Table 4 Results of multivariate regression analysis

ASA classification > 2

1.30

0.80–2.09

0.290

Preoperative SpO₂ ≤ 95%

2.60

1.23–5.51

0.012

Preop. Hb < 10 mg/dL

1.24

0.69–2.21

0.479

Preoperative albumin < 3.5 g/dL

1.70

1.02–2.83

0.040

Duration of surgery (reference < 2 h)

1

 2–3 h

1.05

0.50–2.21

0.900

 > 3 h

2.05

1.00–4.22

0.050

Open surgery

1.49

0.83–2.67

0.187

Emergency surgery

2.84

1.39–5.83

0.004

Crystalloid IV > 1000 mL

1.88

0.89–4.00

0.100