Abstract
Providing anesthesia for the patient with a mediastinal mass is challenging due to the potential for life-threatening complications. Mediastinal masses can compress neighboring structures and cause superior vena cava syndrome, tracheobronchial tree compromise, or compression of the heart and great vessels. While anticipation and prevention of these complications is the best approach, strategies for management of acute cardiopulmonary collapse are vital. Here we present a challenging case describing the management of a patient with an anterior mediastinal mass for general anesthesia and discuss strategies for anesthetic planning.
Keywords
cardiac compression, cardiorespiratory complications, mediastinum, SVC syndrome, tracheobronchial tree compression
Case Synopsis
A 23-year-old previously healthy man is scheduled for cervical mediastinoscopy for tissue diagnosis of a mediastinal mass. He presents with a 3-month history of fatigue and dyspnea on exertion and reports that he cannot sleep on his left side because it makes him feel short of breath. Chest computed tomography (CT) demonstrates a 10 × 8 × 5 cm mass adjacent to the right atrium, ascending aorta, and main pulmonary artery, with no other abnormalities. After induction with propofol and succinylcholine, the patient is easily intubated but rapidly becomes hypoxic. Vigorous manual ventilation fails to improve oxygenation, and the patient becomes progressively hypotensive.
Problem Analysis
Definition
Patients with anterior mediastinal masses are prone to develop certain potentially life-threatening complications because of the influence of these masses on neighboring structures (superior vena cava, tracheal bifurcation or mainstem bronchi, main pulmonary artery, aortic arch, and heart). Principal anesthetic considerations for patients with anterior mediastinal masses involve the following three potential complications:
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Tracheobronchial tree compression or obstruction
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Superior vena cava syndrome
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Compression of the heart and pulmonary vessels
Also, patients may present for anesthesia or monitored anesthesia care for a variety of reasons, including the following:
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Excision of intrathoracic tumor (primary or metastatic)
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Lymph node biopsy (for tissue diagnosis)
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Central line placement (for chemotherapy)
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Biopsy of intrathoracic mass (open or thoracoscopic)
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Any other procedure, either related to the disease (e.g., open reduction and internal fixation of pathologic fracture) or not (cesarean section)
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Imaging studies (children)
Although these masses are referred to as “anterior,” they are often at the confluence of the anterior, superior, and middle mediastina ( Fig. 64.1 ).
Recognition
Tracheobronchial Tree Compression or Obstruction
Tracheobronchial tree compression or obstruction is the most common of the three potential complications arising from anterior mediastinal masses. There can be both static and dynamic components to such compression or obstruction. The dynamic components may not be unmasked until after supine positioning ( Fig. 64.2 ), induction of general anesthesia, or administration of paralytic agents ( Table 64.1 ). Difficulty in mask ventilation in the absence of upper airway obstruction or difficulty ventilating despite successful endotracheal intubation are classic scenarios.
Complication | Manifestation | Mechanism |
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Airway compromise | Difficult intubation | SVC obstruction causing upper airway edema |
Upper airway obstruction | Mass effect or surgical trauma to recurrent laryngeal causing vocal cord dysfunction/paralysis | |
Respiratory compromise | Tracheobronchial obstruction | Distortion, malacia, or dynamic collapse of the trachea and/or mainstem bronchi leading to difficult ventilation/oxygenation |
Pulmonary edema | Left atrial compression causing increased pulmonary venous pressure | |
Hemodynamic compromise | Decreased preload | Cardiac compression of the right or left atrium or right ventricle impairing cardiac filling |
Right ventricular strain/failure | Compression of right ventricular outflow tract or pulmonary artery causing right ventricular pressure overload | |
Hemorrhage | Bleeding from tumor after surgical manipulation, potentially exacerbated by SVC obstruction |