Waiting to deliver second shocks to the heart in cardiac arrest patients does not improve survival rates, according to new research. Researchers said the latest findings go against current hospital guidelines recommending that second attempts at defibrillation be delayed for chest compressions.
Researchers wanted to compare the current guidelines, set in 2005 to allow time for chest compressions, to previous recommendations of allowing minimal time delay between defibrillation attempts.
"Defibrillation is critical in the resuscitation of patients with cardiac arrest due to ventricular tachycardia or ventricular fibrillation (VT/VF)," wrote the researchers of this study. "Resuscitation guidelines have previously called for up to three successive or 'stacked' shocks with minimal time delays between defibrillation attempts. The use of stacked shocks, however, can result in prolonged interruptions of chest compressions that can contribute to poor patient outcomes."
"As a result, in 2005 resuscitation guidelines were revised to support single shock protocols with two minutes of chest compressions between defibrillation attempts to minimize interruptions in compressions," they added.
The latest study involved 2,733 cardiac arrest patients from the national registry of 172 hospitals across the United States. Data analysis revealed that while the percentage of patients receiving delayed second defibrillation attempts doubled from 2004 to 2012, there was no increase in survival rates.
"In a large U.S. national registry of cardiac arrest in hospital, we sought to describe temporal trends in time intervals between defibrillation attempts for persistent ventricular tachycardia or ventricular fibrillation (VT/VF) arrest and to determine the association between the timing of a second defibrillation attempt and patient outcomes," explained researchers.
"The time interval between defibrillation attempts for persistent VT/VF in hospital has increased in the past decade," they continued. "These findings are consistent with adoption of resuscitation guidelines that support single shock protocols with chest compressions between defibrillation attempts. Deferred defibrillation for persistent VT/VF, however, was not associated with improved survival. Further study is necessary to understand whether current guidelines, which recommend against immediate second defibrillation attempts for persistent VT/VF in hospital, need reconsideration."
Experts writing in an accompanying editorial said that the latest findings will help improve treatment of cardiac arrest patients.
"The finding of widespread nonadherence with clinical guidelines should prompt those responsible for organizing or delivering advanced life support to review their practice and ensure that it is informed by the latest clinical guidelines," wrote Keith Couper and Gavin Perkins from the Warwick Medical School.
The study and editorial were published in the British Medical Journal.
