The number of prehospital defibrillation shocks and 1-month survival in patients with out-of-hospital cardiac arrest.
BACKGROUND
The relationship between the number of pre-hospital defibrillation shocks and treatment outcome in patients with out-of-hospital cardiac arrest (OHCA) presenting with ventricular fibrillation (VF) is unknown currently. We examined the association between the number of pre-hospitalization defibrillation shocks and 1-month survival in OHCA patients.


METHODS
We conducted a prospective observational study using national registry data obtained from patients with OHCA between January 1, 2009 and December 31, 2012 in Japan. The study subjects were ≥ 18-110 years of age, had suffered from an OHCA before arrival of EMS personnel, had a witnessed collapse, had an initial rhythm that was shockable [VF/ventricular tachycardia (pulseless VT)], were not delivered a shock using a public automated external defibrillator (AED), received one or more shocks using a biphasic defibrillator by EMS personnel, and were transported to a medical institution between January 1, 2009 and December 31, 2012. There were 20,851 OHCA cases which met the inclusion criteria during the study period. Signal detection analysis was used to identify the cutoff point in the number of prehospital defibrillation shocks most closely related to one-month survival. Variables related to the number of defibrillations or one-month survival in OHCA were identified using multiple logistic regression analysis.


RESULTS
A cutoff point in the number of pre-hospital defibrillation shocks most closely associated with 1-month OHCA survival was between two and three (χ(2) = 209.61, p < 0.0001). Among those patients who received two shocks or less, 34.48% survived for at least 1 month, compared with 24.75% of those who received three shocks or more. The number of defibrillations (odds ratio [OR] = 1.19, 95% CI: 1.03, 1.38), OHCA origin (OR = 2.81, 95% CI: 2.26, 3.49), use of ALS devices (OR = 0.68, 95% CI: 0.59, 0.79), use of epinephrine (OR = 0.33, 95% C: 0.28, 0.39), interval between first defibrillation and first ROSC (OR = 1.45, 95% CI: 1.18, 1.78), and chest compression (OR = 1.21, 95% CI: 1.06, 1.38) were associated significantly with 1-month OCHA survival.


CONCLUSIONS
The cutoff point in the number of defibrillations of patients with OHCA most closely related to one-month survival was between 2 and 3, and the likelihood of non-survival 1 month after an OHCA was increased when ≥3 shocks were needed. Further studies are needed to verify this finding.
Guidance of Medical Service Division, Health Policy Bureau, Ministry of Health, Labour and Welfare, 2-2 Kasumigaseki 1-chome, Chiyoda-ku, Tokyo, 100-8916, Japan. hasegawa-manabu@mhlw.go.jp.
Manabu
M
Hasegawa
Medical Center, Yokohama City University, 4-57 Urafunecho, Minami-ku, Yokohama, Kanagawa, 232-0024, Japan. t-abe@kyudai.jp.
Takeru
T
Abe
Kyushu University Hospital, Department of Emergency and Critical Care Center, Higashi-ku, Fukuoka, 812-8582, Japan. nagata.takashi@kyudai.jp.
Takashi
T
Nagata
Kyushu University Graduate School of Medicine, Department of Health Services Management and Policy, Higashi-ku, Fukuoka, 812-8582, Japan. onozukad@hcam.med.kyushu-u.ac.jp.
Daisuke
D
Onozuka
Kyushu University Graduate School of Medicine, Department of Health Services Management and Policy, Higashi-ku, Fukuoka, 812-8582, Japan. hagihara@hsmp.med.kyushu-u.ac.jp.
Akihito
A
Hagihara
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004554:Electric Countershock; D004632:Emergency Medical Services / Q000458:organization & administration*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality* / Q000628:therapy*; D011446:Prospective Studies; D012042:Registries; D015996:Survival Rate