Impact of advanced cardiac life support-skilled paramedics on survival from out-of-hospital cardiac arrest in a statewide emergency medical service.

BACKGROUND: Prehospital research has found little evidence in support of advanced cardiac life support (ACLS) for out-of-hospital cardiac arrest. However, these studies generally examine city-based emergency medical services (EMS) systems. The training and experience of ACLS-skilled paramedics differs internationally, and this may also contribute to negative findings. Additionally, the frequency of negative outcome in out-of-hospital cardiac arrest suggests that it is difficult to establish sufficient numbers to detect an effect. PURPOSE: To examine the effect of ACLS on cardiac arrest in Queensland, Australia. Queensland has a population of 3.8 million and an area of over 1.7 million km2, and is served by a statewide EMS system, which deploys resources using a two-tier model. Advanced treatments such as intubation and cardioactive drug administration are provided by extensively trained intensive care paramedics. METHODS: An observational, retrospective design was used to examine all cases of cardiac arrest attended by the Queensland Ambulance Service from January 2000 to December 2002. Logistic regression was used to examine the effect of the presence of an intensive care paramedic on survival to hospital discharge, adjusting for age, sex, initial rhythm, the presence of a witness and bystander cardiopulmonary resuscitation. RESULTS: The presence of an intensive care paramedic had a significant effect on survival (OR = 1.43, 95% CI = 1.02 to 1.99). CONCLUSIONS: Highly trained ACLS-skilled paramedics provide added survival benefit in EMS systems not optimised for early defibrillation. The reasons for this benefit are multifactorial, but may be the result of greater skill level and more informed use of the full range of prehospital interventions.