As compared with epinephrine alone, the combination of vasopressin and epinephrine during advanced cardiac life support for out-of-hospital cardiac arrest does not improve outcome, according to a study in the July 3 issue of the New England Journal of Medicine.
During the administration of advanced cardiac life support for resuscitation from cardiac arrest, the researchers said that a combination of vasopressin and epinephrine may be more effective than epinephrine or vasopressin alone, but evidence is insufficient to make clinical recommendations.
In a multicenter study, Pierre-Yves Gueugniaud, MD, from the University of Lyon in France, and colleagues conducted the study from May 1, 2004, through April 30, 2006 in France.
The researchers randomly assigned adults with out-of-hospital cardiac arrest to receive successive injections of either 1 mg of epinephrine and 40 IU of vasopressin, or 1 mg of epinephrine and placebo, followed by administration of the same combination of study drugs if spontaneous circulation was not restored. An additional epinephrine was administered, if needed.
The primary endpoint was survival to hospital admission; the secondary endpoints were return of spontaneous circulation, survival to hospital discharge, good neurologic recovery and one-year survival, according to the authors.
The investigators assigned a total of 1,442 patients to receive a combination of epinephrine and vasopressin, and 1,452 to receive epinephrine alone. The treatment groups had similar baseline characteristics, except that there were more men in the group receiving combination therapy than in the group receiving epinephrine alone, the authors wrote.
Gueugniaud and colleagues found that there were no significant differences between the combination-therapy and the epinephrine-only groups in survival to hospital admission (20.7 vs. 21.3 percent); return of spontaneous circulation (28.6 vs. 29.5 percent); survival to hospital discharge (1.7 vs. 2.3 percent); one-year survival (1.3 vs. 2.1 percent); or good neurologic recovery at hospital discharge (37.5 vs. 51.5 percent).
The researchers said that the primary endpoint “was not optimal, but it more realistically reflects the effects of cardiopulmonary-resuscitation interventions, because medical care in the intensive care units, wards and rehabilitation facilities could not be standardized in our study protocol, although differences in care may have profoundly influenced the outcomes.”
Moreover, the authors also noted that because the study “comparing the use of different vasopressors during cardiopulmonary resuscitation showed no difference in their effects on short-term survival, there is no reason to expect any difference in their effects on survival or neurologic recovery one year later.”