Reported rates of survival following cardiac arrest range from 0.2% to 23%, with a median of 6.4% in the United States. The majority of patients who survive an out of hospital cardiac arrest (OHCA) are resusucitated at the scene of the arrest. For those who cannot be immediately resuscitated, deciding whether to terminate resuscitation efforts can prove extremely challenging for emergency service personnel.
The Ontario Prehospital Advanced Life Support (OPALS) group has derived two sets of termination-of-resuscitation rules – one for basic (BLS) and one for advanced life support (ALS) – from their large registry of cardiac arrest cases. To validate these rules, they performed a retrospective cohort study using data submitted by emergency medical systems and hospitals in eight US cities.
The overall rate of survival to hospital discharge was 7.1% (392/5505 patients). Of the 2592 patients (47.1%) who recieved basic life support, only 5(0.2%) of those who met the OPALS criteria for termination of resuscitation survived to hospital discharge. Of those patients who received advanced life support and met the OPALS criteria (1192, 21.7%), none survived to hospital discharge. Specificity for the BLS rule was 0.987, and for the ALS rule 1.000.
By standardising the practice by which patients are brought to hospital, the authors believe that it should become easier to investigate the wide regional variations in OHCA survival (established in a separate paper in the same issue). There is much disagreement on this – resuscitation science is a rapidly advancing field, and what is valid now may not be in a few years time.
- Nichol G, Thomas E, Callaway CW, et al. Regional variation in out-of-hospital cardiac arrest incidence and outcome. JAMA 2008; 300:1423-1431.
- Sasson C, Hegg AJ, Macy M, et al. Prehospital termination of resuscitation in cases of refractory out-of-hospital cardiac arrest. JAMA 2008; 300:1432-1438.
- Sanders AB and Kern KB. Surviving cardiac arrest. Location, location, location. JAMA 2008; 300:1462-1463.