Table 1. Patient Characteristics.
| Variable | Survivors participating in 6-mo follow-up | |
|---|---|---|
| Hypothermia | Normothermia | |
| No. | 416 | 420 |
| Age at time of cardiac arrest, mean (SD), y | 60 (13) | 59 (14) |
| Sex, No. (%) | ||
| Male | 354 (85) | 346 (82) |
| Female | 62 (15) | 74 (18) |
| University-level education with or without degree, No. (%) | 137 (33) | 130 (32) |
| Medical history (pre-arrest), No. (%) | ||
| Clinical Frailty Scale score 5-9 | 7 (2) | 11 (3) |
| Charlson Comorbidity Index, median (IQR) | 2 (1-3) | 2 (1-3) |
| Poor functional outcome (mRS 4-5) | 0 (0) | 0 (0) |
| Memory problems (self-reported) | 31 (8) | 32 (8) |
| Myocardial infarction | 53 (13) | 62 (15) |
| Heart failure | 23 (6) | 27 (7) |
| Hypertension with pharmacological treatment | 139 (35) | 124 (31) |
| Diabetes | 57 (14) | 55 (13) |
| Prehospital resuscitation variables, No. (%) | ||
| Location of cardiac arrest at home | 175 (42) | 181 (43) |
| Bystander-witnessed arrest | 383 (92) | 388 (92) |
| Bystander-performed cardiopulmonary resuscitation | 353 (85) | 359 (86) |
| First monitored rhythm shockable | 371 (89) | 380 (91) |
| Time (min) from OHCA to sustained ROSC, median (IQR) | 20 (14-30) | 20 (14-30) |
| Data on hospital admission, No. (%) | ||
| Shock | 84 (20) | 85 (20) |
| FOUR motor score, median (IQR) | 0 (0-0) | 0 (0-0) |
| Bilaterally absent pupillary reflexes | 286 (83) | 289 (80) |
| In-hospital data | ||
| Highest NSE value in ng/mL, median (IQR)a | 26 (19-36) | 22 (16-28) |
| CT diffuse and extensive anoxic brain injurya | 7 (3) | 7 (3) |
| MRI diffuse and extensive anoxic brain injury/all MRIa | 3 (9) | 3 (10) |
| Days in intensive care unit, median (IQR) | 6 (4-9) | 5 (3-9) |
| Days in hospital, median (IQR) | 16 (11-25) | 15 (10-24) |
| At time of 6-mo follow-up, No. (%) | ||
| Days from cardiac arrest to follow-up, median (IQR) | 186 (179-202) | 187 (179-201) |
| Known neurological disease | 33 (8) | 27 (7) |
| Married/living as married | 304 (73) | 305 (75) |
| Living at home | 403 (97) | 384 (94) |
| Rehabilitation provided (self-reported), No. (%) | ||
| Cardiac rehabilitation | 121 (29) | 111 (26) |
| Exercise-based cardiac rehabilitation | 79 (19) | 88 (21) |
| Inpatient neurological/cognitive/brain injury rehabilitation | 49 (12) | 50 (12) |
| Outpatient neurological/cognitive/brain injury rehabilitation | 22 (5) | 29 (7) |
| Other | 24 (6) | 18 (4) |
Abbreviations: CT, computed tomography; ERC, European Resuscitation Council; ESICM, European Society of Intensive Care Medicine; FOUR, full outline of unresponsiveness; MRI, magnetic resonance imaging; mRS, modified Rankin Scale; NSE, neuron-specific enolase; OHCA, out-of-hospital cardiac arrest; ROSC, return of spontaneous circulation.
a
Missing data was frequent. NSE was based on the highest value at either 48 or 72 hours. The number included in these analyses were NSE, 416 of 420; CT, 246 of 261; and MRI, 29 of 33 for hypothermia and normothermia, respectively. The CT and MRI criteria for diffuse and extensive anoxic brain injury according to ERC/ESICM guidelines3 was based on information from a local radiologist only.