Aetiology of in-hospital cardiac arrest on general wards

AimAetiology of in-hospital cardiac arrests (IHCAs) on general wards has not been studied. We aimed to determine the underlying causes for IHCAs by the means of autopsy records and clinical judgement of the treating consultants. Furthermore, we investigated whether aetiology and preceding vital dysfunctions are associated with long-term survival.Design and settingProspective observational study between 2009–2011 including 279 adult IHCA patients attended by medical emergency team in a Finnish university hospital’s general wards.ResultsThe median age of the patients was 72 (64, 80) years, 185 (66%) were male, 178 (64%) of events were monitored/witnessed, first rhythm was shockable in 42 (15%) cases and 53 (19%) patients survived six months. Aetiology was determined as cardiac in 141 events, 73 of which were due to acute myocardial infarction. There were 138 non-cardiac IHCAs; most common causes were pneumonia (39) and exsanguination (16). No statistical difference was observed in the incidence of objective vital dysfunctions preceding the event between the cardiac and non-cardiac groups (40% vs. 44%, p = 0.448). Subjective antecedents were more common in the cardiac cohort (47% vs. 32%, p = 0.022), chest pain being an example (11% vs. 0.7%, p < 0.001). Reviewing all 279 IHCAs, only shockable primary rhythm, monitored/witnessed event and low comorbidity score were independently associated with 180-day survival.ConclusionsCardiac aetiology underlies half of the IHCAs on general wards. Both objective and subjective antecedents are common. However, neither the cardiac aetiology nor the absence of preceding deterioration of vital signs were factors independently associated with a favourable outcome.