Table 1.
Baseline characteristics of the intention-to-treat population according to obese status
| Obese patients with obesity (n = 91) | Non-obese patients without obesity (n = 222) | P value | |
|---|---|---|---|
| Characteristics of the patients | |||
| Age, year, mean ± SD | 66 ± 14 | 63 ± 14 | 0.13 |
| Male sex, n (%) | 64 (70) | 148 (67) | 0.53 |
| Body mass index,a kg·m−2, mean ± SD | 35 ± 5 | 24 ± 3 | < 0.0001 |
| SAPS IIb, point, mean ± SD | 49 ± 19 | 52 ± 19 | 0.20 |
| Reason for ICU admission | 0.14 | ||
| Respiratory primary failure, n (%) | |||
| Respiratory infection | 28 (31) | 82 (37) | |
| COPD exacerbation | 8 (9) | 8 (4) | |
| Extra-pulmonary ARDS | 3 (3) | 3 (1) | |
| Pulmonary atelectasis | 2 (2) | 2 (1) | |
| Other | 6 (7) | 27 (12) | |
| Non-respiratory primary failure, n (%) | |||
| Shock | 19 (21) | 47 (21) | |
| Cardiogenic pulmonary edema | 4 (4) | 13 (6) | |
| Neurologic | 7 (8) | 6 (3) | |
| Other | 12 (13) | 24 (11) | |
| Post-operative, n (%) | 2 (2) | 10 (4) | |
| Clinical characteristics | |||
| Oxygen device the last hour before inclusion, n (%) | 0.48 | ||
| Standard oxygen | 38 (42) | 98 (44) | |
| High-flow nasal cannula oxygen | 28 (31) | 77 (35) | |
| Non-invasive ventilation | 25 (27) | 47 (21) | |
| Vasopressor support at inclusion, n (%) | 19 (21) | 43 (19) | 0.76 |
| Bilateral pulmonary infiltrates, n (%) | 54 (71) | 140 (73) | 0.71 |
| Respiratory variables | |||
| Respiratory rate, breaths·min, mean ± SD | 30 ± 7 | 31 ± 8 | 0.50 |
| PaO2/FIO2 ratio, mm Hg, mean ± SD | 152 ± 65 | 142 ± 68 | 0.26 |
| MACOCHA score,c n (%) | 0.003 | ||
| < 3 | 68 (75) | 195 (88) | |
| ≥ 3 | 23 (25) | 26 (12) | |
| Cormack III or IV,d n (%) | 15 (16) | 14 (6) | 0.005 |
| Outcomes | |||
| SpO2 < 80% during intubation procedure, n (%) | 31 (34) | 49 (22) | 0.03 |
| Lowest SpO2 during intubation procedure, %, median (IQR) | 86 (77- 93) | 91 (81–96) | 0.002 |
| SpO2 at the beginning of preoxygenation, %, median (IQR) | 96 (92–98) | 95 (92–99) | 0.82 |
| SpO2 at the end of preoxygenation, %, median (IQR) | 99 (97–100) | 100 (98–100) | 0.04 |
| Intubation Difficulty Scale,e n (%) | 0.29 | ||
| ≤ 5 | 75 (85) | 196 (89) | |
| > 5 | 13 (15) | 23 (11) | |
| Immediate complications, n (%) | |||
| Hypotension | 41 (45) | 115 (52) | 0.28 |
| Sustained cardiac arrhythmia | 0 | 6 (3) | 0.19 |
| Bradycardia or cardiac arrest during and after intubation | 5 (5) | 6 (3) | 0.22 |
| Esophageal intubation | 6 (7) | 8 (4) | 0.24 |
| Regurgitation | 0 | 2 (1) | 0.99 |
| Gastric distension | 3 (3) | 14 (6) | 0.26 |
| Dental injury | 0 (0) | 1 (0) | 0.99 |
| Agitation | 0 (0) | 1 (0) | 0.99 |
| New infiltrate on chest-ray after intubation | 14 (18) | 47 (25) | 0.20 |
| Late outcomes | |||
| Ventilator-associated pneumonia during ICU stay, n (%) | 22 (24) | 44 (20) | 0.39 |
| Death at day 28 | 36 (40) | 75 (34) | 0.33 |
| SOFA score at Day 1, points, mean ± SD | 9 ± 4 | 8 ± 4 | 0.19 |
| SOFA score at Day 7, points, mean ± SD | 6 ± 4 | 5 ± 3 | 0.48 |
| Duration of mechanical ventilation, days, median (IQR) | 9 (5–17) | 7 (4–16) | 0.46 |
| Ventilator-free day at day 28, median (IQR) | 5 (0–19) | 8 (0–22) | 0.26 |
| ICU length of stay, days, median (IQR) | 11 (6–20) | 10 (6–17) | 0.27 |
COPD chronic obstructive pulmonary disease, ARDS acute respiratory distress syndrome, SpO2 pulse oximetry, SD standard deviation, SOFA Sepsis-related Organ Failure Assessment, ICU intensive care unit
aThe body mass index is the weight in kilograms divided by the square of the height in meters
bThe Simplified Acute Physiology Score (SAPS) II is calculated from 17 variables at inclusion, information about previous health status, and from information obtained at admission. Scores can range from 0 to 163, with higher scores indicating more severe disease
cMACOCHA is calculated from 7 variables including Mallampati score III or IV, apnea syndrome, cervical spine limitation, opening mouth less than 3 cm, coma, hypoxia, non-trained operator. Score range from 0 to 12 points, with higher scores indicating risk of difficult intubation
dCormack grade III, if no part of the glottis can be seen, but only the epiglottis, grade IV, if not even the epiglottis can be exposed
eThe Intubation Difficulty Scale denotes the Intubation Difficulty Scale score, 0 easy, 0 to 5 slight difficulty, > 5 moderate to major difficulty for intubation