A 65-year-old female with 50 pack-year tobacco history presents to the ED after being involved in a motor vehicle accident. Her vitals on arrival were:
She underwent a CT head, chest, abdomen, and pelvis. The CT chest demonstrated a 5 cm spiculated nodule in the right middle lobe. Thoracic surgery was consulted for possible lobectomy. Pulmonary function tests were performed which demonstrated a forced expiratory volume (FEV1) of 1.4 L (53% predicted), forced vital capacity (FVC) of 2.39 L (71% predicted), and a diffusing capacity of the lungs for carbon monoxide (DLCO) of 48% predicted.
What would be the next step in management?A. Stair climbing assessment
Correct Answer: B
Prior to pneumonectomy or lobectomy, the American College of Chest Physicians (ACCP) and the British Thoracic Society (BTS)recommend starting with pulmonary function tests. A reduced FEV1 has been associated with increased respiratory mortality rates post surgery In the BTS guidelines, a preoperative FEV1 >2 L (or 80% predicted) generally suggests the patient would tolerate a pneumonectomy well and for lobectomy, the FEV1 cutoff is 1.5 L. In patients with a FEV1 <30%, the incidence of respiratory morbidity has been as high as 43% but drops to 12% in patients with a FEV1 >60%. DLCO is also recommended for all patients prior to lung resection surgery. Ferguson et al. demonstrated that DLCO <60% was associated with 25% mortality and 40% pulmonary morbidity. If patients do not fall into a low-risk category (FEV1 >80% and DLCO >80%), it is recommended that a postoperative (PPO) pulmonary function test be calculated. A PPO calculation involves using the preoperative FEV1 or DLCO and multiplying by 1—the fraction of total perfusion in the to-be-resected lung. This involves the use of a ventilation/perfusion scan. If the PPO FEV1 and PPO DLCO are >60% predicted, no additional testing is recommended. If the PPO FEV1 and PPO DLCO are <60% and greater than 30%, either a stair testing or shuttle testing is recommended. If the PPO FEV1 and PPO DLCO are <30%, a cardiopulmonary exercise test is recommended. An arterial PO2 has not been shown to predict mortality prior to lung resection surgery. For this patient, given the FEV1 and DLCO do not clearly place the patient into a low-risk category, the next best step would be to calculate a PPO and then determine if stair climbing or a cardiopulmonary exercise test was necessary.