Preoperative Pulmonary Assessment for Lung Resection

Baseline Clinical Evaluation

A smoking history of ≥ 20 pack‑years mandates pre‑operative spirometry. 1
Document recent smoking status (cessation within 2 years or current use) as part of the pre‑operative history. 1
Prior pneumonitis, COPD, asthma, or interstitial lung disease should be recorded because they influence pulmonary risk. 1
Presence of cardiac risk factors (ischemic heart disease, angina, arrhythmias, prior myocardial infarction) requires cardiac stress testing before surgery. 1, 2
Any pleural drainage performed within the preceding 3 months must be noted. 1
Continuous supplemental oxygen requirement pre‑operatively excludes the patient from surgical resection. 1
Assessment of functional exercise capacity (e.g., ability to climb stairs) guides the need for further cardiac evaluation. 3, 4

All candidates for lung resection must undergo post‑bronchodilator spirometry (FEV₁) and DLCO measurement, irrespective of baseline lung function, with predicted postoperative (PPO) values calculated for risk stratification. 5, 6
When FEV₁ > 80 % predicted and DLCO > 80 % predicted, no additional pulmonary testing is generally required. 3, 4
PPO FEV₁ for a lobectomy is calculated by:
For pneumonectomy, PPO FEV₁ should be derived using perfusion‑scanning methods rather than segment counting. 5, 6
DLCO measurement is mandatory because ≈ 40 % of patients with normal FEV₁ (>80 % predicted) have an abnormal DLCO (<80 % predicted). 6
The correlation between FEV₁ and DLCO is weak (r < 0.5), supporting systematic DLCO testing in all patients. 6
PPO DLCO is calculated with the same segment‑counting formula used for PPO FEV₁. 5, 6
DLCO is a stronger predictor of postoperative complications and mortality than FEV₁, even in patients without airflow limitation. 6
Chest radiography should be used to identify parenchymal lung disease (which mandates DLCO testing) and pleural effusions that may require drainage. 6, 1
Baseline arterial blood gas analysis is required to detect hypoxemia that may need pre‑operative optimization. 1

PPO Category	Thresholds (predicted)	Recommended Action
Low Risk	PPO FEV₁ > 60 % and PPO DLCO > 60 %	Proceed to surgery; no further testing needed. [2, 5, 6]
Moderate Risk	PPO FEV₁ 30‑60 % or PPO DLCO 30‑60 %	Perform low‑technology exercise testing (6‑minute walk, stair climb, or shuttle walk). If distance < 80 % predicted or oxygen saturation falls < 90 % during test, surgery should be avoided. [3, 4, 1]
High Risk	PPO FEV₁ < 30 % or PPO DLCO < 30 %	Conduct cardiopulmonary exercise testing with VO₂max measurement; consider alternative therapies (SBRT, limited resection, or combined lung‑volume‑reduction surgery). Pulmonology consultation is mandatory. [2, 7, 1]

Historically, PPO FEV₁ and PPO DLCO > 40 % were deemed acceptable risk, but modern techniques permit safe resection in selected patients below this threshold. 5, 7
PPO DLCO < 40 % is associated with increased peri‑operative risk and mortality. 3, 4

Severe COPD – FEV₁ < 1.5 L often requires chronic inhaled steroids and/or bronchodilators; post‑bronchodilator FEV₁/FVC > 70 % or FEV₁ > 50 % predicted is recommended before proceeding. 1
Video‑assisted thoracoscopic surgery (VATS) provides better outcomes than thoracotomy in patients with severe COPD. 7
Cardiac Clearance – Left ventricular ejection fraction must be > 45 % on echocardiography. Patients with adequate exercise tolerance need only an ECG; those with limited capacity require non‑invasive cardiac stress testing. 1, 3, 4

Skipping DLCO measurement in patients with normal FEV₁ misses ≈ 40 % of individuals with impaired gas exchange and elevated surgical risk. 6
Immediate postoperative FEV₁ (day 1) is only ~71 % of the calculated PPO value, rising to ~93 % by day 7; PPO calculations therefore predict lung function at 1‑3 months rather than the critical early postoperative period. 7

The anatomic segment counting method is the recommended approach for lobectomy, rather than perfusion scanning, which is reserved for pneumonectomy, according to the American Thoracic Society 8, 9
The formula for predicted postoperative FEV1 is: PPO FEV1 = preoperative FEV1 × (19 - segments removed) / 19, as recommended by the British Thoracic Society 9, 10
The total number of lung segments is 19, as stated by the American College of Chest Physicians 8, 9
The right upper lobe consists of 3 segments, as defined by the British Thoracic Society 9, 11

A preoperative FEV1 of 1.8 L exceeds the 1.5 L threshold for proceeding directly to surgery without additional testing for lobectomy, according to the British Thoracic Society 9, 10, 12
The predicted postoperative FEV1 should be expressed as a percentage of predicted normal values to properly assess surgical risk, as recommended by the American College of Chest Physicians 8, 9
A predicted postoperative FEV1 of 1.52 L is above the historical 800 mL minimum threshold, but further evaluation is warranted, as stated by the British Thoracic Society 9, 13

If PPO FEV1 >60% predicted, the risk is low, and surgery can proceed, according to the American College of Chest Physicians 14
If PPO FEV1 is 30-60% predicted, the risk is moderate, and low-technology exercise testing should be performed, as recommended by the British Thoracic Society 13, 14
If PPO FEV1 <30% predicted, the risk is high, and cardiopulmonary exercise testing and consideration of limited resection are required, according to the American College of Chest Physicians and the British Thoracic Society 13, 14, 15

Measurement of DLCO and calculation of predicted postoperative DLCO using the same segment counting formula are required, as recommended by the American College of Chest Physicians and the British Thoracic Society 8, 9, 14
Both PPO FEV1 and PPO DLCO must be >40% predicted for acceptable risk, as stated by the British Thoracic Society 9, 13
Oxygen saturation on room air should be measured, as SaO2 <90% indicates increased risk, according to the British Thoracic Society and the American College of Chest Physicians 9, 13, 15