Intraoperative hypotension is associated with acute kidney injury in noncardiac surgery: An observational study.

Abstract

Perioperative acute kidney injury (AKI) is common and increases the risk of morbidity and mortality. To determine the association between intraoperative hypotension, defined as an individual decrease from baseline and the risk of perioperative AKI. Observational cohort study. Karolinska University Hospital, Stockholm, Sweden, from October 2012 to May 2013 and October 2015 and April 2016. All adult patients undergoing major elective noncardiac surgery who were scheduled for an overnight admission in the postoperative unit were included. Patients undergoing phaeochromocytoma surgery were excluded. Preoperative risk factors (comorbidities), intraoperative events (hypotension defined as a more than 40 or 50% decrease in SBP relative to each patient's baseline and lasting more than 5 min) and postoperative data were collected from medical records. AKI within the first two postoperative days. Of the final cohort of 470 patients, 127 (27%) developed AKI in the perioperative period. AKI was associated with male sex [(66 vs. 48%) P < 0.001], a higher preoperative creatinine (81 vs. 73 μmol l, P = 0.003), American Society of Anaesthesiologists class more than two (54 vs. 42%, P = 0.014) and preoperative hypertension (54 vs. 40%, P = 0.005). During surgery, the AKI subgroup had more hypotensive events (>40%, 70 vs. 57%, P = 0.013; >50%, 20 vs. 12%, P = 0.024) and greater blood loss (800 vs. 400 ml, P < 0.001). Postoperatively, in AKI patients a positive fluid balance was more common (3123 vs. 2700 ml, P < 0.001), as was 30-day mortality (4 vs. 1%, P < 0.005). Multivariate analyses demonstrated that an intraoperative reduction of SBP more than 50% was associated with a more than doubled risk of AKI, adjusted odds ratio 2.27; 95% CI, 1.20 to 4.30, P = 0.013. In patients undergoing noncardiac surgery, there was a high incidence of perioperative AKI. Intraoperative avoidance of hypotension may decrease the risk of AKI.