Out-of-hospital cardiac arrest and resource utilisation in the ICU

Introduction

Survival rates for out-of-hospital cardiac arrests (OHCA) remain poor and typically of the order of 10% or less [1]. In the community, bystander CPR and public automated external defibrillators have been promoted, whilst in hospital therapeutic hypothermia and coronary reperfusion are employed to improve outcome. Few studies have assessed how this group of patients impacts on critical care resources [2].

Methods

Patients with a spontaneous circulation following OHCA admitted to the critical care unit of a university teaching hospital between 1999 and 2009 were analysed retrospectively.

Results

A total of 1,656 patients presented to the emergency department following OHCA, of which 217 were admitted to the ICU. The ICU and hospital survivals were 41% and 32.7%, respectively. In the period 1999 to 2003, ICU and hospital survival rates were 37.5% and 22.9%, respectively. In the period 2004 to 2009, ICU and hospital survival rates were 43.8% and 40.5%, respectively. At admission to the ICU, the mean APACHE II score was 22.82, mean pH 6.87 and FIO₂ 52.6%. In those patients who survived hospital discharge, the mean APACHE II score was 19.71, mean pH 6.97 and FIO₂ 47.1%, whilst in nonsurvivors they were 24.33, 6.83 and 55.4%, respectively. Overall ICU and hospital lengths of stay (LOS) were 5.41 and 13.72 days and the average TISS score was 221. In those who survived to hospital discharge, ICU and hospital LOS were 10.1 and 32.4 days and the average TISS score was 380. Amongst patients who died in hospital, the mean ICU and hospital LOS were 3.1 and 4.7 days, the average TISS was 144.

Conclusions

Overall one-third of patients admitted to the ICU in the period 1999 to 2009 with OHCA were discharged from hospital. This increased to 40.5% in the period from 2004 with almost all patients discharged from the ICU surviving to hospital discharge. Nonsurvivors amongst the cohort are unsurprisingly more seriously ill with higher APACHE II scores and deranged physiology. The cost of treating survivors of OHCA in ICU is considerably higher for survivors compared with nonsurvivors. However, as patients who are discharged from ICU usually leave hospital (2004 to 2009), this would appear to be an appropriate utilisation of resources.