CVP Cardiopulmonary Bypass (CPB) Management 4

Question 1

During CPB, a patient's urine output drops to near zero. Which intervention should the perfusionist consider first?

Accepted Answer

Administer mannitol and verify adequate pump flow and MAP

Answer

Low urine output during CPB should prompt verification of adequate flow and MAP (≥50–60 mmHg), then consideration of mannitol or furosemide to promote diuresis.

Question 2

What is the primary mechanism by which alpha-stat pH management differs from pH-stat management during hypothermic CPB?

Accepted Answer

Alpha-stat corrects pH to 37°C values; pH-stat corrects to actual patient temperature

Answer

Alpha-stat maintains pH at 7.40 when corrected to 37°C regardless of patient temperature, while pH-stat corrects blood gases to actual patient temperature and adds CO2 to maintain pH 7.40.

Question 3

Which sign indicates massive air embolism has entered the arterial side of the CPB circuit?

Accepted Answer

Air visible in the arterial line with sudden loss of arterial pressure

Answer

Massive arterial air embolism presents as visible air in the arterial line accompanied by sudden arterial pressure loss, constituting a life-threatening emergency.

Question 4

When using a centrifugal pump for CPB, what is a key difference from a roller pump regarding flow delivery?

Accepted Answer

Centrifugal pumps are afterload-dependent; flow decreases with increased resistance

Answer

Centrifugal pumps are afterload-dependent, meaning outflow decreases as resistance rises, unlike roller pumps which maintain fixed occlusion-based flow.

Question 5

A surgeon requests deep hypothermic circulatory arrest (DHCA). To what core temperature is the patient typically cooled?

Accepted Answer

18–20°C

Answer

DHCA is performed at core temperatures of 18–20°C, at which cerebral metabolic rate is reduced sufficiently to allow safe circulatory arrest for aortic arch repairs.

(CVP) Cardiovascular Perfusionist Practice Test

(CVP) Cardiovascular Perfusionist Practice Test

CVP Cardiopulmonary Bypass (CPB) Management 4