Table 1.
Baseline characteristics of adult EMS-attended OHCA.
| Non-Shockable n = 17,309 |
Shockable n = 3,535 |
P-value | |
|---|---|---|---|
| Demographics | |||
| Age in years, median (IQR) | 71 (59, 82) | 61 (52,70) | <0.001 |
| Male sex, n (%) | 10,447 (60.4%) | 2936 (83.1%) | <0.001 |
| Race, n (%) | <0.001 | ||
| Chinese | 11,933 (68.9%) | 2,311 (65.4%) | |
| Malay | 2,653 (15.3%) | 593 (16.8%) | |
| Indian | 1,905 (11.0%) | 414 (11.7%) | |
| Other | 818 (4.7%) | 217 (6.1%) | |
| Event information | |||
| Arrest location, n (%) | <0.001 | ||
| Private residence | 13,3461 (77.1%) | 1,870 (52.9%) | |
| Healthcare facility | 1,635 (9.5%) | 369 (10.4%) | |
| Public area | 2,328 (13.5%) | 1,296 (36.7%) | |
| Presumed cardiac aetiology, n (%) | 11,025 (63.7%) | 3,265 (92.4%) | <0.001 |
| Witnessed arrest, n (%) | <0.001 | ||
| Unwitnessed | 7,879 (45.5%) | 861 (24.4%) | |
| Bystander witnessed | 7,864 (45.4%) | 2,372 (67.1%) | |
| EMS witnessed | 1,566 (9.1%) | 302 (8.5%) | |
| Medical history, n (%) | |||
| Heart disease | 5,855 (33.8%) | 1,491 (42.2%) | <0.001 |
| Diabetes | 5,723 (33.1%) | 966 (27.3%) | <0.001 |
| Cancer | 1,969 (11.4%) | 150 (4.2%) | <0.001 |
| Hypertension | 9,379 (54.2%) | 1,719 (48.6%) | <0.001 |
| Renal disease | 2,527 (14.6%) | 423 (12.0%) | <0.001 |
| Respiratory disease | 2,200 (12.7%) | 231 (6.5%) | <0.001 |
| Hyperlipidaemia | 6,702 (38.7%) | 1,353 (38.3%) | 0.620 |
| Stroke | 2,380 (13.8%) | 307 (8.7%) | <0.001 |
| CCI, median (IQR) | 4 (2,5) | 3 (1,4) | <0.001 |
| Pre-hospital management | |||
| Bystander CPR, n (%) | 8,449 (48.8%) | 2,139 (60.5%) | <0.001 |
| DA CPR, n (%) | 5,041 (29.1%) | 827 (23.4%) | <0.001 |
| Bystander AED application, n (%) | 690 (4.0%) | 415 (11.7%) | <0.001 |
| Pre-Hospital defibrillation, n (%) | 1,718 (9.9%) | 3,422 (96.8%) | <0.001 |
| Epinephrine, n (%) | 9,219 (53.3%) | 2,095 (59.4%) | <0.001 |
| Times in minutes, median (IQR) | |||
| No-flow time in min, median (IQR)* | 16 (10,25) | 13 (8.6,18.5) | <0.001 |
| Time to Dispatch | 1.7 (1,2.5) | 1.6 (0.9,2.4) | <0.001 |
| Time to Scene | 8∙3 (6.6,10.5) | 8 (6.3,10.2) | <0.001 |
| Time to Patient | 11∙3 (9.2,14.0) | 10∙5 (8.4,13.1) | <0.001 |
| Time at Scene | 19∙8 (15.8,23.8) | 18∙0 (13.9,22.5) | <0.001 |
| Hospital Management, n (%)** | |||
| TTM | 433 (18.3%) | 507 (39.1%) | <0.001 |
| PCI | 217 (9.2%) | 624 (48.1%) | <0.001 |
| Patient Outcomes, n (%) | |||
| Transported | 17,028 (98.4%) | 3,533 (99.9%) | <0.001 |
| Pre-hospital ROSC | 1,051 (6.1%) | 900 (25.5%) | <0.001 |
| Survived to admission | 2,368 (13.7%) | 1,297 (36.7%) | <0.001 |
| Survived to discharge | 233 (1.4%) | 679 (19.2%) | <0.001 |
| CPC 1 or 2 at discharge | 107 (0.6%) | 529 (15.0%) | <0.001 |
Abbreviations: EMS, emergency medical services; OHCA, out-of-hospital cardiac arrest; IQR, inter-quartile range; CCI, Charlson Co-morbidity Index; CPR, cardiopulmonary resuscitation; AED, automated external defibrillator; TTM, targeted temperature management; PCI, percutaneous coronary intervention; ROSC, return of spontaneous circulation; CPC, Cerebral Performance Category.
Numbers are n (%) for categorical variables and median (Q1–Q3) for continuous variables.
Charlson Co-morbidity Index was calculated based on available medical history. Where details were not available, they were assumed to be absent.
Good neurological outcome was defined as CPC 1 or 2.
Time to scene is the interval, in minutes, between the time the call was received by the dispatch center and the time of arrival at scene of either the ambulance or a rapid responder dispatched via the same dispatch center.
Time to patient refers to the interval, in minutes, between time call received by the dispatch center and the time of patient contact by either the ambulance or rapid responder dispatched via the same dispatch center.
No-flow time was unavailable for 164 patients.
The proportions of patient receiving these interventions were based on those who survived to hospital admission, as only these patients were eligible.