Preanesthetic evaluation of children with anterior mediastinal masses.

Respiratory collapse is a well-recognized complication of general anesthesia in patients with an anterior mediastinal mass. Although numerous case reports document this occurrence, only recently have several series provided some guidance in defining which patients are at risk for respiratory collapse. Safe lower limits for two parameters at which general anesthesia can be used appear to be a tracheal area measured by computed tomography (CT scan), which is at least 50% of the area predicted for normals and peak expiratory flow rates, which are at least 50% of predicted. The problems with prebiopsy treatment are presented, and methods of obtaining diagnostic material by aspiration of a pleural effusion or performance of an anterior thoracotomy under local anesthesia are discussed.