Delayed defibrillation in hospital reduces survival
9 January 2008 A study of patients who suffer a cardiac arrest in
hospital has shown that they are more likely to survive if their hearts are
shocked back into rhythm within two minutes, but 30% of such patients aren’t
getting help fast enough.
An estimated 750,000 hospitalized patients experience cardiac arrest and
undergo CPR annually in the US, and less than 30% of those leave the
hospital alive.
Researchers quantified the impact of receiving a life-saving electrical
shock treatment (defibrillation) among hospitalized patients experiencing a
form of cardiac arrest known as ventricular arrhythmia. They found that the
chances of survival for hospitalized patients improve dramatically if
defibrillation is administered within the recommended two minutes following
a cardiac arrest. The study was published in the 3 Jan issue of the
New England Journal of Medicine. Analyzing data from the US National
Registry of Cardiopulmonary Resuscitation, the authors concluded that 30% of
patients with cardiac arrest due to ventricular arrhythmia received
life-saving defibrillation more than two minutes after initial recognition
of their cardiac arrest, a delay that exceeds guidelines-based
recommendations. The delayed defibrillation was linked to a significantly
lower probability of survival to hospital discharge — 22% vs 39% when
defibrillation wasn’t delayed—and a 26% lower likelihood among survivors of
being discharged without major neurological impairment. The findings also
revealed certain hospital characteristics were associated with delayed
defibrillation, including small hospital size (fewer than 250 beds);
occurrence of cardiac arrest in hospitalized patients whose heart rhythm was
not being constantly monitored in specialized units; and occurrence of
cardiac arrest after-hours (i.e., nights and weekends).
“While several prior 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 lead study author Dr Paul Chan, a cardiologist and
researcher from Saint Luke’s Mid America Heart Institute. Dr Chan was
previously with the University of Michigan where he initiated the study with
University of Michigan cardiologist Dr Brahmajee Nallamothu, the new paper’s
senior author. The study used a larger, more statistically significant
registry of nearly 7,000 patients and focused exclusively on appropriate
patients with ventricular arrhythmia. “We found that delayed defibrillation
was common, and that rapid defibrillation was associated with sizable
survival gains in these high-risk patients,” said Dr Chan. “However, the
real work has yet to be done in this field. We now have to develop systems
of care within the hospital to improve defibrillation times nationally.”
“These findings represent a real opportunity to improve patient care,” said
Dr Nallamothu. “We need to understand how delayed defibrillation, which was
more common after-hours and in unmonitored settings, relates to the
immediate availability of medical personnel or equipment, as well as
potential delays in recognition of ventricular arrhythmia.”
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