Pulmonary Clearance for Pre-Operative Surgery
Pulmonary clearance for pre-operative surgery involves a structured assessment of respiratory risk factors and functional capacity to identify patients at increased risk for postoperative pulmonary complications and optimize their management before surgery.
Key Risk Factors to Assess
- Advanced age (≥65 years) significantly increases risk of postoperative pulmonary complications, with odds ratios of 2.09 for patients 60-69 years and 3.04 for those 70-79 years compared to younger patients 1
- Chronic obstructive pulmonary disease (COPD) is the most commonly identified risk factor for postoperative pulmonary complications (odds ratio 1.79) 1
- Functional dependence, congestive heart failure, weight loss, and obstructive sleep apnea are significant risk factors that should be evaluated 1
- Myelopathy may increase risk of postoperative pneumonia and pulmonary embolism in spine surgery patients 1
Pulmonary Function Testing Approach
For lung resection surgery, post-bronchodilator FEV1 values are critical: patients are generally suitable for lobectomy if FEV1 >1.5 liters and for pneumonectomy if FEV1 >2.0 liters 1
For patients not clearly operable based on spirometry alone, additional testing should include:
- Full pulmonary function tests with transfer factor (TLCO)
- Oxygen saturation measurement at rest
- Quantitative isotope perfusion scan if pneumonectomy is being considered 1
Calculate estimated postoperative FEV1 and TLCO as percentage of predicted values:
- If both >40% predicted with O2 saturation >90%: average risk
- If both <40% predicted: high risk
- For other combinations: consider exercise testing 1
For patients with unclear risk after initial assessment, exercise testing is recommended:
- Shuttle walk test <250m or desaturation >4% indicates high risk
- Cardiopulmonary exercise testing with peak oxygen consumption >15 ml/kg/min indicates average risk 1
Important Considerations
- Preoperative spirometry and chest radiography should not be used routinely for predicting postoperative pulmonary complication risk 1
- There is insufficient evidence to support any specific preoperative diagnostic test for predicting postoperative pulmonary adverse events in spine surgery 1
- Despite limited evidence for specific tests, clinicians should perform appropriate preoperative pulmonary tests based on clinical presentation of active pulmonary symptoms or to confirm suspected pulmonary disease 1
Preoperative Optimization Strategies
- Patients with risk factors should be counseled regarding increased risk of perioperative and postoperative pulmonary adverse events 1
- Appropriate preoperative pulmonary interventions should be implemented to treat active pulmonary symptoms or suspected pulmonary disease 1
- Optimization of chronic lung disease management before surgery is recommended 2
- Lung expansion maneuvers and adequate pain control are effective strategies to reduce postoperative pulmonary complications 2
Special Considerations
- Patients with cardiac murmurs should have an echocardiogram 1
- Patients with recent myocardial infarction (within 6 weeks) should normally not undergo lung resection surgery 1
- Patients with multiple adverse medical factors should have their management discussed at a multidisciplinary meeting between a chest physician, surgeon, and oncologist 1
- Nutritional status assessment, including body mass index and serum albumin measurement, should be included in preoperative evaluation 1
Common Pitfalls
- Overreliance on pulmonary function testing alone for surgical decision-making; compelling surgical indications should not be denied solely based on pulmonary function tests 2
- Failure to assess both procedure-related and patient-related risk factors 2
- Neglecting to optimize modifiable risk factors prior to surgery 3
- Inadequate attention to postoperative pulmonary complications, which are as prevalent and contribute similarly to morbidity, mortality, and length of stay as cardiac complications 1