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Table 1 Baseline characteristics of the study cohorts according to subsequent shock delivery a

From: Prognostic implications of conversion from nonshockable to shockable rhythms in out-of-hospital cardiac arrest

Characteristics All patients with initial nonshockable rhythm,n(%) Subsequently shocked cohort,n(%) Subsequently not-shocked cohort,n(%) P-value
Total patients in each group (%) 569,937 (100) 21,944 (3.9) 547,993 (96.1)  
Year        
2005 87,978 (15.4) 3,978 (18.1) 84,000 (15.3) <0.0001
2006 90,942 (16.0) 3,618 (16.5) 87,324 (15.9)  
2007 88,710 (15.6) 3,465 (15.8) 85,245 (15.6)  
2008 97,211 (17.1) 3,504 (16.0) 93,707 (17.1)  
2009 99,024 (17.3) 3,680 (16.8) 95,344 (17.4)  
2010 106,072 (18.6) 3,699 (16.9) 102,373 (18.7)  
Age, yr 77 (65 to 85) 75 (62 to 83) 77 (66 to 85) <0.0001
Male 324,683 (57.0) 13,819 (63.0) 310,864 (56.7) <0.0001
Witnessed OHCA 204,687 (35.9) 10,595 (48.3) 194,092 (35.4) <0.0001
Witnessed OHCA by EMS personnel 30,341 (5.3) 1,226 (5.6) 29,115 (5.3) 0.076
Bystander CPR 224,273 (39.4) 8,842 (40.3) 215,431 (39.3) 0.0035
Presumed cardiac cause 303,947 (53.3) 14,357 (65.4) 289,590 (52.9) <0.0001
Initial cardiac rhythm        
Pulseless electrical activity 138,044 (24.2) 8,008 (36.5) 130,036 (23.7) <0.0001
Asystole 431,893 (75.8) 13,936 (63.5) 417,957 (76.3)  
Call-to-response time, min 7.0 (5 to 9) 7.0 (5 to 9) 7.0 (5 to 9) <0.0001
Time from the initiation of CPR by EMS personnel to hospital arrival, min 30 (24 to 37) 32 (26 to 39) 30 (24 to 36) <0.0001
Shock delivery time, minb 20.0 (15 to 27) 20.0 (15 to 27) No data  
Epinephrine administration 33,772 (5.9) 2,883 (13.1) 30,889 (5.6) <0.0001
Epinephrine administration time, minc 15 (10 to 20) 14 (10 to 20) 15 (10 to 20) 0.006
Outcomes        
Prehospital ROSC 24,028 (4.2) 1,676 (7.6) 22,352 (4.1) <0.0001
1-month survival 15,258 (2.7) 1,055 (4.8) 14,203 (2.6) <0.0001
1-month favorable neurological outcome (CPC category 1 or 2) 3,694 (0.6) 393 (1.8) 3,301 (0.6) <0.0001
  1. aCPC, Cerebral Performance Categories scale; CPR, Cardiopulmonary resuscitation; EMS, Emergency medical services; OHCA, Out-of-hospital cardiac arrest; ROSC, Return of spontaneous circulation. bTime from the initiation of CPR by EMS personnel to the first shock delivery. cTime from the initiation of CPR by EMS personnel to the first epinephrine administration. Values are reported either as either number of patients (%) or median (25th to 75th percentiles). Values were missing for 355 to 422 individuals across time variables.