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
During CPB, a sudden drop in arterial line pressure with unchanged pump flow most likely indicates which of the following?
Answer: Aortic dissection at the cannulation site
A sudden pressure drop with unchanged flow suggests aortic dissection, where blood tracks into the false lumen reducing effective forward perfusion.
Which pulmonary artery catheter parameter is most useful for assessing right ventricular afterload during CPB?
Answer: Pulmonary vascular resistance
Pulmonary vascular resistance (PVR) directly quantifies the impedance against which the right ventricle must eject, making it the best measure of RV afterload.
A mixed venous oxygen saturation (SvO2) of 55% during normothermic CPB at a flow of 2.4 L/min/m² suggests:
Answer: Increased oxygen consumption or reduced flow
SvO2 below 65% at normothermia indicates oxygen extraction is elevated, reflecting either insufficient delivery or increased metabolic demand.
When the arterial blood pressure waveform dampens and the pulse pressure narrows significantly during full CPB, the most likely explanation is:
Answer: A kinked or partially occluded arterial pressure line
A dampened waveform with narrow pulse pressure typically results from a mechanical obstruction or air bubble in the monitoring line rather than a true hemodynamic event.
During hypothermic CPB at 28°C, the target mean arterial pressure recommended to ensure adequate cerebral perfusion in most adult patients is:
Answer: 50–70 mmHg
Most guidelines recommend maintaining MAP between 50–70 mmHg during moderate hypothermic CPB, balancing cerebral perfusion with surgical field conditions.
Which of the following best explains a sudden rise in venous line pressure during CPB without a change in pump speed?
Answer: Venous cannula obstruction or malposition
Elevated venous line pressure at constant pump speed suggests obstruction to venous drainage, often from cannula malposition, kinking, or cavitation.
Cerebral oximetry (rSO2) monitoring during CPB primarily detects imbalances in:
Answer: Regional cerebral oxygen supply-demand ratio
Near-infrared spectroscopy-based cerebral oximetry measures regional cortical oxygen saturation, reflecting the local balance between cerebral O2 supply and demand.