Table 1.
Characterization of All EMS-Treated Victims and Various Subgroups of Interest
| Group 1: EMS-Treated OHCA, Excluding EMS Witnessed | Group 2: Bystander CPR, No AED Applied Before EMS | Group 3: AED Applied Before EMS | Group 4: AED Shock Before EMS | Group 5: Bystander CPR, No AED, EMS Shocked | Group 6: Public Location Only | Group 7: Bystander Witnessed Only | |
|---|---|---|---|---|---|---|---|
| n | 13,769 | 4,403 | 289 | 170 | 1,280 | 2,193 | 5,630 |
| Median age, yrs | 67 (26) | 65 (27) | 62 (24) | 60 (20) | 63 (22) | 60 (21) | 68 (24) |
| Gender | |||||||
| Male | 8,826 (64%) | 2,838 (64%) | 212 (73%) | 141 (83%) | 987 (77%) | 1,814 (83%) | 3,783 (67%) |
| Unknown | 27 (0%) | 10 (0%) | 0 (0%) | 0 (0%) | 2 (0%) | 6 (0%) | 10 (0%) |
| Median EMS response time, min | 5.3 (2.9); 9 | 5.4 (2.8); 9.3 | 5.6 (3.4); 11 | 5.3 (3.2); 9.6 | 5.3 (2.7); 8.9 | 5 (3); 9 | 5.4 (3); 9.1 |
| Public location | 2,193 (16%) | 888 (20%) | 171 (59%) | 130 (76%) | 468 (37%) | 2,193 (100%) | 1,285 (23%) |
| Witnessed bystander | 5,630 (41%) | 2,278 (52%) | 180 (62%) | 130 (76%) | 980 (77%) | 1,285 (59%) | 5,630 (100%) |
| Unknown first rhythm | 1,273 (9%) | 278 (6%) | 25 (9%) | 13 (8%) | 42 (3%) | 156 (7%) | — |
| Shockable | 3,278 (24%) | 1,341 (30%) | 170 (59%) | 170 (100%) | 1,280 (100%) | 1,054 (48%) | 2,122 (38%) |
| Unknown | 808 (6%) | 175 (4%) | 5 (2%) | 0 (0%) | 0 (0%) | 118 (5%) | 229 (4%) |
| Transported to hospital | 8,106 (59%) | 2,553 (58%) | 224 (78%) | 146 (86%) | 999 (78%) | 1,746 (80%) | 3,861 (69%) |
| Survival to hospital discharge | 907 (7%) | 382 (9%) | 69 (24%) | 64 (38%) | 286 (22%) | 368 (17%) | 641 (11%) |
Values are n, n (interquartile range), n (%), and n (interquartile range); 90%. Group 1 = all patients receiving EMS care for presumed cardiac arrest, excluding EMS-witnessed arrests. Group 2 = all non–EMS-witnessed arrests in which a bystander performed CPR. No AED applied before EMS. Group 3 = all non–EMS-witnessed arrests in which an AED was applied before EMS arrival. This was the primary multivariate analysis group. Group 4 = all non–EMS-witnessed arrests in which an AED applied before EMS arrival provided a shock. Group 5 = all non–EMS-witnessed arrest in which a bystander performed CPR, but the first shock was provided by EMS. Group 6 = all non–EMS-witnessed cardiac arrests treated by EMS in a public location. Group 7 = all bystander-witnessed cardiac arrests (must be non–EMS-witnessed).
AED = automatic external defibrillator; CPR = cardiopulmonary resuscitation; EMS = emergency medical services; IQR = interquartile range; OHCA = out-of-hospital cardiac arrest.