Mixed Deck — All CCP Topics Flashcards

How is oxygen saturation typically measured?

Answer: Pulse oximetry

Oxygen saturation is typically measured non-invasively using a pulse oximeter. This device clips onto a finger or earlobe and uses light absorption to estimate the percentage of hemoglobin in the blood that is saturated with oxygen. Pulse oximetry provides a quick, continuous, and convenient assessment of a patient's oxygenation status.

The 'afterdrop' phenomenon after CPB rewarming refers to:

Answer: Continued fall in core temperature after rewarming is stopped

Afterdrop is the continued decrease in core temperature after active rewarming stops, caused by cold blood returning from peripheral tissues.

Polymethylpentene (PMP) oxygenators differ from polypropylene oxygenators primarily because PMP fibers are:

Answer: True membranes with no open pores, preventing plasma leakage

PMP fibers are diffusion membranes without open pores, eliminating plasma breakthrough and enabling longer safe use.

A 'soft-shell' venous reservoir differs from a 'hard-shell' reservoir in that it:

Answer: Collapses as volume decreases, preventing air aspiration by the pump

Soft-shell (collapsible) reservoirs collapse when volume is low, providing a visual warning and preventing the pump from aspirating air.

What is the anion gap in a patient with Na+ 140, Cl- 102, HCO3- 18 mEq/L?

Answer: 20 mEq/L

Anion gap = Na+ − (Cl- + HCO3-) = 140 − (102 + 18) = 20 mEq/L, which is elevated above the normal range of 8–12 mEq/L.

Why is flow rate control critical in extracorporeal circulation?

Answer: Maintains adequate tissue perfusion

Flow rate control is paramount in extracorporeal circulation because it directly determines the amount of blood delivered to the patient's body per minute. Maintaining an adequate flow rate ensures that all tissues and organs receive sufficient oxygen and nutrients, preventing cellular damage and supporting organ function during bypass. Inadequate flow can lead to severe complications.

What causes hypoxemia?

Answer: Low oxygen levels in arterial blood

Hypoxemia is defined as an abnormally low concentration of oxygen in the arterial blood. This condition indicates that the body is not receiving sufficient oxygen, which can impair organ function and lead to various health complications. It is often diagnosed through arterial blood gas analysis or by monitoring oxygen saturation levels.

What is the function of the right ventricle?

Answer: Pumps blood to the lungs

The right ventricle is one of the four chambers of the heart, specifically responsible for pumping deoxygenated blood. It receives blood from the right atrium and then forcefully contracts to push this blood into the pulmonary artery, which carries it to the lungs for oxygenation. This is a crucial step in the pulmonary circulation, preparing blood for systemic distribution.

What is the rationale for recirculating the CPB prime through the circuit for several minutes before initiating bypass?

Answer: To remove residual air, mix additives uniformly, and allow the circuit to equilibrate

Recirculation ensures all residual air is purged, drugs are uniformly distributed, and the circuit components are wetted and equilibrated before patient blood enters the circuit.

What is the primary ethical obligation of a CCP professional when a conflict of interest arises during hemodynamic monitoring during bypass activities?

Answer: Disclose the conflict to all relevant parties and recuse from the decision if necessary

The primary ethical obligation when a conflict of interest arises in hemodynamic monitoring during bypass is to disclose it to all relevant parties and, if necessary, recuse from the decision. This maintains professional integrity and stakeholder trust.

Which factor most significantly affects the gas transfer efficiency of a membrane oxygenator during CPB?

Answer: The ratio of blood flow to membrane surface area (blood-side resistance)

Gas transfer efficiency depends heavily on blood-side resistance; an appropriate sweep gas-to-blood flow ratio and adequate membrane surface area are critical for optimal O2 delivery and CO2 removal.

What is the primary advantage of warm blood cardioplegia ('hot shot') administered just before aortic cross-clamp removal?

Answer: It provides aerobic resuscitation and clears ischemic metabolites

A warm blood cardioplegia terminal dose ('hot shot') delivers oxygen and substrates to repay the oxygen debt and flush metabolic waste before reperfusion.

A patient on CPB receives phenylephrine to treat hypotension. The expected hemodynamic response includes:

Answer: Increased SVR with reflex bradycardia

Phenylephrine is a pure alpha-1 agonist that increases SVR; the resulting rise in blood pressure triggers a baroreceptor-mediated reflex bradycardia.

During CPB at normothermia, a patient has measured PaO2 of 200 mmHg. Calculated oxygen content (CaO2) depends primarily on:

Answer: Hemoglobin concentration and SaO2, with a minor contribution from dissolved O2

CaO2 = (Hb × 1.34 × SaO2) + (0.003 × PaO2); at normal hemoglobin levels, bound oxygen constitutes >98% of total content while dissolved oxygen is minimal.

A perfusionist is asked by a medical student to step away from the pump console to demonstrate equipment. What is the safest response?

Answer: Decline and offer to demonstrate equipment before or after the case

The perfusionist must maintain continuous vigilance at the console during bypass; education should occur outside of active patient care moments.

An intraoperative transesophageal echocardiogram (TEE) shows significant aortic valve regurgitation during CPB. The perfusionist's primary concern should be:

Answer: LV distension from aortic regurgitation compromising myocardial protection

Aortic regurgitation during cardioplegia delivery allows cardioplegia to leak back into the LV, causing ventricular distension and inadequate myocardial protection.

Which blood parameter is critical to monitor for tissue oxygenation?

Answer: Arterial blood gases

Arterial blood gases (ABGs) provide crucial real-time information about a patient's oxygenation, ventilation, and acid-base balance. Perfusionists meticulously monitor parameters such as PaO2 (partial pressure of oxygen), PaCO2 (partial pressure of carbon dioxide), and pH from ABG samples. This allows for precise adjustments to the bypass circuit's gas exchange and flow, ensuring optimal tissue oxygenation and metabolic stability throughout the surgical procedure.

What is the main function of the pulmonary artery?

Answer: Carries deoxygenated blood to lungs

The pulmonary artery is unique among arteries because it carries deoxygenated blood. It originates from the right ventricle of the heart and branches into smaller arteries that deliver this oxygen-poor blood to the capillaries surrounding the alveoli in the lungs. Here, gas exchange occurs, and the blood becomes oxygenated before returning to the heart.

Low molecular weight heparins (LMWH) differ from unfractionated heparin (UFH) in that LMWHs preferentially inhibit:

Answer: Factor Xa more than IIa

LMWHs have an anti-Xa:anti-IIa ratio of approximately 2:1 to 4:1, compared to UFH's 1:1 ratio, due to their shorter chain length.

Which statement best describes the Frank-Starling mechanism as it applies to perfusion management?

Answer: Stroke volume increases with preload up to a point, then plateaus or declines in a failing heart

The Frank-Starling mechanism states that stroke volume increases with preload within physiologic limits, but a failing ventricle may not augment output with further volume loading.