Higher intraoperative mean arterial blood pressure does not reduce postoperative delirium in elderly patients following gastrointestinal surgery: A prospective randomized controlled trial

BACKGROUND: This study aimed to describe the relationship between the different levels of intraoperative mean arterial blood pressure (MAP) and postoperative delirium in elderly patients undergoing gastrointestinal laparoscopic surgery. MATERIALS AND METHODS: This prospective controlled clinical trial enrolled 116 patients aged 65 to 85 years who underwent gastrointestinal laparoscopic surgery. These patients were randomized 1:1 to a MAP goal of 65 to 85 mmHg (L group) or an 86 to 100 mmHg (H group). The primary endpoint was the incidence of postoperative delirium, assessed twice daily with the Confusion Assessment Method (CAM) and Richmond Agitation–Sedation Scale (RASS) during the first five postoperative days. Delirium severity was evaluated with the Delirium-O-Meter (D-O-M). RESULTS: 108 patients (L group n = 55, H group n = 53) were eventually included in intention-to-treat analyses. Postoperative delirium occurred in 18 (32.7%) of 55 cases of L group and in 15 (28.3%) of 53 cases of H group. The incidence of delirium subtypes between the two groups: hypoactive delirium 14.5% (8/55) vs 11.3% (6/53); hyperactive delirium 7.3% (4/55) vs 3.8% (2/53); mixed delirium 10.9% (6/55) vs 13.2% (7/53). However, the L group showed higher D-O-M scores of the first episode of delirium: 14.5 (Q1 = 12, Q3 = 18.5) vs 12 (Q1 = 10, Q3 = 14), which means the delirium is more severe. CONCLUSIONS: Compared with 65 to 85 mmHg, maintaining intraoperative MAP at 86–100 mmHg did not reduce the incidence of postoperative delirium in elderly patients undergoing gastrointestinal laparoscopic surgery. However, the severity of delirium could be reduced and blood loss is a risk factor for postoperative delirium.