Preoperative cognitive impairment associated with oversedation during recovery from anesthesia

Our objective was to examine the association between preoperative cognitive status and postoperative recovery from anesthesia.

We included patients (70-91 years old) from the Mayo Clinic Study of Aging who received general anesthesia and were admitted to the postanesthesia care unit from January 1, 2010 through April 30, 2018. Procedures were categorized according to patient's preoperative cognitive status: cognitive impaired (CI) and cognitive unimpaired (CU). Perioperative records were reviewed and analyses were performed with generalized estimating equations.

A total of 896 procedures from 611 patients were included, with 203 (22.7%) procedures in the CI group. Compared to CU procedures, CI procedures had higher rates of moderate-deep sedation during anesthesia recovery (52 [25.6%] vs. 103 [14.9%]; odds ratio [OR], 1.91; 95% CI, 1.30-2.80; P  < 0.01), postoperative pulmonary complications (22 [10.8%] vs. 34 [4.9%]; OR, 2.36[1.22-4.54]; P  =  0.01), and postoperative delirium (32 [16.2%] vs. 24 [3.5%]; OR, 5.33 [2.88-9.86]; P  <  0.01). When moderate-deep sedation during anesthesia recovery was a covariate, both CI (OR, 3.02[1.60-5.70]; P  <  0.01) and moderate-deep sedation (OR, 3.94[2.19-7.11]; P  <  0.01) were associated with delirium. In multivariable analysis, postoperative pulmonary complications were associated with moderate-deep sedation (OR, 2.14[1.18-3.87]; P  = 0 .01) but not with CI (OR, 1.49 [0.76-2.92]; P  = 0 .25).

Cognitive impairment was associated with higher rates of moderate-deep residual sedation during anesthesia recovery and delirium, while moderate-deep sedation was associated with higher rates of pulmonary complications and delirium. We speculate that tailoring the anesthetic to facilitate faster emergence for CI patients could improve complication rates.