Anterior mediastinal masses can obstruct the SVC, major airways, and even the heart. A series of 105 operations on patients with mediastinal masses showed that 3.8% had cardiorespiratory complications, and 11% had post-operative respiratory complications (7 of which were life-threatening, i.e. 6.67% overall) [Bechard P et al. Anesthesiology 100: 826, 2004]. Risk factors in this study included preoperative signs and symptoms, dysfunctional PFTs, and more than 50% tracheal compression as assessed by CT scanning.
When anterior mediastinal masses are particularly threatening (ex. by Bechard et al.’s criteria), consider preoperative femoral-femoral cannulation and standby cardiopulmonary bypass [Tempe DK et al. J Cardiothrac Vasc Anesth 15: 233, 2001]. Critical to the preoperative assessment are two pieces of information – the CT scan, and determining what happens when the patient lies supine.
There is significant controversy as to whether or not mediastinal masses should be irradiated preoperatively. On one hand, irradiation will often shrink the mass and potentially lower the risks associated with induction. On the other hand, radiation may obscure the diagnosis.