Table 1 The definition of PPCs

Pneumonia [19]

1. Presence of new or progressive infiltrates on chest radiograph

2. Fever (> 38 °C) or leukocyte count (< 4000, ≥12,000 WBC/mm³)

3. New or changed sputum, tachypnea, impaired gas exchange

Pleural effusion [17]

Chest radiograph demonstrating blunting of the costophrenic angle or loss of the sharp silhouette of the hemidiaphragm on the nonoperative side

Atelectasis [17]

Opacities evidenced on chest radiograph with a shift of the mediastinum, hilum, or hemidiaphragm toward the affected area

Prolonged air leakage [20]

Air leak requiring insertion of new chest tube or ≥7 days of postoperative chest tube drainage

Pulmonary embolism [20]

Pulmonary arteriogram or ventilation/perfusion radioisotope scan documenting thrombus

Respiratory failure [20]

Postoperative ventilator dependence ≥24 h or Need of reintubation or noninvasive ventilation