PURPOSE: The development of an unexpandable lung is attributed to either visceral pleural restriction, chronic atelectasis, or endobronchial disease. Visceral pleural restriction due to active inflammation/infection or malignancy is defined as lung entrapment. Trapped lung is defined as visceral pleural restriction with the development of a fibrous pleural membrane in the absence of active inflammation/infection or malignancy. The diagnosis of an unexpandable lung can be made by elevated pleural space elastance using manometry during thoracentesis.
METHODS: We identified 93 (32%) patients with unexpandable lung from a consecutive series of 291 patients with pleural effusion undergoing therapeutic thoracentesis with manometry from 2002 to 2011 at the Medical University of South Carolina. Clinical history, pleural manometry, and pleural fluid analysis were reviewed.
RESULTS: There were 52 cases of trapped lung related to the following diagnoses: Post Cardiac Surgery 12 (23%), Remote Parapneumonic 10 (19%), Repeated Thoracentesis 10 (19%), Uremic Pleuritis 7 (13%), Radiation Fibrosis 4 (7.6%), Constrictive Pericarditis 3 (5%), Other/Dual Diagnosis 3 (5%), Undiagnosed 3 (5%). There were 41 cases of lung entrapment related to the following diagnoses: Malignant 19 (46%), Parapneumonic 9 (22%), Paramalignant 8 (19.5%), Rheumatoid 1 (2.4%), Tuberculosis 1 (2.4%), Idiopathic Fibrosing Pleuritis 1 (2.4%), Old Hemothorax 1 (2.4%), Spontaneous Bacterial Pleuritis 1 (2.4%).
CONCLUSIONS: One in three patients undergoing therapeutic thoracentesis with manometry in our institution had an unexpandable lung. The most common cause of trapped lung is related to prior cardiac surgery, followed by remote parapneumonic, and then repeated thoracentesis. Greater than 60% of cases of lung entrapment are directly or indirectly related to malignancy.
CLINICAL IMPLICATIONS: Given the prevalence of unexpandable lung based on abnormal pleural fluid elastance, we suggest the routine use of manometry for all patients undergoing therapeutic thoracentesis for large volume pleural effusions.
DISCLOSURE: The following authors have nothing to disclose: Matthew Divietro, John Huggins, Peter Doelken, Puncho Gurung, Lisa Kaiser, Steven Sahn
No Product/Research Disclosure Information