Pre-shock chest compression pause effects on termination of ventricular fibrillation/tachycardia and return of organized rhythm within mechanical and manual cardiopulmonary resuscitation.
BACKGROUND
Shorter manual chest compression pauses prior to defibrillation attempts is reported to improve the defibrillation success rate. Mechanical load-distributing band (LDB-) CPR enables shocks without compression pause. We studied pre-shock pause and termination of ventricular fibrillation/pulseless ventricular tachycardia 5s post-shock (TOF) and return of organized rhythm (ROOR) with LDB and manual (M-) CPR.


METHODS
In a secondary analysis from the Circulation Improving Resuscitation Care trial, patients with initial shockable rhythm and interpretable post-shock rhythms were included. Pre-shock rhythm, pause duration (if any), and post-shock rhythm were obtained for each shock. Associations between TOF/ROOR and pre-shock pause duration, including no pause shocks with LDB-CPR, were analyzed with Chi-square test. A p-value <0.05 was considered statistically significant.


RESULTS
For TOF and ROOR analyses we included 417 LDB-CPR patients with 1476 and 1438 shocks, and 495 M-CPR patients with 1839 and 1796 shocks, respectively. For first shocks with LDB-CPR, pre-shock pause was associated with TOF (p=0.049) with lowest TOF (77%) for shocks given without pre-shock compression pause. This association was not significant when all shocks were included (p=0.07) and not for ROOR. With M-CPR there were no significant associations between shock-related chest compression pause duration and TOF or ROOR.


CONCLUSIONS
For first shocks with LDB-CPR, termination of fibrillation was associated with pre-shock pause duration. There was no association for the rate of return of organized rhythm. For M-CPR, where no shocks were given during continuous chest compressions, there were no associations between pre-shock pause duration and TOF or ROOR.
Norwegian National Advisory Unit on Prehospital Emergency Medicine, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: janao@janao.info.
Jan-Aage
JA
Olsen
Oslo Centre for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway.
Cathrine
C
Brunborg
Norwegian National Advisory Unit on Prehospital Emergency Medicine, Oslo University Hospital, Oslo, Norway; University of Oslo, Medical Student Research Program, University of Oslo, Oslo, Norway.
Mikkel
M
Steinberg
Houston Fire Department and the Baylor College of Medicine, Houston, TX, United States.
David
D
Persse
Department of Emergency Medicine, Medical University of Vienna, Vienna, Austria.
Fritz
F
Sterz
Hillsborough County Fire Rescue, Tampa, FL, United States.
Michael
M
Lozano
Gold Cross Ambulance Service, Appleton Neenah-Menasha and Grand Chute Fire Departments, WI, United States; Theda Clark Regional Medical Center, Neenah, WI, United States.
Mark
M
Westfall
Hillsborough County Fire Rescue, Tampa, FL, United States.
David T
DT
Travis
Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, WI, United States.
E Brooke
EB
Lerner
Heart Lung Center, Department of Cardiology, Radboud University Medical Center, Nijmegen, The Netherlands.
Marc A
MA
Brouwer
Norwegian National Advisory Unit on Prehospital Emergency Medicine, Oslo University Hospital, Oslo, Norway.
Lars
L
Wik
D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation / Q000379:methods; D047548:Defibrillators; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000628:therapy; D017063:Outcome Assessment, Health Care; D011673:Pulsatile Flow; D012769:Shock / Q000209:etiology / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000150:complications / Q000628:therapy; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000150:complications / Q000628:therapy
CPR; Cardiac arrest; Defibrillation; Emergency medical services; Mechanical CPR