| Multivariate analysis OR (95% CI) n = 1.624* | β | Risk scorea |
---|---|---|---|
Age, years | |||
  ≤ 50 | 1 |  |  |
 51–80 | 1.4 (0.6–3.3) | 0.331 | 3 |
  > 80 | 5.1 (1.9–13.3) | 1.619 | 16 |
Preoperative SpO2, % | |||
  ≥ 96 | 1 |  |  |
 91–95 | 2.2 (1.2–4.2) | 0.802 | 8 |
  ≤ 90 | 10.7 (4.1–28.1) | 2.375 | 24 |
RTI in preceding month | 5.5 (2.6–11.5) | 1.698 | 17 |
Preoperative anemia (Hb ≤ 10 g/dL) | 3.0 (1.4–6.5) | 1.105 | 11 |
Surgical incision | |||
 Peripheral | 1 |  |  |
 Upper abdomen | 4.4 (2.3–8.5) | 1.480 | 15 |
 Intrathoracic | 11.4 (4.9–26.0) | 2.431 | 24 |
Duration of surgery, hours | |||
  ≤ 2 | 1 |  |  |
  > 2–3 | 4.9 (2.4–10.1) | 1.593 | 16 |
  > 3 | 9.7 (4.7–19.9) | 2.268 | 23 |
Emergency procedure | 2.2 (1.0–4.5) | 0.768 | 8 |