For lesions more easily accessed through the chest, video-assisted thoracoscopic biopsy provides an excellent, minimally invasive approach. Rarely a standard posterolateral incision may be required in order to obtain adequate tissue. Anesthesia Because of their location, anterior mediastinal masses may effect severe respiratory and cardiovascular complications due to obstruction or compression of major airways, the superior vena cava, or the heart. For example, over one-half of children with newly diagnosed mediastinal Hodgkin's disease have tracheobronchial compression. For a number of reasons these may be exacerbated during general anesthesia.
Pulmonary compromise is increased because of lower lung volumes.
This may be due, in part, to increased abdominal muscle tone but decreased inspiratory muscle tone. In addition paralysis eliminates movement of the diaphragm during spontaneous respiration thus reducing the transpleural gradient for air movement. Also contributing to pulmonary compromise is the fact that bronchial smooth muscle relaxation causes increased compressibility of large airways. It is important to recognize that extrinsic compression on the airway may occur distally, either at the carina or mainstem bronchi, where an endotracheal tube might not bypass an obstruction. Additionally, tumor which encases or constricts the heart itself will further diminish the already depressed cardiac output associated with general anesthesia.