Table 2 Definitions of post-operative pulmonary complications*

Respiratory failure

At least one of the following criteria after surgery:

 ▪ SpO₂ <90% and requiring oxygen therapy

 ▪ PaO₂/FiO₂ <300

 ▪ PaO₂ <60 mmHg

Respiratory infection

Postoperative antibiotic therapy administered for suspected respiratory infection with at least one of the following criteria:

 ▪ New or changed sputum

 ▪ New or changed lung opacity on x-ray

 ▪ Fever

 ▪ Leukocyte count >12,000/mL

Pleural effusion

Evidence at chest x-ray of:

 ▪ Blunting of the costophrenic sinus

 ▪ In upright position: loss of the sharp silhouette of the ipsilateral hemidiaphragm

 ▪ In supine position: hazy opacity in 1 hemithorax with preserved vascular shadows

 ▪ Displacement of adjacent anatomic structures

Atelectasis

Evidence at chest x-ray of:

 ▪ New parenchymal opacification

 ▪ Shift of the median structures (mediastinum, hilum or hemidiaphragm) toward the affected area

 ▪ Compensatory overinflation of contralateral lung

Aspiration pneumonitis

Inhalation of gastric content in the perioperative period with subsequent acute lung injury

Broncho spasm

New expiratory wheezing responsive to treatment with bronchodilators

Pneumothorax

At chest x-ray, presence of air within pleural space, with no vascular bed surrounding the visceral pleura