Pneumonectomy

Reviewed and revised [last-modified]

OVERVIEW

• Pneumonectomy is the surgical removal of an entire lung, performed via thoracotomy

INDICATIONS

• usually bronchogenic cancer
• may be performed for chronic infection such as tuberculosis, bronchiectasis, necrotizing pneumonia or lung abscess

PHYSIOLOGICAL EFFECTS

Respiratory

• increased negative pleural pressure on the side of the pneumonectomy
• elevated diaphragm on the side of the pneumonectomy
• intact lung hyperinflated with decreased compliance
• decreased diffusion capacity due to reduced alveolar area
• normal inspired gas distribution (higher at apex) but V-Q distribution more homogeneous
• increased work of breathing (WOB), O2 consumption (VO2) and ventilatory energy expenditure (due to decreased compliance)
• increased respiratory rate (RR) and depth of breathing leads to increase lung efficiency
• normal arterial blood gas (ABG)
• pneumonectomy space initially filled with air, eventually filled with fluid that leaks from parietal pleura and mediastinum

Cardiovascular

• pulmonary blood flow to the remaining lung is doubled
• increased pulmonary artery (PA) and right ventricular (RV) pressures temporarily to compensate for increased blood flow through one remaining lung and reduced gas exchange; however little change in PA pressure in the long term

RADIOLOGY

Radiographic appearance evolves over time

•  immediately after pneumonectomy:
  •  midline position of the mediastinum and gas in the pneumonectomy space
• first few days:
  • ipsilateral hemidiaphragm elevates
  • fluid begins to accumulate within the pneumonectomy space as the gas is resorbed
• first week:
  • 50-70% of the time the hemithorax fills within the first week, sometimes takes weeks-months
  • mediastinum shifts toward the operative side as the remaining lung hyperinflates and herniates across the midline, anterior to the heart
  • the degree of mediastinal displacement depends on the compliance and degree of hyperinflation of the remaining lung
  • Appropriate mediastinal displacement is the most reliable indicator of a normal course after pneumonectomy. Failure of the mediastinum to shift to the operative side indicates an abnormality in the pneumonectomy cavity such as bronchopleural fistula, hemothorax, or empyema.

COMPLICATIONS

Early

• bleeding
  • may not be initially obvious as ICC is clamped; look for hypotension, increased HR, decreased CVP and mediastinal shift
  • if suspected can release clamp to confirm bleeding
  • can be fatal as unable to tamponade effectively without operative intervention
• mediastinal shift
  • some is expected
  •  excessive shift away from good lung, e.g. inappropriate use of UWSD, then hemodynamic compromise from kinking of great vessels may occur: need to clamp ICC +/- reintroduce air
• post-pneumonectomy pulmonary oedema (non-cardiogenic) (4-15%)
  • remaining lung has double usual pulmonary blood flow
  • occurs 12-96h post-operatively
  • worse with fluid overload
  • diagnosis of exclusion
• arrhythmias (5-40%)
  • atrial fibrillation is common
  • usually day 2-3 (<5 days)
• respiratory compromise
  • due to decreased lung volume, poor pain control, sputum retention, fluid overload, new pathology (e.g. pneumonia)
• bronchopleural stump rupture
  • rare — more likely with right pneumonectomy (left-sided stump tends to retract into mediastinum behind aortic arch)
  • causes massive air leak into pneumonectomy space +/- subcutaneous emphysema due bronchopleural fistula
  • respiratory compromise due to mediastinal shift towards good lung, resorption of fluid in pneumonectomy space cause pulmonary oedema and productive cough
  • empyema can also occur due to infective contamination of the pneumonectomy space
• chylothorax
  • rare
  • difficult to diagnose, as the filling of the pneumonectomy space is expected
  • suspect if the mediastinal shift away from the pneumonectomy side
• vocal cord dysfunction (recurrent laryngeal nerve injury) with a hoarse voice, poor cough, dysphagia, and aspiration
• Right to left shunt through a patent foramen ovale (PFO) (due to higher RV filling pressures)
• cardiac herniation (through incised pericardium; rare)

Late

• Post-pneumonectomy syndrome
  • an excessive shift of contralateral lung and mediastinum into empty pleural space causing airway obstruction due to mainstem bronchus stretch and gas trapping
  • presents after months to years with dyspnoea, stridor, and recurrent pneumonia
  • more common after right pneumonectomy
  • main require treatment with a silicone space-filling prosthesis

Right pneumonectomy carries the highest mortality, and morbidity, especially bronchopleural fistula (BPF)

POST-OPERATIVE CARE

General

• high Fowler’s position (sitting upright with a 60-to-90-degree flexion at the hips)
• do not roll onto the side of the intact lung
• if right pneumonectomy then NGT on free drainage
• supportive care and monitoring (e.g. analgesia, physiotherapy)

Intercostal catheter (ICC)

• Reason for use
  • detect bleeding
  • equalize intrathoracic pressure changes: “when the patient is turned from the decubitus to the supine position after the operation, the mediastinum shifts and air in the post-pneumonectomy space becomes compressed, often resulting in immediate subcutaneous emphysema, sometimes massive.” (Weissber, 2002)
•  Options
  • May not be inserted if deemed unnecessary by cardiothoracic surgeon
  • Drains are double clamped with no suction, alternatively a balanced chest drain system with no suction may be used
•  Every hour unclamp the drain for 2 minutes
  • ensures a haemo/pneumothorax is not accumulating
  • do not leave patient unattended
• ICC usually removed day 1 post-operatively
• Do NOT connect to underwater seal drain (UWSD)
  • if connected to UWSD then air will not accumulate in pneumonectomy space causing a mediastinal shift towards that side, resulting in hemodynamic compromise
  • this can be corrected by reintroducing air and clamping the tube

Seek and treat complications

References and Links

Journal articles

• Cerfolio RJ, Bryant AS. The management of chest tubes after pulmonary resection. Thoracic surgery clinics. 2010; 20(3):399-405. [pubmed]
• Groth SS, Burt BM, Sugarbaker DJ. Management of Complications After Pneumonectomy. Thoracic surgery clinics. 2015; 25(3):335-48. [pubmed]
• Morcos K, Shaikhrezai K, Kirk AJ. Is it safe not to drain the pneumonectomy space? Interactive cardiovascular and thoracic surgery. 2014; 18(5):671-5. [pubmed]
• Slinger P. Update on anesthetic management for pneumonectomy. Current opinion in anaesthesiology. 2009; 22(1):31-7. [pubmed]
• Weissberg D. Post-pneumonectomy chest tubes. Texas Heart Institute Journal. 2002; 29(2):155. [pubmed]