Why the Wait: Deciphering in-Hospital Defibrillation Delays
Pub Date: Tuesday, October 27, 2009
Author: Robert Neumar, MD, PhD, FACEP
1. Chan PS, Nichol G, Krumholz HM, Spertus JA, Nallamothu BK., Hospital variation in time to defibrillation after in-hospital cardiac arrest., Archives of internal medicine, 169 (14) 1265-73. View in PubMed
A medical emergency exists when an important outcome depends on the number of minutes to definitive therapy. No outcome is more important than survival without disability, and it is well established that early defibrillation is the most effective way to achieve this outcome in patients with ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). In a previous study of in-hospital VF/pulseless VT cardiac arrest using the NRCPR database, Chan et al., reported that the likelihood of survival without major disability was decreased when initial defibrillation was delayed by more than 2 minutes after cardiac arrest was recognized [adjusted OR 0.74 (95% CI, 0.56-0.96)]. An equally important observation was that delayed defibrillation occurred in 30% of cases. In a follow-up study recently published in the Archives of Internal Medicine, Chan et al., extends these findings by reporting significant inter-hospital variability in the rate of delayed defibrillation (more than 2 minutes) ranging from 2.4% to 50.9%. This study also provides additional evidence that early defibrillation improves outcomes based on the observation that hospitals in the top performing quartile for defibrillation had a higher survival rate compared to the bottom quartile [OR 1.41 (95% CI, 1.1-1.77)]. The observed variability in rates of delayed defibrillation suggests the potential to identify best practices in hospitals with low rates of delayed defibrillation and translate them to hospitals in which a delayed defibrillation occurs frequently. However, based on the hospital level factors examined in this study, we are left with more questions than answers regarding the best way to eliminate defibrillation delays. Clearly, more research is needed.
The current study does provide important insights into how care is impacted by the location of cardiac arrest within the hospital: 59% of VF/pulseless VT arrests occurred in an intensive care unit (ICU), 24% in a telemetry unit, and 17% in a nonmonitored unit. As expected, delayed defibrillation was almost twice as likely to occur when cardiac arrest occurred outside the ICU (OR 1.90). However, unexpected is the observation that delayed defibrillation was equally likely to occur when cardiac arrest occurred in either a monitored or unmonitored unit outside the ICU. Additionally surprising was the lack of detectable association with a number of hospital factors that might be expected to reduce the rate of delayed defibrillation. Included in this list is the use of medical emergency teams and automated defibrillators. However, as the authors point out, this observation should be interpreted with caution because it is unclear whether these factors were in place for the entire duration of the data collection period. The findings do underscore the importance of continually monitoring cardiac arrest incidence and outcomes to quantify the impact of quality-improvement measures.
Overall, this study further demonstrates the fact that delayed defibrillation is an important and correctable quality-of-care issue in the management of in-hospital cardiac arrest. It also highlights our knowledge gaps regarding the root cause of defibrillation delays both inside and outside of the ICU setting. The causes are likely to be multifactorial, and relative contribution of each will vary among different hospitals and among different units within a hospital. The first step for any individual hospital is to monitor the rate of delayed defibrillation. Cases in which delays occur should be examined with the goal of identifying correctable causes. When correctable causes are identified, change should be implemented and the results monitored in a continuous cycle of quality improvement. Further research is needed to identify correctable causes of delayed defibrillation that are common among hospitals, and strategies to reduce delays need to be tested and validated in prospective clinical trials.
- Chan PS, Krumholz HM, Nichol G, Nallamothu BK; American Heart Association National Registry of Cardiopulmonary Resuscitation Investigators. Delayed time to defibrillation after in-hospital cardiac arrest. N Engl J Med 2008;358(1):9-17.
- Chan PS, Nichol G, Krumholz HM, Spertus JA, Nallamothu BK; American Heart Association National Registry of Cardiopulmonary Resuscitation (NRCPR) Investigators. Hospital variation in time to defibrillation after in-hospital cardiac arrest. Arch Intern Med 2009;169(14):1265-1273.
-- The opinions expressed in this commentary are not necessarily those of the editors or of the American Heart Association --