Timing of inflation of an intra-aortic balloon pump (IABP) should be
ExplanationB. IABP is sometimes used to facilitate weaning the patient off cardiopulmonary bypass. This provides a systolic augmentation of blood pressure in addition to improving myocardial oxygen supply during diastole. Timing and location of an IABP are critical for optimal functioning. Ideal inflation of the balloon should be just after the dicrotic notch (closure of aortic valve). Inflation while the aortic valve is still open can increase afterload, worsen aortic regurgitation and left-ventricular (LV) volume. Inflation too late in the diastolic phase will reduce diastolic augmentation and myocardial supply. Similarly, the deflation should be timed just prior to LV ejection to produce an optimal reduction in afterload. Timing is usually synchronized with EKG/arterial pulse. The location of the tip of the IABP should be just distal to the takeoff of the left-subclavian artery, usually confirmed with transesophageal echocardiograph/fluoroscopy.
