A Self-administered Preoperative Visual Paired Comparison Task Is Associated With Postanesthesia Care Unit Delirium

Postanesthesia Care Unit delirium (PACU-D) is associated with significant morbidity, including longer hospital length of stay and postoperative delirium. Identifying at-risk individuals may help mitigate long-term consequences. We sought to determine if there was an association between performance on a preoperative 5-minute visual paired comparison task (VPC) or maximum constriction velocity (automated pupillometry) with the development of PACU-D.

This was a prospective, observational study. Patients undergoing elective surgery under general anesthesia were eligible if PACU recovery was anticipated. All patients underwent VPC testing and pupillometry measurements in the preoperative clinic. Postoperatively, the patients were screened for delirium on 3 scales at 15 and 60 minutes following PACU admission.

Two hundred forty-eight subjects completed preoperative testing, with complete pupillometry and VPC data in 199 subjects. A positive delirium screen was found in 39.5% of 200 subjects at 15 minutes and 21% of 196 subjects at 60 minutes. At 15 and 60 minutes, 30% and 22% of subjects had concordant positive delirium screens on all 3 scales, respectively. VPC ≤ 0.75 was associated with PACU-D on the Confusion Assessment Method for the Intensive Care Unit screen at 60 minutes ( P =0.043, Fisher Exact Test). Continuous VPC (odds ratio [OR] 0.84 per change of 0.05, 95% CI: 0.73-0.98 at 15 min; OR 0.84 per change of 0.05, 95% CI: 0.71-0.98 at 60 min) was associated with PACU-D. Maximum constriction velocity was not associated with PACU-D.

Our study showed that a VPC < 0.75 may be associated with PACU-D.