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Adrenaline provides minimal survival benefit for out-of-hospital cardiac arrest
The use of adrenaline for resuscitation does not improve survival to discharge or neurological outcomes among patients who have out-of-hospital cardiac arrest, according to recent findings.
However, adrenaline for resuscitation results in improved return of spontaneous circulation and survival to hospital admission, the researchers wrote.
In a systematic review and meta-analysis, researchers conducted a literature search of various clinical trial databases through July 2013. Eligible studies included randomized clinical trials (RCTs) and quasi-RCTs that assessed non-traumatic adult patients treated by emergency medical services workers for out-of-hospital cardiac arrest.
Fourteen trials totaling 12,246 patients were included. All trials involved one of the following resuscitation approaches: standard-dose adrenaline vs. placebo (one trial, 534 patients); standard- vs. high-dose adrenaline, defined as >1 mg per dose (six trials of 6,174 patients); standard-dose adrenaline alone compared with adrenaline and vasopressin in combination (six trials of 5,202 patients) and standard-dose adrenaline compared with vasopressin alone (one trial of 336 patients).
Survival to hospital discharge was the primary outcome, with secondary outcomes including return of spontaneous circulation, survival to hospital admission and favorable neurological outcome at discharge.
None of these comparisons or subgroup analyses conducted within the studies yielded significant differences in survival to discharge or neurological outcome according to the evaluated treatment approaches. Compared with placebo, standard-dose adrenaline was linked to increased likelihood of return of spontaneous circulation (RR=2.8; 95% CI, 1.78-4.41) and survival to admission (RR=1.95; 95% CI, 1.34-2.84). Compared with high-dose adrenaline, the standard dose was linked to decreased likelihood of return of spontaneous circulation (RR=0.85; 95% CI, 0.75-0.97) and survival to admission (RR=0.87; 95% CI, 0.76-1). No differences were observed between standard-dose adrenaline and either adrenaline/vasopressin combination or vasopressin alone.
According to the researchers, these findings may reflect the short-term benefits of adrenaline on improving coronary circulation, at the expense of other organs. However, they wrote that many of the trials included in this analysis were published before the widespread availability of post-resuscitation targeted temperature management and PCI, and they emphasized the need for further study.
“There is a need for well-designed, placebo-controlled and adequately powered RCTs to evaluate the efficacy of adrenaline and to determine its optimal dosing,” the researchers wrote. “The question as to the efficacy of adrenaline for [out-of-hospital cardiac arrest] remains unanswered.”
Disclosure: The researchers report no relevant financial disclosures.