Preoperative Physiologic Assessment Prior to Pulmonary Resection
Simon Turner1, Serena Shum2, Tim van Haaften2
1Thoracic Surgery, University of Alberta
2Anesthesiology, University of Alberta
Anatomic lung resection is the gold standard treatment for early stage lung cancer but may be associated with significant risks of postoperative morbidity and mortality. To reduce the incidence of adverse events, patients should be carefully evaluated prior to any anatomic lung resection. This evaluation should take into account the extent of the planned resection, the patient’s baseline pulmonary and cardiac function as well as any other comorbidities, including factors such as frailty and sarcopenia. Modifiable risk factors, such as coronary artery disease, may be amenable to intervention to allow resection with improved outcomes.
- All patients prior to anatomic lung resection should undergo pulmonary function testing with spirometry and diffusion capacity.
- Patients with predicted post-operative FEV1 and/or DLCO below 40% predicted should be considered above average risk for postoperative complications and death. Post-operative FEV1 and/or DLCO below 30% should be considered exceptionally high risk, and either below 20% considered prohibitive risk.
- High risk patients may still be candidates for resection with acceptable outcomes, but consideration should be given to further stratification of such patients with testing such as low-tech exercise testing (e.g. shuttle walk test, stair climb), cardiopulomary exercise testing (CPET aka VO2 max) and/or quantitative VQ scan (Fig. 1).
- Low tech exercise testing such as stair climb, shuttle walk test and 6-minute walk test may be useful to supplement clinical decision making, especially in circumstances where CPET is not readily available. Correlation of these tests with more accurate measures of pulmonary function may vary, especially when performed in non-standardized settings.
- Patients who may require a pneumonectomy are subject to more significant physiologic impacts of surgery and should undergo more thorough testing than other patients. An echocardiogram to rule out pulmonary hypertension and cardiac dysfunction should be considered. A quantitative VQ scan can give a better estimate of post-operative pulmonary function than predictions based on the number of bronchopulmonary segments being resected.
2. All patients prior to anatomic lung resection should be assessed clinically for cardiac risk factors.
- The use of a standardized risk score such as the Thoracic Revised Cardiac Risk Index is recommended (Table 1). A ThRCRI score of 2 or greater should be considered high risk.
ThRCRI Risk Factor Weighted Score Renal failure* 1 Ischemic heart disease 1.5 Cerebrovascular disease 1.5 Pneumonectomy 1.5
Table 1. Thoracic Revised Cardiac Risk Index (ThRCRI). *serum creatinine >177umol/L
- Patients at high risk for cardiac complications, especially those undergoing major resections such as pneumonectomy, should have more formal cardiac testing, including echocardiography or be referred to a cardiologist for consideration of angiography or cardiac stress testing.
- Patients should be assessed for their risk of post-operative atrial fibrillation and managed accordingly. The question of atrial fibrillation prophylaxis is beyond the scope of this review.
- The role of prehabilitation for patients deemed at high risk of post-operative complications is beyond the scope of this review.
3. Age is a marker of potential increased risk but should not be the only reason a patient is denied potentially curative surgery.
- Healthy patients at advanced age may be candidates for anatomic lung resection.
- All patients should have their comorbidities assessed, ideally including the use of a standardized scale such as the Charlson Comorbidity Index.
- Other measures of increased operative risk, such as frailty and sarcopenia should be taken into consideration.
4. Quality of life (current and expected short- and long-term post-operative) should be considered when discussing risks and benefits of surgery compared to other treatment options.
5. The smoking status of all patients undergoing lung surgery should be assessed, and recommendations made to assist patients in smoking cessation. See the CATS recommendation on this topic for more detail.
6. All patients with questionable operability and/or resectability should be reviewed by a dedicated multidisciplinary oncology team.
7. All patients prior to anatomic lung resection should be assessed by an anesthesiologist for further risk stratification and preoperative optimization.
- Physiologic evaluation of the patient with lung cancer being considered for resectional surgery. Diagnosis and Management of Lung Cancer, 3rd Ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest, 2013;143:e166s-e190s.
- ERS/ESTS clinical guidelines on fitness for radical therapy in lung cancer patients (surgery and chemo-radiotherapy). European Respiratory Journal, 2009;34:17-41.
- British Thoracic Society guidelines on the radical management of patients with lung cancer. Assessment of the risks of surgery. Thorax, 2010;65(Suppl III):iii11-iii15.