Lobectomy For Lung Malignancy

Question 1

A 69-year-old male patient is listed for a lung lobectomy for malignancy. He has a history of ischaemic heart disease, COPD and a hiatus hernia. He stopped smoking last year, having been a smoker for 38 years. You are asked to review him in the preoperative assessment clinic.
Which factors determine whether a patient is suitable for a lung lobectomy?

Answer 1

• Informed consent for the procedure (given the risks of the procedure and postoperative complications).
• The tumour should be a non-small cell malignancy (either adenocarcinoma or squamous cell).
• The tumour must be deemed resectable following surgical assessment.
• The patient must be assessed as suitable for general anaesthetic.
• The patient’s postoperative predicted ventilatory capacity, gas exchange
  and CPET results should be within acceptable limits.
• Patients with severe right-sided cardiac failure should be excluded from surgery as a lobectomy causes a permanent increase in pulmonary vascular resistance and thus further severe right ventricular strain.

Question 2

What are the important aspects in the history of this patient prior to surgery?

Answer 2

• This is high-risk surgery in a patient with an increased likelihood of perioperative morbidity and mortality. A thorough preoperative history, examination and investigations are key to determine whether the beneft of surgery outweighs the potential risks.
• Respiratory history: history of COPD and malignancy including recent symptoms, hospital admissions and infections. Pulmonary function tests and CPET are now routine in the majority of patients presenting for this surgery.
• Cardiovascular history: thorough history of symptoms suggestive of worsening cardiac disease or failure e.g. shortness of breath, chest pain and ankle swelling. Patient should be risk stratified based on
  history and further assessed using relevant investigations.
• Nutritional status: recent decrease in body mass index and extreme weight loss can lead to increased perioperative complications and suggest disease spread. Notably, an albumin level of <30 g/L is associated with poor outcomes in this surgery.
• Other comorbidities, social history and anaesthetic history including
  airway assessment.

Question 3

What are the indications for pulmonary function testing?

Answer 3

• Diagnosis of diseases in symptomatic patients.
• Assessing the progress of a condition or its response to treatment.
• In preoperative risk assessment for pulmonary or non-pulmonary
  surgery.
• For disease prognostication purposes.

Question 4

How can pulmonary function be assessed in this patient?

Answer 4

• Oxygen saturations at rest and during exercise.
• Arterial blood gas for baseline oxygenation values.
• Peak expiratory flow rate using a flow meter – mainly used in diagnosis and monitoring of obstructive disease processes.
• Spirometry – giving values of FEV1 and FVC.
• Transfer factor – assesses the gas diffusion capacity of the alveoli.
• Ventilation/perfusion scanning.
• Shuttle walk test/6 minute walk test.
• Cardiopulmonary exercise testing.

Question 5

This patient requires a right upper and middle lobe lobectomy. How can his lung function postoperatively be predicted?

Answer 5

• The total number of lung segments is 19. The right upper lobe has three segments, and the right middle lobe has two segments. Therefore following his procedure, this patient will have 14/19 segments remaining.
• The patient’s postoperative FEV1 and FVC values can be estimated by multiplying the preoperative values by 14/19. Tis can also be done for transfer factor.

Question 6

When would cardiopulmonary exercise testing be considered?

Answer 6

• The British Thoracic Society has produced an algorithm that aids in decision making for preoperative investigations.
• If the patient has an FEV1 value of <1.5L (lobectomy) or <2L (pneumonectomy), they should be referred for spirometry and transfer factor testing.
• If the patient’s predicted postoperative values for FEV1 and transfer factor are <40%, they should be referred for cardiopulmonary exercise testing. Patients with a VO2 max value of<15 mL/kg/minute are con- sidered high risk for surgery.