Jay Heidecker

Pathophysiology of Pneumothorax Following Ultrasound-Guided Thoracentesis

STUDY OBJECTIVES Pneumothorax following ultrasound-guided thoracentesis is rare. Our goal was to explain the mechanisms of pneumothorax following ultrasound-guided thoracentesis in a setting where pleural manometry is routinely used. METHODS We reviewed the patient records and procedure reports of 401 patients who underwent ultrasound-guided thoracentesis. When manometry was performed, pleural space elastance was determined. A model assuming dependence of the pleural space elastic properties on respiratory system elastic properties was used to isolate cases with presumed normal pleural space elastance. Elastance outside mean +/- SD x 2 of the isolated sample was considered abnormal. Four radiographic criteria of unexpandable lung were used: visceral pleural peel, lobar atelectasis, basilar pneumothorax, and pneumothorax with ipsilateral shift. RESULTS There were 102 diagnostic thoracenteses, 192 therapeutic thoracenteses with pleural manometry, and 73 therapeutic thoracenteses without manometry. There was one pneumothorax that occurred from lung puncture and eight unintentional pneumothoraces, all of which showed radiographic evidence of unexpandable lung. Four of eight unintentional pneumothoraces had abnormal elastance; none had excessively negative pleural pressure (< -25 cm H(2)O). CONCLUSIONS Unintentional pneumothoraces cannot be prevented by monitoring for symptoms or excessively negative pressure. These pneumothoraces were drainage related rather than due to penetrating lung trauma or external air introduction. We speculate that unintentional pneumothoraces are caused by transient, parenchymal-pleural fistulae caused by nonuniform stress distribution over the visceral pleura that develop during large-volume drainage if the lung cannot conform to the shape of the thoracic cavity in some patients with unexpandable lung. These fistulae appear to be pressure dependent, and the resulting pneumothoraces rarely require treatment. Drainage-related pneumothorax is an unavoidable complication of ultrasound-guided thoracentesis and appears to account for the vast majority of pneumothoraces occurring in a procedure service.

Four faces of a parapneumonic effusion: Pathophysiology and varied radiographic presentations

Abstract:  We report a patient methicillin‐resistant Staphylococcus aureus pneumonia who developed fluid collections in three spaces in the thorax, the pleural space, the pericardial space, and a pre‐existing bulla, in addition to mediastinal oedema. We discuss the universal pathogenesis for the development of these fluid collections and the explanation for the most common presentation being a parapneumonic effusion.

Pleural Fluid and Peripheral Eosinophilia from Hemothorax: Hypothesis of the Pathogenesis of EPE in Hemothorax and Pneumothorax

Blood and air in the pleural space are the most common conditions associated with an eosinophilic pleural effusion. The recruitment of eosinophils is dependent upon stimulation by cytokines, specifically interleukin (IL)-3, IL-5, granulocyte-monocyte cell stimulating factor (GM-CSF), and RANTES (regulated upon activation, normal t-cell expressed and secreted), that cause eosinophil proliferation in the bone marrow, movement into the circulation, and adhesion and migration across endothelial barriers into tissues. There are several possible mechanisms that can explain eosinophilic pleural effusions. We report a case of an eosinophilic pleural effusion after spontaneous hemothorax that illustrates the course of pleural fluid and blood eosinophilia in following hemothorax and describe the different pathophysiology of eosinophil trafficking in the pleural space and serum following hemothorax and pneumothorax.