Changes over time in 30-day survival and the incidence of shockable rhythms after in-hospital cardiac arrest- A population-based registry study of nearly 24,000 cases

Objective: To determine changes over time in 30-day survival and the incidence of shockable rhythms after in-hospital cardiac arrest, from a countrywide perspective. Methods: Patient information from the Swedish Registry for Cardiopulmonary Resuscitation was analysed in relation to monitoring level of ward and initial rhythm. The primary outcome was defined as survival at 30 days. Changes in survival and incidence of shockable rhythms were reported per year from 2008 to 2018. Also, epidemiological data were compared between two time periods, 2008-2013 and 2014-2018. Results: In all, 23,186 unique patients (38.6% female) were included in the study. The mean age was 72.6 (SD 13.2) years. Adjusted trends indicated an overall increase in 30-day survival from 24.7% in 2008 to 32.5% in 2018, (on monitoring wards from 32.5% to 43.1% and on non-monitoring wards from 17.6% to 23.1%). The proportion of patients found in shockable rhythms decreased overall from 31.6% in 2008 to 23.6% in 2018, (on monitoring wards from 42.5% to 35.8 % and on non-monitoring wards from 20.1% to 12.9%). Among the patients found in shockable rhythms, the proportion of patients defibrillated before the arrival of cardiac arrest team increased from 71.0% to 80.9%. Conclusions: In an 11-year perspective, resuscitation in in-hospital cardiac arrest in Sweden was characterised by an overall increase in the adjusted 30-day survival, despite a decrease in shockable rhythms. An increased proportion, among the patients found in a shockable rhythm, who were defibrillated before the arrival of a cardiac arrest team may have contributed to the finding.