Incidence and risk factors for re-expansion pulmonary oedema following medical thoracoscopy

Re-expansion pulmonary oedema (RPO) is a serious and potentially life-threatening complication following rapid drainage of pleural effusion or pneumothorax. However, the incidence and risk factors for RPO following medical thoracoscopy (MT) remains unknown.

We performed a retrospective cohort study of patients who underwent MT between January 2017 and December 2024. All procedures were performed with a semirigid thoracoscope under conscious sedation.

A total of 362 patients were included in the study. Approximately half (52.8%) of patients had pleural effusions occupying >50% of the hemithorax on preprocedural chest radiographs. Malignant pleural effusion and tuberculous pleuritis accounted for 85.1% (n=308) and 8.6% (n=31) of the final diagnoses, respectively. Six (1.7%) patients developed clinical RPO with hypoxia requiring oxygen supplementation, of whom three required invasive mechanical ventilation, and one patient required non-invasive ventilation. Compared with patients without RPO, those who developed clinical RPO were younger in age (median 55 (IQR: 35-64) vs 69 (IQR: 60-75) years, p=0.031), had a higher proportion of effusions occupying >50% hemithorax (100% (6/6) vs 52.0% (185/356), p=0.031) and greater pleural fluid drainage volumes during MT (median 2795 (IQR:1425-4050) vs 1375 (IQR:1000-1831) mL, p=0.009). Radiological RPO occurred in 20 patients (6.1%). On univariable and multivariable analysis, younger age (<60 years), larger volume of pleural fluid drained and expandable lung following pleural fluid drainage were associated with the development of radiological RPO. There were no deaths related to MT or RPO in our study.

RPO is a clinically significant complication of MT, with younger age and large-volume effusions being possible risk factors. Physicians performing MT should exercise vigilance for RPO to facilitate early recognition and prompt management.