Surgery/Perfusion Techniques to Know

Three compensation mechanisms for acid-base disturbances:

1.buffer systems, which act immediately 2.respiratory compensation which controls the pCO2 and becomes effective within three to four minutes 3.renal compensation, which is able to control H+ and HCO3-. requires 24 - 48 hours to be effective but results in return or buffer components to their normal concentration.

When z-buffing what should you use

1/2 of a sodium bicarbonate per 1 Liter of saline

more than _________ of the CO2 contained by blood is carried in the form of bicarb ions

50%

Bentall Procedure

A Bentall procedure involves a composite graft replacement of the aortic valve, aortic root and ascending aorta, with re-implantation of the coronary arteries into the graft. This operation is used to treat combined aortic valve and ascending aorta disease, including lesions associated with Marfan syndrome.

Stanford Type B

All dissections not involving the ascending aorta (descending)

When doing cerebral perfusion flowing below 100 cc/min, how do you check flow?

Clamp recirc bridge to make sure that there is still glow and that the system (oxygenator) is not acting as a shunt

Antegrade and Retrograde Cardioplegia

Delivers optimal protection to the myocardium. Adapters can be used to connect multiple cardioplegia cannulae and/or vein graft cannulae to a single inlet source, switch between antegrade and retrograde delivery of cardioplegia and provide the option for attaching a vent line to the cardioplegia cannula.

De Bakey Type 2

Originates and is confined to the ascending aorta

De Bakey Type 3

Originates in the descending aorta and extends distally down the aorta

Aortic Root Vent

Site: Aortic root Uses: Deairing, removing blood in aortic root especially after delivering antegrade cardioplegia Why after XClamp:Delivered or flushed antegrade cardioplegia

Aortic Cannula (Arterial)

Site: Ascending Aorta Description: - Cannulation of the ascending aorta is used for the return of oxygenated blood from the pump. - The surgeon ties purse string sutures using 3/0 polypropylene suture material around the pericardial layer surrounding the ascending aorta and performs the aortotomy (direct incision of the aorta) through the adventitia layer of the aorta. The surgeon tightens the purse-string tourniquet to the cannula to achieve hemostasis around the cannula. Indications: Healthy aorta **If a porcelain aorta is found, then different methods must be used. The surgeon cannot cross clamp the ascending aorta, may use different cannula sites, and other different methods. Aortic scanning is also indicated for patients with history of TIA, CVA

Antegrade Cardioplegia Cannula

Site: Ascending aorta, infused through the aortic root, antegrade cannula Description: Preferred technique when aortic valve is competent. Flow path: coronary ostea in the aortic root, coronary arteries, coronary veins, thesebian veins, coronary sinus in the RA.

Femoral Cannula(Arterial)

Site: Femoral Artery Description: - An incision is made in the groin over the femoral artery. - Needle-guidewire-cannula over guidewire technique may be used to insert. - Greatest hazard associated with cannulation of the femoral artery is dissection of the arterial wall extending to the entire aorta after blood is perfused through the cannula. Also associated with limb ischemic complications - Perfusion pressures of the femoral artery are usually higher than perfusion of ascending aorta. Indications: - If there is aneurysm of the ascending aorta or dissection of the aorta - Used prophylactically (prevention/defense). - Reentry sternotomy, where there may be significant risk of cardiac or great vessel injury; for operations in which direct cannulation of aorta is undesirable. - Porcelain ascending aorta - completely calcified (palpable/ touchable calcifications) or rigid aorta - atherosclerosis (fatty deposits/lipids, calcium, macrophage cells, scar tissue/fibrous connective tissue, etc) - If the transverse (aortic arch) and descending aorta has atheroma that may embolize into the brain with retrograde flow from the femoral cannula.

Femoral/ Illiac Vein Cannula

Site: Femoral vein/iliac vein Description: Adequate flow rates using peripheral cannulation require a cannula large as possible and advancing the catheter into the RA guided by transesophageal echocardiography (TEE) Indications: - Reentry sternotomy, where there may be significant risk of cardiac or great vessel injury; for operations in which direct cannulation of aorta is undesirable. - thoacotomys

Field Sucker

Site: Inside chest (mediastinum) Uses: Return blood from the chest to the pump Why after XClamp:Blood inside the chest

Retrograde Cardioplegia Cannula

Site: Purse string stitch in the right atrium near the aotrioventricular groove. Description: - Preferred when there is CAD with high-grade stenosis, aortic valve or aortic root disease, mitral valve disease, or during operations on the ascending aorta. - Cannula has a cuff/balloon tip to occlude the opening of the coronary sinus, forcing cardioplegia flow to the coronary vessel bed of the heart. - Flow path: coronary sinus in the RA, thesebian veins, coronary veins, coronary arteries, coronary ostea in the aortic root.

Dual Stage Cannula(Venous)

Site: Right atrial appendage Wider portion sits in the RA, narrower portion sits in the IVC Description: - This method is faster and less traumatic due to the single incision to the right atrial appendage. - Adequacy of drainage is interfered during manipulation of the heart (e.g. "circumflex position," when lifting the heart to make an anastomosis to the posterior branches of the circumflex coronary arteries). Indications: Generally, AVR, CABG, aortic root replacement, LVAD

Axillary Cannula(Arterial)

Site: Right axillary artery Description: - Cannulation of the right axillary artery is advantageous because arterial return can be established prior to the sternotomy (cutting open the chest) - Provides antegrade (forward natural) flow therefore less likely to cause cerebral atheroembolization - Perfusion of the right common carotid artery can be continued with the aortic arch open when the arch repair is complex and time consuming. Indications: - Porcelain ascending aorta - completely calcified (palpable/ touchable calcifications) or rigid aorta - atherosclerosis (fatty deposits/lipids, calcium, macrophage cells, scar tissue/fibrous connective tissue, etc) - If the transverse (aortic arch) and descending aorta has atheroma that may embolize into the brain with retrograde flow from the femoral cannula. - Evaluated using transesophageal echogram (TEE)

LV Vent

Site: Right superior pulmonary vein Uses: To prevent distension of the left heart Reduce myocardial rewarming Remove blood that enters from the bronchial arterial circulation Why after XClamp: Sources of blood returning to LV: bronchial (through the pulmonary veins) and thebesian veins and blood returning to the right heart that gets by the CPB venous cannula Aortic regurgitation occurs when administering antegrade cardioplegia even when not present preoperatively

Bicaval Cannula(Venous)

Site: SVC (right atrial appendage) & IVC (purse string sutured to the posterior lateral wall of the RA near the IVC) - If a bloodless heart is required. - All venous return to pass through the pump, no air and systemic venous blood entering the right heart. Also known as caval occlusion or total CPB - Surgeon must unsnare before putting volume into the heart. Indications:When right heart is entered. MVR, heart transplant

crystalloid solution

Solution in which the particles will stay uniformly distributed despite gravitational effects

Brownian motion

a random movement of microscopic particles suspended in liquids resulting from impact with molecules of the surrounding liquid

Stanford Type A

all dissections involving the ascending aorta, regardless of the site of origin, could be the whole entire aorta

Starling's Law of the Heart

an intrinsic regulatory mechanism which allows the heart to make moment to moment changes which compensates for alterations in venous return or arterial resistance. Homeometric regulation takes effect. •The heart will automatically eject all of the blood that enters it over a broad range of volumes (t adjusts) •End diastolic volume and stroke volume are proportional •Altering venous return directly effects stroke volume and cardiac output

Respiratory alkalosis

decrease in pCO2. Involves hyperventilation

Respiratory acidosis

increase in pCO2. Involves respiratory insufficiency

Fontan Procedure

inserting graph from the apex of the right atrium to the pulmonary artery used for Atrial Pulmonary Atresia or Hypoplastic l/r heart syndrome

Second Stage Norwood Procedure

it is a modified Fontan used for Hypoplastic left Heart syndrome - right atrial appendage to pulmonary bifurcation

Cannulation Size reference

kgx150= how many cc of flow

Switch / Jantene Procedure

moves aorta to the left ventricle so that the aorta and the pulmonary vein are in the right places

De Bakey Type 1

originates in the ascending aorta ,elongates to the arch and possibly the descending

Metabolic acidosis

primary gain of H+ or loss of HCO3-.

Metabolic alkalosis

primary gain of HCO3- or loss of H+.

Glenn Procedure

superior vena cava is connected to the pulmonary artery. - performed on patients with tricuspid atresia and/or hypostatic left heart syndrome.

if pO2 of venous blood is less than 25...

this indicates that the tissues are extracting more than usual amount of O2 from the blood flow available to them

Rastelli Procedure

tube graph with valve connecting right ventricle and the pulmonary artery -ventricle is functioning normally and can replace valve if needed

Hypothermia Effects

•pCO2 will be decreased in hypothermic states •hypothermia shifts the oxygen-hemoglobin dissociation curve to the left •hypothermia decreases the metabolic rate •decreases the production of carbon dioxide •probably best to maintain pCO2's within the normal range regardless of body temp