Purpose
Cardiopulmonary bypass (CPB) induces a significant inflammatory response that may increase the risk for delirium. We hypothesized that exposure to CPB during coronary artery bypass grafting surgery would correlate with an increased risk of delirium and would be associated with several other outcomes.
Methods
We reviewed clinical data from two databases at our medical center, the Cardiac Surgery Perioperative Outcomes Database and the Society of Thoracic Surgeons Database. Patients undergoing elective coronary artery bypass grafting surgery (on-pump and off-pump) from November 1, 2009 to September 30, 2015 were included in the study. Delirium was defined as any positive CAM-ICU exam following surgery during the ICU course. We performed logistic regression to isolate the association between CPB exposure and delirium adjusted for predetermined risk factors and potential confounders.
Results
During the study period, a total of 2,280 patients underwent elective coronary artery bypass grafting surgery with 384 patients (16.9%) exposed to CPB. Delirium was diagnosed in 451 patients (19.8%). CPB exposure demonstrated a significant independent association with delirium (P = 0.002). The adjusted relative risk (RR) of delirium was 2.18 (95% CI, 1.39 to 3.07; P = 0.002) among patients exposed to CPB for 142 minutes (90th percentile of CPB duration), compared to a RR of only 1.51 (95% CI, 0.92 to 2.29; P = 0.10) for those on CPB for 54 minutes (10th percentile).
Conclusions
CPB use and duration of use were associated with an increased risk of delirium in patients undergoing coronary artery bypass grafting surgery.