|
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
|
- Three patients were excluded because of a missing value for some variables. Logistic regression model constructed with the development subsample, c-index = 0.90; Hosmer-Lemeshow chi-square test = 7.862; P = 0.447
- CI confidence interval, Hb hemoglobin, OR odds ratio, PPC postoperative pulmonary complications, RTI respiratory tract infection, SpO2 oxyhemoglobin saturation by pulse oximetry (breathing room air in the supine position)
- aSimplified risk score was the sum of each logistic regression coefficient (β) multiplied by 10, after rounding off