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Cooling target may improve outcomes of out-of-hospital cardiac arrest
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LOS ANGELES — Pilot study data suggest that a cooling target of 32˚C may improve outcomes for comatose survivors of out-of-hospital cardiac arrest.
Esteban López-de-Sá, MD, head of the cardiac critical care unit and clinical cardiology at La Paz University Hospital in Madrid, Spain, and colleagues presented data on 36 survivors of out-of-hospital cardiac arrest (OHCA). Ten patients had initial rhythm of asystole and 26 had shockable rhythm (VF/VT). Researchers randomly assigned each patient to one of two levels of hypothermia: 32˚C or 34˚C.
At 6 months, 44% of patients who underwent therapeutic cooling to 32˚C after cardiac arrest survived without severe brain dysfunction compared with 11% of patients who underwent cooling to 34˚C group (P=.12). Dysfunction was defined as inability to perform normal tasks of everyday living.
In both groups, all patients whose initial rhythm was asystole died before 6 months. In patients whose initial rhythm was VF/VT, those assigned therapeutic cooling to 32˚C had a higher survival rate free from severe dependence at 6 months vs. those assigned cooling to 34˚C (61.5% vs. 14.3%; P=.029).
The most common complication in the first week after cooling in both hypothermia temperature groups were need for inotropes and hyperthermia.
“This pilot trial suggests that a cooling target of 32˚C may improve the outcome of OHCA patients secondary to ventricular fibrillation or pulseless ventricular tachycardia. Further investigation is needed to address the optimal level of hypothermia in this challenging clinical situation,” López-de-Sá said during a presentation.
The single-center trial was conducted from March 2008 to August 2011. The patients’ mean age was 64 years, 89% were men and all were white.
For the study, therapeutic cooling was administered for 24 hours, followed by gradual rewarming for 12 to 24 hours. – by Samantha Costa
For more information:
López-de-Sá E. Late-breaking clinical trials: Management of LV dysfunction: Devices and drugs. Presented at: the American Heart Association Scientific Sessions; Nov. 3-7, 2012; Los Angeles.
Disclosure: López-de-Sá reports no relevant financial disclosures.
Perspective
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Arthur J. Moss, MD
We certainly all know there are individual cases [of patients who] have had hypothermia and have had dramatic results of recovery. Doing any randomized trial is very important. For those who have neurologic recovery, it is quite obvious that most of them get an ICD, and that reduces mortality by 30% over the course of 2 to 4 years. There is an association of trying to limit the neurologic damage with the hypothermia and then combine that with subsequent ICD therapy. In accord with the importance of this combined therapy, I think we need more randomized trials of this type.
Perspective
Back to TopElliott M. Antman, MD, FAHA
It has now been 32 years that I have cared for patients in the coronary care unit. This is a very challenging set of patients to deal with. Those who have had an OHCA often have horrible neurologic outcomes despite a successful resuscitation. It is no surprise to me that those who had a shockable rhythm were actually the ones who were more successfully treated; that is usually what we see. It also is no surprise that there is more bradycardia when you cool a person to 32˚C instead of 34˚C, since that is what happens with hypothermia.
When the Committee on Scientific Sessions Program saw this paper, our faces lit up because there is very little in the way of randomized trials in the field of resuscitation science to actually have a randomized trial that addresses this important question. We know that cooling is cerebrally protective, but in this era when we really want to do the best for our patients, we are looking for ways to optimize our therapy. So we were very interested in a piece of evidence that would tell us whether 32˚C or 34˚C was better. This was a very interesting study that shed some light on that. Please recognize how difficult it is to do such a study in the hectic circumstances of a cardiac arrest. I found this trial extremely encouraging and look forward to having more trials in this area. It is going to help refine this important therapy for our patients who suffer these very serious events.
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