RESUMEN
BACKGROUND: Intraaortic balloon pumping is known to be ineffective in severe cardiogenic shock. The efficacy of balloon volumes larger than those commonly used is examined. METHODS: In 18 dogs with severe experimental cardiogenic shock (systolic aortic pressure < 60 mm Hg, aortic flow < 45 mL.min-1.kg-1) the effect of three intraaortic balloon volumes (15, 30, and 45 mL) and a 60-mL paraaortic pump was examined. RESULTS: The 45-mL balloon covering the full length of the aorta induced the highest (+ 12.4 +/- 2.2 mL.min-1.kg-1; mean +/- standard error of the mean) and the 15-mL balloon the lowest increase in aortic flow (F = 14.6, p < 0.0001). Only the 45-mL balloon increased (p < 0.05) urine output and renal artery flow. The 60-mL paraaortic pump induced the highest (F = 10.72, p < 0.002) increase (+ 36.6 +/- 6.5 mL.min-1.kg-1) in aortic flow compared to the three balloons. An 80- to 100-mL paraaortic pump maintained the life of 3 patients in severe cardiogenic shock for 4 hours, 8 days, and 54 days, whereas a 40-mL conventional balloon was completely ineffective. CONCLUSIONS: Experimental and clinical data indicate that the effectiveness of intraaortic balloon pumping in severe cardiogenic shock may be improved by increasing the volume of the balloon (i.e., until it fully occupies the aorta).