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Delayed defibrillation, lower survival rates linked for in-hospital cardiac arrest
Hospital settings and patient characteristics account for some treatment disparities.
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Early defibrillation administered during cardiac arrest may improve the prognosis for long-term recovery, but some patient populations are not receiving adequate defibrillation as promptly as recommended.
Researchers examining the relationship between delayed defibrillation for ventricular arrhythmia and survival also determined that many patients did not receive defibrillation within the recommended time of two minutes after the identification of cardiac arrest. This delayed defibrillation was associated with a lower rate of survival to hospital discharge.
The results appear in the New England Journal of Medicine.
Delay linked to problems
Using data from the National Registry of Cardiopulmonary Resuscitation, the researchers identified 6,789 patients from 369 acute care hospitals who had in-hospital cardiac arrest due to ventricular arrhythmia (69.7%) or pulseless ventricular tachycardia (30.3%). The median time between the identification of cardiac arrest and defibrillation was one minute, although 2,045 patients (30.1%) were found to have received defibrillation after the guideline-recommended window of two minutes.
Delayed defibrillation was associated with a lower likelihood of survival to hospital discharge, as well as a lower likelihood of return to spontaneous circulation and survival at 24 hours after cardiac arrest.
“Although several studies have shown an association between defibrillation time and survival, these were relatively small studies that typically included patients whose arrest rhythms would not have benefited from defibrillation,” said Paul S. Chan, MD, cardiologist at Saint Luke’s Mid-America Heart Institute, Kansas City, Mo. “We found that delayed fibrillation was common and that rapid defibrillation was associated with sizable survival gains in these high-risk patients.”
The researchers also reported that factors related to the hospital settings were in part responsible for the delayed defibrillations. The occurrence of cardiac arrest after normal hours of operation or in unmonitored inpatient beds was a factor.
Patient characteristics were also a factor. The results suggested that a disproportionately high number of black patients were recipients of delayed defibrillations, but the researchers were unclear if this was due to the geographic locations and quality of the hospitals or to disparities in care.
The researchers reported limitations. Due to the study’s observational design, some subtleties of physician performance and diagnostic abilities were not captured. In addition, the data on time to defibrillation was taken from information reported in medical records and may have not been entirely accurate due to synchronization problems between clocks in the hospital. Missing data concerning neurological and functional status were also reported. - by Eric Raible
It is pretty clear that systems to get defibrillating shocks to patients as fast as possible improve outcomes, both in the field and in the hospital. The poorer outcome in the black population could reflect some of the underlying ethnic-based differences in defibrillation efficacy, although I am much more inclined to the view that this will track with disparities in health care expenditures. There are a number of caveats in this article like incomplete data sets for outcomes and the voluntary nature of reporting. Nevertheless, the results strongly reinforce the benefit of rapid defibrillation and point to potential inadequacies in systems designed to deliver that therapy, especially in small hospitals and for patients not admitted for cardiac indications.
— Dan Roden, MD
For more information:
- Chan P, Krumholz H, Nichol G, et al. Delayed time to defibrillation after in-hospital cardiac arrest. N Engl J Med. 2008;358:9-17.