CASE 5-2014 challenging perioperative management of a massive anterior mediastinal mass in a symptomatic adult.

HE ANESTHETIC MANAGEMENT of an adult with an anterior mediastinal mass is considered to be extremely high risk due to the possibilities of airway obstruction and/or cardiopulmonary collapse during the perioperative period. 1–3 In this case conference, the perioperative course of a severely symptomatic young man with a giant anterior mediastinal mass is presented followed by 2 expert commentaries. The clinical value of a cohesive multidisciplinary approach to perioperative management and complications is emphasized in this challenging scenario. CASE SUMMARY A 24-year-old man with no past medical history presented for biopsy of a newly diagnosed anterior mediastinal mass. The patient initially presented to the referring hospital with 2 weeks of fatigue, fevers, hoarseness, severe coughing episodes, and dyspnea while lying flat. His physical examination was unremarkable. There was no evidence of great vein compression. The patient was unable to lie flat. Computed tomographic chest imaging revealed a giant anterior mediastinal mass with compression of the superior vena cava and right pulmonary artery and greater than 50% compression of the distal trachea. Clinical concern about the risk of a rapid cardiorespiratory decline prompted thoracic surgery consultation for urgent tissue diagnosis to guide further management. The patient was scheduled for urgent left anterior mediastinotomy (Chamberlain procedure). Given the high operative risk, a thorough multidisciplinary discussion of the operative plan was undertaken among the anesthesia, cardiac surgery, and the thoracic surgery teams. The patient was anxious and expressed a strong reluctance to undergo neuraxial blockade but consented to local anesthesia with sedation, keeping general anesthesia as a rescue option. The anesthetic plan was to maintain sedation with a dexmedetomidine infusion. On arrival to the operating room, the patient was placed in a comfortable Fowler’s position. After standard noninvasive monitoring was established, oxygen was administered via a nonrebreathing mask. After titrated sedation with intravenous midazolam, large-bore peripheral venous access and left radial arterial monitoring were achieved. Further sedation was achieved by gradual titration of a dexmedetomidine infusion. 5 The cardiac surgical team then secured femoral venous and arterial access under local anesthesia. A perfusionist primed a cardiopulmonary bypass (CPB) machine and was immediately available in the operating room. The equipment for rigid bronchoscopy by the thoracic surgeon was also on hand in the operating room. The thoracic procedure was commenced. Despite serial increases in the dexmedetomidine infusion and a surgical field block with local anesthesia, acceptable surgical conditions proved impossible. The team decided to proceed with induction of general anesthesia. Following adequate denitrogenation, general anesthesia was induced with titrated intravenous propofol (at a dose of 3 mg/ kg) and remifentanil (at a dose of 2 µg/kg) with the goal to achieve acceptable tracheal intubating conditions without neuromuscular blockade. 4 Mask ventilation was not attempted. Prompt direct laryngoscopy yielded a full laryngeal view, and an 8.0-mm endotracheal tube was passed easily through the vocal cords. Just after endotracheal intubation, vigorous coughing ensued that precipitated severe hypotension with a mean arterial pressure of 40 mmHg. The coughing was aborted immediately by further increasing anesthetic depth with additional titrated propofol and volatile anesthetic. Rapid hemodynamic improvement was achieved with titrated bolus epinephrine and phenylephrine followed by infusion of both agents at doses sufficient to maintain his baseline hemodynamics. General anesthesia was maintained