Table 1.
Demographic and clinical characteristics of, and prehospital treatment received by, subjects with a cardiac arrest who received cardiopulmonary resuscitation (CPR) outside hospital: 233 patients during run-in phase of trial* and 1586 during evaluable period. Values are numbers (percentages) of patients unless stated otherwise
| Characteristic or treatment | Run-in phase (n=233) | Evaluable period | |
|---|---|---|---|
| Feedback-off (n=771) | Feedback-on (n=815) | ||
| Study site: | |||
| King County, Washington | 97 (42) | 367 (48) | 432 (53) |
| Thunder Bay, Ontario | 18 (8) | 5 (1) | 38 (5) |
| Pittsburgh, Pennsylvania | 118 (51) | 399 (52) | 345 (42) |
| Mean (SD) age (years) | 66 (17) | 66 (17) | 65 (17) |
| Male | 152 (65) | 480 (62) | 520 (64) |
| Cardiac arrest witnessed: | |||
| By emergency medical services | 22 (9) | 82 (11) | 83 (10) |
| By known bystander† | 79/211 (37) | 265/689 (38) | 284/732 (39) |
| Bystander CPR† | 101/211 (48) | 347/689 (50) | 383/732 (52) |
| Cardiac arrest in public location | 34 (15) | 98 (13) | 112 (14) |
| Mean (SD) response times for emergency medical services (minutes): | |||
| From emergency phone call to first arrival | 5.9 (2.8) | 5.8 (2.5) | 5.5 (2.2) |
| From dispatch to shock assessment | 10.6 (5.2) | 11.4 (6.1) | 11.7 (7.9) |
| First cardiac rhythm recorded: | |||
| Ventricular fibrillation or pulseless ventricular tachycardia‡ | 45/232 (19) | 182/769 (24) | 191/811 (24) |
| Pulseless electrical activity‡ | 62/232 (27) | 177/769 (23) | 210/811 (26) |
| Asystole‡ | 111/232 (48) | 319/769 (41) | 336/811 (41) |
| Other | 14/232 (6) | 91/769 (12) | 74/811 (9) |
| Prehospital treatment: | |||
| >1 shock given‡ | 61/233 (26) | 186/770 (24) | 180/815 (22) |
| Mean (SD) No of shocks per case§ | 3.0 (0.2) | 2.9 (0.2) | 3.4 (0.2) |
| Advanced life support on scene | 231 (99) | 770 (100) | 813 (100) |
| Endotracheal intubation | 195 (84) | 595 (77) | 646 (79) |
| Other advanced airway support | 11 (5) | 96 (12) | 85 (10) |
| Mean (SD) total adrenaline (epinephrine) dose given (mg) | 3.3 (2.5) | 2.8 (2.3) | 2.8 (2.3) |
*Trial of CPR provided by emergency medical services with monitor-defibrillator providing real-time feedback on CPR process (“feedback-on”) or not providing feedback (“feedback-off”).
†Percentage of arrests not witnessed by emergency medical services.
‡Percentage of cases not missing data.
§Among those receiving shocks.