How Should I Wean Intra-aortic Balloon Pump? Differences In Hemodynamic Response Between Progressive "volume-" and "rate-" Weaning

Objectives: To evaluate the best method to wean a patient from intra-aortic balloon pump (IABP) after cardiogenic shock. Methods: Thirty consecutive patients needing intraoperative IABP because of cardiogenic shock were enrolled in the study and randomized in the Intensive-Care Unit (ICU) to 2 different weaning protocols. Fifteen patients were randomized to be weaned by ratio (4 consecutive hours of 1:2 assisting ratio followed by 1 hour of 1:3 ratio; Group-R), 15 by progressive volume deflation (10 cc every hour for 5 consecutive hours; Group-V). Weaning protocol started if cardiac index >2.5 L/min/m2, CVP≤12 mm/Hg, blood lactate <2.5mmol/L, mean arterial pressure >65 mm/Hg with a preserved diuresis of at least 5 consecutive hours. Five hours were “a-priori” set as weaning duration. IABP lasting >5hours was defined “failure”. Pressure recording analytical method(PRAM) collected cardiac index(CI), indexed systemic vascular resistances(SVRI), and cardiac cycle efficiency(CCE) at 8 different time-points (T1 to T5 for the first 5 weaning hours, T6: 2 hours post-withdrawal; T7: 12 hours post-withdrawal; T8: ICUdischarge). Central venous pressure(CVP) at the same time-points, time from IABP-withdrawal to ICU-discharge and weaning failure were also recorded. Perioperative troponin-I and lactate leakage were compared. Repeated measures ANOVA assessed group, time and group*time interactions. Results: All patients were successfully weaned and discharged home. Group-V showed better preserved CI, CCE and CVP (group*time p=.0001 for all). Group-R had worse CCE since T3 to T8 (p≤.001), CVP since T4 to T8 (p≤.0001) and CI since T5 to T8 (p≤.0001). SVRI proved comparable during the entire weaning period (p=NS). Despite no differences were detected in troponin-I leakage, lactate proved lower in V-group since T5 to T8 (p≤.027). Time from IABP-withdrawal to ICU-discharge proved longer in Group-R (p=.0001). Conclusions: Despite the quite similar clinical outcome, weaning the IABP by volume deflation after cardiogenic shock better preserved the hemodynamic parameters.