When four or more of the following criteria* are present anytime in the 24-h period 00:01 to 24:00 on a single postoperative day:  1. New abnormal breath sounds on auscultation different to preoperative assessment+  2. Production of yellow, green, or brown sputum different to pre-morbid status+  3. Pulse oximetry oxygen saturation (Sp02) < 90% on room air or FiO2 on 0.21 on more than one consecutive postoperative day**  4. Raised maximum tympanic temperature ≥ 38 °C on more than one consecutive postoperative day  5. Chest radiograph report of collapse/consolidation# ***  6. Presence of infective organisms on sputum culture report***  7. White cell count > 11 or < 3  8. Physician’s diagnosis of postoperative pulmonary complication (e.g. atelectasis, pneumonia, AECOPD, respiratory failure, upper respiratory tract infection) OR prescription of an antibiotic specific for respiratory infection |