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Lower survival rates seen with intra-arrest transport

Reuters Health - 15/09/2020 - Among patients with out-of-hospital cardiac arrest (OHCA), those who undergo intra-arrest transport during resuscitation have lower rates of survival to hospital discharge than do those with continued on-scene resuscitation, according to a registry study.

"Some emergency medical systems (EMS) employ strategies in which patients for whom circulation cannot be restored with initial on-scene efforts are transported to hospital with ongoing CPR," explained Dr. Brian Grunau of St. Paul's Hospital and the University of British Columbia, in Vancouver, Canada.

"Our study demonstrated that this strategy (in comparison to continued on-scene efforts) is associated with a decreased probability of survival, and rather supports a strategy that paramedics dedicate effort and expertise on scene rather than prioritizing transport to hospital," he told Reuters Health by email

Some EMS agencies transport nearly all patients, regardless of return of spontaneous circulation (ROSC), while others wait for ROSC before transport. Which strategy is associated with better outcomes remains unclear.

Dr. Grunau and colleagues used data from the Resuscitation Outcomes Consortium to evaluate the association of intra-arrest transport versus continuation of on-scene resuscitation with survival at hospital discharge.

Among nearly 44,000 patients included in the study, 26% underwent intra-arrest transport and 74% were treated with on-scene resuscitation until ROSC or termination of resuscitation.

Survival to hospital discharge was 3.8% for patients who were transported during the cardiac arrest versus12.6% for those who received on-scene resuscitation, the researchers report in JAMA.

In the propensity-score-matched analysis, survival to hospital discharge was significantly lower among patients who had intra-arrest transport (4.0% vs. 8.5%).

Survival with favorable neurological outcome was also significantly lower among patients treated with intra-arrest transport (2.9% vs. 7.1%).

The subgroups of initial shockable and non-shockable rhythms and EMS-witnessed and unwitnessed cardiac arrests all showed significant association between intra-arrest transport and lower probability of survival to hospital discharge.

"We did find, however, that for patients who remained in refractory arrest past 30 minutes and were still undergoing active resuscitation, that intra-arrest transport was associated with improved outcomes," Dr. Grunau said. "The reasons for this may be multifactorial, including bias introduced by differences in the duration of resuscitation attempted."

"The decision not to transport a patient with refractory out-of-hospital cardiac arrest to hospital may be seen as providing a less aggressive resuscitative effort," he said. "However, the true question is not whether to transport to hospital or terminate the resuscitation, but rather whether to transport to hospital or continue resuscitation on-scene. The appropriate duration of resuscitation prior to consideration of termination is a separate clinical question, which should not cloud the clinical question of optimal resuscitation location."

Dr. Grunau added, "In regions where additional management strategies are available in hospital, such as extracorporeal cardiopulmonary resuscitation (ECPR), there may be a rationale for intra-arrest transport. This hypothesis requires randomized clinical trial data to inform practice."

"These findings challenge the 'scoop and run' model for OHCA by suggesting a strong clinical benefit associated with continuing the resuscitation on scene until a definitive outcome has been achieved," writes Dr. Alexander X. Lo of Feinberg School of Medicine, in Chicago, in a linked editorial. "Before embracing this model, and substantially changing the out-of-hospital approach to OHCA, more definitive studies, including high-quality randomized trials, will be needed."

"However," he added, "future trials must embrace the diversity and heterogeneity across different patient populations and EMS systems. Although this heterogeneity poses a challenge to future studies, it also offers a valuable opportunity to design a truly patient-centered, community-specific research program to examine the differences in OHCA management and outcomes, which should emphasize survival and intact neurological function."

By Will Boggs MD

SOURCE: https://bit.ly/3iC3o12 and https://bit.ly/3kjldCt JAMA, September 15, 2020.

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