Table 1.
Abridged Patient Characteristics, Stratified by Nested Exposure Window
| Characteristic | 1-d Exposure | 3-d Exposure | 5-d Exposure | 7-d Exposure |
|---|---|---|---|---|
| n | 19,593 | 10,571 | 6,391 | 4,318 |
| Hyperoxemia dose, kPa | 0.54 (0.01–1.75) | 0.30 (0.04–0.86) | 0.26 (0.04–0.68) | 0.27 (0.06–0.65) |
| Any hyperoxemia exposure (yes) | 15,182 (77.5) | 8,865 (83.9) | 5,580 (87.3) | 3,912 (90.6) |
| Cumulative hyperoxemia exposure, kPa ⋅ h | 13.00 (0.4–42.1) | 21.84 (2.6–61.6) | 31.41 (5.3–81.9) | 45.03 (10.6–108.7) |
| Pre-ICU hospital length of stay, d | 1 (1–2) | 1 (1–3) | 1 (1–3) | 1 (1–3) |
| Age, yr | 65 (51–74) | 65 (51–75) | 64 (49–74) | 63 (48–74) |
| Weight, kg | 77 ± 20 | 77 ± 19 | 77 ± 20 | 77 ± 20 |
| Sex | ||||
| F | 7,834 (40.0) | 4,149 (39.2) | 2,431 (38.0) | 1,621 (37.5) |
| M | 11,758 (60.0) | 6,421 (60.7) | 3,959 (61.9) | 2,696 (62.4) |
| Not available | 1 (0.0) | 1 (0.0) | 1 (0.0) | 1 (0.0) |
| APACHE II score | 15.4 ± 5.8 | 16.5 ± 6.0 | 17.2 ± 6.2 | 17.7 ± 6.3 |
| Prior dependency (none) | 16,239 (82.9) | 8,575 (81.1) | 5,115 (80.0) | 3,433 (79.5) |
| Patient type | ||||
| Surgical | 10,721 (54.7) | 4,652 (44.0) | 2,319 (36.3) | 1,290 (29.9) |
| Medical | 8,861 (45.2) | 5,913 (55.9) | 4,067 (63.6) | 3,025 (70.1) |
| Not available | 11 (0.1) | 6 (0.1) | 5 (0.1) | 3 (0.1) |
| Surgical classification | ||||
| Elective | 6,758 (34.5) | 2,597 (24.6) | 1,144 (17.9) | 539 (12.5) |
| Scheduled | 1,557 (7.9) | 804 (7.6) | 372 (5.8) | 176 (4.1) |
| Urgent | 1,025 (5.2) | 412 (3.9) | 220 (3.4) | 145 (3.4) |
| Emergency | 1,702 (8.7) | 1,029 (9.7) | 699 (10.9) | 517 (12.0) |
| Not applicable (medical) or not available | 8,551 (43.6) | 5,729 (54.2) | 3,956 (61.9) | 2,941 (68.1) |
| Ethnicity | ||||
| Asian/Asian British Indian | 335 (1.7) | 180 (1.7) | 112 (1.8) | 85 (2.0) |
| Asian/Asian British other | 335 (1.7) | 206 (1.9) | 152 (2.4) | 119 (2.8) |
| Black/black British African | 555 (2.8) | 288 (2.7) | 188 (2.9) | 128 (3.0) |
| Black/black British Caribbean | 430 (2.2) | 211 (2.0) | 123 (1.9) | 82 (1.9) |
| Other or not stated | 4,746 (24.2) | 2,592 (24.5) | 1,574 (24.6) | 1,031 (23.9) |
| White British | 11,880 (60.6) | 6,337 (59.9) | 3,759 (58.8) | 2,541 (58.8) |
| White other | 1,312 (6.7) | 757 (7.2) | 483 (7.6) | 332 (7.7) |
| ICU length of stay, d | 3.5 (2.0–6.6) | 6.0 (4.1–11.0) | 9.2 (6.6–16.8) | 13.1 (9.1–21.7) |
| ICU mortality (deceased) | 835 (4.3) | 577 (5.5) | 435 (6.8) | 360 (8.3) |
Definition of abbreviation: APACHE = Acute Physiology and Chronic Health Evaluation.
Variables are presented as mean (SD), median (interquartile range), or count (%) as appropriate. For all characteristics, please see Table E1.