Intra-aortic balloon inflation and deflation timing

The timing of balloon inflation and deflation is adjusted in the 1:2 mode. The inflation point is moved rightward (later) until it occurs in late diastole, and the dicrotic notch is uncovered. The inflation timing is moved progressively earlier in the cardiac cycle until the dicrotic notch on the central aortic tracing just disappears. Examples of early, late, and correct inflation are shown in the top two tracings. Similarly, the deflation knob is moved leftward (earlier) and then slowly advanced toward the right (later in the cardiac cycle) until the end-diastolic pressure dips 10 to 15 mmHg below the patient's unassisted diastolic pressure. This will produce a maximal lowering of the patient's unassisted systolic pressure. Examples of early, late, and correct deflation timing are shown in the bottom two traces.