Antecedents to cardiac arrests in a hospital equipped with a medical emergency team

Abstract

Background: Studies conducted before the conception of medical emergency teams (METs) revealed that cardiac arrests were often preceded by deranged vital signs. METs have been implemented in hospitals to review ward patients whose conditions are deteriorating in order to prevent adverse events, including cardiac arrest. Antecedents to cardiac arrests in a MET-equipped hospital have not been assessed.

Objectives: To determine what proportion of patients who had cardiac arrests had documented MET criteria before the arrest, and what proportion had a premorbid status suggesting they were unsuitable resuscitation candidates.

Design and setting: Prospective observational study of cardiac arrests at the Austin Hospital, Melbourne, Australia, 1 April - 30 September 2010. Data were obtained from the patients' records and electronic "respond blue" database.

Main outcome measures: Patients' premorbid medical condition and functional status; prior "not-for-resuscitation" (NFR) order; presence or absence of a MET call before cardiac arrest; time and rhythm of cardiac arrest; and in hospital mortality.

Results: 27 patients had a cardiac arrest during the study period, 22 of whom had no prior documented NFR order. Among these 22 patients, 18 (82%) had an initial rhythm of asystole or pulseless electrical activity, and 16 (73%) died in hospital. Fifty per cent of arrests were detected between midnight and 08:00. All six patients classified as unsuitable resuscitation candidates died in hospital, and there were trends for increased age and poorer functional status when compared with suitable candidates. A further six patients had documented MET criteria in the 6 hours before the arrest, but did not receive MET review.

Conclusions: In this 6-month audit, about half the patients with cardiac arrest may have been unsuitable for resuscitation, or had objective warning signs that were not acted on. Further improvements in advanced care planning and optimisation of MET activation may further reduce cardiac arrest calls at our hospital.