Higher versus lower mean arterial pressure target management in older patients having non-cardiothoracic surgery: A prospective randomized controlled trial

This study aimed to evaluate the effects of low versus high mean arterial pressure (MAP) levels on the incidence of postoperative delirium during non-cardiothoracic surgery in older patients.Multicenter, randomized, parallel-controlled, open-label, and assessor-blinded clinical trial.University hospital.Three hundred twenty-two patients aged ≥65 with an American Society of Anesthesiologists physical status of I-II who underwent non-cardiothoracic surgery with general anaesthesia.Participants were randomly assigned into a low-level MAP (60-70 mmHg) or high-level MAP (90-100 mmHg) group during general anaesthesia. The study was conducted from November 2016 to February 2020. Participants were older patients having non-cardiothoracic surgery. The follow-up period ranged from 1 to 7 days after surgery. The primary outcome was the incidence of postoperative delirium.In total, 322 patients were included and randomized; 298 completed in-hospital delirium assessments [median (interquartile range) age, 73 (68-77) years; 173 (58.1%) women]. Fifty-four (18.1%) patients total, including 36 (24.5%) and 18 (11.9%) in the low-level and high-level MAP groups [relative risk (RR) 0.48, 95% confidence interval (CI) 0.25 to 0.87, P = 0.02], respectively, experienced postoperative delirium. The adjusted RR was 0.34 (95% CI 0.16 to 0.70, P < 0.01) in the multiple regression analysis. High-level MAP was associated with a shorter delirium span and a higher intraoperative urine volume than low-level MAP.In older patients during non-cardiothoracic surgery, high-level blood pressure management might help reduce the incidence of postoperative delirium.