Epidemiology of in-hospital cardiac arrest patients admitted to the intensive care unit in Australia: a retrospective observational study.

BACKGROUND:In-hospital cardiac arrest (IHCA) affects approximately 3000 patients annually in Australia. Introduction of the National Standard for Deteriorating Patients in 2011 was associated with reduced IHCA-related intensive care unit (ICU) admissions and reduced in-hospital mortality of such patients. AIMS:To assess whether the reduction in IHCA-related ICU admissions from hospital wards seen following the implementation of the national standard (baseline period 2013-2014) was sustained over the follow-up period (2015-2019) in Australia. METHODS:A multi-centre retrospective cohort study to compare the characteristics and outcomes of IHCA admitted to the ICU between baseline and follow-up periods. The primary outcome was the proportion of patients admitted to ICU from the ward following IHCA. Secondary outcomes included ICU and hospital mortality of IHCA-related ICU admissions. Data were analysed using hierarchical multivariable logistic regression. RESULTS:The proportion of cardiac arrest-related admissions from the ward was lower in the follow-up period when compared to baseline (4.1 vs 3.8%; P = 0.04). Such patients had lower illness severity and were more likely to have limitations of medical treatment at admission. However, after adjustment for severity of illness, the likelihood of being admitted to ICU following cardiac arrest on the ward increased in the follow-up period (odds ratio (OR) 1.13 (1.05-1.22); P = 0.001). Hospital mortality was lower in the follow-up period (50.3 vs 46.3%; P = 0.02), but after adjustment the likelihood of death did not differ between the periods (OR 1.0 (0.86-1.17); P = 0.98). CONCLUSION:After adjustment for the severity of illness, the likelihood of being admitted to ICU after IHCA slightly increased in the follow-up period.