Table 1.

Grade scale for postoperative pulmonary complications

Grade scale	Detailed description
Grade 1	Cough, dry Microatelectasis: abnormal lung findings and temperature >37.5°C without other documented cause; results of chest radiograph either normal Dyspnoea, not due to other documented cause
Grade 2	Cough, productive, not due to other documented cause Bronchospasm: new wheezing or pre-existent wheezing resulting in change in therapy Hypoxaemia Atelectasis: radiological confirmation plus either temperature >37.5°C or abnormal lung findings Hypercarbia, transient, requiring treatment, such as naloxone or increased manual or mechanical ventilation
Grade 3	Pleural effusion, resulting in thoracentesis Pneumonia, suspected: radiological evidence without bacteriological confirmation Pneumonia, proved: radiological evidence and documentation of pathological organism by Gram stain or culture Pneumothorax Re-intubation postoperative or intubation, period of ventilator dependence (non-invasive or invasive ventilation) ≤48 hours
Grade 4	Ventilatory failure: postoperative non-invasive ventilation dependence ≥48 hours, or re-intubation with subsequent period of ventilator dependence ≥48 hours