Association between perioperative hypotension and postoperative delirium and atrial fibrillation after cardiac surgery: A post-hoc analysis of the DECADE trial

Abstract

Study objective: To test the hypotheses that in adults having cardiac surgery with cardio-pulmonary bypass, perioperative hypotension increases the risk of delirium and atrial fibrillation during the initial five postoperative days.

Design: Sub-analysis of the DECADE multi-center randomized trial.

Setting: Patients who had cardiac surgery with cardiopulmonary bypass at the Cleveland Clinic.

Interventions: In the underlying trial, patients were randomly assigned 1:1 to dexmedetomidine or normal saline placebo.

Measurements: Intraoperative mean arterial pressures were recorded at 1-min intervals from arterial catheters or at 1-5-min intervals oscillometrically. Postoperative blood pressures were recorded every half-hour or more often. The co-primary outcomes were atrial fibrillation and delirium occurring between intensive care unit admission and the earlier of postoperative day 5 or hospital discharge. Delirium was assessed twice daily during the initial 5 postoperative days while patients remained hospitalized with the Confusion Assessment Method for the intensive care unit. Assessments were made by trained research fellows who were blinded to the dexmedetomidine administration.

Main results: There was no significant association between intraoperative hypotension and delirium, with an adjusted odds ratio of 0.94 (95% CI: 0.81, 1.09; P = 0.419) for a doubling in AUC of mean arterial pressure (MAP) <60 mmHg. An increase in intraoperative AUC of MAP <60 mmHg was not significantly associated with the odds of atrial fibrillation (adjusted odds ratio = 0.99; 95% CI: 0.87, 1.11; P = 0.819). Postoperative MAP <70 mmHg per hour 1.14 (97.5% CI: 1.04,1.26; P = 0.002) and MAP <80 mmHg per hour 1.05 (97.5%: 1.01, 1.10; P = 0.010) were significantly associated with atrial fibrillation.

Conclusions: In patients having cardiac surgery with cardio-pulmonary bypass, neither intraoperative nor postoperative hypotension were associated with delirium. Postoperative hypotension was associated with atrial fibrillation, although intraoperative hypotension was not.

Keywords: Anesthesia; Atrial fibrillation; Delirium; Hypotension.