A patient’s odds of surviving out-of-hospital cardiac arrest (OHCA) fluctuate an average of 56 percent from one emergency medical services (EMS) agency to another, researchers reported Sept. 26 in JAMA Cardiology.
And that’s even after adjusting for patient-level and EMS agency-level characteristics, suggesting there is “substantial unexplained variation” in OHCA survival across EMS agencies, wrote lead author Masashi Okubo, MD, MS, and colleagues.
The study used Resuscitation Outcomes Consortium network data from 10 regional coordinating sites across North America. It included 43,656 adults who suffered OHCA and were treated by any of 112 EMS agencies from April 2011 through June 2015.
There was wide variation between EMS providers on three important outcomes: survival to hospital discharge (0 to 28.9 percent), return of spontaneous circulation upon emergency department arrival (9 to 57.1 percent) and survival with a favorable functional outcome (0 to 20.4 percent). After adjusting for patient and EMS agency factors, the median variation from one EMS agency to another was for 1.56-fold for survival, 1.5-fold for return of spontaneous circulation upon ED arrival and 1.53-fold for survival with a favorable functional outcome—defined as a score of 3 or lower on the modified Rankin scale.
“We observed similar variation in those surviving to hospital care with adjustment for post-resuscitation treatments (e.g., PCI within 24 hours after hospital arrival and induced targeted temperature management) and in all sensitivity analyses,” wrote Okubo, with the University of Pittsburgh School of Medicine, and coauthors. “These data suggest that the between-agency variation resulted from unmeasured patient, EMS agency, hospital, and/or community characteristics, because the variation in outcomes persisted after adjustment for multiple measured factors.”
EMS agencies in the top quartile of patient survival tended to treat more patients with initial shockable rhythms and bystander interventions. They also were more likely to offer treatment with more than six responding personnel, more quickly offer EMS defibrillation following the emergency telephone call and more likely to offer treatment by an advanced life support/basic life support tiered system (36.4 percent for lowest-survival quartile; 75.9 percent for highest-survival quartile).
“Our findings justify further efforts to identify potentially modifiable factors that may explain this residual variation in outcomes and could be targets of public health interventions,” the researchers wrote. “Such factors in EMS might include whether the decision to transport for further care is evidence based (i.e., the Termination of Resuscitation Guideline) or left to the discretion of the paramedics or direct medical oversight. They may also include other factors in EMS culture and practice, such as EMS team design, team composition and roles, communication and leadership, and training and education.”
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.