Position-Dependent Symptoms of Pneumothorax During Mechanical Ventilation: A Case Report.

A 54-year-old male with severe hypoxia was transferred to our hospital after choking on a mochi. Chest computed tomography revealed negative pressure pulmonary edema without pneumothorax. Endotracheal intubation was performed, and pressure-controlled ventilation was initiated. Following admission to the intensive care unit, his respiratory condition was stable in both the supine and left decubitus positions. However, every time he was placed in the right decubitus position, the tidal volume decreased by half, and SpO₂ dropped rapidly to 80%, which recovered soon after returning to the supine position. Chest radiography was performed the following day, revealing grade II right pneumothorax, and a chest tube placement stabilized his respiratory status in the right decubitus position. Air leakage ceased within a few hours. Extubation was successful on the fifth hospital day, and the chest tube was removed on the eighth hospital day. To our knowledge, there are no previous reports on position-dependent symptoms of pneumothorax during mechanical ventilation. Clinicians should consider the possibility of pneumothorax on that same side when respiratory deterioration is observed only in one lateral decubitus position during mechanical ventilation.