Long-term Survival Comparison of Patients Admitted to Icu Following in-hospital Cardiac Arrest in Perioperative and Ward Settings: a Multicentre Retrospective Cohort Study

Purpose: Perioperative in-hospital cardiac arrests (Perioperative IHCAs) may have better outcomes than IHCAs in the ward (ward IHCAs), due to enhanced monitoring and faster response. However, quantitative comparisons of their long-term outcomes are lacking, posing challenges for prognostication. Methods: This retrospective multicentre study included adult ICU admissions from theatre/recovery or wards with a diagnosis of cardiac arrest between January 2018 and March 2022. We used data from 175 ICUs in the ANZICS Adult Patient Database. The primary outcome was a survival time of up to four years. We used the Cox-proportional hazards model adjusted for SOFA score, age, sex, comorbidities, hospital type, and ICU treatments. Subgroup analyses examined age (≥65 years), intubation within the first 24 hours, elective vs emergency admission, and survival on discharge. Results: Of 702,675 ICU admissions, 5,659 IHCAs were included (Perioperative IHCA 38.0%; ward IHCA 62.0%). Perioperative IHCA group were younger, less frail, and less comorbid. Perioperative IHCA were most frequent in patients admitted to ICU after cardiovascular, gastrointestinal, or trauma surgeries. Perioperative IHCA group had longer four-year survival (59.9% vs. 33.0%, p<0.001) than the ward IHCA group, even after adjustments (adjusted HR: 0.63, 95%-CI: 0.57-0.69). This was concordant across all subgroups. Of note, older patients with Perioperative IHCA survived longer than both younger and older patients with ward IHCA. Conclusions: Patients admitted to the ICU following Perioperative IHCA had longer survival than ward IHCA. Future studies on IHCA should distinguish these patients.