Subsequent shock deliveries are associated with increased favorable neurological outcomes in cardiac arrest patients who had initially non-shockable rhythms.
BACKGROUND
Previous studies evaluating whether subsequent conversion to shockable rhythms in patients who had initially non-shockable rhythms was associated with altered clinical outcome reported inconsistent results. Therefore, we hypothesized that subsequent shock delivery by emergency medical service (EMS) providers altered clinical outcomes in patients with initially non-shockable rhythms.


METHODS
We tested for an association between subsequent shock delivery in EMS resuscitation and clinical outcomes in patients with initially non-shockable rhythms (n = 11,481) through a survey of patients after out-of-hospital cardiac arrest in the Kanto region (SOS-KANTO) 2012 study cohort, Japan. The primary investigated outcome was 1-month survival with favorable neurological functions. The secondary outcome variable was the presence of subsequent shock delivery. We further evaluated the association of interval from initiation of cardiopulmonary resuscitation to shock with clinical outcomes.


RESULTS
In the univariate analysis of initially non-shockable rhythms, patients who received subsequent shock delivery had significantly increased frequency of return of spontaneous circulation, 24-hour survival, 1-month survival, and favorable neurological outcomes compared to the subsequent not shocked group (P < 0.0001). In the multivariate logistic regression analysis, subsequent shock was significantly associated with favorable neurological outcomes (vs. not shocked; adjusted P = 0.0020, odds ratio, 2.78; 95% confidence interval, 1.45-5.30). Younger age, witnessed arrest, initial pulseless electrical activity rhythms, and cardiac etiology were significantly associated with the presence of subsequent shock in patients with initially non-shockable rhythms.


CONCLUSIONS
In this study of cardiac arrest patients with initially non-shockable rhythms, patients who received early defibrillation by EMS providers had increased 1-month favorable neurological outcomes.
Department of Emergency and Critical Care Medicine, Kimitsu Chuo Hospital, 1010 Sakurai, Kisarazu-City, Chiba, 292-8535, Japan. kitaccm-cib@umin.ac.jp.
Nobuya
N
Kitamura
Department of Emergency and Critical Care Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-City, Chiba, 260-8677, Japan. taka.nakada@nifty.com.
Taka-Aki
TA
Nakada
Department of Emergency and Critical Care Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-City, Chiba, 260-8677, Japan. shino@gk9.so-net.ne.jp.
Koichiro
K
Shinozaki
National Cerebral and Cardiovascular Center Hospital, 5-7-1 Fujishiro-dai, Suita, Osaka, 565-8565, Japan. tahara@ncvc.go.jp.
Yoshio
Y
Tahara
Division of Emergency and Critical Care Medicine, Department of Acute Medicine, Nihon University School of Medicine, 30-1 Oyaguchikamicho, Itabashi-ku, Tokyo, 173-0032, Japan. sakurai.atsushi@nihon-u.ac.jp.
Atsushi
A
Sakurai
National Center of Neurology and Psychiatry, Translational Medical Center, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8551, Japan. nyonemoto@gmail.com.
Naohiro
N
Yonemoto
Nihon University Surugadai Hospital, 1-6 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8309, Japan. nagao.ken@nihon-u.ac.jp.
Ken
K
Nagao
Department of Critical Care and Emergency Medicine, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku-ku, Tokyo, 162-8666, Japan. ayaguchi@ccmc.twmu.ac.jp.
Arino
A
Yaguchi
Department of Emergency Medicine, Yokohama City University Medical Center, 4 -57 Urafunecho, Minami-ku, Yokohama-City, Kanagawa, 232-0024, Japan. molimula@r6.dion.ne.jp.
Naoto
N
Morimura
D000368:Aged; D004554:Electric Countershock / Q000379:methods; D005260:Female; D006323:Heart Arrest / Q000150:complications / Q000628:therapy*; D006801:Humans; D008297:Male; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy; D011446:Prospective Studies; D017211:Treatment Failure; D016896:Treatment Outcome