Pleural antiseptic irrigation (PAI) is used in conjunction with open drainage for treating adults with chronic post-thoracotomy empyema. The antiseptic povidone-iodine can safely be instilled into the pleural cavity for the purpose of pleurodesis and has recently been described for pleural irrigation in the acute management of paediatric pleural infection with good outcomes. A recent case report demonstrated the safe use of povidone-iodine pleural irrigation in a patient with complex pleural empyema with successful medical management. In a previous pilot study, antiseptic irrigation led to less referral to surgery and shorter length of hospital stay in comparison to no irrigation.

This study aims to investigate the effect of antiseptic pleural irrigation (using povidone iodine) on the inflammatory response in adults patients with pleural infection in comparison to irrigation with normal saline alone. A reduction in the systemic inflammatory response can be inferred to correlate with reduction in the infection burden in the pleural space.

Inclusion Criteria:

• Adults (18 year-old or more)
• Pleural infection diagnosed by: the presence of pus in the pleural space, OR any of the following in the setting of acute lower-respiratory tract infection symptoms: pleural fluid PH<7.2 or pleural fluid glucose <40 mg/dL, positive gram stain or culture from pleural fluid
• Predominantly unilocular pleural collection treated with chest tube drainage
• Acute response at presentation as evidenced by fever (>37.80C) and/or blood leucocytosis (>11X103/mm3) and/or high serum C-reactive protein, CRP (>50 mg/L)

Exclusion Criteria:

• Known or suspected thyroid disease
• Allergy to iodine
• Persistent large collection on follow-up imaging 24-48 post tube insertion that is deemed to require additional interventions (e.g., another drainage procedure, intrapleural fibrinolytic)
• Evidence or suspicion of broncho-pleural fistula (suspected when there is air-fluid level without previous intervention, or if the participant is coughing large volume of purulent sputum that is physically similar to drained pleural fluid)
• Tuberculous, post-operative or post-haemothorax pleural infections

These spreadsheet with individual participant data will be stored after trial conclusion with the principal investigator and will be accessible to other members of the study team. Request to access study data by other researchers will be expected via email and access will be granted by the principal investigator if the request is deemed reasonable.

Data will be available for a minimum of five years after study conclusion

Request for access will be granted when reasonable reasons for request are given