ANAEROBIC METABOLISM IN PATIENTS UNDERGOING INTRAAORTIC BALLOON COUNTERPULSATION FOR CARDIOGENIC-SHOCK

To find the best predictors of outcome for patients undergoing intra-a ortic balloon counterpulsation (IABP) for cardiogenic shock, we prospe ctively studied 30 consecutive patients by examining hemodynamic param eters and cardiac lactic acid extraction ratios before the procedure, 1 hour after and then every 6 hours for 3 days. Complete hemodynamic d ata were obtained from the recordings of Sivan-Ganz catheterization. B lood samples were drawn from the peripheral artery, central vein. pulm onary artery wedge position (PAW) and right atrium (RA) to quantify la ctic acid levels. The simplified lactic acid extraction ratio was defi ned as the concentration of lactic acid in RA - the concentration of l actic acid in PAW/the concentration of acid in PAW. The traditional sy stemic lactic acid production ratio was defined as the concentration o f lactic acid in the central vein - the concentration of lactic acid i n the peripheral artery/the concentration of lactic acid in the periph eral artery. Of the 30 patients studied, 19 died of cardiogenic shock, (group 1), while the surviving 11 patients formed group 2. The lactic acid extraction ratios at each of the time periods after the procedur e were all significantly different, while the differences in the syste mic lactic acid production ratio and hemodynamic parameters, including the systemic arterial pressure, cardiac output, cardiac index and PAW pressure, became significant at varying times after IABP. In group 2, the lactic acid extraction ratios 1 hour after IABP and later were al l significantly higher than at baseline. This trend was not seen in gr oup 1. By linear regression analysis, the systemic lactic acid product ion ratio correlated well with the hemodynamic parameters, while the s implified lactic acid extraction ratio did not because of different ti me sequences in its evolution. The lactic acid extraction ratio is the best and earliest predictor of the outcome of patients undergoing IAB P for cardiogenic shock.