Circulation. 2016 Sep 13;134(11):797-805. 

Background: Patients successfully resuscitated by paramedics from out-of-hospital cardiac arrest (OHCA) often suffer severe neurological injury. Laboratory and observational clinical reports have suggested that induction of therapeutic hypothermia during cardiopulmonary resuscitation (CPR) may improve neurological outcomes. One technique for induction of mild therapeutic hypothermia during CPR is a rapid infusion of large-volume cold crystalloid fluid.

Methods: In this multi-centre, randomized, controlled trial we assigned adults with OHCA undergoing CPR to either a rapid intravenous infusion of up to two-litres cold saline or standard care. The primary outcome measure was survival at hospital discharge; secondary end-points included return of a spontaneous circulation (ROSC). The trial was closed early (at 48% recruitment target) due to changes in temperature management at major receiving hospitals.

Results: A total of 1198 patients were assigned to either therapeutic hypothermia during CPR (618 patients) or standard pre-hospital care (580 patients). Patients allocated to therapeutic hypothermia received a mean (SD) of 1193 (647) mL cold saline. For patients with an initial shockable cardiac rhythm, there was a decrease in the rate of ROSC in patients who received cold saline compared with standard care (41.2% compared with 50.6%, P=0.03). Overall 10.2% of patients allocated to therapeutic hypothermia during CPR were alive at hospital discharge compared with 11.4% who received standard care (P=0.71).

Conclusions: In adults with OHCA, induction of mild therapeutic hypothermia using a rapid infusion of large-volume, intravenous cold saline during CPR may decrease the rate of ROSC in patients with an initial shockable rhythm and produced no trend towards improved outcomes at hospital discharge.

Current Opinion in Critical Care: June 2016;22(3):218-224.
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Purpose of review: Cardiopulmonary resuscitation (CPR) represents the cornerstone of cardiac arrest resuscitation care. Prompt delivery of high-quality CPR can dramatically improve survival outcomes; however, the definitions of optimal CPR have evolved over several decades. The present review will discuss the metrics of CPR delivery, and the evidence supporting the importance of CPR quality to improve clinical outcomes.
Recent findings: The introduction of new technologies to quantify metrics of CPR delivery has yielded important insights into CPR quality. Investigations using CPR recording devices have allowed the assessment of specific CPR performance parameters and their relative importance regarding return of spontaneous circulation and survival to hospital discharge. Additional work has suggested new opportunities to measure physiologic markers during CPR and potentially tailor CPR delivery to patient requirements.
Summary: Through recent laboratory and clinical investigations, a more evidence-based definition of high-quality CPR continues to emerge. Exciting opportunities now exist to study quantitative metrics of CPR and potentially guide resuscitation care in a goal-directed fashion. Concepts of high-quality CPR have also informed new approaches to training and quality improvement efforts for cardiac arrest care.
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New England Journal of Medicine (NEJM) 2016, 4 April.

BACKGROUND: Antiarrhythmic drugs are used commonly in out-of-hospital cardiac arrest for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, but without proven survival benefit.

METHODS: In this randomized, double-blind trial, we compared parenteral amiodarone, lidocaine, and saline placebo, along with standard care, in adults who had nontraumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after at least one shock, and vascular access. Paramedics enrolled patients at 10 North American sites. The primary outcome was survival to hospital discharge; the secondary outcome was favorable neurologic function at discharge. The per-protocol (primary analysis) population included all randomly assigned participants who met eligibility criteria and received any dose of a trial drug and whose initial cardiac-arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia was refractory to shock.

RESULTS: In the per-protocol population, 3026 patients were randomly assigned to amiodarone (974), lidocaine (993), or placebo (1059); of those, 24.4%, 23.7%, and 21.0%, respectively, survived to hospital discharge. The difference in survival rate for amiodarone versus placebo was 3.2 percentage points (95% confidence interval [CI], −0.4 to 7.0; P=0.08); for lidocaine versus placebo, 2.6 percentage points (95% CI, −1.0 to 6.3; P=0.16); and for amiodarone versus lidocaine, 0.7 percentage points (95% CI, −3.2 to 4.7; P=0.70). Neurologic outcome at discharge was similar in the three groups. There was heterogeneity of treatment effect with respect to whether the arrest was witnessed (P=0.05); active drugs were associated with a survival rate that was significantly higher than the rate with placebo among patients with bystander-witnessed arrest but not among those with unwitnessed arrest. More amiodarone recipients required temporary cardiac pacing than did recipients of lidocaine or placebo.

CONCLUSIONS: Overall, neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favorable neurologic outcome than the rate with placebo among patients with out-of-hospital cardiac arrest due to initial shock-refractory ventricular fibrillation or pulseless ventricular tachycardia.

Westfall, Mark DO; Krantz, Steve EMT-P; Mullin, Christopher MS; Kaufman, Christopher PhD

Objective:  The objective of this study was to conduct a meta-analysis of literature examining rates of return of spontaneous circulation from load-distributing band and piston-driven chest compression devices as compared with manual cardiopulmonary resuscitation.