Effect of Prehospital Induction of Mild Hypothermia on Survival and Neurological Status Among Adults With Cardiac Arrest

Abstract

improves outcome after cardiac arrest, but prehospital cooling immediately after return of spontaneous circulation may result in better outcomes.OBJECTIVE To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF. DESIGN, SETTING, AND PARTICIPANTSA randomized clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomization. MAIN OUTCOMES AND MEASURESThe primary outcomes were survival to hospital discharge and neurological status at discharge. RESULTSThe intervention decreased mean core temperature by 1.20°C (95% CI, −1.33°C to −1.07°C) in patients with VF and by 1.30°C (95% CI, −1.40°C to −1.20°C) in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% [95% CI, 57.0%-68.0%] vs 64.3% [95% CI, 58.6%-69.5%], respectively; P = .69) and among patients without VF (19.2% [95% CI, 15.6%-23.4%] vs 16.3% [95% CI, 12.9%-20.4%], respectively; P = .30). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% [95% CI, 51.8%-63.1%] of cases had full recovery or mild impairment vs 61.9% [95% CI, 56.2%-67.2%] of controls; P = .69) or those without VF (14.4% [95% CI, 11.3%-18.2%] of cases vs 13.4% [95% CI,10.4%-17.2%] of controls; P = .30). Overall, the intervention group experienced rearrest in the field more than the control group (26% [95% CI, 22%-29%] vs 21% [95% CI, 18%-24%], respectively; P = .008), as well as increased diuretic use and pulmonary edema on first chest x-ray, which resolved within 24 hours after admission.CONCLUSION AND RELEVANCE Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF.

Delphi Analysis of Science Gaps in the 2015 American Heart Association Cardiac Arrest Guidelines

“…Nationally, there are ≈167 000 emergency medical service–treated OHCAs in the United States, with a survival rate of ≈12% 1, 27. In systems in which telecommunicator CPR is optimized, all rhythm survival from OHCA is ≈37% 28. If telecommunicator CPR were implemented nationally, as recommended by the AHA,29 the expected impact on OHCA survival would be 41 810 lives saved annually, doubling overall survival.…”

What is new in the 2015 American Heart Association guidelines, what is recycled from 2010, and what is relevant for emergency medicine in Canada

“…29 Based on a large number of observational studies, emergent coronary angiography is recommended for patients with ROSC after out-of-hospital cardiac arrest (OHCA) with ST-elevation on ECG. 6 Emergent angiography is suggested for select patients who are comatose with ROSC after OHCA of presumed cardiac origin but no ST-elevation on ECG.…”

Applying Hospital Evidence to Paramedicine: Issues of Indirectness, Validity and Knowledge Translation

“…8 After numerous small studies confirming that TH initiated by EMS is feasible and affordable, a recent trial found that EMS-initiated TH did not result in any long-term benefits for the patient. 9 Since the post-arrest period is a dynamic period where paramedics must monitor and manage a complex patient with limited human and technological resources, removing any unnecessary procedures and distractions should be favored over the implementation of a therapy with no evidence of value. This is true in any patient care setting, but may be of particular relevance in the resource-limited EMS context.…”

“…Examples of EMS-specific research include therapeutic interventions for cardiac arrest, the use of continuous positive airway pressure for respiratory distress, fibrinolysis for STEMI in rural settings, therapeutic hypothermia for post-arrest, and reducing ED visits for nursing home patients through collaborative models of care. 2,8,9,11,[17][18][19][20][21][22] Similarly, EMS researchers have addressed policy matters, such as termination of resuscitation, hospital bypass, and ED offload delay. 23,24 Workforce issues, such as clinical judgment, workplace violence, and occupational hazards, have also been scientifically investigated.…”