Pre-hospital predictors of long-term survival from out-of-hospital cardiac arrest.

OBJECTIVE: To identify predictors of longer-term outcomes from adult out-of-hospital cardiac arrest of presumed cardiac aetiology.

METHODS: In this retrospective cohort study, three large routinely collected databases were linked: 1)QAS Out-of-Hospital Cardiac (OHCA) Registry; 2)Queensland Hospital Admitted Patient Data Collection; and 3)Queensland Registrar General Death Registry. Participants were adult (18years+) residents of Queensland, who suffered an OHCA of presumed cardiac aetiology and had resuscitation attempted by QAS paramedics between 2002 and 2014. Four mutually exclusive outcomes were analysed: 1) No pre-hospital return of spontaneous circulation (ROSC) sustained to the Emergency Department (ED) or ROSC in ED; 2) Survival< 30 days (Pre-hospital ROSC sustained to ED or ROSC in ED but death within 30 days; 3) survival between 30 and 364 days; and 4) survival to 365 + days. Multinomial logistic regression was used to calculate odds ratios and 95 % confidence intervals.

RESULTS: Variables significantly predictive of survival to 365 + days after adjusting for all measured confounders are: an initial shockable rhythm; bystander witnessed events with bystander CPR; paramedic witnessed events; intubation placement; time of day (midday-2.59 pm); and attendance by Critical Care Paramedic (CCP).

CONCLUSION: From a service provision perspective, attendance of a CCP at an OHCA may be an important factor to achieve preferred long-term outcomes. Enhanced experience, exposure and expertise, together with extended clinical practice, may explain this finding.