Abstract Background and objectives
Postoperative delirium is common in
critically ill patients and is known to have several predisposing and
precipitating factors. Seasonality
affects cognitive function which has a more dysfunctional pattern during winter. We, therefore, aimed to test whether
seasonal variation is associated with the occurrence of
delirium and
hospital Length Of Stay (LOS) in
critically ill non-cardiac surgical
populations.
Methods We conducted a retrospective
analysis of
adult patients recovering from non-
cardiac surgery at the Cleveland Clinic between March 2013 and March 2018
who stayed in
Surgical Intensive Care Unit (SICU) for at least 48 hours and had daily
Confusion Assessment
Method Intensive Care Unit (CAM-ICU) assessments for
delirium. The
incidence of
delirium and LOS were summarized by
season and compared using
chi-square test and non-parametric tests, respectively. A
logistic regression model was used to assess the
association between
delirium and LOS with
seasons, adjusted for potential
confounding variables. Results Among 2300
patients admitted to SICU after non-cardiac surgeries, 1267 (55%) had
postoperative delirium. The
incidence of
delirium was 55% in spring, 54% in summer, 55% in fall and 57% in winter, which was not significantly different over the four
seasons (p= 0.69). The median LOS was 12 days (IQR = [8, 19]) overall. There was a significant difference in LOS across the four
seasons (p= 0.018). LOS during summer was 12% longer (95% CI 1.04, 1.21; p= 0.002) than in winter. Conclusions In
adult non-cardiac
critically ill surgical
patients, the
incidence of
postoperative delirium is not associated with
season. Noticeably, LOS was longer in summer than in winter.