Effects of advanced life support on patients who suffered cardiac arrest outside of hospital and were defibrillated.

BACKGROUND: The effects and relative benefits of advanced airway management and epinephrine on patients with out-of-hospital cardiac arrest (OHCA) who were defibrillated are not well understood.

METHODS: This was a prospective observational study. Using data of all out-of-hospital cardiac arrest cases occurring between 2005 and 2013 in Japan, hierarchical logistic regression and conditional logistic regression along with time-dependent propensity matching were performed. Outcome measures were survival and minimal neurological impairment [cerebral performance category (CPC) 1 or 2] at 1month after the event.

RESULTS: We analyzed 37,873 cases that met the inclusion criteria. Among propensity-matched patients, advanced airway management and/or prehospital epinephrine use was related to decreased rates of 1-month survival (adjusted odds ratio 0.88, 95% confidence interval 0.80 to 0.97) and CPC (1, 2) (adjusted odds ratio 0.56, 95% confidence interval 0.48 to 0.66). Advanced airway management was related to decreased rates of 1-month survival (adjusted odds ratio 0.89, 95% confidence interval 0.81to 0.98) and CPC (1, 2) (adjusted odds ratio 0.54, 95% confidence interval 0.46 to 0.64) in patients who did not receive epinephrine, whereas epinephrine use was not related to the outcome measures.

CONCLUSIONS: In defibrillated patients with OHCA, advanced airway management and/or epinephrine are related to reduced long-term survival, and advanced airway management is less beneficial than epinephrine. However, the proportion of patients with OHCA who responded to an initial shock was very low in the study subjects, and the external validity of our findings might be limited.