RCIS Intra-Aortic Balloon Pump and Mechanical Circulatory Support 1 — Questions and Answers
Question 1: The intra-aortic balloon pump (IABP) inflates at which point on the arterial waveform?
- QRS complex
- Dicrotic notch (Correct answer)
- Systolic peak
- T-wave end
Correct answer: Dicrotic notch
The IABP inflates at the dicrotic notch, which represents aortic valve closure and the onset of diastole, maximizing diastolic augmentation.
Question 2: Which of the following is an absolute contraindication for IABP insertion?
- Severe mitral regurgitation
- Moderate aortic stenosis
- Significant aortic regurgitation (Correct answer)
- Left bundle branch block
Correct answer: Significant aortic regurgitation
Significant aortic regurgitation is an absolute contraindication because IABP inflation during diastole worsens regurgitant flow back into the left ventricle.
Question 3: What is the primary hemodynamic benefit of IABP counterpulsation?
- Increased heart rate
- Decreased diastolic aortic pressure
- Increased coronary perfusion pressure (Correct answer)
- Increased left ventricular preload
Correct answer: Increased coronary perfusion pressure
Diastolic balloon inflation augments diastolic aortic pressure, which directly increases coronary perfusion pressure since coronaries fill during diastole.
Question 4: The optimal tip position of an IABP catheter on chest X-ray is:
- At the aortic valve
- 2 cm distal to the left subclavian artery (Correct answer)
- At the level of the renal arteries
- In the descending thoracic aorta at the diaphragm
Correct answer: 2 cm distal to the left subclavian artery
The balloon tip should be positioned 2 cm distal to the left subclavian artery to avoid occluding the subclavian or carotid arteries during inflation.
Question 5: IABP deflation should occur:
- At the dicrotic notch
- During mid-diastole
- Just before systole (end diastole) (Correct answer)
- At the systolic peak
Correct answer: Just before systole (end diastole)
Deflation just before systole reduces afterload by creating a pressure void, decreasing left ventricular work during the ejection phase.
Question 6: Which trigger mode for IABP is preferred when a patient has an irregular cardiac rhythm?
- ECG R-wave trigger
- Arterial pressure trigger (Correct answer)
- Internal asynchronous trigger
- Pacemaker spike trigger
Correct answer: Arterial pressure trigger
The arterial pressure trigger is preferred in irregular rhythms because it responds directly to the arterial pressure waveform, which is more reliable than the ECG in arrhythmias.
Question 7: A 1:2 IABP assist ratio is used to:
- Maximize hemodynamic support in cardiogenic shock
- Wean the patient off IABP support (Correct answer)
- Treat ventricular fibrillation
- Increase heart rate
Correct answer: Wean the patient off IABP support
A 1:2 assist ratio (balloon inflates every other beat) is used during weaning to gradually reduce dependence on IABP support before removal.
RCIS Intra-Aortic Balloon Pump and Mechanical Circulatory Support 1
The intra-aortic balloon pump (IABP) inflates at which point on the arterial waveform?