Table 3.
Multivariable logistic regression of risk factor for postoperative pulmonary complications in the development cohort (simplified risk score)
| β coefficient | Odds ratio (95% Cl) | Risk scorea | |
|---|---|---|---|
| Demographic characteristics | |||
| Age (years) | |||
| ≤ 46 | 1 (Reference) | 1 (Reference) | |
| 47–67 | 0.291 | 1.34 (0.99 to 1.81) | 3 |
| ≥ 68 | 0.407 | 1.50 (1.07 to 2.11) | 4 |
| ASA PS | |||
| < 3 | 1 (Reference) | 1 (Reference) | |
| ≥ 3 | 0.644 | 1.90 (1.49 to 2.44) | 6 |
| Preoperative anaemia | 0.483 | 1.62 (1.01 to 2.59) | 5 |
| Preoperative SpO2 | |||
| > 96 | 1 (Reference) | 1 (Reference) | |
| ≥ 96 | 0.249 | 1.28 (1.01 to 1.62) | 2 |
| Cancer | 0.538 | 1.71 (1.17 to 2.50) | 5 |
| Obstructive sleep apnoea | 0.900 | 2.46 (1.38 to 4.39) | 9 |
| Surgical characteristics Condition of surgery | |||
| Elective | 1 (Reference) | 1 (Reference) | |
| Urgency | 0.760 | 2.14 (1.53 to 2.98) | 8 |
| Emergency | 0.943 | 2.57 (1.45 to 4.55) | 9 |
| Duration of surgery (min) | |||
| ≤ 55 | 1 (Reference) | 1 (Reference) | |
| 56–134 | 0.390 | 1.48 (1.08 to 2.01) | 4 |
| ≥ 135 | 1.121 | 3.07 (2.23 to 4.21) | 11 |
| Intra-operative characteristics | |||
| Use of supraglottic device | −0.644 | 0.525 (0.31 to 0.87) | −6 |
| Type of anaesthesia | |||
| Totally intravenous | 1 (Reference) | 1 (Reference) | |
| Volatile | −0.010 | 0.99 (0.70 to 1.40) | 0 |
| Balanced | 0.535 | 1.71 (1.14 to 2.56) | 5 |
| Desaturation | 1.229 | 3.42 (2.29 to 5.10) | 12 |
| Need of vasoactive drug | 0.473 | 1.60 (1.25 to 2.05) | 5 |
| Mechanical ventilation characteristics | |||
| PEEP (cmH2O) | |||
| ≤ 2 | 1 (Reference) | 1 (Reference) | |
| 3–4 | 0.358 | 1.43 (1.05 to 1.95) | 3 |
| ≥ 5 | 0.400 | 1.49 (1.14 to 1.96) | 4 |
ASA PS, American Society of Anaesthesiology physical score; CI, confidence interval; PEEP, positive end-expiratory pressure; SpO2, peripheral oxygen saturation.
a
The simplified risk score was the sum of each β logistic regression coefficient multiplied by 10, after rounding off its value.c-index (95% CI): 0.778 (0.755 to 0.801) (P < 0.001 ).Hosmer-Lemeshow Chi-square test: 15.414 (P = 0.052).