Is Hypothermia After Cardiac Arrest Effective in Both Shockable and Nonshockable Patients?

Abstract

Background— Although the level of evidence of improvement is significant in cardiac arrest patients resuscitated from a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia [VF/V t ]), the use of therapeutic mild hypothermia (TMH) is more controversial in nonshockable patients (pulseless electric activity or asystole [PEA/asystole]). We therefore assessed the prognostic value of hypothermia for neurological outcome at hospital discharge according to first-recorded cardiac rhythm in a large cohort. Methods and Results— Between January 2000 and December 2009, data from 1145 consecutive out-of-hospital cardiac arrest patients in whom a successful resuscitation had been achieved were prospectively collected. The association of TMH with a good neurological outcome at hospital discharge (cerebral performance categories level 1 or 2) was quantified by logistic regression analysis. TMH was induced in 457/708 patients (65%) in VF/V t and in 261/437 patients (60%) in PEA/asystole. Overall, 342/1145 patients (30%) reached a favorable outcome (cerebral performance categories level 1 or 2) at hospital discharge, respectively 274/708 (39%) in VF/V t and 68/437 (16%) in PEA/asystole ( P <0.001). After adjustment, in VF/V t patients, TMH was associated with increased odds of good neurological outcome (adjusted odds ratio, 1.90; 95% confidence interval, 1.18 to 3.06) whereas in PEA/asystole patients, TMH was not significantly associated with good neurological outcome (adjusted odds ratio, 0.71; 95% confidence interval, 0.37 to 1.36). Conclusions— In this large cohort of cardiac arrest patients, hypothermia was independently associated with an improved outcome at hospital discharge in patients presenting with VF/V t . By contrast, TMH was not associated with good outcome in nonshockable patients. Further investigations are needed to clarify this lack of efficiency in PEA/asystole.

Mechanical Cardiopulmonary Resuscitation and Hospital Survival Among Adult Patients With Nontraumatic Out‐of‐Hospital Cardiac Arrest Attending the Emergency Department: A Prospective, Multicenter, Observational Study in Japan (SOS‐KANTO [Survey of Survivors after Out‐of‐Hospital Cardiac Arrest in Kanto Area] 2012 Study)

“…The mCPR was associated with worse survival in patients who had better prognostic factors (Figure 2). 54 Second, we were not able to analyze the association between mCPR and neurological outcome after OHCA because of the few events. Thus, the role of mCPR in the ED on neurocognitive function after OHCA remains undetermined.…”

Pediatric Neurocritical Care

“…However, the poor quality of evidence argued the need for a well-designed randomized controlled trial to address the question [166]. In addition, a contemporaneous study examining data from a large prospectively collected data registry included more than 400 adult patients presenting with asystole or pulseless electrical activity found no benefit from induced hypothermia in adult patients presenting with nonshockable rhythms and a possible association with harm [167].…”

“…The groundwork for this study has been well built. Three large, retrospective cohort studies that included patients from 15 hospitals affiliated with the Pediatric Emergency Care Applied Research Network have examined the outcome and identified risk factors associated with poor outcome for both in-hospital and out-of-hospital pediatric cardiac arrest [161][162][163][164][165][166][167][168][169][170][171]. Surveys from the United Kingdom and the United States have demonstrated both variability in the practice of cooling, and a widespread willingness and interest in a randomized controlled trial to study its use [172,173].…”

Therapeutic Hypothermia for Acute Neurological Injuries

“…Experts favor the following definitions: mild hypothermia (T c 34°C to 35.9°C), moderate hypothermia (T c 32°C to 33.9°C), moderate-deep hypothermia (T c 30°C to 31.9°C), and deep hypothermia (T c <30°C) [3]. Despite the lack of consensus in terminology, previous studies demonstrated that body temperature does not need to be less than 32°C to achieve neuroprotection [1,2,[4][5][6][7]. In fact, induced hypothermia to temperatures below 32°C has been associated with significant side effects, such as refractory cardiac arrhythmias and coagulopathies that can be very difficult to manage [8,9].…”