Due to staffing changes at scheduled intervals and decreases in essential staff in the evenings, late intensive care unit (ICU) arrivals may be at risk for suboptimal outcomes. Utilizing a regional collaborative, we sought to determine the effect of ICU arrival timing on outcomes in elective isolated coronary artery bypass.

Adults undergoing elective, isolated coronary artery bypass from 17 hospitals between 2013 and 2023 were identified. Patients with missing predicted risk of mortality or missing ICU arrival time were excluded. Late ICU arrival time was defined as between 6:00 pm and 6:00 am. Hierarchical logistic regression with appropriate predicted risk scores was utilized for outcome risk adjustment.

We identified 11,638 patients, with 972 (8.4%) experiencing late ICU arrival. Late ICU arrival patients had higher predicted risk of morbidity or mortality (8.2%; [interquartile range {IQR}, 5.6%, 12.0%] vs 7.7% [IQR, 5.5%, 11.5%], P = .048) compared with early ICU arrival patients with longer median cardiopulmonary bypass times (96 minutes [IQR, 78, 119] vs 93 [IQR, 73, 116], P < .001). Late ICU arrival patients experienced more unadjusted complications including prolonged ventilation (7.7% vs 4.2%, P < .001) and operative mortality (2.0% vs 1.1%, P = .02), although no difference in failure-to-rescue (11.0% vs 10.4%, P = .84). Logistic regression with risk adjustment demonstrated late ICU arrival as a predictor of prolonged ventilation (odds ratio, 1.49 [95% CI, 1.12-1.99], P = .006).

After adjustment, late ICU arrivals experienced higher rates of prolonged ventilation, although this did not translate to failure-to-rescue.