Table 1 Primary analysis cohort (MIMIC-IV) characteristics
| Â | Total (N (%)) | Oxygen device in use at eligibility (N (%)) | ||
|---|---|---|---|---|
High-flow nasal cannula | Noninvasive ventilation | Non-rebreather mask | ||
Total | 3,357 | 536 (16) | 483 (14) | 2,338 (70) |
Age-group (years) | ||||
 18–39 | 220 (7) | 39 (7) | 27 (6) | 154 (7) |
 40–49 | 259 (8) | 41 (8) | 32 (7) | 186 (8) |
 50–59 | 575 (17) | 100 (19) | 89 (18) | 386 (17) |
 60–69 | 745 (22) | 128 (24) | 121 (25) | 496 (21) |
 70–79 | 742 (22) | 127 (24) | 120 (25) | 495 (21) |
 80 or more | 816 (24) | 101 (19) | 94 (20) | 621 (27) |
Sex | ||||
 Female | 1,500 (45) | 223 (42) | 232 (48) | 1,045 (45) |
 Male | 1,857 (55) | 313 (58) | 251 (52) | 1,293 (55) |
Race/ethnicity | ||||
 White | 2,396 (71) | 395 (74) | 326 (68) | 1,675 (72) |
 Black | 342 (10) | 29 (5) | 71 (15) | 242 (10) |
 Hispanic | 117 (4) | 17 (3) | 19 (4) | 81 (4) |
 Asian | 93 (3) | 14 (3) | 5 (1) | 74 (3) |
 Other / unknown | 409 (12) | 81 (15) | 62 (13) | 266 (11) |
Year of ICU admission | ||||
 2008 – 2010 | 1,409 (42) | 106 (20) | 166 (34) | 1,137 (49) |
 2011 – 2013 | 740 (22) | 66 (12) | 90 (19) | 584 (25) |
 2014 – 2016 | 635 (19) | 126 (24) | 113 (23) | 396 (17) |
 2017 – 2019 | 573 (17) | 238 (44) | 114 (24) | 221 (10) |
Intensive care unit type | ||||
 Cardiac | 807 (24) | 85 (16) | 135 (28) | 587 (25) |
 Medical-surgical | 2,117 (63) | 396 (74) | 304 (63) | 1,417 (61) |
 Neuro-trauma | 433 (13) | 55 (10) | 44 (9) | 334 (14) |
Comorbidities | ||||
 Chronic obstructive pulmonary disease | 696 (21) | 148 (28) | 175 (36) | 373 (16) |
 Congestive heart failure | 1,435 (43) | 198 (37) | 285 (59) | 952 (41) |
Baseline clinical variables (median [IQR]) | ||||
 Peripheral oxygen saturation | 96 [93, 99] | 94 [92, 97] | 95 [92, 98] | 96 [93, 99] |
 Fraction of inspired oxygen | 0.66 [0.57, 0.68] | 0.70 [0.60, 1.0] | 0.51 [0.48, 0.66] | 0.66 [0.57, 0.66] |
 Saturation-to-inspired oxygen (SF) ratio | 148 [136, 174] | 131 [98, 165] | 186 [145, 200] | 147 [139, 164] |
 Respiratory rate | 23 [19, 28] | 23 [20, 28] | 23 [19, 29] | 23 [19, 27] |
Oxygen device used at any point | ||||
 High-flow nasal cannula | 818 (24) | 536 (100) | 75 (16) | 207 (9) |
 Noninvasive ventilation | 729 (22) | 57 (11) | 483 (100) | 189 (8) |
 Non-rebreather | 2,741 (82) | 210 (39) | 195 (40) | 2,338 (100) |