Triggers for IABP

Triggers for IABP

Intra-Aortic Balloon Pump inflates the balloon in descending aorta in diastole and deflates it at the onset of systole.

This image of the IABP screen shows diastolic augmentation in the pressure tracing. Period during which the balloon remains inflated is shown as a horizontal bar below the ECG tracing at the top. Live visual indication of balloon inflation will also be there in the balloon inflation indicator at the bottom of the screen when the IABP is operational. Any of the several types of triggers can be used for timing for inflation in diastole.

1. ECG trigger: Balloon will be inflated in the middle of the T wave and deflated at the peak of the R wave. ECG triggering becomes unreliable in case of arrhythmias and poor ECG quality.
2. Pressure trigger: Arterial waveform is used to trigger in this mode. Aortic valve closure corresponds to the dicrotic notch in the pressure tracing and initiates balloon inflation. Aortic valve opening corresponds to the point immediately before the systolic upstroke of the pressure tracing and initiates balloon deflation.
3. Internal trigger: Internal trigger mode is an asynchronous mode which can be set at an empirical heart rate. This mode is used in asystolic cardiac arrest when ECG trigger and pressure trigger are not possible. It can also be used during cardiopulmonary bypass to give pulsatile flow which may improve whole body perfusion.
4. Pacer triggers: Pacer ventricular/Atrioventricular trigger modes initiates balloon inflation based on the ventricular pacing spike. Usually this mode can be used only when the subject has 100% pacing as these modes are set for fixed rates rather than demand pacing.
5. Atrial fibrillation trigger: Some consoles have an AF trigger mode in which the system analyzes the QRS complexes and times balloon deflation on sensing an R wave. This mode rejects pacing spikes and artifacts.

Reference

1. Webb CA, Weyker PD, Flynn BC. Management of intra-aortic balloon pumps. Semin Cardiothorac Vasc Anesth. 2015 Jun;19(2):106-21. doi: 10.1177/1089253214555026. Epub 2014 Oct 27. PMID: 25348545.