CPB Flashcards
Q:
What should the activated clotting time (ACT) be before starting cardiopulmonary bypass (CPB)?
A:
The ACT should typically be greater than 400–480 seconds before initiating CPB to ensure adequate anticoagulation.
Q:
What can cause hypotension during CPB if the flow rate is deliberately decreased?
A:
Hypotension can occur if the perfusionist decreases the flow rate intentionally, such as when the surgeon is clamping the aorta or managing bleeding.
Q:
What causes inadequate flow and hypotension during CPB?
A:
Inadequate flow can result from an arterial cannula that is too small for the patient’s body surface area (BSA), a kinked or clamped arterial line, or poor roller head occlusion.
Q:
What causes low systemic vascular resistance (SVR) during CPB, and how can it be managed?
A:
Low SVR can be due to vasodilation or hemodilution. It can be managed by administering phenylephrine to increase vascular tone.
Q:
How can cytokines affect blood pressure during CPB?
A:
Cytokines released from the sudden return of pooled blood via pump suckers can cause hypotension.
Q:
What can cause high central venous pressure (CVP) during CPB?
A:
High CVP can result from poor venous drainage due to:
Inadvertently snaring the superior vena cava (SVC) proximal to the cannula, obstructing venous return.
A catheter abutting the SVC wall, being obstructed by the venous pipe, or being inadvertently snared by the surgeon.
Q:
What criteria must be met before discontinuing CPB?
A:
-No conditions requiring CPB, such as residual valve leaks or bleeding.
-Satisfactory cardiac rhythm with a ventricular rate >60 bpm, paced if necessary, and adequate cardiac function with minimal intracardiac air.
-Nasopharyngeal temperature between 36.5–37.5°C.
-Potassium (K⁺) levels between 4.0–5.0 mmol/L.
-pH between 7.30–7.50.
-Partial pressure of oxygen (pO₂) >16 kPa (120 mmHg).
Anesthesiologist has resumed ventilating the lungs.
