A47-13 Vacuum-Sealed: The Curious Case of the Non-Expanding Lung

Abstract Introduction Ex vacuo pneumothorax is a rare form of non-expandable lung that occurs due to the negative intrapleural pressure following a loss of lung volume. It represents a chronic pneumothorax that typically forms adjacent to an atelectatic lobe. Common etiologies include acute lobar collapse secondary to bronchial obstruction or failure of lung re-expansion after pleural drainage. Most patients remain asymptomatic depending on the extent of volume loss. Management focuses on addressing the underlying cause of the non-expanding lung rather than further chest tube placement. Recognizing this entity is crucial to avoid unnecessary procedures that can cause harm, such as repeated thoracentesis or chest tube placement. Case Report This is a 65-year-old male with a past medical history of chronic obstructive pulmonary disease (COPD), tobacco use, and previous traumatic pneumothorax who presents for shortness of breath, initially placed on high flow nasal cannula. Admission chest x-ray showing no acute findings, noted hyper-aeration of the lung fields. Given persistent tachycardia and hypoxia, a CT angiogram of the chest was obtained on the first night of admission, revealing a new large right lower lobe (RLL) pneumothorax and chronic appearing right middle lobe (RML) atelectasis with collapse. Overnight ICU team placed a pigtail chest tube for decompression of secondary spontaneous pneumothroax. Post-procedure noted adequate re-expansion of the RLL, with persistent RML atelectasis. An air leak was noted but resolved within 24 hours and over 3 days chest tube was successfully weaned and removed. Following removal, CT of the chest showed a stable moderate right lower lobe pneumothorax consistent with pneumothorax ex vacuo attributed to chronically collapsed RML. A bronchoscopy was planned inpatient; however, the patient elected for outpatient follow-up. Discussion In this case, before presentation, the RML was chronically collapsed. However, he developed a secondary spontaneous pneumothorax originating in the RLL because of his COPD, introducing air into the pleural space. The chest tube decompressed the atelectasis of the remaining RLL and allowed for re-expansion; however, RML was non-expandable due to a suspected bronchial obstruction. The chest tube insertion permitted sufficient air into the pleural cavity to equilibrate the negative pressure created by the non-expanding RML, resulting in a pneumothroax ex vacuo. This case highlighted the importance of focusing treatment on the underlying cause of atelectasis; reinsertion of the chest tube was not correctly pursued. Conclusion Clinicians must be aware of this condition to avoid pursuing unnecessary and potentially harmful pleural interventions. This abstract is funded by: None