Journal Club Summary

Methodology Score: 4.5/5              
Usefulness Score:  4.5/5
Nichol G, et al.  N Engl J Med. 2015 Dec 3;373(23):2203-14

Continuous or Interrupted Chest Compressions for Cardiac Arrest

Koster RW. N Engl J Med. 2015; 373:2278-2279
This is a robust cluster randomized cross-over trial of 114 EMS agencies in North America that tested modifications to the early phase of resuscitation care in out-of-hospital cardiac arrests. Results from the study showed that among patients with out-of-hospital cardiac arrest in whom high quality CPR was performed by well-trained EMS providers, continuous chest compressions with asynchronous positive-pressure ventilation (CCC) did not result in significantly higher rates of survival to discharge or favorable neurologic status when compared to the strategy of chest compressions interrupted for ventilation (ICC). This is the first randomized trial to look CCC vs ICC. The group felt that this was a large study with strong methodology. It was also felt that this study provided evidence to support doing either CCC or ICC in early resuscitation of out-of-hospital cardiac arrests as long as good quality CPR is being performed.
By: Dr. Samantha Calder-Sprackman
(Presented Feb 2016)

Epi lesson: 

Cluster Randomized Controlled Trials 
A cluster randomized trial is a trial in which individuals are randomized in groups (i.e. the group is randomized, not the individual); for example, all patients treated by a particular EMS service or at a particular hospital. Reasons for performing cluster randomized trials vary. Sometimes the intervention can only be administered to the group, for example an addition to the water supply; sometimes the motivation is to avoid contamination amongst health care providers; sometimes the design is simply more convenient or economical. Such trials are often appropriate when the intervention is a psychomotor task (e.g. CPR) but not when the intervention is a drug. Specific sample size and data analytic approaches are required. 
By: Dr. Ian Stiell