Table 1.
Baseline characteristics of the study patientsa
| Patient characteristics | All patients (N = 12,108) |
Hypoxia/poor O2 exchange (n = 8,904) |
Normoxia (n = 1,919) |
Hyperoxia (n = 1,285) |
|---|---|---|---|---|
| Mean age, yr (±SD) | 64 (16) | 64 (16) | 62 (18) | 65 (17) |
| Male sex, n (%) | 7,802 (64) | 5,778 (65) | 1,228 (64) | 796 (62) |
| Indigenous Australians, n (%) | 515 (5) | 388 (5) | 74 (4) | 53 (4) |
| Hospital admission source from home, n (%) | 8,175 (68) | 5,986 (67) | 1,273 (66) | 916 (71) |
| Acute renal failure, n (%) | 2,368 (20) | 1,916 (22) | 237 (12) | 215 (17) |
| Chronic comorbidities, n (%) | ||||
| Cardiovascular disease, n (%) | 2,395 (20) | 1,821 (20) | 357 (19) | 217 (17) |
| Liver disease, n (%) | 194 (2) | 158 (2) | 17 (1) | 19 (1) |
| Renal disease, n (%) | 668 (6) | 488 (5) | 100 (5) | 80 (6) |
| Respiratory disease, n (%) | 1,044 (9) | 831 (9) | 102 (5) | 111 (9) |
| Cirrhosis, n (%) | 195 (2) | 158 (2) | 18 (1) | 19 (1) |
| Hepatic failure, n (%) | 70 (1) | 52 (1) | 10 (1) | 8 (1) |
| Immune suppression, n (%) | 329 (3) | 243 (3) | 41 (2) | 45 (4) |
| Cancer, n (%) | 413 (3) | 320 (4) | 48 (3) | 45 (4) |
| Markers of severity | ||||
| Median APACHE III risk of death (IQR) | 66% (36 to 84) | 69% (40 to 86) | 50% (20 to 73) | 66% (36 to 84) |
| Median APACHE III risk of death (no oxygen)b (IQR) | 58% (27 to 79) | 60% (29 to 80) | 47% (18 to 71) | 58% (29 to 80) |
| ICU admission source, n (%) | ||||
| Emergency department | 5,756 (48) | 4,123 (46) | 1,035 (54) | 598 (47) |
| Operating theatre | 1,261 (10) | 925 (10) | 217 (11) | 119 (9) |
| Other hospital | 1,958 (16) | 1,445 (16) | 319 (17) | 194 (15) |
| Ward | 3,113 (26) | 2,397 (27) | 344 (18) | 372 (29) |
| Treatment limitationc | 562 (5) | 429 (5) | 68 (4) | 65 (5) |
aAPACHE III, Acute Illness Severity and Chronic Health Evaluation III; IQR, interquartile range; ICU, intensive care unit; bAPACHE III risk of death with oxygen component removed from APACHE III score; ctreatment limitation order or coded for palliative care.