What do resuscitation drugs do?

You've seen it over and over again. EMS personnel respond to the call. The victim has been “down” for an undetermined period of time. ACLS measures are in progress upon arrival. There has been no response but you continue resuscitation a while longer. After half an hour or so things look futile, then boom! The epi has kicked in and the patient has a bounding pulse. The patient is admitted to the ICU but never recovers brain function. Do we have resuscitation drugs to thank for these outcomes? Maybe in some cases according to this study:

Design, Setting, and Patients Prospective, randomized controlled trial of consecutive adult patients with out-of-hospital nontraumatic cardiac arrest treated within the emergency medical service system in Oslo, Norway, between May 1, 2003, and April 28, 2008.

Interventions Advanced cardiac life support with intravenous drug administration or ACLS without access to intravenous drug administration...

Results Of 1183 patients for whom resuscitation was attempted, 851 were included; 418 patients were in the ACLS with intravenous drug administration group and 433 were in the ACLS with no access to intravenous drug administration group. The rate of survival to hospital discharge was 10.5% for the intravenous drug administration group and 9.2% for the no intravenous drug administration group (P=.61), 32% vs 21%, respectively, (P less than .001) for hospital admission with return of spontaneous circulation, 9.8% vs 8.1% (P=.45) for survival with favorable neurological outcome, and 10% vs 8% (P=.53) for survival at 1 year. The quality of CPR was comparable and within guideline recommendations for both groups. After adjustment for ventricular fibrillation, response interval, witnessed arrest, or arrest in a public location, there was no significant difference in survival to hospital discharge for the intravenous group vs the no intravenous group (adjusted odds ratio, 1.15; 95% confidence interval, 0.69-1.91).

Conclusion Compared with patients who received ACLS without intravenous drug administration following out-of-hospital cardiac arrest, patients with intravenous access and drug administration had higher rates of short-term survival with no statistically significant improvement in survival to hospital discharge, quality of CPR, or long-term survival.

So resuscitation drugs increase survival to hospital admission but not discharge. It's tempting to think that arrival to the ICU with return of spontaneous circulation might give future patients a chance to benefit from some of the newer advances in post resuscitation science. However, it appears the patients in this study got state of the art post resuscitation care, with over 70% receiving therapeutic hypothermia.

It's not time to abandon resuscitation drugs just yet. We already knew this regarding amiodarone. Drug effects may be more meaningful for in hospital cardiac arrest and in the context of the new cardiocerebral resuscitation which will be more widely adopted in the near future.