Author(s): Henry K. Su, Xiaodong Bao

1. Patients scheduled for thoracic surgery should undergo the standard preoperative assessment as detailed in Chapter 1: Evaluating the Patient Before Anesthesia.

   1. Any patient undergoing elective thoracic surgery should be carefully screened for underlying bronchitis or pneumonia and treated appropriately before surgery.

   2. Patients with tracheal stenosis or mediastinal masses should be evaluated for signs or symptoms of positional dyspnea, static or dynamic airway collapse, and evidence of hypoxemia. The history may also suggest the probable location of the lesion.

2. An arterial blood gas (ABG) may help clarify the severity of underlying pulmonary disease but is not routinely necessary.

3. Pulmonary function tests (PFTs) are useful for assessing the pulmonary risk of lung resection.

   1. Preoperative PFTs should include spirometry and the diffusing capacity of the lungs for carbon monoxide (DLCO). Both the forced expiratory volume in 1 second (FEV1) and DLCO are independent predictors of outcomes after lung resection.

   2. If either of these values is less than 80% of the predicted, the patient’s predicted postoperative FEV1 (ppoFEV1) and predicted postoperative DLCO (ppoDLCO) should be calculated.

   3. If both ppoFEV1 and ppoDLCO are ≥60%, then the patient is considered to be of low risk for surgery.

   4. If either is <60% but both are ≥30%, then the patient should undergo a stair-climbing test (SCT) or a shuttle walk test (SWT). If SCT is ≥22 m or SWT ≥25 shuttles, the patient is considered to be of low risk.

   5. If either ppoFEV1 and ppoDLCO are <30%, or performance on the SCT or SWT is not satisfactory, cardiopulmonary exercise test to calculate maximum oxygen consumption (Vo₂ max) is needed. Vo₂ max >20 mL/kg/min or >75% indicates low-risk, while Vo₂ max of <10 mL/kg/min or <35% is high-risk group, and surgery is not recommended. Vo₂ max 10 to 20 mL/kg/min or 35% to 75% indicates moderate-risk and Vo₂ max <10 mL/kg/min or <35% indicates high-risk group and surgery is not recommended.

   6. Quantitative ventilation/perfusion (V/Q) scan can also be used to calculate ppoFEV1 in patients scheduled to undergo pneumonectomy.

4. Cardiac screening should be conducted in accordance with the ACC/AHA guidelines for noncardiac surgery (see Chapter 3: Specific Considerations for Patients With Cardiac Disease). Cardiac function should be assessed if there is a question about the relative contribution of cardiac and pulmonary diseases to the patient’s functional impairment.

   1. Echocardiography can be used to assess right ventricular function. Echocardiographic estimation of right ventricular systolic pressure

      can be used as a screening tool for pulmonary hypertension, although right heart catheterization is required for definitive diagnosis. This is especially important for procedures requiring clamping of a pulmonary artery (eg, pneumonectomy).

5. Chest imaging, such as chest radiography, computed tomography (CT), and magnetic resonance imaging (MRI), are useful to determine the presence and extent of tracheobronchial, pulmonary, and mediastinal pathology.

   1. Imaging studies can also reveal the nature and degree of involvement of other thoracic structures in the disease process. Three-dimensional CT reconstruction can be used to define the anatomy of a stenotic airway.

   2. Imaging studies can also be helpful in planning for lung isolation if required.

6. Preoperative sedation should be given carefully to patients with tracheal or pulmonary disease.

   1. Heavy sedation may impair postoperative deep breathing, coughing, and airway protection. Patients with poor pulmonary function will be more prone to hypoxemia when their respiratory drive is suppressed. When sedating these patients, it is prudent to monitor oxygenation and administer supplemental oxygen.

   2. In the presence of airway obstruction, oversedation may profoundly suppress ventilation, but an anxious patient may make exaggerated respiratory efforts. In this case, the increased turbulence may impair effective ventilation, leading to increased anxiety. Benzodiazepines, reassuring words, careful monitoring, and an expeditious start to the procedure are the best approaches.

   3. In patients with airway stenosis, administration of a mixture of 80% helium and 20% oxygen (Heliox) may reduce airway resistance, albeit at the cost of a lower fraction of inspired oxygen (FiO₂).

   4. Glycopyrrolate may be given to decrease oral secretions.