectively).14 Therefore it is important to ensure that the V lead (brown) of the ECG is correctly placed at the forth intercostal space midclavicular line. Automated ST segment analysis is also recommended because it has a high sensitivity and specificity for detection of intraoperative ischemia. Three-lead ECG systems are not recommended for monitoring perioperative ischemia.15

Which fo the following should not be observed in patients with mitral stenosis A. Increase preload B. Decrease HR C. Increase PVR D. Maintain SVR

C.

Which of the following is a characteristic of a diastolic HF A. Often in males B. Depressed EF C. Caused by COPD D. Dilated LVH

C.

Which of the following is a normal Pulmonary capillary wedge pressure A. 2 B. 4 C. 8 D. 16

C.

These These maneuvers compress cardiac chambers and distort valvular apparatuses, resulting in well-documented hemodynamic compromise and acute ischemia A. Steep tendelenburg position B. Physiologic position C. Verticalizing the apex D. Horizontalizing the apex

C. Anesthetic Considerations and Surgical Options for Off-Pump CABG The first off-pump coronary artery bypass (OPCAB) procedures were attempted in the 1950s, but there has been a resurgence in their popularity since retractors and epicardial stabilizing devices such as the Octopus (Medtronic Inc., Minneapolis, MN, USA) were developed in the 1990s. Off-pump surgery is also called beating heart bypass surgery. Although the procedure is typically performed through a full median sternotomy without the aid of CPB, a perfusionist and a primed or dry pump (based on surgical preference) should be in the OR on standby throughout the case. Occasionally, a limited anterior thoracotomy (minimally invasive coronary artery bypass [MIDCAB]) approach is used. The implications of the MIDCAB incision are detailed in the section on minimally invasive surgery. It is estimated that OPCAB accounts for 20% to 30% of all CABG procedures.143 OPCAB is performed to avoid the risks and complications associated with conventional CABG and CPB, but further research is needed to determine its relative safety. Aortic cross-clamping is avoided, theoretically decreasing the risk of debris embolization. Studies comparing the techniques showed that patients from both groups had equivalent rises in inflammatory biomarkers153 and similar neuropsychologic outcomes.154 Additionally, incomplete revascularization was slightly more common in the OPCAB patients. and 1-year patency significantly worse.154 The STS recommends OPCAB as a blood conservation technique.51 Anesthetic implications and monitoring are similar to those of on-pump CABG, with a few additional concerns. The procedure is usually limited to patients with relatively good LV function, and bleeding is less of a concern, so patients are even more likely to be candidates for a fast-track anesthetic pl

This acts immediately to reduce preload by decreasing vascular tone; in higher doses, it also decreases coronary artery resistance. A. Metoprolol B. Diltiazem C. Nitroglycerin D. Milrinone

C. Anesthetic Considerations and Surgical Options for On-Pump CABG The anesthetist should carefully review preoperative cardiac tests to determine the location and extent of the lesions, to assess ventricular function, and to detect the possible presence of concurrent cardiac abnormalities such as AS. Table 26.2 reviews significant findings on cardiovascular preoperative testing. Preoperative ventricular function correlates with the risk of developing postoperative low cardiac output syndrome (LCOS). Patients with ACS or NYHA class IV heart failure (see Table 26.5) are at high risk of LCOS. If the patient develops cardiogenic shock, often requiring an IABP to maintain stable hemodynamics, the patient is in the highest risk category. Patients who have had BMSs implanted within 3 months of surgery and/or DESs within 1 year of surgery will have special considerations because of their antiplatelet therapy. The general management of drugs affecting coagulation has already been discussed. However, in patients with recent coronary stents, the cardiologist and surgeon collaborate to determine the best management for the individual patient. For emergency procedures, both aspirin and GPIIb/IIIa inhibitors may be continued, despite the increased risk of bleeding.143 Optimizing myocardial O2 supply and minimizing myocardial O2 demand are clearly key anesthetic considerations in CABG surgery (see Fig. 26.1). The patient must be monitored carefully for ischemia throughout the procedure. Using a combination of ECG and TEE findings, together with direct inspection of the heart, is advised.144 Table 26.1 outlines causes of and treatments for myocardial ischemia. Anesthetic considerations are summarized in Table 26.9. It is most important to keep a relatively high MAP to maintain coronary perfusion, while keeping the heart rate and LVED

Long isolation is mostly required in which cardiac surgery A. Traditional median sternotomy B. Minithoracotomy C. Robotic surgery D. Endoscopic approach

C. Anesthetic Considerations. Regardless of the surgical approach adopted, all minimally invasive mitral valve procedures require a general anesthetic. Principles applied to the anesthetic management of patients with mitral valve disease (discussed earlier in the chapter) are also applicable to the patient undergoing a minimally invasive mitral valve procedure, but with some additional considerations. A fast-track approach to the selection of induction and maintenance of medications is usually appropriate. Judicious use of narcotics and muscle relaxants will facilitate achieving the goal of early extubation. It is imperative that the level of muscle relaxation be closely monitored because unwanted patient movement during a robotic procedure could cause significant harm. Measures to maintain normothermia, such as fluid warming devices, circuit humidifiers, forced air warming devices, and raising the room temperature, must also be considered, especially if early extubation is a goal. For robotic surgery, patients are positioned supine with a roll placed under the right scapula to elevate the hemithorax 25 to 30 degrees.191,192 The right arm is carefully positioned (slightly deviated from body to allow port access) and padded along the right side of the patient's body to prevent it from interfering with the robotic device. External defibrillator pads should be placed on all patients because the use of internal defibrillation paddles is not possible with limited incisions.193 If a minithoracotomy approach is selected, the surgeon makes a 3- to 4-cm right submammary, minithoracotomy incision at the fourth to fifth intercostal space, along with separate smaller chest incisions for port access or for robotic instrumentation access.179,186 If a total endoscopic approach is selected, only several small chest incisions are usual

This is the most common valvular lesion among patients in industrialized countries. Approximately 1% to 2% of the population has a congenitally bicuspid valve A. Mitral regurgitation B. Mitral stenosis C. Aortic stenosis D. Aortic regurgitation

C. Aortic Stenosis AS is the most common valvular lesion among patients in industrialized countries. Approximately 1% to 2% of the population has a congenitally bicuspid valve.160,163 A bicuspid valve has a smaller orifice and tends to open and close abnormally, which subjects the valve apparatus to increased sheer stress and degeneration. Hence, the majority of younger patients (30-50 years of age) undergoing valve replacement have bicuspid valves.164 Risk factors for the development of acquired AS are the same as those for atherosclerosis: increased age, male gender, smoking, hypertension, and hyperlipidemia. The prevalence of degenerative AS increases markedly with age, and there is often concomitant AR.163-165 Many times, aortic valve replacements (AVRs) are combined with CABG. Some patients will be referred for AVR in preparation for subsequent noncardiac surgery because symptomatic AS is one of the cardiac conditions for which the AHA and ACC recommend intensive management before noncardiac surgery.30 Pathophysiology. The normal AV area measures 3 cm2 ± 1 cm2. Stenosis is considered severe when the valve area decreases to 1 cm2 or less.80 The stenotic orifice obstructs the LV outflow, and the ventricle compensates by becoming thicker (concentric hypertrophy), attempting to generate enough pressure to push the blood forward past the stenosis. This forward motion causes accelerated, turbulent blood flow as it crosses the valve, somewhat like the water flow when a garden hose is partially occluded. Secondary to the Venturi effect, this increased flow results in a pressure drop as it crosses the valve so that pressure in the aorta is significantly less than the pressure in the LV. A jet velocity of 4 m/sec or more and a mean pressure gradient drop of 40 mm Hg or more suggests severe AS, and a jet velocity of 6 m/sec

Before the aortic cannula is placed, MAP less than __mm Hg to decrease the risk of aortic dissection A. 50 B. 60 C. 70 D. 80

C. Cannulation. Cannulation is the next major event in the prebypass period. Full heparinization is essential before cannulation. Heparin (300-400 units/kg) is administered through a central line after aspiration of blood confirms line patency, to ensure intravascular administration. The ACT or heparin concentration assay is checked 3 to 5 minutes after the heparin is administered. Muscle relaxants are given if needed because movement during cannulation could prove disastrous. The aortic cannula is placed first, followed by the single venous cannula or double venous cannulae (see Figs. 26.9 and 26.10). Then, the antegrade and retrograde cardioplegia cannulae may be inserted, or the surgeon may wait until after CPB is initiated. Surgical manipulation of the heart and great vessels during cannulation often leads to hypotension and dysrhythmias; therefore careful attention and clear communication between the anesthetist, surgeon, and perfusionist are critical. Before the aortic cannula is placed, BP is decreased to a systolic blood pressure (SBP) of 90 to 100 mm Hg or a MAP less than 70 mm Hg to decrease the risk of aortic dissection. To achieve this goal, the anesthetic level can be deepened, or vasodilators can be carefully titrated. The aortic cannula and aortic line from the CPB machine are connected and inspected, and all air bubbles are purged. Complications of aortic cannulation include arterial dissection, hemorrhage, plaque or air embolization, and inadvertent placement of the distal tip of the cannula in an aortic arch vessel. Once aortic cannulation is completed, the perfusionist will confirm intraarterial placement of the arterial cannula by verifying pressure variation in the manometer connected to the aortic line (called checking the swing). Then, a test transfusion is administered to confirm normal flow an

This is the biggest predictor for type 1 neurologic injury in patient that undergo CPB A. Age B. History of stroke C. Atherosclerosis D. Hypertension

C. Heart. Myocardial injury can occur even when protection strategies seem adequate. The injury can vary from being asymptomatic, with only an elevation of cardiac enzymes postoperatively, to severe, with a marked decrease in cardiac function that results in failure to separate from bypass. Substantial increases in cardiac enzymes resulting from the activation of SIRS and/or ischemic injury can occur from embolization and hypoperfusion during CPB. Due to the very nature of the surgery, cardiac insult and ischemia after CPB may occur even with use of myocardial protection techniques. Myocardial injury manifesting as increased cardiac enzymes after CABG has been shown to increase the risk of both early and late death.55 Management strategies and devices that may become necessary after myocardial injury during cardiac surgery and bypass are discussed later in the chapter. Brain. Injury to the brain or the central nervous system (CNS) after cardiac surgery is a devastating outcome for both the patient and family. Neurologic deficits have been categorized into type 1 outcomes, which include death due to stroke/encephalopathy, stroke, coma, or transient ischemic attack (TIA), and type 2 outcomes, which include new deterioration in intellectual function such as confusion, agitation, disorientation, memory deficit, or seizure. A classic prospective study of 2108 CABG patients found that the incidence of type 1 injury was 3.1%, and the incidence of type 2 injury was 3.0%. The patients who experienced the type 1 outcomes had a substantial increase in mortality, length of hospital stay, and need for long-term care.56 Atherosclerotic disease of the ascending aorta is the biggest predictor for type 1 injury, but increased age is also predictive. Most of the type 2 outcomes have been shown to improve in the first 3 months after sur

What is absent in patient with mitral regurgitation A. Isovolumetric relaxation B. Atrial contraction C. Isovolumetric contraction D. Diastasis

C. Mitral Regurgitation or Insufficiency MR, or mitral insufficiency, occurs during systole when blood is ejected back into the left atrium because of an incompetent mitral valve. The causes of MR are considered organic or structural, when the regurgitation is due to a problem with the valve leaflets or chordae; or functional, when insufficiency results from a dilated LV stretching a structurally normal valve. In developed countries, MR is usually caused by degenerative processes, but it can also arise secondary to infective endocarditis, mitral annular calcification, RHD, collagen diseases, and connective tissue disorders such as Marfan syndrome. Functional MR is most often caused by ischemic heart disease, but it can also develop in patients who have idiopathic cardiomyopathy. The presentation of the patient with MR varies depending on the etiology or acuity of the condition.175 Pathophysiology. In patients with MR, there is no isovolumetric contraction phase of systole, because the left atrium (LA) acts as a low-resistance vent for ventricular ejection. Both the LA and the LV are volume-overloaded because the total SV is equivalent to the volume of blood that goes antegrade down the aorta plus the amount of blood that is ejected retrograde into the LA. Consequently, the EF that is calculated by TEE overestimates the actual forward flow. Pressure and volume overload lead to LA dilation. AF develops in approximately 50% of patients who undergo surgery.82 The amount of regurgitation is dynamic, and is based on the size of the mitral orifice, the pressure gradient between the LA and LV, the time available for regurgitant flow, and the compliance of the receiving chamber. The LA and LV compensate for the chronic volume overload by dilating eccentrically (series replication of sarcomeres) and increasing compliance to acco

These have been correlated with improved outcomes in cardiac anesthesia A. 100% O2 B. B-Blocker C. Inhalation anesthetic D. Muscle Relaxant

C. Induction and Intubation. The plan for induction is based on the length and complexity of the proposed procedure, as well as multiple patient-specific considerations, including cardiac pathology, comorbidities, ventricular function, and the airway examination. No combination of induction medications has proven superior in cardiac anesthesia. Rather, the artful skill each practitioner uses to administer preferred drugs to achieve hemodynamic stability and block the stimulating effects of laryngoscopy based on the individual patient's history is most important. Generally, a combination of a sedative, hypnotic, opioid, volatile agent, and muscle relaxant, with or without lidocaine and/or a β-blocker, is used. Achieving hemodynamic stability can be especially challenging when a difficult airway must be secured. After intubation and confirmation of correct ETT placement, the fresh gas flows are adjusted. One hundred percent O2 has been advocated for cardiac surgery to maximize O2 tensions, but a lower inspired concentration may prevent absorption atelectasis and reduce the risk of O2 toxicity.117 Inhalation anesthetics have been correlated with improved outcomes in cardiac anesthesia (most likely because of the preconditioning effect), and they are usually included in the maintenance plan. Patients with severe LV dysfunction may require a primary narcotic technique because all inhalational agents cause some degree of myocardial depression and afterload reduction.

Minimally invasive AV surgery has several demonstrated advantages that include the following except A. decreases in length of ICU and hospital stay B. fewer blood transfusions C. lesser difficulty with ventricular de-airing D. less postoperative narcotic use

C. Minimally Invasive Aortic Valve Replacement The surgical approach for AV surgery has traditionally been through a full median sternotomy incision extending from the sternal notch to the xiphoid process, allowing complete exposure of the heart and ascending aorta. Minimally invasive aortic surgical approaches that are in use today include the hemisternotomy (ministernotomy), right parasternal approach, and right minithoracotomy approach.82,82,196,197 These approaches may be utilized for isolated AVR or in combination with other cardiac surgical procedures.196 Minimally invasive AV surgery has several demonstrated advantages over traditional sternotomy. These include not only improved cosmesis, but also decreases in length of ICU and hospital stay, fewer blood transfusions, less postoperative narcotic use, and less need for postoperative ventilatory support.196-201 The mini AV approaches are also selected for reoperations to avoid a sternotomy that could potentially disrupt patent bypass grafts. Reported disadvantages of the minimally invasive aortic approach include limited surgical exposure, greater difficulty with ventricular de-airing, potential difficulty in placing a coronary sinus catheter for retrograde cardioplegia, and the potential for postoperative femoral wound infection.196-201 Mini-AVR approaches employ CPB. An arterial cannula may be placed directly into the aorta, or arterial access may be obtained from the femoral artery or subclavian artery.82 Venous cannulation may be accessed directly from the right atrium.82 If direct venous cannulation limits surgical exposure, then venous access to the right atrium may be obtained from either the internal jugular or femoral vein. Femoral access obtained for venous or arterial cannulation requires TEE guidance to place the cannula and confirm proper positioning.

This is a percutaneous catheter-based device designed to perform the Alfieri edge-to-edge repair on the mitral valve to reduce MR. A. TAVR B. MAVR C. MitraClip D. CAVClip

C. Percutaneous Mitral Valve Repair The MitraClip system is a percutaneous catheter-based device designed to perform the Alfieri edge-to-edge repair on the mitral valve to reduce MR. The MitraClip system is the most common percutaneous mitral valve repair technique used today to treat degenerative and functional MR.179,227,234-237 More than 20,000 procedures have been performed worldwide since Alfieri first performed it in 1991.238 The MitraClip system was CE marked in 2008 and Food and Drug Administration (FDA) approved in 2013 for symptomatic patients with severe degenerative MR who are deemed too high risk for surgery.234,236 The MitraClip system using the Alfieri edge-to-edge repair technique is a transcatheter valve procedure intended to reduce the degree of MR by delivering a clip to help secure and suture the free edge of the anterior mitral leaflet to the free edge of the posterior leaflet at the site of regurgitation if there is sufficient central leaflet surface to allow grasping by the device clip.237 The technique results in the creation of a double-orifice mitral valve (resembling a figure eight) from a central suture that connects the opposing leaflets.227,235 A femoral venous or transseptal approach is used, and the procedure is performed under the guidance of TEE and fluoroscopy.237 A general anesthetic is usually administered for the MitraClip procedure because continuous TEE assessment is required; however, the use of conscious sedation has also been reported.227,236,237,239 Results thus far for the MitraClip procedure have shown a reduction in MR (less than 2+) in the majority of patients, low rates of morbidity and mortality, and reduced hospital length of stay compared with traditional mitral valve surgical repair.227,234,237,239 Not only is the percutaneous mitral valve repair technique evolving,

Coumadin not required unless patient is in atrial fibrillation. At age 40, 50% chance of lasting 15 years, but generally less durable if younger and more durable if older at age of implantation. Straightforward, relatively low risk A. Valve Repair B. Mechanical valve replacement C. Bioprosthetic valve replacement D. Allograft replacement E. Ross procedure

C. Replacement With a Bioprosthetic (Tissue) Valve

This induction agent causes less myocardial depression than propofol; therefore it may be preferable for use in patients who have reduced left ventricular function A. Propofol B. Ketamine C. Etomidate D. Dexmedetomidine

C. Sedation. Sedation prior to induction can be accomplished with low doses (1-4 mg) of midazolam. Caution is advised because the combination of a benzodiazepine and fentanyl-type drugs reduces systemic vascular resistance (SVR) and causes myocardial depression, leading to hypotension. Sedation for transport to the ICU is often facilitated with infusions of propofol or dexmedetomidine. Induction Agents. Induction of anesthesia can be accomplished with any of the agents alone or in combination with narcotics, volatile agents, or benzodiazepines. Etomidate causes less myocardial depression than propofol; therefore it may be preferable for use in patients who have reduced left ventricular function. The significance of the adrenal suppression caused by etomidate has been the subject of much debate. A large review of studies involving single-dose etomidate induction versus other standard induction agents showed an increase in adrenal insufficiency in critically ill patients.113 However, a 2015 study of patients having cardiac surgery concluded that the adrenal suppression caused by etomidate lasted less than 24 hours and had no significant impact on outcome. Furthermore, etomidate provided more stable hemodynamic parameters when used for induction of anesthesia as compared to propofol in patients with poor LV function.114 If adrenal insufficiency is suspected, a dose of a steroid such as hydrocortisone (100 mg) may be administered. Etomidate and propofol may cause pain with injection, but this can be blunted by diluting the drug and giving it slowly and/or by administering IV lidocaine or narcotic prophylactically. Muscle Relaxants. Muscle relaxants are needed to facilitate tracheal intubation, to prevent movement during cannulation, and to attenuate shivering and skeletal muscle contraction from defibrillation. Most nond

This is the most common valvular defect requiring surgical intervention A. Mitral regurgitation B. Mitral stenosis C. Aortic stenosis D. Aortic regurgitation

C. Valvular Heart Disease and Valve Surgery Rheumatic heart disease (RHD) is still the primary cause of valvular disease worldwide. However, in industrialized countries like the United States, its prevalence has decreased, and degenerative heart disease, which correlates closely with advanced age, predominates. It is estimated that 2.5% of the overall US population has VHD, but prevalence rises dramatically with increasing age, reaching 13.2% after the age of 75.159-161 Infective endocarditis is also an important cause of valvular disease, and a condition that can be exceptionally challenging for both the surgeon and the anesthetist. The proportion of cardiac surgeries that include valvular procedures has doubled over the past two decades. Currently, 20% of cardiac surgeries involve valve repair or replacement, and a significant proportion of these cases will include multiple lesions or concurrent myocardial revascularization. AS is the most common valvular defect requiring surgical intervention, followed by MR, AR, and finally, mitral stenosis (MS). Right-sided valvular disease occurs much less frequently.160,162,163 Often, multiple lesions are present, and a valve may exhibit both stenosis and regurgitation. In this condition, usually one problem predominates, and management is dictated by the pathology causing the majority of the patient's symptoms. VHD causes abnormalities in the pressure and volume-loading conditions of the heart that result in structural and functional changes. Management requires a clear understanding of the anatomy, pathophysiology, and natural history of each lesion, as discussed in Chapter 25. Echocardiography is an invaluable tool in the diagnosis and management of VHD. Three factors determine valvular flow: valve area, the pressure gradient across the valve, and the duration of flow in syst

Which of the following are the last resorts for ventricular support for an inability to separate from CPB A. TEE B. Milrinone C. IABP D. ECMO E. VAD

D & E Separation From CPB. The perfusionist uses a clamp to gradually occlude the venous return to facilitate filling of the right ventricle. The right ventricle moves volume through the pulmonary system and into the LV. As the beating heart continues to fill, ejection resumes, and arterial pressure rises. Then the perfusionist gradually decreases CPB flow. Volume (preload) can be added through the arterial pump line until loading conditions are optimized. Once adequate volume has been supplied through the in situ arterial cannula, the line is clamped, and the time of separation from CPB is recorded. The immediate postbypass period demands close attention because hemodynamic instability and cardiovascular collapse may occur. If a radial A-line is present, the practitioner must be aware of the potential discrepancy between the radial and aortic pressures.99 If a PAC was pulled back during the procedure and is now in the right ventricle, it can be repositioned into the PA. If pulmonary pressures rise precipitously with concurrently falling arterial pressures, this may indicate severely decreased ventricular function and an inability to separate from CPB. If the patient fails separation despite significant efforts at support, CPB can be reinstituted and the situation reevaluated, focusing on potentially reversible causes of failure. TEE is an invaluable tool to assist in diagnosis and guide management. Visual inspection of the operative field may reveal a surgically correctable problem, such as a kinked bypass graft. If, however, no obvious anatomic problem is identified, a period of resting perfusion on CPB will help resolve the cardiac stunning that commonly occurs after cardiac surgery. Pharmacologic inotropic or vasopressor support is initiated or increased. If pharmacologic support is insufficient for separation from

Which of the following should be decreased in the management of patients with aortic insufficiency A. Preload B. Compliance C. Heart rate D. SVR

D.

Which of the following should be increased in patients with mitral regurgitation A. SVR B. PVR C. Preload in volume overload D. Hear rate

D.

Coronary perfusion pressure (CPP) is autoregulated between a mean arterial pressure (MAP) of A. 30-110 mmHg B. 40-120 mmHg C. 50-130 mmHg D. 60-140 mmHg

D. Key Physiologic Principles Appropriate management of the cardiac surgical patient begins with a comprehensive understanding of normal cardiac anatomy, physiology, pharmacology, and monitoring, as well as the pathophysiologic response to disease. The reader is advised to review the excellent discussions of these topics found in Chapters 13, 17, 20 and 25 as background for the information presented in this chapter. There are certain key principles that apply to most cardiac surgical patients. An imbalance in myocardial oxygen (O2) supply and demand, often as a result of CAD, leads to ischemia or infarction. The abnormal pressure and volume loads caused by stenotic and regurgitant valves likewise cause the ventricle to compensate by altering its structure, function, and neurohormonal balance. As a result of these imbalances, the left ventricle (LV) hypertrophies by thickening or dilating. Although each disease starts with a different etiology and pathophysiologic process, with progression of the disease, the limits of compensation are reached, and severe decompensated heart failure then ensues. Myocardial Oxygen Supply and Demand Myocardial injury, or infarction, is the most frequent complication following cardiac and major vascular surgery, as well as the primary cause of hospital morbidity and mortality.5 Clearly, optimizing the balance between myocardial O2 supply and demand is of paramount importance (Fig. 26.1). Coronary perfusion pressure (CPP) is equal to the aortic diastolic blood pressure (BP) minus the left ventricular end-diastolic pressure (LVEDP) divided by the coronary vascular resistance. Normally, CPP is autoregulated between a mean arterial pressure (MAP) of 60 to 140 mm Hg. The heart alters the coronary vascular resistance based on the local metabolic need of the myocardium. MAP is therefore the most

An ACT of more than ____ seconds is necessary before CPB is initiated A. 100 B. 200 C. 300 D. 400

D. Anticoagulation Systemic anticoagulation is always essential prior to cannulation and initiation of CPB. The absence of proper anticoagulation can cause clots to form in the pump, which can lead to serious neurologic injury or death. Heparin, derived from porcine intestinal mucosa or bovine lung, is the preferred anticoagulant for cardiac surgery. It is a mucopolysaccharide that potentiates circulating antithrombin (AT III) by binding to AT III and thrombin. Heparin increases the inhibitory effect of AT III on the procoagulant effect of thrombin by binding to it by one thousand-fold. Heparin increases the speed of the reaction between AT III and multiple clotting factors, including factors II, IX, X, XI, XII, and XIII. The standard cardiac dosage is 300 to 400 units/kg, preferably administered through a central venous line. Adequate anticoagulation is most commonly measured with point-of-care testing that includes activated clotting times (ACT) or heparin concentration assays (Hepcon). A baseline ACT is obtained sometime prior to heparin administration. The normal value is approximately 80 to 120 seconds. The ACT is measured 3 to 5 minutes after heparin administration. An ACT of more than 400 seconds (or more than 480 seconds, in some centers) is necessary before CPB is initiated. The lower ACT limit of 400 seconds was determined in 1978 using monkeys on CPB. This level prevented the appearance of fibrin monomers in the CPB circuit.39 A heparin concentration monitor such as Hepcon HMS Plus (Medtronic, Inc., Minneapolis, MN) can be used in place of, or in addition to, the ACT measure. The Hepcon generates a heparin dose response (HDR) curve that can then be used to calculate the most appropriate dose of heparin to initiate CPB and maintain an adequate level of anticoagulation during bypass. The amount of protamine ne

Which valvular pathology causes a bounding pulse, a wide pulse pressure (systolic-diastolic pressure), and an arterial waveform with a rapid rise in systolic pressure and a low dicrotic notch. Sometimes a double systolic peak called pulsus bisferiens can be seen on the A-line. A. Mitral regurgitation B. Mitral stenosis C. Aortic stenosis D. Aortic regurgitation

D. Aortic Insufficiency or Regurgitation AI, or AR, occurs when malcoaptation of the AV leaflet or annular dilation allows a portion of the ejected SV to be regurgitated, or flow backward, during diastole from the aorta into the LV. The regurgitant blood flow causes the LV to be volume-overloaded. AI can develop acutely or chronically, and can be caused by a primary disease affecting the valve itself or can be secondary to aortic root dilation. Acute AI results in rapid deterioration, and is most frequently caused by trauma, endocarditis, or aortic dissection. Chronic AI can be tolerated for decades, and has multiple etiologies that include: long-standing calcific degeneration, a congenitally bicuspid AV, rheumatic fever, inflammatory or connective tissue disease, idiopathic aortic root or valve dilation, hypertension-induced aortoannular ectasia, syphilis, Marfan syndrome, or Ehlers-Danlos syndrome.175 Pathophysiology. The increased LVEDV causes increased diastolic wall tension that leads to a pattern of LV enlargement known as eccentric hypertrophy, whereby the sarcomeres replicate in series. By virtue of the Frank-Starling mechanism, the increased preload results in a large SV that in turn rapidly raises aortic systolic pressure. Diastolic run-off is rapid as well because blood can progress forward down the aorta or retrograde through an incompetent AV back into the LV. The rapid systolic ejection and diastolic run-off causes a bounding pulse, a wide pulse pressure (systolic-diastolic pressure), and an arterial waveform with a rapid rise in systolic pressure and a low dicrotic notch. Sometimes a double systolic peak called pulsus bisferiens can be seen on the A-line. The magnitude of the regurgitant volume is directly proportional to regurgitant orifice size, diastolic time, and SVR. Ventricular compliance is incre

Advantages of the robotic system over the thorascopic video-assisted approach to mitral valve repair include the following except A. reduction in surgeon tremor B. increased mobility with instrumentation C. three-dimensional vision D. shorter cross-clamp times

D. CPB Cannulation and Cardioplegia. Minimally invasive mitral valve surgery employs CPB. CPB cannulation is usually obtained from the femoral artery and vein under TEE guidance to confirm placement.82 Complications of femoral CPB cannulation include retrograde aortic dissection, limb ischemia, and chest wall hemorrhage.190 If additional venous drainage is needed, the surgeon can perform SVC cannulation by passing a wire through a 16-gauge right internal jugular catheter using the Seldinger technique. The 16-gauge catheter is often placed by the anesthetist after induction and then later prepped into the surgical field. An alternative is cannulating the SVC directly from the surgical field. The anesthetist may also access the right internal jugular vein for placement of a specialized catheter that allows delivery of percutaneous retrograde cardioplegia into the coronary sinus (Fig. 26.19). Before placement of the percutaneous coronary sinus catheter, 70 to 100 units/kg of heparin is usually administered to avoid coronary sinus thrombus. Placement of the coronary sinus catheter by the anesthetist is performed under fluoroscopy and/or TEE guidance, or it may be placed directly by the surgeon through the surgical incision.82 Proper positioning of the retrograde cannula in the coronary sinus can occasionally be quite challenging. If right internal jugular access is obtained for surgical CPB purposes, the left internal jugular vein will have to be accessed by the anesthetist for the administration of central IV medication. Antegrade cardioplegia may be delivered to the aortic root by an aortic cannula inserted into the ascending aorta by the surgeon through a stab or thoracotomy incision.186 Administration of antegrade cardioplegia also can be delivered by an endoaortic occlusion cannula that is advanced through a second op

Which of the following is an absolute contraindication for pulmonary artery catheter displacement A. RBBB B. LBBB C. Inability to use right IJ D. Pacemaker leads placed 5 weeks ago

D. Central Venous Access. Central venous access is mandatory in adult cardiac surgery for volume resuscitation and administration of vasoactive medications. In most cases, central access is obtained after the induction of anesthesia. However, it may be prudent to place the central line prior to induction if the patient is hemodynamically unstable prior to induction or likely to decompensate on induction. Occasionally, preinduction central access is obtained because of inadequate peripheral access. The right internal jugular vein is the preferred cannulation site because it is relatively easy to access and provides a straight, short course to the right atrium. If the left internal jugular vein is used, the anesthetist must be careful to avoid the thoracic duct and the left brachiocephalic vein, which crosses the internal jugular vein at a right angle. Some providers prefer to use a short introducer on the left for this reason. Catheters placed in the external jugular or subclavian vein, especially on the left, are prone to kinking during chest wall retraction. The use of ultrasound to guide placement is becoming increasingly common, especially if the patient has had prior neck surgery, has carotid atherosclerosis, or has been anticoagulated prior to surgery. Studies suggest decreased rates of infection and complications when ultrasound is used.101 A PAC is frequently placed instead of a central venous pressure (CVP) monitor when more hemodynamic information is desired. Although considered an extended monitor, the PAC may be placed in order to measure intracardiac pressures (Table 26.7) and CO using thermodilution. The information obtained can then be used to derive several other hemodynamic parameters to assist patient management (Table 26.8). Generally, a PAC is preferred in patients undergoing complex surgery in which

Which of the following drugs should be continued on the day of surgery A. Lisinopril B. Warfarin C. Clopidogrel D. Metroprolol

D. Management of Preoperative Medications. Cardiac surgical patients are likely to be on multiple medications to manage their primary disease and comorbidities. As a general rule, the patient should receive medicines that are used to manage his or her medical conditions on the morning of surgery with a sip of water.82 However, a few medications merit further discussion. Clinical research has demonstrated the benefit of perioperative β-blocker therapy to improve hemodynamic stability, decrease dysrhythmias, and reduce morbidity and mortality.83-85 Unless there is a contraindication, patients having coronary surgery should receive β-blockers preoperatively, and patients who are on β-blockers for any reason preoperatively should have them continued in the perioperative period.30,80,81,86 Medical management of heart failure includes the use of several drugs (see Fig. 26.5). Controversy has arisen regarding administering ACEIs and angiotensin receptor blockers (ARBs) within 10 hours prior to induction. Some studies report moderate to profound intraoperative hypotension in patients who have received these drugs,87-89 whereas other studies claim that these medications actually improve hemodynamic stability.30,90,91 It is generally agreed that ACEIs and ARBs in patients on chronic therapy should be reinstituted in the postoperative period if the patient is stable, but the safety of preoperative administration remains uncertain.80,80,81 ACEIs and ARBs have also been implicated as a cause of postoperative vasoplegic syndrome. Patients who are resistant to phenylephrine may exhibit increased responsiveness to small doses of norepinephrine (16 mcg) or vasopressin (1 unit).92 (See Chapter 13 for a further discussion of vasoplegic syndrome.) With regard to medications that affect coagulation, most institutions follow the STS reco

This is the induction agent of choice during mediastinal re-exploration of a cardiac tamponade A. Propofol B. Etomidate C. Dexmedetomidine D. Ketamine

D. Postoperative Bleeding and Cardiac Tamponade Bleeding is not uncommon after cardiac surgery, and in approximately 4% to 5% of cases, patients must return to surgery to have the chest re-explored for persistent bleeding, tamponade, or unexplained hemodynamic instability that is presumed to be tamponade.8 Cardiac tamponade is reported to occur in up to 8.8% of patients after cardiac surgery, depending on the complexity of the surgical procedure and the presence of comorbidities.132,133 Cardiac tamponade occurs when fluid trapped in the pericardial sac increases in volume enough to cause myocardial compression.8 The compression then limits diastolic filling of the heart, thus reducing SV and CO.8 Severe hypotension, myocardial ischemia, and eventually cardiac arrest can ensue once venous pressures fall below pericardial pressures, causing ventricular collapse.8 Pericardiocentesis, subxiphoid drainage, or mediastinal exploration must occur without delay once decompensated cardiac tamponade occurs, to prevent complete cardiac collapse.134,135 Cardiac tamponade can occur due to nonloculated pericardial effusions, which can be caused by many medical conditions such as malignancies, viral pericarditis, uremia, and bacterial infections.135 Coagulopathy, postoperative bleeding, and/or localized compression from blood that is in contact with the heart may all contribute to tamponade that occurs in the period immediately following cardiac surgery.8,82,133 Cardiac tamponade should be suspected after cardiac surgery if there is a sudden dramatic decrease in chest tube drainage with concomitant hypotension, tachycardia, increased and equalizing filling pressures, and decreased cardiac indices, despite increased inotropic and vasopressor support.8,133 Pulsus paradoxus, electrical alternans, and the Beck triad are all considered cla

Which of the following is not appropriate during the preincision period A. OGT placement B. TEE probe insertion C.Insulin IV therapy for bS 190 D. K+ replacement for K of 3

D. Preincision Period. The preincision period is generally not very stimulating, so the anesthetic level can often be reduced. Occasional boluses of phenylephrine may be required for hemodynamic support. A second peripheral intravenous (PIV) line is inserted if necessary, and central access obtained. The stomach is decompressed with an oral gastric (OG) tube before placement of the TEE probe. A generous amount of water-soluble jelly is placed in the oropharynx to facilitate placement of the probe, and the probe is unlocked prior to insertion. Many institutions use a mouth guard to protect the patient and the probe. Probe placement is facilitated by lifting the tongue and jaw manually or displacing them with the aid of a laryngoscope. Once the probe is in the posterior pharynx, turning the head slightly to the right helps it to advance smoothly to the 30-cm marking. To prevent damage to the mouth, pharynx, or esophagus, force is never applied when placing the TEE probe. The TEE examination is completed by a credentialed provider. If the TEE cannot be placed, the surgeon can perform a transthoracic echocardiogram using a sterile glove filled with sterile saline between the probe and the cardiac structures to improve visualization. The urinary catheter (which often incorporates a temperature monitor) is inserted, and a nasopharyngeal temperature probe is placed, if necessary. Next, the patient is carefully positioned, and pressure points are padded. All routine positioning precautions apply, along with some areas of special concern. Brachial plexus injury can occur if the arms are hyperextended or if the chest wall retraction is excessive. Brachial and radial artery or nerve compression can occur if the upper arm is compressed by the ether screen or the post that is sometimes used to support the chest wall retractor durin

Which of the following is usually deferred until after induction unless otherwise necessary A. Peripheral IV B. Deactivation of ICD C. A-line insertion D. Central venous access

D. Preinduction Period. During the preinduction period, the patient is identified and interviewed before entering the OR. The information from the preoperative assessment is reviewed, and the anesthetist confirms that there have been no significant changes in the patient's medical condition, with a particular focus on worsening symptoms and recent infectious illness. The airway is re-examined, and the lungs and heart are auscultated. Medications taken within the last 24 hours are recorded. The patient's willingness to accept blood products is confirmed. The interview also gives the anesthesia provider an opportunity to assess patient anxiety, communicate expectations, and provide emotional support. Once in the OR, areas prone to pressure ischemia like the sacrum and heels may be protected by the application of foam pads. The perioperative management of ICDs and pacemakers, if present, was discussed earlier. External adhesive defibrillator pads are usually placed for patients with deactivated ICDs or a history of recent serious ventricular ectopy, as well as those having minimally invasive surgery or a repeat sternotomy. A time out is performed where the surgeon and patient, together with the nursing, anesthesia, and perfusion teams review the operative plan, needed equipment, and safety checklists. Next, the patient is moved to the OR table, and standard monitors are applied (see Table 26.7). Pulse oximetry volume is adjusted to a level that is loud enough to provide an audible warning to the clinician in case of decreasing O2 saturation while attention is focused on another task. Some centers routinely administer supplemental O2 during the preinduction phase, whereas others use O2 as needed. A large-bore peripheral IV catheter (14 or 16 gauge) is placed, using local anesthesia for patient comfort. Patients with normal

Which should be avoided during separation for cardiopulmonary bypass A. IV magnesium B. IV lidocaine C. PEEP to 30cm H2O D. Temporary pacemaker to DDD

D. Preparation for Separation From CPB. Box 26.4 outlines many of the factors that must be considered in preparation for separation from CPB. The need for possible inotropic or vasopressor support is anticipated, and infusions prepared. Rewarming begins as the surgeon is completing the repair. The process is begun early enough to facilitate slow, gradual warming to an nasopharyngeal or esophageal temperature of 36°C to 37°C.119 During rewarming, the bladder temperature may lag 2°C to 4°C behind the nasopharyngeal or esophageal temperatures.120 Arterial and venous blood gases are normalized before termination of CPB. Potassium levels are addressed if greater than 5.5 mEq/L or less than 4.0 mEq/L, to decrease the incidence of dysrhythmias. If the patient is hyperkalemic, calcium may also be given to counteract the potassium and stabilize the membrane to prevent dysrhythmias. The administration of calcium is controversial. Some clinicians have a low threshold for treating low ionized calcium, given its beneficial positive inotropic effects and its essential role in the coagulation cascade. Other clinicians avoid calcium because it contributes to coronary vasospasm and may exacerbate reperfusion injury. Magnesium (2-4 g IV) is frequently administered prophylactically to minimize dysrhythmias. In a recent meta-analysis, CABG patients who received IV magnesium intraoperatively experienced a significant reduction in postoperative AF.121 Treatment for high glucose levels should continue, but the rate of insulin infusion often can be lowered significantly, especially in a nondiabetic patient after separation from CPB. An adequate circulating blood volume is necessary for separation from CPB. The amount needed varies with the patient's weight, prebypass volume status, ventricular function, and comorbidities. As previously in

This is an innovative, minimally invasive percutaneous procedure for the correction of severe AS. It does not require sternotomy or CPB. A retrograde (transfemoral) approach via the femoral artery or an antegrade (transapical) approach via the left ventricular apex is most commonly used to implant a bioprosthetic valve into the native calcified valve. A. MIDCAB B. TECAB C. PA-CAB D. TAVR

D. Transcatheter Aortic Valve Replacement TAVR or transcatheter aortic valve implantation (TAVI) is an innovative, minimally invasive percutaneous procedure for the correction of severe AS. It does not require sternotomy or CPB. A retrograde (transfemoral) approach via the femoral artery or an antegrade (transapical) approach via the left ventricular apex is most commonly used to implant a bioprosthetic valve into the native calcified valve. Approximately 30% of patients with critical AS are not considered candidates for traditional sternotomy and CPB because of advanced age and the presence of comorbidities making the risk prohibitively high.211-214 Trials in both Europe and the United States have shown the superiority of this technology over standard medical therapy in reducing the 1-year death rate by 20%, as well as improving quality of life.215-218 Over the last decade, TAVR has become a reasonable and standard alternative to surgery for many patients with AS who are considered high-risk surgical candidates.219-221 Several randomized trials such as the Placement of AoRTic TraNscathetER Valves (PARTNER) II Cohort A, the Surgical Replacement and Transcatheter Aortic Valve Implantation trial (SURTAVI), and the United Kingdom TAVI trials are now assessing the effectiveness of TAVI in intermediate risk patients.220

Shed blood can then be returned to the patient in one of two ways. First, the blood can be returned to a portion of the venous reservoir known as the A. Heat exchanger B. Arterial Filter C. Oxygenator D. Main Pump E. Cardiotomy

E. Accessory Pumps and Devices Cardiotomy and Basket Suction. As illustrated in Fig. 26.8, the perfusionist also operates several accessory roller pumps (generally located to the right of the main pump), used to control suction devices and deliver cardioplegia. A surgical assistant helps improve the surgeon's view by aspirating blood from the surgical field using a Yankauer or other suction tip. A "basket" type suction device can be placed in an open cardiac cavity to help drain the blood (see Fig. 26.8). This shed blood can then be returned to the patient in one of two ways. First, the blood can be returned to a portion of the venous reservoir known as the cardiotomy. The cardiotomy portion of the venous reservoir has a separate integrated filter that defoams the blood and removes air and debris that is picked up by the suction tip (pump sucker) used in the surgical field or the vents used to drain the heart. Blood returned via the cardiotomy may contain fat, bone, and other debris. For that reason, some surgeons prefer an alternate method to return this blood, which is using a separate cell-saver reservoir. Cell-saver blood is later centrifuged, washed, and returned to the patient. Research shows that systemic inflammatory markers decrease when shed blood is not returned to the patient undergoing CABG on CPB.36-38 The disadvantage of this approach is that the volume of blood in the pump is reduced, especially if there is significant bleeding. If bleeding is a problem, the cell-saver blood can be washed and returned to the venous reservoir, but this requires time for processing.

True of False The BIS monitor has been shown to reliably prevent recall

False Transesophageal Echocardiography. TEE has become an invaluable source of information about cardiovascular anatomy and function during cardiac surgery. It is the most sensitive clinical monitor for detecting wall motion abnormalities caused by myocardial ischemia. Additional uses include evaluation of: right and left systolic and diastolic ventricular function; valvular area, function, and pathology; intravascular volume status; intracardiac air or pulmonary embolism; aortic atheroma and dissection; pericardial effusions or tamponade; and cannula or catheter placement. Unless there is a contraindication, TEE is recommended for all open chamber procedures and catheter-based valve procedures. TEE should be considered for CABG procedures. Absolute contraindications to TEE include pathologic conditions of the esophagus, including strictures, diverticula, tumors, traumatic interruption, or recent suture lines.104 A comprehensive exam encompasses at least 20 views, but a targeted perioperative exam can be completed using 11 selected views.104,105 The TEE exam is completed before CPB by a credentialed provider to identify baseline pathology and function. This information is communicated to the surgeon and used for comparison after bypass to immediately evaluate the surgical repair(s) and identify new pathology or dysfunction after CPB. Although even an introductory discussion of TEE is beyond the scope of this chapter, a basic understanding of TEE is valuable for nurse anesthetists to help them monitor ventricular function and intravascular volume status. More advanced diagnoses should be made by credentialed providers. The use of other extended monitors is related to personal preference (e.g., bispectral index [BIS] monitor) or case requirement (e.g., spinal fluid pressure in descending thoracic aneurysms [TAs]). The BI

True or False Emergency medications and airway equipment are gathered for transport because transfer to the ICU represents a particularly vulnerable time outside of the OR.

True Chest Closure. When hemostasis has been achieved and the patient is hemodynamically stable, preparations are made for chest closure and transport to the ICU. The lungs are deflated temporarily when the sternum is pulled together to facilitate chest closure and prevent the kinking of bypass grafts, if present. The CO and echocardiogram (if available) are reviewed before and after chest closure because the preload decreases and the afterload increases with chest closure. If the patient becomes unstable, the wires are released, and the situation reevaluated. Patients who have received massive transfusions or require high-dose pharmacologic and/or mechanical support may not tolerate the hemodynamic consequences of chest closure. In this situation, the patient may have the chest left open with a negative pressure wound dressing (V.A.C., KCI, San Antonio, TX, USA) applied. The patient is maintained in the ICU for the next 24 to 48 hours until hemostasis and hemodynamic stability are achieved. Then, the patient is returned to the OR for chest closure. Once the chest is closed, preparations for safe transport to the ICU are initiated. Emergency medications and airway equipment are gathered for transport because transfer to the ICU represents a particularly vulnerable time outside of the OR. The echocardiogram probe is removed at the end of the procedure, and an OG tube is inserted to decompress the stomach. Although some stable patients may be extubated at the end of the procedure, most surgeons prefer that fast-tracking occur in the ICU. Transport. With the numerous monitors, invasive lines, chest tubes, pharmacologic infusions, and requisite airway equipment, moving a patient safely to the ICU can be complicated and hazardous. Most patients are sedated with propofol or dexmedetomidine infusions during transport and init

True or False Despite advances in prevention and treatment, cardiovascular disease (CVD) remains the leading cause of death globally, accounting for 31% of mortality.

True Despite advances in prevention and treatment, cardiovascular disease (CVD) remains the leading cause of death globally, accounting for 31% of mortality. The World Health Organization estimates that CVD will remain the predominant cause of mortality, resulting in 23.6 million deaths by 2030, mostly from coronary artery disease (CAD).1 In the United States, CVD causes 1 of every 2.9 deaths, half of them due to CAD.2 Because of the aging population, degenerative valvular heart disease (VHD) is on the rise. There are currently more than 290,000 heart valve operations performed annually worldwide. That number is expected to triple by 2050, reaching 850,000 annually.3 Both CAD and VHD lead to heart failure, which impacts more than 5 million Americans. The mortality rate for symptomatic patients is a staggering 45%, worse than that of most cancers.4 The Centers for Disease Control and Prevention estimates that $316.6 billion, or $1 out of every $6 in health care costs, is spent on CVD treatment.2 Clearly CVD presents an enormous public health burden. Scientific and medical communities, together with governmental agencies, have worked tirelessly to improve this situation. Consequently, new knowledge about these diseases is accumulating exponentially, and technologic advancements have led to the development of cardiac procedures that were once inconceivable. Percutaneous techniques, hybrid operating rooms (ORs), mechanical assist devices, robotics, and minimally invasive technology now play significant roles in the practice of cardiothoracic anesthesia. The field has become more diverse, exciting, challenging, and rewarding than ever before. Care of these high-risk patients with regard to the complex, ever-evolving surgical procedures may seem intimidating at first. But as Richard Morris, a pioneer in the field of cardioth

True or False What actually constitutes a minimally invasive approach is quite variable. In some cases, only the skin incision is smaller, and the sternotomy is full. In other cases, the approach is robotic and/or endoscopic.

True Minimally Invasive Surgical Approaches Overview Minimally invasive cardiac surgical techniques have evolved considerably in the past two decades. Much of the technology was first developed for other surgical specialties and then adapted to cardiac surgery. The driving force behind the growth has been twofold: first, to reduce the use of CPB, and second, to make the procedures less invasive. As the population ages, the prevalence of comorbidities and aortic atherosclerosis increases. Avoidance of CPB, aortic manipulation, and cross-clamping ideally would prevent some of the known complications. Indeed, TAVR was recently approved for patients with AS who are deemed too high-risk for traditional surgery. Additionally, the public assumes that less is more, so they seek out minimally invasive surgeons on the internet. What actually constitutes a minimally invasive approach is quite variable. In some cases, only the skin incision is smaller, and the sternotomy is full. In other cases, the approach is robotic and/or endoscopic. Fig. 26.15 shows some of the common incisions that are used in minimally invasive surgery. The field is rapidly evolving, but this chapter focuses on the most innovative approaches at the time of its writing.

True or False no single intervention limited the adverse outcomes related to SIRS and CPB.

True Physiologic Effects of Cardiopulmonary Bypass Despite improvements in perfusion, anesthesia, and cardiac surgery, patients are still at risk for developing organ dysfunction after CPB. CPB causes a systemic inflammatory response syndrome (SIRS) that potentially can impact every organ system of the body. The inflammatory response to CPB can be mild and asymptomatic, or result in multiple organ dysfunction syndrome. SIRS and ischemia related to emboli or hypoperfusion within an organ seem to be the common pathophysiologic mechanisms for organ dysfunction after CPB. The heart, brain, lungs, kidneys, and gastrointestinal system are all at risk for negative impact or trauma. Finally, hemostasis is impaired as related to CPB. Systemic Inflammatory Response. SIRS is thought to be activated as a result of CPB when the blood is exposed to the foreign surfaces of the CPB machine. Ischemia-reperfusion injury or embolization may occur and cause the release of endotoxins, primarily from splanchnic hypoperfusion. Endothelial damage occurs, and the cellular immune response is activated, as are the complement and coagulation cascades. When bypass is initiated, the body exhibits a marked stress response: cortisol, catecholamines, arginine vasopressin, and angiotensin levels are elevated. Large amounts of O2-free radicals are also produced. More research is needed into protective strategies. A 2014 critical review of the literature regarding attenuating the systemic inflammatory response to CPB in adults showed that no single intervention limited the adverse outcomes related to SIRS and CPB. The most promising interventions were those that targeted multiple inflammatory pathways. These interventions included surgical/perioperative measures, perfusion-related measures, and pharmacologic measures. The most widely-studied intervention

True or False Prior to induction, the anesthetist should confirm the validity of the patient's type and cross-match, as well as the anticipated blood product availability.

True Preparation for Possible Blood Loss. Because cardiac surgical procedures are associated with significant blood loss, the anesthesia provider must confirm with all patients their willingness to accept blood products. In patients with specific religious beliefs or personal preferences, the permissibility of specific products and/or cell-saver devices should be discussed and documented.51 Prior to induction, the anesthetist should confirm the validity of the patient's type and cross-match, as well as the anticipated blood product availability. This is particularly important in patients who have a positive antibody screen, because it can sometimes take multiple hours to secure cross-matched units. Patients having "re-do" operations should have blood immediately available prior to sternotomy. Psychological Preparation and Preoperative Sedation. Because the cardiac OR is a fast-paced, high-intensity environment, it is easy for the team to become task-oriented, inadvertently overlooking the emotional needs of the patient. Patients facing major surgery are acutely aware of their mortality, and are often apprehensive about the procedure and pain. Concerns about the future of loved ones, especially those who are dependent upon them for support, are common. The preoperative interview provides a unique opportunity to gather needed data and share information about what to expect. Ideally, the provider caring for the patient during the surgery should conduct the preoperative interview so that he/she can establish rapport and address the patient's and family's concerns. Patients who are mentally prepared will be more calm, confident, and cooperative in the OR and in the intensive care unit (ICU). Preoperative sedation is selected on an individual basis taking into consideration the patient's functional status and anxiety level.