Intensive care utilization following major noncardiac surgical procedures in Ontario, Canada: a population-based study

Patients are sometimes admitted to intensive care units (ICU) after elective noncardiac surgery for advanced monitoring and treatments not available on a general postsurgical ward. However, patterns of ICU utilization are poorly understood. Our aims were to assess the incidence and determinants of ICU utilization after elective noncardiac surgical procedures.

Population-based cohort study included adult patients who underwent 13 types of major elective noncardiac surgical procedures between 2006 and 2014 in Ontario, Canada. Primary outcome was early admission to ICU within 24 h after surgery. A prespecified analysis using multilevel logistic regression modeling separately examined patient- and hospital-level factors associated with early ICU admission within distinct groups of surgical procedures.

Early ICU admission occurred in 9.6% of the included 541,524 patients. Patients admitted early to ICU showed higher median age (68 vs. 65 years), burden of prehospital comorbidities (Charlson comorbidity index score ≥ 2, 33.1 vs. 10.4%), 30-day mortality rates (2.4 vs. 0.3%), and longer median postoperative hospital stays (6 vs. 4 days) than patients admitted to a ward. There was wide variation in proportions of patients admitted early to ICU across different surgery types (0.9% for hysterectomy to 90.8% for open abdominal aortic aneurysm repair) with generally low 30-day mortality across procedures (0.1–2.8%). Within individual procedures, there was wide interhospital variation in the range of early ICU admission rates (hysterectomy 0.07–14.4%, lower gastrointestinal resection 1.3–95%, endovascular aortic aneurysm 1.3–95.2%). The individual hospital where surgery was performed accounted for a large proportion of the variation in early ICU admission rates, with the median odds ratio ranging from 2.3 for hysterectomy to 21.5 for endovascular aortic aneurysm.

There is a wide variation in early ICU admission across and within surgical procedures. The individual hospital accounts for a large proportion of this variation. Further research is required to identify the basis for this variation and to develop better methods for allocating ICU resources for postoperative management of surgical patients.