Trends in Incidence and Outcomes of Cardiac Arrest Occurring in Swedish ICUs.

Objective: To determine temporal trends in the incidence of cardiac arrest occurring in the ICU (ICU-CA) and its associated long-term mortality.
Design: Retrospective observational study.
Setting: Swedish ICUs, between 2011 and 2017.
Patients: Adult patients (≥18 yr old) recorded in the Swedish Intensive Care Registry (SIR).
Interventions: None.
Measurements and Main Results: ICU-CA was defined as a first episode of cardiopulmonary resuscitation and/or defibrillation following an ICU admission, as recorded in SIR or the Swedish Cardiopulmonary Resuscitation Registry. Annual adjusted ICU-CA incidence trend (all admissions) was estimated using propensity score-weighted analysis. Six-month mortality trends (first admissions) were assessed using multivariable mixed-effects logistic regression. Analyses were adjusted for pre-admission characteristics (sex, age, socioeconomic status, comorbidities, medications, and healthcare utilization), illness severity on ICU admission, and admitting unit. We included 231,427 adult ICU admissions. Crude ICU-CA incidence was 16.1 per 1,000 admissions, with no significant annual trend in the propensity score-weighted analysis. Among 186,530 first admissions, crude 6-month mortality in ICU-CA patients was 74.7% (95% CI, 70.1-78.9) in 2011 and 68.8% (95% CI, 64.4-73.0) in 2017. When controlling for multiple potential confounders, the adjusted 6-month mortality odds of ICU-CA patients decreased by 6% per year (95% CI, 2-10). Patients admitted after out-of-hospital or in-hospital cardiac arrest had the highest ICU-CA incidence (136.1/1,000) and subsequent 6-month mortality (76.0% [95% CI, 73.6-78.4]).
Conclusions: In our nationwide Swedish cohort, the adjusted incidence of ICU-CA remained unchanged between 2011 and 2017. More than two-thirds of patients with ICU-CA did not survive to 6 months following admission, but a slight improvement appears to have occurred over time.
Competing Interests: This study was conducted partially with support from an industry-sponsored (Abbvie) research scholarship from the Swedish Society of Anaesthesiology and Intensive Care (awarded to Dr. Flam). Dr. Skrifvars received speaker fees from BARD Medical (Ireland). The remaining authors have disclosed that they do not have any potential conflicts of interest.
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