Anesthesia for Thoracic Surgery - Mediastinal Operations
Mediastinoscopy is conducted to evaluate the extrapulmonary spread of pulmonary tumors and to investigate mediastinal masses. Mediastinoscopy is performed through an incision just superior to the manubrium. A rigid endoscope is then introduced beneath the sternum, and the anterior surfaces of the trachea and the hilum are examined. The patient is supine with the neck extended.
- Any general anesthetic technique may be used, provided the patient remains immobile. Although the procedure is not very painful, intermittent stimulation of the trachea, carina, and mainstem bronchi occurs.
- Complications include pneumothorax, rupture of the great vessels, and damage to the airways. Large-bore IV access is required, and the patient should have blood cross-matched in the case of hemorrhage. IV access should be placed in the right upper extremity as the left innominate vein may be compressed during mediastinoscopy. There is a risk of stroke from innominate artery occlusion by compression between the mediastinoscope and the posterior surface of the sternum. As stated previously, perfusion to the right arm should be monitored by pulse oximetry or blood pressure measurement. Blood pressure monitoring in the left arm is essential to monitor systemic blood pressure in the event of innominate arterial compression. Should innominate arterial compression occur and the surgeon be incapable of relieving the pressure (i.e., while managing hemorrhage through the mediastinoscope), the mean systemic pressure must be increased to encourage collateral flow to the right cerebral hemisphere. The trachea may be intermittently compressed by the mediastinoscope, and the position of the patient and surgeon increases the chance of accidental disconnection of the breathing circuit.
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