Pneumonectomy - 20 Marks Answer (MBBS Final)

Definition

• Bailey and Love's Short Practice of Surgery 28th Ed., p. 1011

Types

Indications

Malignant Causes (most common)

1. Lung carcinoma - centrally placed tumours involving the main bronchus, or tumours straddling the fissure that cannot be resected by lobectomy
   • Right pneumonectomy: tumours in middle/lower lobe with metastasis to station 11s lymph nodes and invasion of bronchial wall; large central tumours significantly infiltrating the proximal pulmonary artery
   • Left pneumonectomy: tumours infiltrating proximal pulmonary artery over significant length; lower lobe tumours metastasizing to station 11 (interlobar) lymph nodes with pulmonary artery involvement at the fissure
2. Malignant pleural mesothelioma (EPP)
3. Metastatic tumours involving the entire lung

Benign Causes

1. Pulmonary tuberculosis - destroyed lung, multidrug-resistant TB with extensive localised disease, massive haemoptysis, persistent bronchopleural fistula
2. Bronchiectasis - severe, unilateral, symptomatic disease not amenable to lobectomy
3. Lung abscess - massive, uncontrolled
4. Congenital abnormalities - large congenital cystic lesions
5. Trauma - emergency pneumonectomy following severe thoracic trauma with hilar injury (historically near 100% mortality, but selected cases survive)

• Fischer's Mastery of Surgery 8th Ed.; Bailey & Love 28th Ed.

Preoperative Assessment

Pulmonary Function Tests

• Spirometry: FEV1 and FVC
• Diffusion capacity (DLCO)
• Predicted Postoperative FEV1 (ppo-FEV1): calculated as:

  ppo-FEV1 = preoperative FEV1 × (1 - % of functional lung tissue removed)

• A ppo-FEV1 < 30% of predicted = high risk; surgery generally contraindicated
• ppo-FEV1 > 40% with good exercise tolerance = acceptable risk
• ppo-DLCO should also be > 30-40%

Cardiovascular Assessment

• Recent MI: avoid surgery within 30 days
• Echocardiography if pulmonary hypertension suspected
• Cardiopulmonary exercise testing (CPET): VO2 max ≥ 15 mL/kg/min required

Exercise Tolerance Testing

• Shuttle walk test (cut-off 400 m)
• 6-minute walk test

Other Investigations

• Chest X-ray, CT thorax
• PET-CT scan (staging)
• Mediastinoscopy / EBUS (lymph node staging)
• Arterial blood gases (resting PaO2, PaCO2)
• Pulmonary perfusion scan (split lung function)
• Bailey & Love 28th Ed., NICE guidelines table; Morgan & Mikhail Clinical Anesthesiology 7th Ed.

Surgical Technique (Right Pneumonectomy)

1. Position: Lateral decubitus (lateral thoracotomy position)
2. Incision: Posterolateral thoracotomy through 5th intercostal space
3. Lung isolation: Double-lumen endotracheal tube (DLT) for one-lung ventilation
4. Steps:
   • Divide inferior pulmonary ligament
   • Incise mediastinal pleura anterior and posterior to the hilum
   • Divide inferior pulmonary vein (stapler)
   • Divide superior pulmonary vein (stapler in anterior hilum)
   • Dissect and remove hilar and subcarinal (station 7) lymph nodes
   • Divide main pulmonary artery - clamp central side, fire stapler
   • Divide main bronchus - around the 3rd cartilage from the carina; TA stapler placed in "Sweet direction"; reinforce with 2-0 Prolene interrupted sutures
   • Remove the lung en bloc
   • Check bronchial stump is airtight (submerge under saline, positive pressure ventilation)
   • Intercostal drain inserted (or no drain used - see post-op management)
   • Close chest in layers

• Fischer's Mastery of Surgery 8th Ed., pp. 2172-2175

Postoperative Management

The Empty Hemithorax

• Mediastinal shift
• Infection of the space
• Bronchopleural fistula

Drain Management

• Preferred: NO drain, or drain removed at 24 hours (released hourly to allow blood to drain, then clamped)
• A slightly negative pressure in the empty hemithorax is ideal - encourages space obliteration without compressing the remaining lung

Ideal Postoperative Chest X-ray Position

• Mediastinum deviated slightly toward the operated side (trachea slightly toward operated side)
• This is the ideal state - neither full negative pressure nor positive pressure in the empty cavity

Common Errors in Post-op Care

• Attributing breathlessness to bronchitis rather than mediastinal shift
• Ignoring new atrial fibrillation or mental confusion - both can result from mediastinal shift and hypoxia
• The mediastinum does NOT become "fixed" within 24 hours - it remains mobile for longer
• Pye's Surgical Handicraft 22nd Ed., pp. 235-237

Complications

Intraoperative

• Haemorrhage (pulmonary artery injury)
• Injury to phrenic nerve, vagus nerve, recurrent laryngeal nerve
• Air embolism

Early Postoperative (within 30 days)

Late Complications

Bronchopleural Fistula - Key Points

• Pathophysiology: Bronchial stump breakdown → bacterial contamination from bronchial tree → infects pneumonectomy space → severe systemic reaction; fluid from space can flood remaining lung → death
• Presentation: Sudden expectoration of large volumes of brown fluid; or subtle with "bronchitis" at base of remaining lung
• Radiology: Cardinal sign = positive air space (semicircular shape) on operated side on CXR, instead of triangular shape of normal negative space
• Diagnosis: Clinical suspicion paramount; bronchoscopy detects larger lesions only; dye injection may fail due to loculation
• Principles of treatment: Drainage, antibiotics, subsequent surgical repair of stump or thoracoplasty
• Pye's Surgical Handicraft 22nd Ed., pp. 237; Fishman's Pulmonary Diseases 2-Vol Set; Bailey & Love 28th Ed.

Mortality and Outcomes

• 30-day operative mortality: 5-8% (right pneumonectomy slightly higher than left)
• Respiratory complications: most common cause of postoperative mortality
• Cardiac complications, bleeding, bronchopleural fistula, and empyema account for the remainder
• Post-pneumonectomy FEV1 < 30% of predicted: associated with significantly increased risk of death
• Due to complications and higher mortality compared to lobectomy, pneumonectomy now makes up < 5% of lung cancer surgery in the UK; sleeve resections are preferred when feasible to spare lung tissue
• Bailey & Love 28th Ed., p. 1011; Fishman's Pulmonary Diseases 2-Vol Set

Summary Table