Near-simultaneous intensive care unit (ICU) admissions and all-cause mortality: a cohort study

Purpose Prior studies have reported the adverse effects of strain on patient outcomes. There is a paucity of literature about a type of strain that may be caused by near-simultaneous intensive care unit (ICU) admissions. We hypothesized that when multiple admissions arrive nearly at the same time, the ICU teams are excessively strained, and this leads to unfavorable patient outcomes. Methods This is a retrospective cohort study of consecutive adult patients admitted to an academic medical ICU of a tertiary referral center over five consecutive years. Primary outcomes were the all-cause hospital and ICU mortality. Results We enrolled 13,234 consecutive ICU admissions during the study period. One-fourth of the admissions had an elapsed time since the last admission (ETLA) of < 55 min. Near-simultaneous admissions (NSA) had on average, a higher unadjusted odds ratio (OR) of ICU death of 1.16 (95% CI 1-1.35, P = 0.05), adjusted 1.23 (95% CI 1.04-1.44, P = 0.01), unadjusted hospital death of 1.11 (95% CI 0.99-1.24, P = 0.06), adjusted 1.20 (95% 1.05-1.35, P = 0.004), and a lower adjusted OR of home discharge of 0.91 (95% CI 0.84-0.99, P = 0.04). NSA was associated with 0.16 (95% CI 0.04-0.29, P = 0.01) added days in the ICU. For each incremental unit increase of the logarithmic transformation of ETLA [log (ETLA in minutes)], the average adjusted hospital mortality OR incrementally decreased by an added average OR of 0.93 (95% CI 0.89-0.97, P = 0.001). Conclusion Our results suggest that near-simultaneous ICU admissions (NSA) are frequent and are associated with a dose-dependent effect on mortality, length of stay, and odds of home versus nursing facility discharge.