Table 1.
Baseline characteristics
| Complete Cases (N = 433) | No Severe Hypoxemia (n = 340) | Severe Hypoxemia (n = 93) | P Value | |
|---|---|---|---|---|
| Age, yr | 58 (47; 67) | 59 (48; 68) | 53 (45; 62) | 0.002 |
| Body mass index, kg/m2 (n = 427) | 27.8 (23.7; 32.8) | 27.4 (23.4; 32.2) | 28.9 (24.8; 34.2) | 0.08 |
| Male | 241 (56) | 192 (56) | 49 (53) | 0.52 |
| Race (n = 431) | 0.03 | |||
| White | 321 (75) | 243 (72) | 78 (84) | |
| Black | 87 (20) | 77 (23) | 10 (11) | |
| Other | 23 (5) | 18 (5) | 5 (5) | |
| APACHE II score | 22 (17; 26) | 22 (17; 26) | 21 (17; 25) | 0.29 |
| Sepsis | 212 (49) | 156 (46) | 56 (60) | 0.02 |
| Septic shock | 111 (26) | 79 (23) | 32 (34) | 0.03 |
| Indication for intubation | <0.001 | |||
| Hypercarbic respiratory failure | 34 (8) | 34 (10) | 0 (0) | |
| Hypoxemic respiratory failure | 154 (36) | 105 (31) | 49 (53) | |
| Other | 245 (57) | 201 (59) | 44 (47) | |
| Preoxygenation | ||||
| 100% Non-rebreather mask | 198 (46) | 152 (45) | 46 (49) | 0.42 |
| Noninvasive ventilation | 119 (27) | 95 (28) | 24 (26) | 0.70 |
| Bag-valve mask | 112 (26) | 88 (26) | 24 (26) | 1.00 |
| Nasal cannula | 23 (5) | 19 (5) | 5 (5) | 0.94 |
| Other | 11 (2) | 4 (1) | 7 (8) | 0.003 |
| None recorded | 21 (5) | 18 (5) | 3 (3) | 0.44 |
| Laryngoscopy type | 0.64 | |||
| Direct | 281 (65) | 223 (66) | 58 (62) | |
| Video | 151 (35) | 116 (34) | 35 (38) | |
| Flexible fiber optic | 1 (<1) | 1 (<1) | 0 (0) | |
| Neuromuscular blockade | 0.92 | |||
| Succinylcholine | 190 (44) | 149 (44) | 41 (44) | |
| Rocuronium | 230 (53) | 181 (53) | 49 (53) | |
| Other | 2 (0.5) | 2 (0.6) | 0 (0) | |
| None | 11 (3) | 8 (2) | 3 (3) | |
| Operator experience, No. of intubations | 61 (40; 85) | 67 (40; 90) | 56 (29; 75) | 0.02 |
| Operator with <100 prior intubations | 341 (79) | 259 (76) | 82 (88) | 0.01 |
| Operator training | 0.13 | |||
| Pulmonary and critical care fellow | 401 (93) | 311 (91) | 90 (97) | |
| Critical care fellow | 4 (1) | 3 (1) | 1 (1) | |
| Anesthesia resident | 23 (5) | 22 (6) | 1 (1) | |
| CRNA | 5 (1) | 4 (1) | 1 (1) |
Definition of abbreviations: APACHE II = Acute Physiology and Chronic Health Evaluation II; CRNA = certified registered nurse anesthetist.
Data are presented as median (25th percentile; 75th percentile) or n (%). P value for significance obtained by chi-square or Fisher exact test for categorical data and Wilcoxon rank-sum test for continuous data. Percentages may not sum to 100 because of rounding. For preoxygenation, patients may have received more than one category.