In-hospital data
| All patients (n=537) | Missing | Mild | Moderate | Severe | P values* | |
| (32°C–35°C) | (28°C–31°C) | (<28°C) | ||||
| (n=192) | (n=227) | (n=118) | ||||
| Body temperature, median (IQR) | 30.8 (28.2–32.6) | 0 (0.0) | 33.2 (32.5–34.0) | 30.1 (29.1–31.0) | 26 (24.7–27.0) | <0.001 |
| Systolic blood pressure category | 0 (0.0) | <0.001 | ||||
| Cardiac arrest | 21 (3.9) | 7 (3.6) | 1 (0.4) | 13 (11) | ||
| Unmeasurable | 36 (6.7) | 5 (2.6) | 11 (4.8) | 20 (16.9) | ||
| 40–90 mm Hg | 107 (19.9) | 31 (16.1) | 55 (24.2) | 21 (17.8) | ||
| >90 mm Hg | 373 (69.5) | 149 (77.6) | 160 (70.5) | 64 (54.2) | ||
| Heart rate, median (IQR) | 65 (48–84) | 6 (1.1) | 74 (59–90) | 65 (50–84) | 45 (34–68) | <0.001 |
| GCS score, median (IQR) | 11 (7–14) | 69 (12.8) | 13 (9–14) | 11 (9–14) | 8 (4–11) | <0.001 |
| Biological data | ||||||
| Serum pH, median (IQR) | 7.31 (7.23–7.37) | 67 (12.5) | 7.35 (7.28–7.39) | 7.3 (7.21–7.36) | 7.27 (7.16–7.33) | <0.001 |
| Serum HCO3 (mEq/L), median (IQR) | 20.7 (15.4–25.6) | 73 (13.6) | 22 (16.2–25.6) | 20.4 (14.3–25.7) | 19.6 (15.0–25.4) | 0.278 |
| Serum lactate (mmol/L), median (IQR) | 3.1 (1.3–6.8) | 105 (19.6) | 2.7 (1.3–5.6) | 3.1 (1.2–7.1) | 3.4 (1.5–8.2) | 0.158 |
| Serum sodium (mEq/L), median (IQR) | 140 (135–143) | 9 (1.7) | 139 (135–143) | 139 (135–143) | 140 (136– 143) | 0.641 |
| Serum potassium (mEq/L), median (IQR) | 4.1 (3.6–4.7) | 8 (1.5) | 4 (3.6–4.6) | 4.1 (3.6–4.7) | 4.2 (3.5–5.1) | 0.885 |
| Serum glucose (mg/dL), median (IQR) | 128 (91–190) | 47 (8.8) | 124 (93–169) | 122 (82–191) | 157 (103–225) | 0.012 |
| SOFA score† | 5 (3–8) | 35 (13.2) | 5 (2–7) | 4 (3–7) | 6 (5–9) | <0.001 |
| Cold exposure‡ | 422 (81.2) | 17 (3.2) | 136 (72.7) | 177 (81.2) | 109 (94.8) | <0.001 |
| Associated condition | ||||||
| Acute medical illness | 271 (50.5) | 90 (46.9) | 125 (55.1) | 57 (48.3) | 0.249 | |
| Trauma | 73 (13.6) | 27 (14.1) | 31 (13.7) | 15 (12.7) | 0.944 | |
| Alcohol intoxication | 50 (9.2) | 23 (12) | 17 (7.5) | 10 (8.5) | 0.271 | |
| Drowning | 33 (6.1) | 20 (10.4) | 4 (1.8) | 9 (7.6) | 0.001 | |
| Self-harm | 34 (6.3) | 18 (9.4) | 11 (4.8) | 5 (4.2) | 0.095 | |
| Other | 137 (25.5) | 47 (24.5) | 66 (29.1) | 24 (20.3) | 0.193 | |
| Rewarming procedure | ||||||
| Active external or minimally invasive‡ | 506 (94.8) | 3 (0.6) | 175 (91.6) | 221 (97.8) | 110 (93.2) | 0.018 |
| Warm intravenous fluids | 393 (73.6) | 130 (68.1) | 166 (73.5) | 97 (82.9) | 0.016 | |
| Warm blanket | 373 (69.9) | 137 (71.7) | 175 (77.4) | 61 (52.1) | <0.001 | |
| Forced warm air | 82 (15.4) | 13 (6.8) | 43 (19) | 26 (22.2) | <0.001 | |
| Heating pads | 23 (4.3) | 2 (1) | 9 (4) | 12 (10.3) | 0.001 | |
| Warm bath | 16 (3) | 3 (1.6) | 9 (4) | 4 (3.4) | 0.339 | |
| Active internal | 91 (17) | 15 (7.9) | 25 (11.1) | 51 (43.6) | <0.001 | |
| Lavage | 45 (8.3) | 6 (3.1) | 18 (7.9) | 21 (17.8) | <0.001 | |
| Intravascular | 4 (0.7) | 1 (0.5) | 0 (0.0) | 3 (2.6) | 0.03 | |
| Haemodialysis | 26 (4.9) | 5 (2.6) | 7 (3.1) | 14 (12) | <0.001 | |
| ECMO | 22 (4.1) | 3 (1.6) | 1 (0.4) | 18 (15.4) | <0.001 | |
| Other treatment | ||||||
| Endotracheal intubation | 35 (6.5) | 0 (0.0) | 8 (4.2) | 9 (4) | 18 (15.3) | <0.001 |
| Catecholamines | 99 (18.4) | 0 (0.0) | 14 (7.3) | 4017.6) | 45 (38.1) | <0.001 |
| Emergent transvenous cardiac pacing | 7 (1.3) | 0 (0.0) | 2 (1) | 3 (1.3) | 2 (1.7) | 0.885 |
| Admission ward | 0 (0.0) | <0.001 | ||||
| No admission | 34 (6.2) | 22 (11.5) | 5 (2.2) | 7 (5.9) | ||
| General ward | 238 (44.3) | 93 (48.4) | 109 (48) | 36 (30.5) | ||
| Intensive care unit | 26 5 (49.3) | 77 (40.1) | 113 (49.8) | 75 (63.6) | ||
Values are expressed as numbers (percentages) unless indicated otherwise.
*Comparisons between the three groups were evaluated with Kruskal-Wallis test for numerical variables and χ2 test for categorical variables.
†Calculated with patients admitted to intensive care units.
‡We could not obtain the detailed information on ‘Active external or Minimally invasive rewarming’ in three patients. Percentage for a variable is counted using cases with data only.
ECMO, extracorporeal membrane oxygenation; SOFA, sequential organ failure assessment.