What else would you like to know about her history?

(a) Respiratory effects of an anterior mediastinal mass?

(b) Other symptoms?

(c) Is her perioperative plan likely to be influenced by the above?

Her labs are unremarkable.

(a) What other studies would you like to know the results of or obtain?

(b) How will the results influence your planning? Of what consequence will that be for the patient and family?

While thymomas are rare, they nevertheless are the most common tumor of the anterior superior mediastinum. Paraneoplastic syndromes are relatively common, with myasthenia gravis symptoms in about 50 %. In addition, mechanical effects on the anterior mediastinum include cough, dyspnea, dysphagia, and signs of superior vena cava syndrome. There may also be comorbidities associated with immune deficiencies because of abnormalities of T-cell function. Depending on the range and severity of associated abnormalities, the site of her recovery as well as perioperative management such as postoperative mechanical ventilation may be influenced.

Additional studies might include pulmonary function testing with a specific emphasis on a dynamic airway assessment such as a vital capacity maneuver. Imaging studies should have included chest x-ray and CT scan to evaluate the encroachment of the mass on the trachea and main conducting airways. There is an association of airway collapse with tracheal encroachment of more than 50 % (age and gender adjusted). For patients with significant airway compromise from an anterior mediastinal mass, induction in an upright position with spontaneous breathing may be the safest technique. A sedated “awake” intubation with nerve blocks is another technique. Neuromuscular blockade in patients with high-grade tracheal obstruction is fraught with danger as far as airway collapse, and to the extent that the mass encroaches on venous return or the right ventricular outflow tract, cardiovascular function may be compromised as well [1, 2].

Routine noninvasive monitors are already planned for this case; does it require anything else?

The surgeons request single-lung ventilation.

Assume that the patient did have a myasthenia picture preoperatively; what are your considerations for neuromuscular blockade? Does this patient require it?

In the left lateral position with one-lung ventilation and the surgeons dissecting in the mediastinum, the oxygen saturations have decreased to 89 % with an F_iO₂ of 1.0.

The SpO₂ is now 88 % on 100 % O₂ and the blood pressure 60/40 mmHg; how does this influence your analysis? What would you do?

The need for an arterial line is influenced by the extent of the tumor and its local effects as well as how much anticipated dissection there will be according to the surgeons. In addition, if there is a component of myasthenia gravis, regardless of whether the patient will be mechanically ventilated postoperatively, in all likelihood the patient will go to the ICU, who will undoubtedly appreciate the presence of an arterial line for frequent checking of arterial blood gases. Because of the proximity to vital structures during the dissection, an arterial line is a very reasonable choice. Adequate vascular access is crucial, and this patient should have (at least) two large-bore IVs. Routine noninvasive monitoring is indicated, plus an arterial line. A CVP might assist with assessing intravascular volume, but the absolute number would not be diagnostic nor could it be relied upon intraoperatively as long as intrathoracic pressures were being manipulated and scopes were surrounding it. As the vena cava is dissected, the assessment may become unreliable as a result of mechanical displacement or intrathoracic pressure from insufflation [3].