Nearly a month ago, my husband and I were sitting on the couch watching LOST (yes, I have been living under a rock). My review of outdated pop culture was interrupted by the sound of a car crash. We ran outside. The car had been going quite slowly, and there was minimal damage. But, the driver was limp and unresponsive. No signs of trauma. Also, no sign that he had hit the brakes. A quick assessment suggested that he had become unresponsive prior to the accident. He was maybe 60 years old. He had no pulse and he was not breathing. My husband pulled him out of the car and laid him on the ground. I started chest compressions and asked if anyone else in the amassing small crowd knew CPR. No one. As I delegated instructions to call 911 and asked vainly for information, I carried on with continuous chest compressions. EMS arrived quickly, and I was relieved from my duty.
The EMS crew worked as a team. They started compressions at 30:2 with interruptions for bag mask ventilation. They applied the AED pads, shocked him, administered epinephrine, and shocked him again. Return of spontaneous circulation! –This may be a success! Have you ever noticed that your mind wanders to weird places during times like these? Mine went from amazement that this field resuscitation effort had actually worked to “I wonder if they really needed to stop for breaths…” Why? Well, as an editorial fellow at NEJM, I knew we had in process a report on continuous vs. interrupted chest compressions. That research report has now been published.
In this week’s NEJM, Nichol and colleagues report the results of a large cluster-randomized, crossover trial in which 114 EMS agencies were assigned to provide either continuous compressions at a rate of 100 compressions/min with asynchronous bag mask at a rate of 10/min (intervention group) or to interrupt compressions for breaths at 30:2, the old-fashioned way (control group). You may have heard that there is evidence for continuous compressions. That is what I heard when I refreshed my BLS/ACLS in June. The authors of this trial, however, wondered if it actually changed clinical outcomes. The primary outcome for this study was survival to hospital discharge – a clinically meaningful outcome. After all, that’s what friends and family ask when my husband tells this anecdote. “Did he make it?” Everyone knows that’s what matters. (Sorry to report, I don’t know if he survived to hospital discharge).
So, what did the study results show? Continuous chest compressions by EMS providers did not significantly improve survival to hospital discharge, when compared to interrupted chest compressions. There was essentially no difference in the primary outcome between the two groups, and there were possibly some advantages on secondary outcomes for interrupted chest compressions (such as for hospital-free survival). So, the next time my date-night binge watching is interrupted, and I have to give compressions by myself, I will do continuous compressions. But, if I am lucky enough to have a buddy in that situation, interrupted chest compressions at 30:2 may be the way to go.