CVP Physiological and Pathophysiological Concepts 5

Question 1

Alpha-stat pH management during hypothermic CPB maintains pH at 7.40 (temperature-uncorrected). Compared to pH-stat management, alpha-stat:

Accepted Answer

Preserves cerebrovascular autoregulation and reduces cerebral microembolism risk

Answer

Alpha-stat management preserves cerebrovascular autoregulation by maintaining physiologic enzyme function, and is associated with reduced cerebral microembolism.

Question 2

In a patient with severe mitral regurgitation undergoing CPB, inadequate left heart venting can lead to:

Accepted Answer

Left ventricular distension and subendocardial ischemia

Answer

Blood regurgitating back into the LV plus bronchial venous return causes LV distension, elevating LVEDP and compromising subendocardial perfusion.

Question 3

The phenomenon of 'stunned myocardium' following ischemia-reperfusion is characterized by:

Accepted Answer

Prolonged but reversible contractile dysfunction despite restored blood flow

Answer

Myocardial stunning is a temporary post-ischemic contractile dysfunction that resolves over hours to days after reperfusion despite restored coronary flow.

Question 4

During CPB, a sudden rise in line pressure on the arterial side of the circuit most likely indicates:

Accepted Answer

Arterial cannula malposition or partial obstruction

Answer

Arterial line pressure rise reflects increased resistance downstream, most commonly from cannula malposition, kinking, or aortic dissection.

Question 5

Which metabolic derangement is most likely to cause ventricular fibrillation during rewarming from hypothermic CPB?

Accepted Answer

Hyperkalemia from cardioplegia washout and cell lysis

Answer

Elevated serum potassium from cardioplegia washout and cellular release during rewarming depolarizes myocytes and predisposes to ventricular fibrillation.

(CVP) Cardiovascular Perfusionist Practice Test

(CVP) Cardiovascular Perfusionist Practice Test

CVP Physiological and Pathophysiological Concepts 5