Wednesday, January 2, 2008

Delayed defibrillation in one third of in-hospital cardiac arrests

Delayed defibrillation in one third of in-hospital cardiac arrests

January 2, 2008 Michael O'Riordan

Kansas City, MO - Delays in the time to defibrillation are common in hospitalized patients with cardiac arrest, with more than 30% of patients with cardiac arrest due to ventricular arrhythmia undergoing defibrillation more than two minutes after the initial recognition of arrest, a new study has shown [1]. Patients who received delayed defibrillation were less likely to survive to hospital discharge and more likely to have worsened neurologic and functional status upon discharge, report investigators.

"We need to start looking at this issue seriously and creatively, and to have the will to implement the processes of care that will reduce the amount of time it takes to defibrillate a patient undergoing cardiac arrest in the hospital setting," said lead investigator Dr Paul Chan (St Luke's Mid America Heart Institute, Kansas City, MO). "Time to defibrillation should be a measure of care," he added, "much in the same way that door-to-balloon time is now a marker of quality of hospital care."

The results of the study are published in the January 2, 2008 issue of the New England Journal of Medicine.

Little known about in-hospital cardiac arrest defibrillation times
The current recommendations for hospitalized patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) state that the patient should be shocked within two minutes of the recognition of cardiac arrest. Speaking with heartwire, Chan said little is currently known about in-hospital defibrillation times or the factors that might result in delays to defibrillation because much of the data are based on out-of-hospital cardiac arrest. As a result, there are minimal data about the processes of care needed to reduce in-hospital delays.

With that in mind, Chan and colleagues, including Drs Harlan Krumholz (Yale University School of Medicine, New Haven, CT), Graham Nichol (University of Washington, Seattle), and Brahmajee Nallamothu (University of Michigan, Ann Arbor), obtained data from the American Heart Association National Registry of Cardiopulmonary Resuscitation (NRCPR), an analysis that included 369 acute-care hospitals participating in the NRCPR and 6789 patients who had cardiac arrest due to VF or pulseless VT. The investigators examined the association between delayed defibrillation and survival to discharge in patients with cardiac arrest in intensive care units (ICUs) or inpatient beds.

Of the patients included in the registry, delayed defibrillation occurred in 30.1%. Because this number only includes patients in hospitals participating in the NRCPR, and likely includes hospitals with systems of care in place, Chan said the prevalence of delay is probably even higher.

The investigators also showed that delays in defibrillation resulted in a lower likelihood of survival to discharge and being less likely to be discharged without neurologic complications compared with those who were shocked within the guideline-recommended two minutes. Increasing time to defibrillation also led to lower rates of survival with each minute of delay. The investigators noted several different characteristics associated with the delay. Among them are black race, a noncardiac admitting diagnosis, and the occurrence of cardiac arrest in a small hospital, after hours, or in an unmonitored hospital bed.

Factors associated with delayed time to defibrillation in multivariable analysis

Adjusted odds ratio (95% CI)

After-hours cardiac arrest
1.18 (1.05-1.33)

Type of hospital bed

Inpatient, unmonitored

Intensive care unit
0.39 (0.33-0.46)

Inpatient, monitored by telemetry
0.47 (0.41-0.53)

Hospital size

>500 beds

<250 beds
1.27 (1.08-1.47)

250-499 beds
1.02 (0.90-1.17)

Admitting diagnosis


Medical, cardiac
0.67 (0.55-0.82)

Surgical, cardiac
0.67 (0.51-0.86)

Chan said the reasons for the delays in defibrillation are complex and the investigators can only speculate why such delays occur. Outside the ICU setting or in smaller hospitals, upon the recognition of cardiac arrest, there might be delays locating the "crash cart," or delays as nurses and other staff wait for the doctor. In that situation, making it easier to perform defibrillation, through device modifications to replicate public automated external defibrillators (AEDs), would allow first responders to shock the patient. Rapid-response teams that respond only to the code alerts and work with nurses and doctors to identify high-risk cardiac arrest patients might also work.

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