Table 3. Baseline Characteristics of the Propensity Score–Matched Cohort According to the Type of ALS Professional.
| Characteristic | Propensity Score–Matched Cohort | |||
|---|---|---|---|---|
| ALS by Physician (n = 814) | ALS by EMS Personnel (n = 814) | Standardized Difference | P Value | |
| Pretreatment variable | ||||
| Calendar year | ||||
| 2013 | 432 (53.1) | 424 (52.1) | 0.0200 | .69 |
| 2014 | 382 (46.9) | 390 (47.9) | −0.0200 | |
| Sex | ||||
| Male | 546 (69.3) | 567 (69.7) | −0.0087 | .87 |
| Female | 250 (30.7) | 247 (30.3) | 0.0087 | |
| Age, mean (SD), y | 58.5 (22.2) | 58.4 (22.2) | 0.0045 | .90 |
| ≤17 | 36 (4.4) | 31 (3.8) | 0.0303 | .82 |
| 18-64 | 387 (47.5) | 392 (48.2) | −0.0140 | |
| ≥65 | 391 (48.0) | 391 (48.0) | 0.0000 | |
| Witness | ||||
| Witnessed | 553 (67.9) | 561 (68.9) | −0.0215 | .67 |
| Unwitnessed | 261 (32.1) | 253 (31.1) | 0.0215 | |
| Bystander CPR | ||||
| Any CPR | 173 (21.3) | 164 (20.1) | 0.0296 | .58 |
| No CPR | 641 (78.7) | 650 (79.9) | −0.0296 | |
| First rhythm | ||||
| VF | 12 (1.5) | 10 (1.2) | 0.0260 | .97 |
| VT | 1 (0.1) | 2 (0.2) | −0.0258 | |
| PEA | 304 (37.3) | 303 (37.2) | 0.0021 | |
| Asystole | 444 (54.5) | 444 (54.5) | 0.0000 | |
| Other | 53 (6.5) | 55 (6.8) | −0.0120 | |
| Response time from emergency call to contact with patient, min | ||||
| Median (IQR) | 9 (7-14) | 9 (7-13) | NA | .84 |
| Mean (SD) | 11.3 (6.8) | 11.1 (6.5) | 0.0301 | .91 |
| Response time interval, min | ||||
| <10 | 413 (50.7) | 409 (50.2) | 0.0100 | .84 |
| ≥10 | 401 (49.3) | 405 (49.8) | −0.0100 | |
| Posttreatment variable | ||||
| Transport time from contact with patient to hospital arrival, min | ||||
| Median (IQR) | 31 (20-47) | 27 (20-37) | NA | <.001 |
| Mean (SD) | 35.8 (20.0) | 29.9 (13.9) | 0.3426 | <.001 |
| Total time from emergency call to hospital arrival, min | ||||
| Median (IQR) | 43 (30-59) | 37 (29-49) | NA | <.001 |
| Mean (SD) | 47.1 (22.5) | 40.9 (16.6) | 0.3136 | <.001 |
Abbreviations: ALS, advanced life support; CPR, cardiopulmonary resuscitation; EMS, emergency medical service; IQR, interquartile range; NA, not applicable; PEA, pulseless electrical activity; VF, ventricular fibrillation; VT, ventricular tachycardia.