Table 1.
Characteristics of the patients at randomization*
| Characteristic | Nicotine (n = 106) | Placebo (n = 112) |
|---|---|---|
| Age, years | 59.9 ± 11.7 | 61.8 ± 11.5 |
| Male—no. | 71 (67%) | 81 (72%) |
| Body mass index, kg/cm2 | 32.8 ± 7.7 | 31 ± 6.8 |
| SAPS II | 50.1 ± 15.7 | 52.5 ± 16.3 |
| SOFA score | 9.8 ± 2.6 | 9.3 ± 2.6 |
| Comorbidities | ||
| Hypertension | 60 (57%) | 68 (61%) |
| Diabetes | 36 (34%) | 54 (48%) |
| Ischemic cardiomyopathy | 8 (8%) | 10 (9%) |
| COPD | 4 (4%) | 3 (3%) |
| Other chronic respiratory disease | 2 (2%) | 2 (2%) |
| Former smoker | 43 (41%) | 41 (37%) |
| Immunocompromised | 6 (6%) | 7 (6%) |
| Time from | ||
| 1st symptoms to hospital admission, days | 7 ± 3 | 7 ± 4 |
| 1st symptoms to ICU admission, days | 8 ± 4 | 9 ± 4 |
| 1st symptoms to intubation, days | 10 ± 5 | 10 ± 5 |
| Treatments before or at randomization | ||
| Anticoagulants | 18 (17%) | 18 (16%) |
| Antibiotic agent | 10 (9%) | 10 (9%) |
| Remdesivir | 0 (0%) | 0 (0%) |
| Tocilizumab | 1 (1%) | 0 (0%) |
| Dexamethasone | 58 (55%) | 58 (52%) |
| Other glucocorticoids | 13 (12%) | 11 (10%) |
| ACE inhibitors or ARB | 40 (45%) | 49 (54%) |
| Vasopressor support | 62 (58%) | 56 (50%) |
| Concomitant bacterial pneumonia | 3 (3%) | 11 (10%) |
| Mechanical ventilation settings | ||
| Tidal volume, ml/kg PBW | 6 ± 1.2 | 5.9 ± 1 |
| Respiratory rate, /min | 26 ± 5 | 26 ± 5 |
| Plateau pressure, cmH2O | 25 ± 5 | 24 ± 4 |
| PEEP, cmH2O | 12 ± 3 | 12 ± 3 |
| Driving pressure, cmH2O | 13 ± 4 | 12 ± 3 |
| Compliance, ml/cmH2O | 33 ± 14 | 34 ± 13 |
| Arterial blood gases | ||
| pH | 7.39 ± 0.08 | 7.38 ± 0.08 |
| PaCO2, mmHg | 44 ± 13 | 43 ± 9 |
| PaO2, mmHg | 93 ± 36 | 93 ± 38 |
| Bicarbonate, mmol/l | 26 ± 4 | 25 ± 5 |
| PaO2/FiO2 | 155 ± 79 | 163 ± 78 |
| Laboratory results | ||
| Creatinine, micromol/l | 89 ± 61 | 98 ± 64 |
| Platelet, × 103/mm3 | 263 ± 107 | 286 ± 110 |
| Haemoglobin, g/dL | 12 ± 1.9 | 11.6 ± 1.9 |
| Lymphocyte count per mm3 | 0.99 ± 1.03 | 0.96 ± 1.36 |
| White blood cells per mm3 | 11.1 ± 5.4 | 11.7 ± 8.6 |
| Fibrinogen, mg/L | 6.6 ± 1.7 | 6.1 ± 1.8 |
| Adjuvant ARDS therapy | ||
| Prone positioning | 46 (43%) | 47 (42%) |
| Inhaled Nitric oxide or prostacyclin | 7 (7%) | 3 (3%) |
| ECMO | 10 (9%) | 9 (8%) |
| Renal replacement therapy | 0 (0%) | 3 (3%) |
| Pneumothorax | 1 (1%) | 3 (3%) |
*Plus–minus values are means ± SD
SAPS II Simplified Acute Physiology Score, SOFA Sequential Organ Function Assessment, COPD chronic obstructive pulmonary disease, ICU intensive care unit, ACE angiotensin conversion enzyme, ARB angiotensin receptor blocker, PBW predicted body weight, PEEP positive end-expiratory pressure, PaCO2 partial pressure of arterial carbon dioxide, PaO2 partial pressure of arterial oxygen, FiO2 the fraction of inspired oxygen, PaO2/FiO2 the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen, ARDS acute respiratory distress syndrome, ECMO extracorporeal membrane oxygenation
No significant differences were observed between the groups among characteristics evaluated at randomization