Nagelhout Ch. 26 Cardiac Surgery

Why is pt shivering bad?

- Shivering can be induced because of hypothermia, even slight shivering greatly increases O2 consumption manifesting in low O2 reading on the venous cannula gas sensor - Pt must be reparalyzed, PNS should be checked more frequently to ensure TOF is completely suppressed

Why do we care about the bypass grafts being the perfect length?

- Short LITA grafts can be overstretched with lung inflation - Short SVG grafts can be overstretched when the heart is filled - Long grafts kink when the chest is closed

What are hemodynamic interventions for postop pt with volume dilating heart, poor contractility on TEE, increased PAP, increased LVEDP, decreased BP, decreaesd CI, and decreased EF?

- Showing systolic HF - CPB resumed until heart can rest and improve function, drips started - TEE determines type of failure - LVF- inotropes (epi, dobutamine), afterload decrease with SNP to decrease SVR, Milrinone = increased inotropy, decreases afterload and increases flow through new grafts - RVF- epi, NTG, milrinone, NO and epoprostenol to decrease PVR - If all fails, IABP, ECMO, VAD for mechanical support

What's a hot shot?

- Single terminal dose of warm blood (37C) with glucose, glutamine, aspartate that helps accelerate myocardial recovery from global ischemia - Given right before aortic cross clamp removed

What is the debate regarding calcium admin at CPB end?

- Some treat low ionized calcium because of its positive inotropic effects and its role in coag cascade - Others avoid it d/t risk of coronary vasospasm and potential to exacerbate reperfusion injury

Describe the sequence of events for cannulation and CPB

- Sternotomy - Dissection and/ harvesting for CABG - Pericardium opening - Heparinization- check ACT > 400-480s - Aortic cannula- want SBP 90-100mmHg or MAP < 70 - Venous cannula - Cardioplegia cath - Pull PAC back 2-3 cm - Venous clamp released then aortic clamp removed - CPB full flow - Aortic clamp placed - Anterograde/retrograde cardioplegia begins - Surgery- check ABG q 30 min - Gentle lung reinflation to help deair the heart - Surgeon may give a hot shot - Perfusionist decreases CPB flow for aortic cross clamp removal - Check heart for air - Resume ventilation - Monitors, gas machine back on, check echo for LV function - Clamp venous cannula to allow R heart to fill - Aortic cannula clamped - Decannulation- blood given back to pt - Blood left sent to cell saver for wash/reinfusion - Protamine for heparin reversal - echo, chest closure, echo

Which layer of the heart is most at risk for ischemia? Why?

- Subendocardium- inner 1/3 of the heart because it is the deepest layer, closest to the LV cavity and thus most affected by increased LVEDP during peak systole - If LVEDP is high, driving pressure gradient for coronary perfusion decreases - During systole, myofibril tension compresses subendocardial vessels, limiting perfusion - Both increased HR and increased LVEDP elevate ischemia risk for the subendocardium by reducing myocardial blood supply and increasing demand

How does Law of Laplace relate to systolic HF?

- Systolic dysfunction = HEFrEF = eccentric LVH - MI or too much volume causes supply ischemia- increased LV compliance/dilation + thin walls series sarcomeres decreased contractions - Decreased EF < 40% - LV dilates to hold more volume and preserve SV but leads to ineffective contraction and decreased EF

IABP inflation should be timed with?

- The dicrotic notch of the arterial waveform so that the balloon inflates once the AV closes and diastole begins - The inflated balloon (during diastole) will act as a seal within the proximal descending aorta, increasing pressure and displacing blood flow antegrade toward the coronary arteries- enhanced CA perfusion and myocardial O2 delivery - Deflation of the balloon occurs immediately before the onset of systole at the beginning of R wave of the ECG - Deflation creates a vacuum effect that lowers the aortic pressure to reduce afterload, improves ventricular ejection, relieves ventricular workload, and reduces myocardial O2 demand - IABP is synchronized with either the ECG or arterial pressure waveform

What is the goal of myocardial preservation during CPB and how is it achieved?

- To protect the heart and brain from injury by decreasing metabolic rate, O2 consumption, and decreasing excitatory NT release - Achieved via systemic hypothermia and cold cardioplegia after aortic clamp is placed - Some may also pack ice around the heart

Who would likely need a PAC?

- Useful for thermodilution and measuring intracardiac pressures - Mainly for pts who are frail, comorobidities, undergoing complex surgeries or who have history of PHTN, poor LV/RV function

Discuss characteristics of pts with systolic HF

- Usually 50-70 years - Males - LVEF < 40% - LV dilated with eccentric LVH - CXR = congestion + cardiomegaly - HTN = ++ - DM = ++ - Previous MI = +++ - Obesity = + - COPD = 0 - Sleep apnea = ++ - Dialysis = 0 - afib = usually persistent - Gallop = 3rd heart sound

State 3 complications that may develop with hypertrophic cardiomyopathy

- Ventricular tachydysrhythmias- can lead to sudden cardiac death (young athletes) - Progressive DHF, despite normal LV systolic function - Afib- predisposition to stroke

What are signs of cardiac tamponade postop?

-Occurs when fluid (blood) is trapped in the pericardial sac causing myocardial compression which does not allow the heart to fill- leads to decreased SV, CO, BP and leads to MI and death if untreated - Bleeding is common after cardiac surgery, and tamponade can occur in 8.8% of cases if bleeding trapped in pericardial sac Sx usually immediately postop: - Sudden decrease in chest tube output - Sudden decrease in BP, CI, increased HR, PAP, CVP despite inotropes and vasopressors - Pulsus paradoxus, electrical alterans - Beck's triad- muffled heart sounds, JVD, hypotension

What is the critical aortic valve stenosis?

0.7 cm2 or less

What is severe stenosis?

1 cm2 or less

What is normal RA pressure?

1-10 mmHg

When rewarming begins it should be done gradually to maintain a temp gradient greater than what in the heat exchanger?

10C - Temp gradients between the arterial outlet and venous inflow on the oxygenator during CPB coiling or rewarming should not exceed 10C to avoid generations of gaseous emboli - Slight hyperthermia in pts with cerebral ischemia or infarction may excarebate any damage - Limit blood temp to < 37 to avoid cerebral hyperthermia

To achieve deep hypothermia, pt must be cooled to a temp of what?

14.1 C to 20C

Normal RV pressure?

15-30/0-8 mmHg

Normal PA pressure?

15-30/5-15 mmHg Mean = 10-20 mmHg

What is the normal aortic valve area?

2-4 cm2

Mitral valve stenosis symptoms don't appear until the valve area is less than what?

2.5 cm2 or less

Normal CI?

2.8-4.2L/min/m2

Normal SI?

30-65 ml/beat/m2

What is the arrhythmia a/w MS?

33% of pts develop AF - Rapid HR is the primary cause of HD instability, rather than loss of atrial kick - Pts with MS + AF have an embolic stroke rate of 7-15% - Long term anticoags and HR control are important in the mgmt of MS

Normal LA pressure?

4-12 mmHg

Normal LVEDP?

4-12 mmHg

What is normal mitral valve area?

4-5 cm2

Normal CO?

4-8 L/min

Pts with severe AS have a mean gradient pressure of what?

40 mmHg

Normal PCWP?

5-15 mmHg

Pts with MR who undergo surgery develop what type of arrhythmia?

50% of pts who undergo surgery develop AF

Normal SV?

50-110 mL/beat

What is the maximum ischemic time for a donor heart?

< 4 hrs

What is the prime? Who cares?

- 1-2L of crystalloid used to fill and de air the CPB machine before venous drainage - Made of isotonic balanced solutions - Perfusionist may add certain meds during the case (mannitol, epi, heparin, bicarb, colloid, blood) to prime depending on pt need/surgeons request

Why should we conserve blood in cardiac surgery?

- 15% of nation's blood products used in cardiac surgery - PRBCs are expensive - Risks from blood transfusions - Transfusions in cardiac surgery a/w short and long-term survival - Dose related increase in PRBC to postop infection

Which ECG settings best determine intraop ischemia? Where should the brown lead be placed during heart surgery?

- 5 lead ECG with ST analysis on- high sensitivity and specificity for ischemia - Best leads for MI = V4 > V3> V5 - Place brown lead 4th ICS MCL to correlate with V4- most sensitive location for ischemia detection - In CV surgery, V lead may be placed more posteriorly and in the 5th ICS because chest will be open- use leads 2 and V5, have ST analysis on

When does the LV receive the majority of its blood flow? What decreases this perfusion time?

- 80% of BF to LV occurs during diastole when myofibril tension is low which allows for better coronary perfusion to the innermost subendocardial layer (better CPP driving pressure) - As HR increases diastolic time decreases which reduces LV perfusion time

What is the effect of CPB on the kidneys?

- AKI = major complication of heart surgery and a/w increased risk of M&M -Reduced pump time and maintaining CO and volume status reduce risks of ARF

What hormones does the heart secrete and why does it do this?

- ANP- released from the atria d/t volume overload - BNP released from ventricles d/t increased wall stress - Both hormones released during heart stress, CHF exacerbations - Both hormones cause diuresis, naturesis, and vasodilation to reduce preload, afterload, and overall demand

Discuss preop considerations for ASA/plavix

- ASA preop increases risk of bleeding so can be held for elective heart surgery in pts without CAD - With PCI wait DES x1 year, BMS 4-6 weeks for elective surgery, can stop DAPT - High risk pt on DAPT, ASA continued, hold or bridge antiplt with cangrelor drip and resume postop

How are VADs categorized?

- According to type of BF (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 - Source of driving power- pneumatic or electric

What are 3 preop factors linked to bleeding and blood transfusions?

- Age > 70 - Low RBC volume preop (anemia, small size) - Urgent or complex sx with prolonged CPB time

What will starting inotropes on a pt with CI 1.9L/min at baseline cause?

- Anesthesia decreases O2 demand and this CI will be sufficient to meet the body's demands - If started on inotropes, it may increase their myocardial demand and increase risk for ischemia

What is the treatment for cardiac tamponade?

- Back to OR for percardiocentesis, subxiphoid drainage, mediastinal exploration - Avoid or decrease anesthetics, sedatives, narcs until tamponade fixed, heart is already depressed - Use ketamine- sympathomimetic preservation of HR, BP, myocardial function - Don't depress HR because its a compensatory mechanism to support systemic perfusion

Why are temporary pacing wires placed and what setting should they be in?

- Because intrinsic conduction may be temporarily or permanently altered - SR at 80-90 = balance between adequate cardiac performance and myocardial O2 demand - AV pacing is best for bradycardic rhythms- atrial kick helps maintain better CO, 2V wires placed instead of A wire - Once wires are placed, should be set at rate of 80 bpm in asynchronous mode (VOO or DOO) to avoid accidental electrocautery induced pacemaker inhibitor - If pt has an intrinsic rhythm, PM should be placed in DDD or VVI to reduce risk of R on T phenomenon - Chronic afib pts should have only v wires- unable to conduct from a wires

What is SIRS and why is it a/w CPB?

- Begins with exposure of blood to foreign machine parts as well as other risks - Increased SNS response to bypass initation causing increased cortisol, vasopressin, angiotensin, and catecholamine secretion, splanchnic hypoperfusion causing endotoxin release and O2 free radical production from SIRS response - May have no s/s to multisystem organ dysfunction

Explain the different aortic valves

- Bioprosthetic tissue valve- most popular, does not require anticoags, shorter life span - For 50 yo pts, valve usually lasts 15 years -Tissue heart valves tend to last longer as the recipient's age increases - Aortic homograft (cadaver valve) - Ross procedure- uses native pulmonic valve - Mechanical valve- may last a lifetime but requires anticoags (warfarin) and antibiotic prophylaxis agains endocarditis

What is the effect of CPB on coagulation?

- Blood contact with CPB activates intrinsic and extrinsic coag pathways and fibrinolysis - Plts and coag factors get diluted by pump prime and denatured by CPB mechanical trauma from pumps

What is myocardial stunning?

- Brief periods of ischemia < 20 min causing reversible contractile dysfunction that can last for 12-24 hrs and may require inotropic support after CPB - Myocardial stunning does not lead to necrosis

What is ischemic preconditioning and how can CRNAs induce this state?

- Brief periods of ischemia improve tolerance to longer subsequent ischemic periods - Volatile agents induce anesthetic preconditioning and can reduce myocardial damage and death during cardiac and non-cardiac surgery -Volatile agents and other anesthetics (opiates, BB, lidocaine) can reduce infarct severity a/w activation of receptors that trigger ischemic preconditioning

Where should the arterial flow and MAP maintained while on CPB? For what patient population should this range be increased and why?

- CPB = nonpulsatile systemic BF - Aims to maintain normal cardiac index 2.0-2.5 L/min/m2 arterial flow and MAP at least 50-70 mmHg - MAP should be increased for pts with known carotid atherosclerosis, stenosis, or old age to ensure cerebral perfusion

Discuss use of etomidate and side effects

- Can cause adrenal suppression but good for pts with decreased LV function d/t more stable hemodynamics - adrenal suppression lasted only 24 hrs- can be avoided with admin of 100mg hydrocortisone

How does CPB negatively impact the heart??

- Can range from asymptomatic, slightly elevate enzymes, to high enzymes with reduced heart function in which heart cannot come off bypass - Elevated cardiac enzymes after CPB increases risk of death

What is anterograde cardioplegia?

- Cardioplegia delivered down the coronary arteries - Catheter inserted into aortic root proximal to the aortic clamp and flow is antegrade down the root into the coronary arteries - May be insufficient if substantial CAD or severe AR causes cardioplegia accumulation in LV ( can lead to increased LVEDP, increased risk of MI- why patent LV vent is important

What is retrograde cardioplegia?

- Cardioplegia delivered via coronary sinus (posterior side of heart) to cardiac veins If aortic root will be opened for surgery or AV repair, coronary ostia can be directly cannulated - Direct insertion into the coronary sinus requires lifting the heart which can cause arrhythmias and hypotension - Synchronized cardioversion may be required to correct arrhythmia (afib usually) and increased BP - Retrograde cardioplegia begins via the cardiac veins, protecting areas distal to the occluded vessels - Useful for pts with CAD blockages

What is the leading cause of death globally?

- Cardiovascular disease- CAD - Valvular heart disease d/t aging population - CVD and VHD both lead to heart failure

What is the purpose of the LV vent?

- Catheter in LV through R pulmonary vein to drain blood accumulating in LV from bronchial arteries (arise from aorta or intercostal arteries), thebesian arteries (coronary veins that ddrain into the heart -> physiologic shunt, or from cardioplegia/blood accumulation from AR - LV distension can increase LVEDP and increase risk of MI - Vent prevents LV distension by suctioning blood out and draining into the cardiotomy reservoir

After chest closure pt becomes hypotensive and SpO2 drops. TEE shows LV difficulty ejecting. What is the issue, what should you do?

- Chest closure decreases preload and increases afterload= decreased CO, decreased BP patient can quickly become unstable - Wires may need to be released, check TEE to try and ID problem and start appropriate drips - If pt received a lot of blood products or are requiring a lot of medication/ mechanical support, may not tolerate chest closure- stay open in ICU for 24-48 hrs

Why are the venous cannulation sites different for CABG and AVR vs open cavity procedures of the MV, TV, PV, PFO?

- Closed heart procedures for CABG and AVR can be done with some blood inside the heart- SVC and RA venous cannulation sufficient - Open cardiac procedures need a bloodless field so venous cannula is placed into SVC and IVC- bicaval/ two vessel venous cannulation

What are Type 2 neurologic deficits from CPB?

- Confusion, agitation, seizure, memory deficit- can improve 3 months after surgery

What are hemodynamic interventions for postop pt with preop LVH/ diastolic dysfunction, high LVEDP, HTN with low CO?

- D/t noncompliant LV not holding volume= low CO, diastolic HF risk - Volume dependent, reassess TEE - Give volume- initial bolus may cause HTN even though Co still low - NTG- helps LV relax and accept volume, dilates coronaries - LVH prone to ischemia- keep MAP high and maintain SR, need a kick for 40% LVEDV - Use levo drip if volume optimized and hypotensive still, want MAP to stay high - Pt with septal hypertrophy risk for LVOT obstruction with SAM of MV- want full heart, slow normal HR, increased SVR

How does Law of Laplace relate to dystolic HF?

- Diastolic dysfunction = HEFpEF = concentric LVH - Pressure overload causes demand ischemia - Increased LV thickness (parallel sarcomeres) + decreased chamber size = preserved EF against high afterload but pulmonary congestion occurs

Discuss different Aline locations for different cardiac surgeries

- Do not place below a site that had a previous cut down surgery- go above, or use other arm - Accessing below cut down site increases risk of thrombosis and waveform distortion - If radial artery graft, put aline in ipsilateral brachial artery above the AC or contralateral radial artery

What are the anesthetic considerations for L systolic HF?

- Give inotropes - Decreased preload- diuresis or NTG - Afterload reduction while maintaining coronary perfusion - May see higher pump volumes on CPB- diuresis, ultrafiltration

What factors determine venous cannula drainage? What risks are a/w VAVD devices?

- Gravity, cannula size, cannula location, pt volume status, VAVD - VAVD suction pressures > -40 mmHg have higher risk of hemolysis and air embolism

After coming off bypass you notice PA pressures 50/22, CI 0.5, and BP decreasing, what could be happening?

- Heart may not be tolerating separation from CPB and is failing - Check TEE to assess LV function and treat reversible causes - If LV empty give volume - Reduced wall motion: - Hypoperfusion, give pressors Levo - Kinked bypass graft, fixed by surgeon - Inotropes - If all fails, pt may have severe cardiac stunning necessitating resumption of CPB or IABP, ECMO, or VAD

What is cardiac hibernation and how does this mechanism help chronically ischemic LVs during CABG?

- Hibernation = self preservation effect- steady state ischemia from chronically reduced flow through vessels with plaque causes LV perfusion matching- LV contraction strength reduced to match O2 and BF supplied - Hearts with hibernation = fair better after CABG than hearts that experience stunning

What are considerations for redo sternotomy?

- High risk of bleeding d/t adhesions, fibrosis, previous CABG may have grafts directly under the sternum, heart may be adhering to the sternum - Pt with chest radiation (breast CA) - Preop MRI and CT can help assess proximity of cardiac structures to sternum - PRBCs should be readily available for redo - If structures close to the sternum, surgeon may cannulate femoral or subclavian vessels before sternotomy and start bypass during dissection with heart still beating - Expose and prep femoral or subclavian incase CPB needed fast

How should a pt with type 2 DM undergoing CABG be managed?

- Hold OHA 24 hrs, 1/2 dose basal NPH, surgery ok if BG < 180 mg/dL - Intraop- maintain BG < 180, check BG q 30 min-1 hr, start insulin drip and bolus regular insulin prn - Postop- continue drip if BG > 180 mg/dL, if infusion stopped when transferred to ICU subq insulin should be ordered

What are hemodynamic interventions for postop pt with persistent low BP after CPB despite normal to high CO?

- Hyperdynamic circulation, possible septic (preop endocarditis) or vasoplegic syndrome - Vasodilatory shock d/t preop admin of ACEi, CCB, amio, IV heparin, DM, poor to moderate LV function - Hypotension early in CPB needing frequent neo or levo may indicate vasoplegic syndrome - Vaso more effective in vasoplegic syndrome - Maintain high Hct for good preload and BP - May still need low dose inotrope despite normal Co so contraction can be sustained

What is cardioplegia?

- Hyperkalemic cold crystalloid and blood infusion - Induction dose 2-5C with hypothermic diastolic circulatory arrest in 1-2 min - Induction dose has 20-30 meq/L K and maintenance has 12-16 meq/L - Goal temp = 8-10C - Redosed based on myocardial temp increase, ECG activity, volume, time (every 15-20 min while aorta clamped) to maintain asystole

Discuss preop considerations for ACEi/ARBs

- If they have taken ACEi/ARB they may have refractory hypotension or postop vasoplegic syndrome - May be resistant to neosynephrine- use small dose norepinephrine (16mcg) and vaso (1 unit)

What is HIT? Can a pt with HIT history receive heparin for CPB?

- Immune reaction to heparin exposure diagnosed with c-serotonin assay and enzyme immunosorbent assay which detects HIT antibodies - Pts who had HIT 3 months before cardiac surgery have a lower risk of HIT - Negative antibodies on DOS = can use heparin for intraop anticoagulation - Positive antibodies and surgery cannot be postponed, CPB can be performed with bivalirudin (direct acting thrombin inhibitor)

What are Type 1 neurologic deficits from CPB?

- Include stroke, coma, encephalopathy, TIA- a/w old age and atherosclerotic disease of the ascending aorta

What is the most significant cause of periop ischemia and why?

- Increased HR- it increases demand and decreases supply - Increased HR is an independent predictor for all cause M&M in men and women even without CVD

Pt enters VF coming off bypass- how can this be treated?

- Internal defib by surgeon at 10-20 J - Give antidysrhythmis like lido or amiodarone - Maintain MAP with neo to ensure CPP to LV is maintained to ensure better LV function - Prior to aortic cross clamp removal, the prophylactic admin of lido 100 mg, mag 1-2g, can reduce risk of arrhythmias

After aortic cross clamp removal, you notice sudden transient ST depression in II, III, AVF. What is happening, and how can this be treated?

- Intracardiac air may migrate into RCA because it is anatomically superior (air rises) and leads to ischemia in inferior (II, III, aVF) - Surgeon may shake heart or use a needle to remove - Use TEE to help locate air to aid in removal before coming off bypass

Where would you put the aline for R sided ITA/ IMA dissection?

- L radial- requires R subclavian artery clamping

What is happening if PAP increases and the LV now looks full?

- LV shunt may be kinked, blocked, or malfunctioning because it allows fluid to accumulate in the heart causing a rise in PAP - Notify surgeon and perfusionist of the issue so they can fix the shunt decompress the LV - Increased LVEDP from a malfunctioning shunt can increase risk of MI

What are causes of more persistent hypotension on CPB?

- MAP < 30 mmHg may be aortic dissection- confirm on TEE or by surgeon seeing hematoma on aorta - Stop CPB until recannulated distal to dissection, resume CPB and fix dissection - Vasoplegia - Sepsis

What are the anesthetic considerations for pts with left diastolic HF?

- Maintain EF, maintain MAP - Give volume based on TEE LVEDV - Avoid increase HR- phenylephrine, cardiovert early - Normal CPB pump volume

What are the anesthetic considerations for pts with R heart failure?

- Maintain RV contraction and reduce RV afterload (decreased PHTN/ decreased PVR) - No N2O or des (increases PVR) - Use vasoconstricting drugs - Avoid atelectasis, hypoxemia, hypercarbia, acidosis- trigger HPV- increaesed PVR, leads to PHTN - Maintain diastole time- RV perfusion now occurs more in diastole d/t myocardial remodeling changes

What are considerations for previous blood transfusion and transfusing uncrossmatched blood for cardiac surgery?

- May still have antibodies from previous transfusions - Needs to be crossmatched, and redo sternotomy is blood

Why are lower doses of opioids preferred now in cardiac surgery?

- New goal = early extubation in 6hrs - Low-mod dose narcotics (fent 5-20mcg/kg) + VG preferred anesthetic for faster wake ups - High dose narcs can cause sudden bradycardia, chest rigidity, prolonged intubation, recall

What tests are used to determine the presence of ischemia and cardiac tissue viability?

- Nuclear imaging tests and dobutamine stress echo - Important to differentiate ischemic myocardium vs necrosed b/c ischemic regions can benefit significantly after revascularization surgery

Discuss characteristics of pts with diastolic HF

- Often elderly - Females - Preserved LVEF > 40% - Normal LV cavity with concentric LVH - CXR = congestion + or - cardiomegaly - HTN = +++ - DM = +++ - Previous MI = + - Obesity = +++ - COPD = ++ - Sleep apnea = ++ - Dialysis = ++ - Afib = usually paroxysmal - Gallop rhythm = 4th heart sound

What are anesthesia considerations for pt with CIED and ICD/ pacemaker

- PM asynchronous mode should be reprogrammed to a rate > 70 bpm - ICD should have defib pads but not directly on the generator

What is heparin resistance? How does it occur and how is it treated?

- Patients exposed to heparin recently will not achieve ACT > 480, or require additonal doses (100-200U/kg) - May be d/t ATIII deficiency - May need to give 2 FFP or ATIII concentrate, or recombinant ATIII

What is the impact of CPB on the lungs?

- Ranges from mild ateletasis d/t no ventilation during bypass - Severe dysfunction- pump lung/ALI or ARDS - Atelectasis and pleural effusions can occur in 60% of cases but hemothorax, pneumothorax, pulm edema, respiratory disease exacerbation are possible - Prolonged CPB, embolic insults, and SIRS increase pulmonary capillary permeability and increase risk of ALI/ARDS

What are some findings of aortic regurg?

- Rapid ejection + diastolic run off causes a bounding pulse, wide pulse pressure, and arterial waveform with a rapid rise in systolic pressure and a low dicrotic notch - Sometimes a double peak (pulsus bisferiens) can be seen on the aline

Most common valvular defect requiring surgery?

AS, followed by MR, AR, MS

What are some complications following a TAVR?

AV block requiring a permanent pacemaker placement, perivalvular leak, stent malpositioning, coronary obstruction, and stroke

When is TEE contraindicated? What is done instead?

Absolute contraindications = esophageal pathologies- strictures, tumors, diverticula, trauma, new sutures - Surgeon can perform transthoracic echo with sterile glove filled with sterile saline placed between cardiac structures and probe for better visualization

Contraindication to VAD?

Active infection Sepsis Irreversible renal or hepatic dysfunction Severe PHTN unrelated to cardiac disease Metastatic cancer Major coagulation disorders (von willebrand and hemophilia)

What is the function of the heat exchanger?

Active warming through the heat exchanger will reduce gas solubility, increasing the risk of air embolus fomation - Arterial filter will purge this air before blood is returned to systemic arterial circulation

What are the advantages of robot-assisted mitral valve surgery?

Advantages of the robotic system over thorascopic video assisted-reduction in surgeon tremor, increased mobility with instrumentation and 3D vision

What is the classic triad of AS?

Angina Syncope Congestion causing dyspnea

Complications with using ECMO?

Anti coag with heparin is necessary with ECMO to prevent clot and thrombus formation - Bleeding becomes a major risk factor - Other = stroke, infection, multiorgan dysfunction, and limb ischemia

What are some methods for blood conservation in cardiac surgery?

Antifibrinolytics- Amicar, TXA Blood salvage- cell saver blood Reduced amount of pump prime- smaller circuits, VAVD, RAP with pts blood to prevent hemodilution Ultrafiltration- filters blood and removes excess fluid to prevent transfusing diluted hgb Multidisciplinary blood management

What are the hemodynamic parameters for CPB cannulation?

Aortic cannulation- SBP 90-100 and MAP < 70 to decrease risk of dissection Venous cannulation- if RAP back priming is the plan, BP should be increased to prime the circuit, CVP < 5 to facilitate good venous drainage or a negative value if VAVD used

What is pulsus paradoxus?

Arterial SBP variation > 10mmHg during inspiration

What are the major risks a/w arterial cannulation?

Arterial dissection Hemorrhage Plaque rupture? Air embolization Distal tip in aortic arch vessel

What nerve injuries are common with cardiac surgery?

Brachial plexus- from sternal retraction, arms hyperextended, radial artery damage from compression by ether scree or the post used to support the chest retractor during IMA retrieval

Nasal and tympanic temp is monitored as a reflection of?

Brain temp

What are advantages of transcatheter aortic valve implantation?

Does not require a sternotomy or CPB

Why is it important to prevent SNS stimulation with cardiac surgery?

Events trigger SNS induced HTN and tachycardia- increased risk for MI, dysrhythmias, HF - Preemptive treatment with narcs, VG helps and short acting BB can be used for hyperdynamic pt - Make sure pt is paralyzed for most stimulating parts

Where would you put the aline for a redo sternotomy?

L radial preferred - If surgeon concerned for cardiac structure damage, he may cannulate R subclavian artery prior to sternotomy

The LITA is anastamosed to which artery?

LAD

Repeat CABG pts may be at increased risk for what during sternotomy?

LITA or other grafts are directly underneath the sternum and sternotomy can lead to marked ischemia if the flow in the vessel is disrupted

What are some of the etiologies of chronic AR?

Long standing calcific degeneration Congenitally bicuspid AV Rheumatic fever Inflammatory or connective tissue disease Idiopathic aortic root or valve dilation HTN induced aortoannular ectasia Syphilis Marfan syndrome Ehlers- Danlos syndrome

What is the most common complication following cardiac and major vascular sx and #1 cause of hospital M&M?

MI - optimize O2 supply and demand - Increase supply, and decrease demand

Mitral regurg occurs during systole or diastole?

MR occurs during systole when blood is ejected back into the L atrium because of an incompetent mitral valve

Is MV repair recommended over replacement and why?

MV repair is almost alway recommended over replacement whenever possible - Advantages of repair = improved postop LV function, increased long term and short term survival, improved quality of life, lower risk of complicatoins, and less need for long term anticoags

How would you manage SVR with a CABG?

Maintain - Hypertension better tolerated than hypotension - Treat hypotension promptly with phenylephrine

How would you manage PVR with a CABG?

Maintain - Usually not a problem

How would you manage rhythm with a CABG?

Maintain sinus - Maintains atrial contribution to cardiac output

When is a transfemoral approach for a TAVR indicated?

May be selected if there has been a previous L thoracotomy, chest radiation , or pathology in or near the LV apex - Transfemoral approach delivers the bioprostheic AV in retrograde fashion via the abd and thoracic aorta into the AV annulus

What are indications for IABP?

Medical uses include management of cardiogenic shock, MI, intractable angina, and arrhythmias - Perioperative setting used to stabilize pts preop and/or to help wean a pt who is having difficulty separating from CPB - Helps support coronary perfusion to pts during OPCAB procedures

Why is Mag frequently given as prophylactic nearing CPB end?

Minimizes dysrhythimas like postop AF, give 2-4G IV for goal lab > 2 md/dL

How can you prevent SAM?

Minimizing increases in HR and contractility - Ensuring adequate preload and afterload

Are benzos contraindicated in heart surgery? What can be used instead for ICU transport?

NO- can be given 1-4mg but are usually avoided bc benzo synergism with narcs causes decreased SVR/BP and myocardial depression - Prop or precedex drip can be used instead of benzos for transport to ICU

What is the best place to measure core temps for open heart surgery?

NP and PAC- once chest is opened and packed with ice, PAC may not be accurate but nasal = brain temp - Foley bladder temp is NOT core, but can be used for correlation during cooling and rewarming - Bladder will lag behind core by 2-4C

What will ischemia look like at this layer on the ECG?

NSTEMI = ST depression and T wave inversions

Which vasodilator is preferred during a CABG?

NTG is superior to SNP in CABG pts- decreases preload by decreasing vascular tone and coronary artery resistance at higher doses

Cardiac transplant candidates must meet what criteria?

NYHA clas IV HF, EF , 20%, and a dx of end stage heart disease that is terminal in 1-2 years if transplant does not occur

Explain the difference between orthotopic and heterotropic heart transplant?

Native heart is left in an new heart is laced in the anterior R thorax with parallel flow - Indicated with irreversible pulmonary HTN that is likely to cause acute RHF - Orthotopic heart transplant- Recipient heart removed, donor heart placed instead

Why should you be careful with giving you pt with AS nitrates for angina?

Nitrates can lead to hypotension and decreased coronary artery perfusion and ischemia - Can cause pt to arrest and die - Cardiac compressions hardly generate enough pressure to adequately perfuse the coronaries to revive the pt promptly and treat hypotension with vasoconstrictors like phenylephrine

Would the EF on the TEE be accurate on a pt with mitral regurg?

No, EF is overestimated because it calculates both forward and regurgitant flow

Should VG be increaesd with harvesting and dissecting in heart surgery? Why not?

No, they are not as stimulating- decrease anesthesia

How do you manage a pt with multiple lesions (stenosis and regurg)?

Often multiple lesions are present and a valve may have both stenosis and regurg - Management is dictated by the pathology causing the majority of pts symptoms

What are 2 key anesthetic considerations for CABG surgery?

Optimizing myocardial O2 supply and minimizing myocardial O2 demand

When and why would you pull back a swan catheter during cardiac surgery?

PAC can advance and become wedged during CPB into the PA and rupture as heart being manipulated - Pull back 2-3cm with balloon down before CPB begins

What major factors determine total coronary blood flow

Perfusion pressure gradient- CPP = DBP - LVEDP - Coronary vascular resistance : increased resistance = decreased flow - Coronary flow time: increased HR = decreased diastolic fill time = decreased left coronary artery fill time - Coronary anatomy: increased CAD/stenosis/atherosclerosis

What is the drug of choice to treat hypotension in pts with aortic stenosis?

Phenylephrine - AS pts are preload dependent

What are considerations for nasal temp probe placement?

Place before heparinization, so before cannulation

What happens if the pts neck on the right side begins to swell?

Possible venous cannula dislodgement can interfere with venous return to SVC causing SVC syndrome - Notify the surgeon so they can fix the cannula location

What are hemodynamic goals for MR?

Preload- cautiously increase or decrease to enhance forward flow HR- high normal Rhythm- sinus or AF control ventricular rate Maintain compliance and contractility Decrease SVR, PVR CPB- LV dysfunction can be unmasked after surgery

What are contraindications to the transfemoral approach?

Presence of ascending aortic aneurysm and femoral iliac arteries that have a small diameter, small stent implantations, high degree of calcification, or tortuous

What factors affect determination of blood volume amount coming off bypass?

Pt weight Pre-bypass volume status Ventricular function Comorbidities

Where would you put the aline for L sided internal thoracic artery dissection?

R radial- requires L subclavian artery clamping - Decreases L arm BP

Most heart transplant recipients are scheduled on short notic and are considered full stomachs. How would you induce these pts?

RSI

What is the most common cause of short term morbidity after transplant?

RV failure d/t fixed PHTN

What is worrisome about retrograde cardioplegia cath placement?

Retrograde cath usually placed by blind palpation into the coronary sinus on posterior side of the heart - Almost always causes hypotension and arrhythmias - Some surgeons will wait until on bypass to place

What is the primary cause of MS?

Rhematic heart disease

Why are R sided central lines preferred over L during heart surgery?

Right is a straight shot to the RA where as the L IJ is crossed by the thoracic duct and L brachiocephalic vein at at right angle requiring a shorter catheter to cannulate

What is the effect of CPB on the GI tract?

Risk is rare but occurs if greatly increased r/o MI, death, ARF, stroke

Which pump mechanism is losing favor and why?

Roller pumps- compress tubing, increase risk of hemolysis, increase plt destruction - Centrifugal pumps are increasing in popularity

What is the SBP goal with aortic aneurysms?

SBP < 120 to prevent dissection

Normal SVR?

SVR = (MAP-CVP) x 80/CO 900-1400 dynes/s/cm^-5

What are contraindications to IABP?

Sepsis Descending aortic disease Severe PVD Severe AR

When should you start correcting pt's acid base imbalances and electrolyte imbalances?

Should be optimized before coming off CPB

Amount of MR is based on what?

Size of mitral orifice Pressure gradient between the LA and LV Time available for regurg flow Compliance of the receiving chamber

How would you manage HR with a CABG?

Slow normal - Too fast leads to ischemia, consider BB - Too slow = not enough CO for coronary perfusion

What would you see on the aline tracing with AS?

Slow upstroke and high dicrotic notch with a classic narrow pulse pressure

What is systolic anterior motion (SAM)?

Some HCM pts have basal septal hypertrophy that is so extensive it obstructs the LVOT- ventricular contraction becomes hyperdynamic- forces blood to eject at high velocity to pass the obstruction - This rapid blood flow can lead to the venturi effect that causes anterior leaflet of the MV or the chordal structures to be pulled into the basal septal wall during systole- called SAM of mitral valve

Which cases require anterograde vs retrograde cardioplegia?

Some use both baed on the location of occlusions or to maximize coronary protection

What are hemodynamic interventions for postop pt with good LV function preop, separated from CPB easily, and good BP and EF at case end?

Stable, transfer to ICU for monitoring

Discuss preop considerations for warfarin

Stop at least 3 days before surgery until INR normalized ( < 1.5) - Pt can be bridged with heparin if high risk

What is the venous reservoir?

Stores venous drainage on one side and blood suctioned and vented from the surgical field on the other (cardiotomy) - Volume must be kept at a certain level to avoid air embolus - Alarm will sound if levels are below normal- blood, medication, fluids can be added to the reservoir

What is a risk with vigorous lung reinflation at CABG CPB case end?

Stretching or disrupting the new in-situ ITA graft - Inflate gently while watching lungs, keep PIP < 30 cmH2O

Half of hypertrophic cardiomyopathy cases is a/w what?

Sudden cardiac death

With retrograde cardioplegia infusion, baseline catheter pressure is normal at 20 mmHg. What could sudden decrease or increase of this parameter represent?

Sudden increase (> 40 mmHg) = cath moved too distal, increasing risk of coronary sinus rupture Sudden decrease (< 20 mmHg) = cath maybe fell into RA

Indications for aortic valve replacement?

Symptomatic pts with severe AS Asymptomatic pts with a LVEF < 50% Those having cardiac surgery for another indication

What is the most sensitive intraop exam to detect wall motion abnormalities?

TEE- can detect emboli, air, valve function, ventricular function, heart filling

What test can determine the occurrence of ischemia before ECG changes?

TEE- can detect regional wall motion abnormalities and increased LVEDP/ volume changes a/w systolic dysfunction before ECG - TEE is the most sensitive intraop monitor for detecting myocardial ischemia

Why do we want to avoid tachycardia in pts with AS?

Tachycardia decreases diastolic filling time and increases myocardial O2 demands - Depends on diastolic time to perfuse coronary arteries

Why are AS pts prone to ischemia?

Thick hypertrophied muscle mass has a high O2 requirement - Increased ventricular pressure inhibits coronary perfusion - High prevalence of coexisting CAD

When is the RV perfused?

Throughout the cardiac cycle

What are the latest transfusion guideline suggestions?

Transfuse for Hgb < 6, but ok to transfuse if higher Hgb if clinical indicators suggest pt needs (cerebral O2 delivery at risk) - Hct should be kept around 22-25%

Acute AR is usually d/t what?

Trauma Endocarditis Aortic dissection

Why should you check pts pupils during aortic cannulation?

Unequal pupils may indicate arterial cannula tip too deep and is only perfusing one carotid body or there was an embolus- air, plaque, fat

What are accessory roller pumps?

Used to control suction and deliver cardioplegia - Suctioned blood is returned to pt via cardiotomy or cell saver - LV vent - Cardioplegia pump

Explain how IABP works?

Uses synchronized counter pulsation to enhance myocardial perfusion by reducing afterload during systole, and increasing coronary blood flow to the heart during diastole

Why are most cardiac surgeries performed with volatile gases, and why do some pt populations benefit from TIVA?

VG induce cardiac preconditioning= better cardiac outcomes for the pt's postop than with TIVA - TIVA may be better since gases cause cardiac depression and hypotension in pts that cannot tolerate further reduction in myocardial function

List 3 factors that determine valvular flow

Valve area Pressure gradient across the valve Duration of flow in systole or diastole

What is the criteria for severe mitral valve stenosis?

Valve area < 1.5cm2, the mean pressure gradient exceeds 5-10 mmHg, and PA systolic pressures are > 30 mmHg

Complications a/w IABP?

Vascular injuries such as ischemia distal to the site of the balloon (most common), infection, thrombocytopenia

How do you manage an LVAD pt that develops vasoplegic syndrome?

Vasopressin- will help increase R heart afterload

What are the two types of ECMO?

Venovenous ECMO- preferred for pts with respiratory failure and gas exchange but cardiac function is intact - Cannulation sites, femoral and IJ veins - Blood is drained from the SVC and IVC through a cannula in the RIJ and/or femoral vein - Blood is oxygenated by the ECMO circuit and returned to the RA through the same vein or different vein- separate drainage and return cannula or single double lumen cannula Venoarterial ECMO - For pts that require cardiac pulmonary support - Bypasses pulmonary circulation altogether and a higher arterial oxygenation is achieved - Cannulation may be central- deoxy blood drained directly from a cannula in the R atrium and oxygenated blood directly returned through a cannula inserted into the ascending aorta - may also be peripheral where deoxy blood is drained from R IJ and/or femoral vein, and returned to the circulation via fem artery

What is commonly used to prolong life in pts waiting for a heart transplant?

Ventricular assist device - Used to assume the fxn of the failing ventricle as a bridge to recovery, transplant, or as a destination therapy

What is unique about MS compared to other valvular lesions?

Volume management challenging because adequate preload is required to maintain flow across the stenotic valve - Overloading the pt- pulmonary congestion - Majority of pts have normal LV function- the increase in ventricular volume that occurs after valve replacement can cause the LV to dilate - If failure occurs, it is responsive to inotropic support

Describe how the Law of Laplace relates to heart failure

Wall tension = transmural pressure x radius/ 2x wall thickness - Law can describe the factors that determine LV wall stress

What is deairing the heart?

Will ask to give a large positive pressure breath gently to help push air out ot heart and pulmonary vessels - Beware of overinflation of the LIMA graft- may damage or stretch the graft

Is a decrease in Hct on CPB normal?

Yes- will cause dilutional anemia hct 22-25% = normal, can help reduce blood viscosity a/w cold blood during CPB

Bladder and PA temp reflect what?

core and shell temps

Which heart failure patient would benefit the least from compressions during cardiac arrest and why?

Compressions for Diastolic HF rarely work because it is difficult to generate an adequate amount of external pressure to perfuse the noncompliant and stiff LV

Hypertrophic cardiomyopathy primary pathology is a/w concentric or eccentric LVH?

Concentric LVH = primary pathology - HCM can induce LVOT obstruction, MR, diastolic dysfunction, ischemia, dysrhythmias - HCM can either be obstructive or nonobstructive based on the degree of outflow tract obstruction and presence or abscence of mitral valve SAM

What type of LV hypertrophy do pts with AS typically have?

Concentric hypertrophy- increased LVEDP and O2 demand

Discuss preop considerations for metoprolol

Continue preop

How is coronary flow regulated in a CAD pt after blood passes the obstructed vessel areas?

Coronary flow becomes pressure dependent after the area of partial obstruction, especially when MAPs below 70 mmHg

What can you give prior to aortic crossclamp to prevent a hyper acute immune response?

Glucocorticoid- methylprednisone

What are HR and SBP goals for aortic dissection?

HR 60 and SBP 120, give BB and vasodilators

What is the only treatment for end stage HF?

Heart transplant

Most commonly used LVAD in the US?

Heartmate II - Intracorporeal and nonpulsatile continuous flow device 10L/min Complications- stroke, postop bleeding, RV failure

What are common initial causes of hypotension once bypass starts?

Hemodilution- perfusionist can give pressors Reduced blood viscosity = decreased SVR Usually respond to pressors

What do you need to prepare to give for emergent femfem CPB with redo sternotomy?

Heparin 300-400U/kg through central line - Maintain BP high enough to maintain perfusion but avoid HTN- will speed bleedin - Give blood, if readily available

Where should MAP and HR be maintained in a pt with CAD or increased LVEDP (LVH, AS)?

High MAP Low HR ( < 70 bpm)

What are the disadvantages of robot assisted mitral valve surgery?

Higher cost Increased complexity Longer XC times

Pts with status 1A have the highest or lowest priority?

Highest

What are the most commonly used conduits?

ITAs- internal thoracic artery, formerly known as IMAs and greater saphenous veins

If UOP is decreased but MAP is stable and pump volume is adequate, what can you do?

IV diuretics like lasix, mannitol especially if pt is on diuretics preop

What are the earliest to latest sign of the myocardial ischemia cascade

- Perfusion abnormalities - Diastolic dysfunction: increased LVEDP, decreased compliance - Systolic dysfunction: wall motion abnormalities, decreased EF - ECG changes: ST depression, ST elevation, T wave inversion - Clinical symptoms: SOB, angina, diaphoresis - Infarction: CHF, cardiogenic shock

What are anesthetic consideration for off-pump CABG?

- Perfusionist and a primed or dry pump should be in the OR on standby throughout the case - HD compromise and acute ischemia can occur when the surgeon compresses on the cardiac chambers requiring immediate conversion to bypass - Limited to pts with good LV function - Bleeding is less of a concern - Higher risk of incomplete revascularization - Pts require crystalloids and/or colloid solutions to correct fluid deficit and HD changes inherent to the procedure - Pt temp cannot be corrected on pump so hypothermia becomes a concern - Normothermia maintained by warming room, fluid warmers, warm water mattresses, or bair hugger - Anticoag is necessary but decision to partially heparinize to keep ACT > 300 sec or fully heparinize is surgeon dependent - Monitor ACT q 30 min and give heparin as needed to maintain coagulation - Amicar not routinely used because blood is not exposed to CPB

What factors increase a pt risk for heart failure after CPB?

- Poor preop ventricular function - Long CPB runs - Complex procedures - Uncorrected structural defects - Inadequate myocardial preservation while on bypass

What is the MOA of heparin, dose, and when should it be given during CPB?

- Potentiates ATIII by binding ATIII to thrombin 1000x, increased ATIII inhibitor effects to thrombin clot formation - Also need factors 9,10, 11, 12 to work - Dose = 300-400U/kg - Given through central line, make sure to aspirate blood before giving heparin - ACT normal = 80-120s - ACT for CPB = > 400-480

Considerations of a denervated transplanted heart?

- Preload dependent - Indirect acting medications like ephedrine and anticholinergic meds like atropine are ineffective in increasing HR or CO - Only epi or isoproterenol will increase HR

What is the dose, timing, and considerations for protamine administration?

- Protamine neutralizes heparin via electrostatic reaction forming a heparin-protamine complex- inactivates heparin - 10mg test dose given in case of anaphylaxis - Whole dose give once decannulate over 10-15 min to prebent hypotension - Slow admin to r/o type I (histamine and vasodilation systemic) and type III (pulmonary vasoconstriction and delayed anaphylactoid) but type II anaphylaxis will occur at any time - Dose: 1mg protamine/100U heparin - ACT or HDR checked which determines optimal protamine dose and residual heparin after protamine - Additional 50-100mg can be given if ACT not at baseline or bleeding at site

What may cause L radial aline dampening with chest wall retratction?

Chest wall retractors can compress sublavian artery between the clavicle and first rib and during left internal thoracic artery dissection

What is occipital alopecia?

Baldness from not repositioning the head frequently

What happens hemodynamically with manipulation of the heart? how can this be treated?

Causes hypotension and arrhythmias - Place in Tburg, small doses of phenylephrine, ask surgeon to stop manipulation

What can be causes/treatments of oozy pt at case end?

Causes- complex surgeries, long pump run, inadequate heparin reversal - Check ACT, give more protamine - Hypothermia- ensure normothermic - Check coags- blood products may be needed to supplement - Plt dysfunction preop- give DDAVP - Severe, uncontrolled refractory bleeding despite product replacement- recombinant factor 7

Which drugs can be used to treat vasospasm?

CCB Topical papaverine (antispasmodic/ opium alkaloid) and nitro

How is CPB used in minimally invasive surgery?

CPB cannulation obtained from the femoral artery and vein under TEE guidance to confirm placement - Complications with femoral CPD cannulation- retrograde aortic dissection, limb ischemia, and chest wall hemorrhage

What is the goal CPB flow rate, CI, and ideal systemic pressure?

CPB maintained at 50-60 ml/kg/min for CI 2.0-2.5 L/min/m2 and MAP 50-70 mmHg depending on pt age and comorbidities

What is the equation for CPP?

CPP = (DBP-LVEDP/ coronary vascular resistance - LVEDP normally 10 mmHg - CPP usually 50-80 mmHg - DBP = major determinant of CPP MAP = most useful clinical measure of CPP in the clinical setting

What MAP is CPP autoregulated between?

CPP maintained between MAP 60-140 mmHg

How would you manage a pt with MS that has PHTN and RV failure?

Can be manage with mild hypocapnia, vasodilator therapy, and inotropic support (milrinone, epi) - Extreme cases- inhaled nitric oxide or PG may be used to dilate pulmonary vasculature and reduce RV afterload

What are you concerned about with PAC and LBBB?

Can cause RBBB in 3% of pts, can interfere with RVOT - Baseline LBBB, can cause complete heart block - MUST have external defib pads on in case pacing is needed - Some will leave PAC tip in SVC until chest is open this way if CHB occurs, rapid CPB can begin

What happens if the CPB vaporizer is improperly positioned/seated on the oxygenator gas inlet?

Can impair gas flow to the oxygenator causing hypoxemia

How can cardioplegia be achieved with a pt with aortic insufficiency?

Cardioplegia given directly into the coronary ostia and /or retrograde throug hthe coronary sinus

Which gases should be avoided in cardiac surgery?

Des- sudden increase in concentration can increase HR and HTN, not goof for pts with CAD, HCM, AS N2O- air expansion increases embolus risk, PHTN, increased catecholamine release, LV dysfunction

Which pts require placement of defib pads?

Deactivated ICD Recent serious ventricular ectopy Minimally invasive surgery (chest wont be open for internal defib) Repeat sternotomy LBBB with PAC insertion

How would you manage preload during CABG?

Decrease - Decrease LVEDP will increase myocardial O2 supply and decrease demand - NTG selectively dilates coronary vessels

Why should the nasal probe or TEE be placed before heparin administration?

Decrease risk of bleeding

List some benefits of VAD?

Decrease wall tension + myocardial O2 demand, stabilizing multiorgan failure in end stage HF pts awaiting transplant

List the benefits of minimally invasive MV procedures

Decreased hospital length of stay Faster pt recovery Decreased blood loss Decreased hospital cost Improved cosmetic appearance compared to traditional median sternotomy

Explain the features of basic CPB circuit and the flow of blood

Deoxy blood drained from vena cava/RA -> venous reservoirs-> main arterial pump -> oxygenator/ CO2 removal -> heat exchanger -> arterial line filter to remove debris/air -> arterial cannula enters ascending aorta (or femoral, or subclavian artery)

How would you manage contractility with a CABG?

Depress if normal LVF, support if decreased LVF - Decrease contractility leads to decreased myocardial O2 consumption - If poor LVF, may not tolerate depression

Aortic regurg is a/w what type of hypertrophy?

Eccentric

What is a MAZE procedure?

For treatment of afib - Several incisions are made around the atria to create a maze of scar tissue to block any reentry circuits that would cause afib - Conduction impulse from the sinus to the AV node still occurs - Coz Maze utilizing bipolar radiofrequency ablation and cryoablation instead of incisions - 90% freedom from AF at 12 months

What are hemodynamic goals for hypertrophic cardiomyopathy?

Full preload Low normal HR Maintain SR Improve compliance Decrease contractility Avoid reductions in SVR Maintain PVR

How would you manage compliance with a CABG?

Improve - Concentric LVH (common with history of HTN) will decrease compliance

List the contraindications for minimally invasive MV repair

Inability to obtain TEE Severe AR Aortic and/or thoracic disease Marfans syndrome Previous aortic and/or thoracic surgery

What are the most stimulating parts of pre-bypass period?

Incision Intubation Sternal cutting/spreading Pericardium opening

During endoscopic vein harvest, how can you compensate for increased CO2?

Increase RR

What are hemodynamic goals for aortic regurg?

Increase preload High normal HR Sinus rhythm Maintain compliance and contractility Decrease SVR Maintain PVR Decrease LV distension with CPB

What are hemodynamic goals for MS?

Increase preload Low normal HR If AF, control rate Maintain compliance, maintain LV contractility Maintain SVR Decrease PVR

How would you manage hemodynamic parameters for a pt with AS?

Increase preload Slow normal HR Maintain SR Improve compliance Maintain contractility Maintain SVR- maintain coronary perfusion gradient Maintain PVR

State the risk factors for acquired AS?

Increased age Male Smoking HTN HLD