Hemodynamic Monitoring During Bypass Flashcards
7 cards from real CCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Hemodynamic Monitoring During Bypass flashcards as text
A perfusionist notices the reservoir level is falling despite adequate venous return. Which hemodynamic sign would first alert the team to impending venous air entrainment?
Answer: Visible air bubbles in the venous line
Visible air bubbles in the venous line are the earliest direct sign of air entrainment before it reaches the oxygenator or arterial circuit.
During CPB, systemic vascular resistance (SVR) is calculated using which formula?
Answer: (MAP – CVP) / CO × 80
SVR = (MAP – CVP) / CO × 80, where the pressure gradient across the systemic circulation is divided by cardiac output and converted to dyne·s·cm⁻⁵.
An arteriovenous oxygen content difference (AVDO2) greater than 6.0 mL/dL during CPB most likely reflects:
Answer: Inadequate perfusion flow relative to oxygen demand
An AVDO2 above 6 mL/dL indicates tissues are extracting an unusually large fraction of delivered oxygen, consistent with inadequate perfusion flow.
Which variable, when monitored continuously, provides the most direct real-time index of global oxygen delivery adequacy during CPB?
Answer: Mixed venous oxygen saturation (SvO2)
Continuous SvO2 monitoring reflects the real-time balance between oxygen delivery and consumption across the entire body, making it the best continuous global index.
During rewarming on CPB, a perfusionist observes a gradual decline in MAP from 65 to 45 mmHg. The most appropriate first intervention is:
Answer: Administer a vasopressor such as phenylephrine
Vasodilation during rewarming commonly causes hypotension; administering a vasopressor to restore SVR is the primary hemodynamic intervention.
Left atrial pressure monitoring during CPB is most valuable for detecting:
Answer: Left ventricular distension from aortic insufficiency
Elevated left atrial pressure during a cross-clamped, non-ejecting heart indicates LV distension, often from aortic regurgitation allowing blood to pool in the ventricle.
Which condition would cause a falsely elevated arterial blood pressure reading from a radial arterial line during CPB?
Answer: Peripheral vasoconstriction with radial-to-aortic pressure gradient
Peripheral vasoconstriction can create a radial-to-aortic gradient where the radial artery reads lower than central aortic pressure, but in some hypothermic states the reverse occurs, yielding a falsely high peripheral reading.