A 76-year-old female who is a former smoker with a 30 pack-year history is admitted to the ICU with new productive cough, fevers, dyspnea, and hypoxia. She is started on high flow nasal cannula, steroids, and antibiotics with workup initiated for COPD exacerbation versus pneumonia. Her admission chest X-ray reveals a new focal lesion in the left upper lobe (LUL); follow-up CT shows a solitary tumor involving a portion of the LUL with PET scan finding no evidence of metastases. The patient’s recent pulmonary function testing demonstrates a forced expiratory volume in one second (FEV1) and diffusion capacity (DLCO) of 100%. She is being evaluated by your thoracic surgery team for possible left upper lobectomy. Using the lung segment model, what is her predicted postoperative (PPO) FEV1 and DLCO and what additional testing is necessary to further stratify her operative risk?A. Her predicted postoperative (ppo)-FEV1 and ppo-DLCO are approximately 75%; no further testing is necessary as she is considered low risk for anatomic lung resection
Correct Answer: A
It is vital to understand the role of preoperative testing and risk stratification in lung resection surgery candidates, as poor candidate selection can lead to profound morbidity and mortality. There are evidencebased guidelines to help clinicians risk stratify individual patients and pursue further testing for higher risk candidates based on PPO function. According to the American College of Chest Physicians (ACCP): “In patients with lung cancer being considered for surgery, it is recommended that both FEV1 and DLCO be measured in all patients and that both PPO FEV1 and PPO DLCO are calculated” (Brunelli et al 2013, pg. e173S).
The anatomic lung segment model divides the lungs into 19 total segments; the left upper and left lower lobe each respectively contain 5 and 4 segments while the right upper, middle, and lower lobes respectively contain 3, 2, and 5 segments. To calculate the PPO FEV1 or DLCO, first determine the percent reduction in lung volume; in your patient, a left upper lobectomy would eliminate 5 of the 19 segments, or roughly 25% (5/19 = 0.26). Therefore, the new FEV1 (or DLCO) would be:
According to ACCP Guidelines, “In patients with lung cancer being considered for surgery, if both PPO FEV1 and PPO DLCO are >60% predicted, no further tests are recommended” (Brunelli et al 2013, pg e175S). For those whose ppo-FEV1 and/or ppo-DLCO is less than 60%, additional testing is required and depends on the severity of disease (see Brunelli et al 2013, pg e179S).