Call to integrate therapeutic hypothermia protocol for cardiac arrest
MedWire News: US researchers have called for a therapeutic hypothermia (TH) protocol to be integrated into regional ST-segment elevation myocardial infarction (STEMI) networks for out-of-hospital cardiac arrest (OHCA) patients.
TH involves the cooling and subsequent rewarming of OHCA patients using an automated, noninvasive cooling device. Following recent positive studies on TH and the release of a position statement by the American Heart Association (AHA) recommending its use, Michael Mooney (Minneapolis Heart Institute Foundation, Minnesota, USA) and colleagues have now shown that TH improves survival and confers neuroprotection in OHCA patients.
"We have demonstrated that TH protocols that incorporate simple, noninvasive cooling before hospital arrival can provide an effective rescue therapy for OHCA and should be readily adopted within the context of existing STEMI networks," they write in the journal Circulation.
The study involved 140 OHCA patients who remained unresponsive after return of spontaneous circulation (ROSC) and who underwent TH between February 2006 and August 2009. These included 68 STEMI patients who received cardiac intervention (angiography and percutaneous coronary intervention) and TH simultaneously.
The primary outcomes of interest were survival to hospital discharge, and positive neurological result on survival, defined as Cerebral Performance Category 1 or 2 at discharge.
The findings revealed that overall, 56% of the patients survived to hospital discharge, and among these survivors, 92% were discharged with a positive neurological outcome.
Patients with non-ventricular fibrillation arrest (76%) and cardiogenic shock (44%) had significantly higher rates of mortality than patients without these conditions. However, survivors with these conditions went on to have high rates of positive neurological recovery (100% and 89%, respectively).
Importantly, for every 1 hour in delay from ROSC to cooling initiation, the risk for death increased by 20%.
"With the efficacy of TH established, the opportunity to improve outcomes from OHCA lies in the study of how best to deploy the therapy to larger numbers of patients," the authors conclude.
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By Piriya Mahendra