Intraoperative hypotension is not associated with postoperative cognitive dysfunction in elderly patients undergoing general anesthesia for surgery: results of a randomized controlled pilot trial

Abstract

Study objective: To assess the effect of different intraoperative blood pressure targets on the development of POCD and test the feasibility of a larger trial.

Design: Randomized controlled pilot trial.

Setting: Perioperative care in a tertiary care teaching hospital with outpatient follow-up.

Patients: One hundred one patients aged ≥75 years with ASA physical status <4, undergoing elective, non-cardiac surgery under general anesthesia and 33 age-matched healthy controls.

Interventions: Randomization to a personalized intraoperative blood pressure target, mean arterial pressure (MAP) ≥ 90% of preoperative values (Target group), or to a more liberal intraoperative blood pressure management (No-Target group). Strategies to reach intraoperative blood pressure target were at discretion of anesthesiologists.

Measurements: An experienced neuropsychologist performed a validated battery of neurocognitive tests preoperatively and 3 months after surgery. Incidence of POCD at three months and postoperative delirium were assessed. Intraoperative time spent with MAP ≥ 90% of preoperative values, recruitment and drop-out rate at 3 months were feasibility outcomes.

Main results: The Target group spent a higher percentage of intraoperative time with MAP ≥90% of preoperative values (65 ± 25% vs. 49 ± 28%, p < 0.01). Incidence of POCD (11% vs. 7%, relative risk 1.52; 95% CI, 0.41 to 6.3; p = 0.56) and delirium (6% vs. 14%, relative risk, 0.44; 95% CI, 0.12 to 1.60; p = 0.21) did not differ between groups. No correlation was found between intraoperative hypotension and postoperative cognitive performance (p = 0.75) or delirium (p = 0.19). Recruitment rate was of 6 patients/month (95% confidential interval (CI), 5 to 7) and drop-out rate at 3 months was 24% (95% CI, 14 to 33%).

Conclusions: Intraoperative hypotension did not correlate with postoperative cognitive dysfunction or delirium occurrence in elderly patients undergoing general anesthesia for non-cardiac surgery. A multicenter randomized controlled trial is needed in order to confirm the effect of intraoperative blood pressure on the development of POCD.

Trial registration number: NCT02428062www.clinicaltrials.gov.

Keywords: Anesthesia, general; Blood pressure; Cognitive dysfunction; Delirium; Frail elderly.