Cardiac

Question 1

How do you calculate CaO2?

Answer 1

CaO2 = (Hgb x 1.34 x SaO2) + (0.003 x PaO2)

Question 2

How do you calculate CBF (coronary blood flow)?

Answer 2

CBF = CPP/CVR (CVR stands for coronary vascular resistance)

Question 3

Coronary blood flow is autoregulated between what MAPs?

Answer 3

50-150mmHg

Question 4

How do you calculate CPP?

Answer 4

CPP = diastolic - LVEDP

Question 5

What causes the O2 dissociation curve to shift to the right?

Answer 5

Increases in “CADET” (CO2, Acidity, 2-3 DPG, Exercise, Temperature)

Question 6

What are the three cardiac factors that contribute to myocardial O2 demand?

Answer 6

HR, contractility, wall stress

Question 7

How is wall stress calculated?

Answer 7

wall stress = (P x r)/(2 x wall thickness)

Question 8

Define preload. What is it a result of? What does it reflect?

Answer 8

Preload is the load placed on myocardium before contraction. It’s a combination of diastolic volume and filling pressure. Reflects stretch of ventricular myofilaments.

Question 9

What is afterload? What does it reflect?

Answer 9

Afterload is the load placed on myocardium DURING contraction. Reflects distensibility of aorta and SVR.

Question 10

What drugs are given for post-CPB bleeding? What class are they?

Answer 10

amicar or TXA; anti-fibrinolytics

Question 11

What drugs are typically set up as infusions for cardiac cases?

Answer 11

epi & NE

Question 12

What EKG leads are most important to look at prior to induction for cardiac anesthesia?

Answer 12

ST segments of leads II and V5

Question 13

What lines should you have for CPB?

Answer 13

a-line, central line +/- PAC

Question 14

What are some advantages to having a central line?

Answer 14

monitor CVP, enable volume replacement, enable pharmacologic therapy, insert PAC or other monitors

Question 15

What is the most common vein for CVP?

Answer 15

R internal jugular

Question 16

What are some of the things a TEE can assess?

Answer 16

valvular abnormalities, preload, contractility, pulmonary HTN, RWMA, EF, pericardial effusion, cardiac abnormalities

Question 17

What must occur before cannulation for CPB?

Answer 17

anticoagulation

Question 18

What is the dosage of heparin for CPB?

Answer 18

300U/kg

Question 19

how is heparin metabolized?

Answer 19

50% liver, 50% unchanged and renal excretion

Question 20

What’s a normL ACT? What is needed for CPB?

Answer 20

90-120sec normal; for CPB minimum 300s, 400s< preferred

Question 21

What factor does heparin bind to? What factors does it inhibit?

Answer 21

binds to antithrombin III; inhibits II, IX, X, XI, XII, XIII

Question 22

Where is the arterial cannula placed for CPB?

Answer 22

ascending aorta

Question 23

Where is the venous cannula placed for CPB?

Answer 23

dual stage IVC/RA for external procedures; single stage (one bifurcating tube) bicaval cannula in SVC/IVC for valvular procedures

Question 24

What’s in cardioplegia?

Answer 24

KCl, mannitol, glucose, blood with other additives

Question 25

What is antegrade cardioplegia?

Answer 25

needle placed below aortic clamp/above aortic valve and cardioplegia administered into coronary arteries via aortic root

Question 26

What is retrograde cardioplegia?

Answer 26

balloon-tipped cannula placed into coronary sinus and administered into coronary veins

Question 27

What MAP range is typically maintained during CPB?

Answer 27

50-70mmHg (below that perfusion suffers, above that you start to get noncoronary collateral bloodflow into heart)

Question 28

What are the 6 “C’s” for CPB termination?

Answer 28

cold (>36*C), conduction (HR 70-100), Ca++ (available), CO, cells (>7g/dL), coagulation (anticipate)

Question 29

What are the 4 “V’s” for CPB termination?

Answer 29

ventilation, vaporizer, volume expanders, visualization

Question 30

What are the 6 “P’s” for CPB termination?

Answer 30

predictors (difficulty weaning from pump), protamine (drawn up), pressure, pressors, pacer (external available), potassium

Question 31

Why can’t protamine be given when patient is on the pump?

Answer 31

blood will coagulate and clog the circuit

Question 32

When is protamine given?

Answer 32

typically before aortic cannula removal; coordinate with surgeon!

Question 33

What are signs of a mild protamine reaction?

Answer 33

isolated HoTN, normal-low filling pressures, normal airway pressures

Question 34

What are signs of severe protamine reaction?

Answer 34

HoTN, tachycardia, elevated PA pressure, evidence of acute RV failure

Question 35

Turning up desflurane quickly can cause what response?

Answer 35

(sympathetic) tachycardia, HTN, bronchospasm

Question 36

What CV effects does CAD have?

Answer 36

decreased HR and contractility

Question 37

The dicrotic notch corresponds with what?

Answer 37

aortic valve closure

Question 38

A rapid upstroke on an arterial blood pressure curve indicates what?

Answer 38

good contractility

Question 39

What size ETT is used for cardiac surgeries?

Answer 39

8.0mm

Question 40

How long does it take for ischemia to show up on the EKG? TEE?

Answer 40

60-100s; immediately

Question 41

What are the three most popular vessels used in bypass and in what order?

Answer 41

saphenous vein > internal mammary artery > radial artery

Question 42

What is the purpose of priming the CPB?

Answer 42

to remove air from the circuit

Question 43

Which cannula should be placed first in CPB and why?

Answer 43

arterial - venous runs risk of hemorrhage and blood can be transfused through arterial

Question 44

How frequently is cardioplegia re-dosed?

Answer 44

every 15-20 min

Question 45

What BP (MAP) should be maintained during CPB? Why?

Answer 45

50-70mmHg; below is inadequate, above and too much blood returns to heart and washes out cardioplegia

Question 46

What happens to blood glucose in diabetics when they are taken off CPB?

Answer 46

increases dramatically