Perioperative supplemental oxygen and NT-proBNP concentrations after major abdominal surgery - A prospective randomized clinical trial.

Abstract

STUDY OBJECTIVE\nSupplemental oxygen is a simple method to improve arterial oxygen saturation and might therefore improve myocardial oxygenation. Thus, we tested whether intraoperative supplemental oxygen reduces the risk of impaired cardiac function diagnosed with NT-proBNP and myocardial injury after noncardiac surgery (MINS) diagnosed with high-sensitivity Troponin T.\n\n\nDESIGN\nParallel-arm double-blinded single-centre superiority randomized trial.\n\n\nSETTING\nOperating room and postoperative recovery area.\n\n\nPATIENTS\n260 patients over the age of 45\xa0years at-risk for cardiovascular complications undergoing major abdominal surgery.\n\n\nINTERVENTION\nAdministration of 80% versus 30% oxygen throughout surgery and for the first two postoperative hours.\n\n\nMEASUREMENTS\nThe primary outcome was the postoperative maximum NT-proBNP concentration in both groups, which was assessed within 2\xa0h after surgery, and on the first and third postoperative day. The secondary outcome was the incidence of MINS in both groups.\n\n\nMAIN RESULTS\n128 patients received 80% oxygen and 130 received 30% oxygen throughout surgery and for the first two postoperative hours. There was no significant difference in the median postoperative maximum NT-proBNP concentration between the 80% and the 30% oxygen group (989\xa0pg.mL-1 [IQR 499; 2005] and 810\xa0pg.mL-1 [IQR 409; 2386], effect estimate: 159\xa0pg.mL-1, 95%CI -123, 431, p\xa0=\xa00.704). There was no difference in the incidence of MINS between both groups. (p\xa0=\xa00.703).\n\n\nCONCLUSIONS\nThere was no beneficial effect of perioperative supplemental oxygen administration on postoperative NT-proBNP concentration and MINS. It seems likely that supplemental oxygen has no effect on the release of NT-proBNP in patients at-risk for cardiovascular complications undergoing major abdominal surgery.\n\n\nTRIAL REGISTRATION\nClinicalTrials.gov: NCT03366857. https://clinicaltrials.gov/ct2/results?cond=NCT+03366857&term=&cntry=&state=&city=&dist=.