ECG and pressure tracing on IABP
Pressure tracing and ECG while on intra aortic balloon counterpulsation. The upper channels shows the ECG and the lower channel shows the arterial pressure tracing. It can be clearly seen that the diastolic pressure (after the T wave on the electrocardiogram) is much higher than the systolic pressure. This is because the intra aortic balloon is inflated in diastole and deflated in systole. IABP is inserted to support the left ventricle and to reduce the after load. Inflation of the balloon in diastole enhances the coronary perfusion and is very useful in cardiogenic shock due to myocardial infarction. The balloon is inserted percutaneously through the femoral artery. The upper part of the balloon is kept below the left subclavian artery in the descending thoracic aorta. The lower part is above the renal arteries. The balloon size is chosen according to the size of the individual to meet the above criteria.
IABP monitor screen shot
The upper most green tracing is the electrocardiogram which is used to time the inflation and deflation of the balloon. The augmentation time is marked just below the tracing to indicate the exact point of inflation and deflation. The arterial pressure tracing just below that indicates the diastolic augmentation. The figure on the top in green colour (130) indicates the heart rate. The figures below are the peak, trough and mean pressures from the arterial line. Augmentation level and alarm limit for the augmentation are the lower figures. The filling level of the helium tank is also indicated. The diagram of the graduated balloon will show the filling in real time by the flickering of light on and off. Helium is used for filling the balloon because it is the lightest inert gas which can move in and out rapidly according to the cardiac cycle. Balloon inflation and deflation can be triggered either by the ECG or by the pressure tracing. In auto mode the choice is done by the circuitry automatically. IABP will not work in the presence of significant aortic regurgitation. Significant aortic disease is another contraindication for the insertion of an IABP.