Effect of intraoperative goal-directed balanced crystalloid versus colloid administration on postoperative maximum NT-proBNP concentration in patients undergoing noncardiac surgery

Abstract

Background: N-terminal pro brain natriuretic peptide (NT-proBNP) and troponin T are released during myocardial wall stress and/or ischemia and are strong predictors for postoperative cardiovascular complications. However, the effect of goal-directed crystalloid versus colloid administration on NT-proBNP and troponin T, especially in relatively healthy patients undergoing moderate- to high risk abdominal surgery, still remains unclear. Thus, we evaluated in this sub-study the effect of a goal-directed crystalloid versus a goal-directed colloid fluid regimen on postoperative maximum NT-proBNP concentration. We further evaluated the incidence of MINS between both study groups. Methods: 30 patients were randomly assigned to receive additional intravenous fluid boluses of 6% hydroxyethyl starch 130/0.4 and 30 patients to receive lactated Ringer´s solution. Intraoperative fluid management was guided by oesophageal Doppler-according to a previously published algorithm. The primary outcome were differences in postoperative maximum NT-proBNP (maxNT-proBNP) between both groups. As our secondary outcome we evaluated the incidence of MINS between both study groups. We defined maxNT-proBNP as the maximum value measured within 2 hours after surgery and on the first and second postoperative day. Results: In total 56 patients were analysed. There was no significant difference in postoperative maximum NT-proBNP between the colloid group (258.7 ng/L (IQR 199.4 to 782.1)) and the crystalloid group (440.3 ng/L (IQR 177.9 to 691.2)) during the first 2 postoperative days (P = 0.29). 5 patients in the colloid group and 7 patients in the crystalloid group developed MINS (P = 0.75).Conclusions: Based on this relatively small study goal-directed colloid administration did not decrease postoperative maxNT-proBNP concentration as compared to goal-directed crystalloid administration. Trial registration: ClinicalTrials.gov (NCT01195883)