BACKGROUND:For patients with COVID-19, pneumothorax and hydrothorax are suggested to be negative prognostic indicators. However, the management of these two conditions has rarely been discussed. We aimed to describe the clinical outcomes of pleural drainage in critically ill patients with COVID-19. METHODS:A total of 17 pleural drainages were performed in 11 critically ill patients with pneumothorax or hydrothorax. Either chest tubes or central venous catheters (CVCs) were used. The clinical outcomes, including respiratory and circulation indicators at 24 h and 1 h before the procedure and 24 h and 48 h after the procedure, were retrospectively recorded. RESULTS:(1) Following pleural drainage, there was a 19.1% improvement in the PaO2/FiO2 ratio from 147.4 mmHg (-1 h) to 175.5 mmHg (24 h), while the mean positive end expiratory pressure (PEEP) decreased from 10.7 cmH2O (-1 h) to 8.9 cmH2O (24 h) and 8.1 cmH2O (48 h). The A-a gradients decreased from 313.3 mmHg (-1 h) to 261.3 mmHg (24 h). (2) The dosage of norepinephrine increased from 0.15 μg/kg/min (-1 h) to 0.40 μg/kg/min (24 h). (3) No haemorrhagic or infectious complications were observed. (4) A total of 41.6% of CVCs were partially or fully obstructed, while no chest tubes were obstructed. CONCLUSION:For critically ill patients with COVID-19, pleural drainage leads to a significant improvement in oxygenation and gas exchange, but the deterioration of circulation is not reversed. It is safe to perform pleural drainage even though anticoagulation therapy and glucocorticoids are widely used. Chest tubes rather than CVCs are recommended.