Pre-operative Assessment
History & examination
History: active symptoms and the "4 Ms" of a lung mass — Mass effects (obstruction, SVC, nerve involvement), Metastases, Metabolic (paraneoplastic) effects, and Medications (chemotherapy / radiotherapy). Quantify smoking (pack-years); screen for ischaemic heart disease and exercise tolerance.
Examination: cyanosis, clubbing, tracheal deviation, wheeze, reduced/absent breath sounds, SpO₂. Hoover's sign (paradoxical inward movement of the lower ribs = diaphragmatic flattening/dysfunction) and the tripod position of severe airflow limitation.
Examination: cyanosis, clubbing, tracheal deviation, wheeze, reduced/absent breath sounds, SpO₂. Hoover's sign (paradoxical inward movement of the lower ribs = diaphragmatic flattening/dysfunction) and the tripod position of severe airflow limitation.
| Investigation | Purpose |
|---|---|
| CBC | Polythaemia (chronic hypoxia), ↑ TLC (infection) |
| Sputum culture & sensitivity | Active infection |
| LFT, KFT, coagulation | Organ function, chemo effects, bleeding |
| PET-CT | Staging / metastases |
| ECG & echocardiography | Cardiac reserve; whether further cardiac testing is needed |
| PFT (spirometry & DLCO) | Respiratory mechanics & parenchymal function |
| ABG | Baseline gas exchange (PaO₂, PaCO₂) |
The "three-legged stool" of pre-thoracotomy respiratory assessment
Assess all three legs — not just spirometry
Leg 1Respiratory mechanicsppoFEV₁ (best single test), MVV, RV/TLC, FVC
Leg 2Cardiopulmonary reserveVO₂max (gold standard), stair-climbing, 6-minute walk test
Leg 3Lung parenchymal functionppoDLCO, PaO₂, PaCO₂
🔢 Predicted post-operative FEV₁ (ppoFEV₁) — the key number
ppoFEV₁ = pre-op FEV₁ × (total segments − segments resected) / total segments (19 segments total).
- ppoFEV₁ > 40% → low risk of post-operative pulmonary complications (POPC); extubate on table if awake, warm, conscious.
- ppoFEV₁ 30–40% → moderate risk; extubate guided by exercise tolerance (METs), DLCO, V/Q scan and associated disease.
- ppoFEV₁ < 30% → high risk; plan staged weaning, extubate if >20% and thoracic epidural analgesia (TEA) in place.
| Leg 2 — exercise tests | Good | Poor / contraindication |
|---|---|---|
| VO₂max (gold standard) | >20 mL/kg/min → ↓ POPC | <15 → ↑ POPC · <10 → absolute contraindication to resection |
| Stair climbing (~20 steps/flight) | >2 flights (VO₂max >20) | <2 flights (≈ VO₂max <12 mL/kg/min) |
| 6-minute walk test | >2000 ft, exercise SpO₂ desaturation <4% | Exercise desaturation >4% → ↑ POPC |
Leg 3 thresholds: ppoDLCO >40%, PaO₂ ≥60 mmHg, PaCO₂ <45 mmHg favour resection; PaO₂ <60 and PaCO₂ >45 are relative contraindications. A V/Q scintigraphy / split-lung function study is added when pre-op FEV₁ or DLCO is <40%, to estimate the post-operative situation.