Table 1 Preoperative risk classes of postoperative pulmonary complications (PPCs)

Neurosurgery

8

  ≥ 80 years

17

 70–79 years

13

 60–69 years

9

 50–59 years

4

 Totally dependent

10

 Partially dependent

6

Weight loss > 10% in past 6 months

7

History of chronic obstructive pulmonary disease

5

History of cerebrovascular accident

4

General anesthesia

4

Impaired sensorium

4

  < 2.86 mmol/L (< 8 mg/dl)

4

 7.85–10.7 mmol/L (22–308 mg/dl)

2

  ≥ 10.7 mmol/L (≥ 30 mg/dl)

3

Transfusion > 4 units

3

Emergency surgery

3

Steroid use for chronic condition

3

Current smoker within 1 year

3

Alcohol intake > 2 drinks/day in the past 2 weeks

2