Table 2 Characteristics and outcome in three subgroups of patients. Response interval and bystander CPR proportion are only calculated for non-ambulance witnessed arrest. Group differences in age and response interval are analyzed with Kruskal-Wallis test. Gender, presumed cause of arrest (cardiac vs non-cardiac) and bystander CPR started are analyzed with Chi-square test. Post-hoc tests are performed between specific groups and all p-values are corrected for multiple testing by Bonferroni correction. Only significant p-values are reported. CPR, cardiopulmonary resuscitation. IQR, interquartile range. VF/VT, ventricular fibrillation/ventricular tachycardia. PEA, pulseless electrical activity. ROSC, return of spontaneous circulation
| Â | Group 1 CPR duration | Group 2 CPR duration | Group 3 CPR duration | Statistical tests |
|---|---|---|---|---|
|  | <  15 min | 15–29 min | >  30 min |  |
n | 716 | 528 | 720 | Â |
Male, n (%) | 544 (76) | 358 (68) | 522 (73) | P < 0.05 1 vs 2, P = 0.004 |
Age, median (IQR) | 61 (52–69) | 65 (55–70) | 65 (56–70) | P < 0.01 1 vs 2, P < 0.001 1 vs 3, P < 0.001 |
Arrest witnessed by ambulance, n (%) | 233 (33) | 96 (18) | 180 (25) | P < 0.001 1 vs 2, P < 0.001 1 vs 3, P = 0.006 2 vs 3, P = 0.01 |
Response time (min), median (IQR) | 7 (5–10) | 8 (6–11) | 9 (7–12) | P < 0.01 1 vs 3, P < 0.001 2 vs 3, P < 0.001 |
CPR duration (min), median (IQR) | 6 (3–11) | 22 (19–26) | 55 (35–55) |  |
Presumed cause, n (%) |  |  |  | P = 0.01 |
 Cardiac | 569 (80) | 391 (74) | 583 (81) | Post-hoc tests |
 Respiratory | 89 (12) | 86 (16) | 101 (14) | non-significant |
 Overdose/intoxication | 28 (4) | 24 (5) | 17 (2) |  |
 Strangulation | 30 (4) | 27 (5) | 19 (3) |  |
Bystander CPR, n (%) | 422 (87) | 353 (82) | 437 (81) | P = 0.01 1 vs 2, P = 0.05 1 vs 3, P = 0.02 |
Initial rhythm, n (%) | ||||
 VF/VT | 427 (60) | 171 (32) | 275 (38) |  |
 PEA | 121 (17) | 126 (24) | 163 (23) |  |
 Asystole | 105 (15) | 214 (41) | 251 (35) |  |
 Unknown | 63 (9) | 17 (3) | 31 (4) |  |
Centrality class, n (%) | ||||
 1 (most central) | 204 (28) | 120 (23) | 127 (18) |  |
 2 | 121 (17) | 88 (17) | 99 (14) |  |
 3 | 161 (22) | 134 (25) | 181 (25) |  |
 4 | 90 (13) | 66 (13) | 114 (16) |  |
 5 | 44 (6) | 38 (7) | 85 (12) |  |
 6 (least central) | 11 (2) | 6 (1) | 28 (4) |  |
 missing | 85 (12) | 66 (13) | 86 (12) |  |
Sustained ROSC, n (%) | 609 (85) | 251 (48) | 132 (18) | Â |
30-day survival, n (%) | 459 (64) | 102 (19) | 52 (7) | Â |