Table 1.
Baseline characteristics of the full analysis set population.
| Characteristic | H2 (n = 39) | Control (n = 34) |
|---|---|---|
| Demographic characteristics | ||
| Age, median (range), y | 68 (22–80) | 68 (24–79) |
| Male sex, n (%) | 32 (82) | 27 (79) |
| Female sex, n (%) | 7 (18) | 7 (21) |
| Medical history, n (%) | ||
| Myocardial infarction | 4 (10) | 1 (3) |
| Angina pectoris | 1 (3) | 1 (3) |
| Arrhythmia | 4 (10) | 5 (15) |
| Hypertension | 15 (38) | 12 (31) |
| Cerebrovascular disease | 1 (3) | 7 (21) |
| Type 2 diabetes | 8 (21) | 9 (26) |
| Heart failure | 5 (13) | 3 (9) |
| Chronic lung disease | 2 (5) | 6 (18) |
| Chronic kidney disease | 3 (8) | 2 (6) |
| Malignant tumour | 2 (5) | 2 (6) |
| Characteristics of the CA | ||
| CA at public location, n (%) | 22 (56) | 16 (47) |
| Bystander-witnessed CA, n (%) | 29 (74) | 22 (65) |
| Bystander-performed CPR, n (%) | 29 (74) | 21 (62) |
| Initial cardiac rhythm | ||
| Shockable rhythm | 29 (74) | 18 (53) |
| Ventricular fibrillation | 22 (56) | 15 (44) |
| Ventricular tachycardia | 0 | 0 |
| ROSC after bystander-initiated defibrillation | 1 (3) | 3 (9) |
| Unknown rhythm, shock administered | 6 (15) | 0 |
| Non-shockable rhythm | 10 (26) | 16 (47) |
| Pulseless electrical activity | 5 (13) | 6 (18) |
| Asystole | 3 (8) | 8 (24) |
| Other | 2 (5) | 1 (3) |
| Unknown rhythm, no shock administered | 0 | 1 (3) |
| Time from CA to ROSC, mean (SD), min | 28 (15) | 26 (11) |
| Time from CA to gas inhalation, mean (SD), min | 258 (55) | 271 (60) |
| Clinical characteristics on admission | ||
| Heart rate, mean (SD), bpm | 86 (17) | 81 (18) |
| Systolic arterial pressure, median (IQR), mmHg | 139 (120–162) | 126 (112–149) |
| Diastolic arterial pressure, mean (SD), mmHg | 77 (18) | 77 (19) |
| Catecholamine used, N (%) | 13 (30) | 17 (50) |
| Arterial pH, mean (SD) | 7.343 (0.1) | 7.354 (0.1) |
| Arterial oxygen partial pressure, mean (SD), Torr | 161.5 (108) | 163.1 (94) |
| Arterial carbon dioxide partial pressure, mean (SD), Torr | 41.1 (8) | 39.9 (8) |
| Arterial bicarbonate level, mean (SD), mg/dL | 22.1 (5) | 21.7 (4) |
| Arterial base excess, mean (SD), mmol/L | −3.2 (6) | −3.5 (4) |
| Arterial lactate level, mean (SD), mmol/L | 2.92 (2.6) | 4.13 (4.4) |
| ST elevation Myocardial infarction, N (%) | 12 (31) | 13 (30) |
| SOFA score, median (IQR) | 3 (1–5.25) | 4 (2–6) |
Abbreviations: bpm, beats per minute; CA, cardiac arrest; CPR, cardiopulmonary resuscitation; IQR, interquartile range; ROSC, return of spontaneous circulation.