1

How should a patient undergoing thoracic surgery be assessed?

Confirmation of diagnosis.

Indication for surgery.

Fitness and comorbidities, including cardiopulmonary reserve.

Risk stratification.

If a malignant tumour is present:

a)

resectability – which indicates that the tumour can be completely excised with clear margins (R0 resection possible);

b)

operability – which indicates that the tumour is resectable with an acceptable risk of death or morbidity for the patient.

2

What are the important factors that should be considered when taking a clinical history of a patient undergoing thoracic surgery?

Basic patient demographics.

Occupational exposure, including asbestosis, berylliosis, Farmer’s lung, silicosis and aspergillosis.

Assessment of symptoms, including dyspnoea, cough, chest wall pain, haemoptysis, hoarseness, fever, weight loss and night sweats.

Symptoms suggestive of metastatic disease, such as new-onset headaches, focal neurologic symptoms, new seizure disorder, fractures or new bone pain.

Symptoms linked to paraneoplastic syndromes, such as central obesity (Cushing’s syndrome), bone pain (hypercalcaemia) and confusion (syndrome of inappropriate anti-diuretic hormone).

Functional capacity of the patient, including performance status.

Risk factors for coronary artery disease.

Past medical history for systemic diseases and previous tumours, including chemotherapy and radiotherapy.

Past surgical history, including resection of tumours and cardiothoracic procedures.

History of general anaesthesia and any associated complications.

Medication history and allergies, including peri-operative warfarin and antiplatelet therapy.

Substance misuse, such as tobacco smoking, alcohol and other drug usage.

Family history, including:

a)

early chronic obstructive pulmonary disease (COPD), which may be suggestive of α1-antitrypsin deficiency;

b)

respiratory infections at a younger age, which may be suggestive of cystic fibrosis;

c)

pulmonary nodule with telangiectasia, which may be suggestive of Osler-Weber-Rendu syndrome.

Social history, including recent travel, exposure to TB, exposure to animals or birds and beliefs on blood transfusion.

3

How is performance status evaluated?

Various scoring systems can be used to define the functional or performance status of the patient, including:

a)

Karnofsky performance status;

b)

Eastern Cooperative Oncology Group (ECOG)/World Health Organisation (WHO)/Zubrod score.

The ECOG/WHO/Zubrod system is the most commonly used and is outlined in Table 1.

4

Describe the modified Medical Research Council (MRC) dyspnoea score

0 – dyspnoeic on strenuous exercise.

1 – dyspnoeic on walking up a slight hill.

2 – dyspnoeic on walking on level ground; must stop occasionally due to breathlessness.

3 – must stop for breathlessness after walking 100 yards or after a few minutes.

4 – cannot leave the house, breathless on dressing and undressing.

5

What are the important features of the clinical examination of a patient undergoing thoracic surgery?

Most patients may have a normal or near-normal physical examination.

General examination of the patient should include:

a)

overall comfort of the patient, pulse (rate and rhythm), respiratory rate, use of accessory muscles and the need for any additional oxygen;

b)

evaluation for nicotine stains, cyanosis, clubbing (present with COPD, intrathoracic malignancy or congenital heart disease), ptosis, miosis, pallor, telangiectasia, raised jugular venous pressure (JVP), movement at the cervical spine and the presence of cervical lymphadenopathy.

Inspection should include assessment of:

a)

spinal deformities, such as kyphosis or scoliosis;

b)

shape of the chest (barrel chest, pectus deformity), volume loss and movement with respiration;

c)

dilated veins, scars, drains and swellings;

d)

small mouth opening, as it will hamper double-lumen intubation and rigid bronchoscopy, especially in elderly patients with generalised arthritis or patients with a connective tissue disorder.

Palpation should include:

a)

position of the trachea;

b)

chest expansion;

c)

tactile vocal fremitus:

i)

increased tactile vocal fremitus – pneumonia;

ii)

decreased tactile vocal fremitus – pleural effusion, pneumothorax, COPD.

Percussion should be carried out anteriorly in the mid-clavicular line, then laterally and posteriorly, comparing the left with right:

a)

resonant percussion note – normal;

b)

hyper-resonant percussion note – pneumothorax, gross emphysema;

c)

dull percussion note – pleural thickening, consolidation, collapse, atelectasis;

d)

stony dull percussion note – pleural effusion.

Auscultation of the entire thorax:

a)

vesicular breath sounds – normal;

b)

bronchial breath sounds – consolidation;

c)

reduced air entry – COPD, pleural effusion, atelectasis, asthma;

d)

wheeze – COPD, asthma;

e)

crackles – left ventricular failure, pneumonia, pulmonary fibrosis;

f)

pleural rub – asbestosis, chest wall tumours, pulmonary embolism, pneumonia, pleurisy, post-surgery.

Following this, examination of the other organ systems should be performed, including:

a)

heart – murmurs (valvular heart disease), S3 (heart failure), loud P2 (pulmonary hypertension), muffled heart sounds (pericardial effusion);

b)

abdomen – scars, ascites, hepatomegaly, other palpable masses;

c)

central nervous system – focal neurological deficits.

6

Which blood tests should be used to investigate a patient undergoing thoracic surgery?

Full blood count – haemoglobin, white cell count, differential count, platelet count.

Coagulation profile – prothrombin time (PT), international normalised ratio (INR), activated partial thromboplastin time (APTT).

Liver function tests – serum liver enzymes, bilirubin and albumin.

Renal function tests and electrolytes – serum urea, creatinine, estimated glomerular filtration rate (GFR), sodium and potassium.

7

What imaging is required for patients undergoing thoracic surgery?

Chest radiograph (CXR) is routinely performed for every patient undergoing thoracic surgery.

Contrast-enhanced computed tomography (CT) is indicated in every patient undergoing lung resection and for patients needing evaluation of the lung parenchyma, mediastinum and the pleural space. Patients with lung cancer should have the lower neck and upper abdomen included in the scan.

Fusion CT-positron emission tomography (CT-PET) is indicated in all patients considered for radical treatment of a thoracic cancer.

Magnetic resonance imaging (MRI) may be indicated in certain patients, including:

a)

MRI thorax:

i)

all patients being considered for radical treatment;

ii)

patients with suspected invasion of vascular structures or the spine, such as superior sulcus tumours and lesions in the paravertebral gutter;

b)

MRI brain:

i)

small cell lung cancer;

ii)

Stage III non-small cell lung cancer;

iii)

patients with suspected brain involvement.

Barium or Gastrografin^® swallow to evaluate oesophageal compression, obstruction or leak from the oesophageal lumen.

8

What investigations are used to evaluate pulmonary function (Table 2)?

Spirometry. Forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC) and maximal voluntary ventilation (MVV) are the most commonly used measurements for assessment prior to thoracic surgery. A low MVV is non-specific but is very useful for estimating the capacity of a patient prior to major lung resection. Estimation of predicted postoperative FEV₁ is used for the risk stratification of the patient.

Gas transfer studies. The diffusing capacity of the lungs for carbon monoxide (DLCO) estimates the diffusion of carbon monoxide across the alveolar capillary membrane and reflects the functional surface area of the lung. A low DLCO is an independent predictor of postoperative morbidity and mortality. Estimation of predicted postoperative DLCO is, therefore, routinely used for risk stratification of the patient undergoing lung resection.

Arterial blood gas (ABG) analysis on room air provides important information on PaO₂ and PaCO₂ levels. Low PaO₂ levels are not a contraindication to pulmonary resection, since the abnormal lung to be resected may be a contributing factor. High resting PaCO₂ levels increase postoperative morbidity and mortality but it is not an absolute contraindication to proceed with surgery.

Ventilation-perfusion scintigraphy (V/Q scan) is performed to estimate the number of functioning segments and, therefore, predict postoperative lung function but only if a significant ventilation or perfusion mismatch is suspected. Results from the scans may underestimate the actual postoperative function.

A cardiopulmonary exercise test (CPEX) is a core diagnostic test to assess a patient’s cardiopulmonary reserve by measuring VO_{2 max} (maximum oxygen consumption). CPEX can simultaneously assess the subject’s cardiac, respiratory and skeletal muscle function. Lower levels of VO_{2 max} are associated with increased morbidity after pulmonary resection. It is generally performed for functional assessment in patients with moderate to high risk of postoperative dyspnoea, using VO_{2 max} >15mL/kg/min as a cut-off for good function. Due to the heterogeneity in the studies, however, it is difficult to extrapolate a ‘cut-off’ for prohibitive resection. CPEX is associated with a high cost and is not readily available at all centres.

Shuttle walk test. The patient is asked to walk in shuttles around two cones placed 9m apart, so as to cover a 10m distance whilst walking around the cones for each shuttle. The pulse and oxygen saturations should be monitored during the exercise. A distance walked of >400m is considered a cut-off for good function.

Six-minute walk test (6MWT). The test measures the distance a patient can walk quickly on a flat, hard surface in 6 minutes. It is easier to administer and better tolerated. Measurement of pulse oximetry can be added to record significant desaturations. Studies have demonstrated better surgical outcomes in patients with good performance at the 6MWT.

Stair climbing. A symptom-limited stair climbing exercise can be performed, with pulse rate and oxygen saturations measured using a portable pulse oximeter to detect desaturation during exercise. The maximal altitude reached during the stair climbing exercise and desaturations of >4% are independent predictors of postoperative complications.

9

How should lung function be assessed prior to consideration of pulmonary resection for NSCLC? (Figure 1)

The British Thoracic Society (BTS) guidelines for selection of patients undergoing pulmonary resection for lung cancer can be used to determine the risk of dyspnoea following surgery.

FEV₁ and DLCO should be obtained in all patients prior to lung resection. Patients with a postoperative predictive FEV₁ or TLCO <40% are at moderate to high risk of postoperative dyspnoea, where pre-operative functional assessment is moderate or poor.

Where patients have heterogeneous upper zone emphysema in the setting of an upper lobe tumour, criteria for lung volume reduction surgery (LVRS) should be considered, as postoperative lung function might be improved in these patients despite postoperative predictive values below 40%.

Segment counting is utilised to predict postoperative lung function (see below).

The additional benefit of information obtained by split-lung function testing is uncertain. VQ scans, quantitative CT scanning and perfusion MRI may be utilised in high-risk cases to demonstrate non-functioning areas prior to resection.

The 6MWT, shuttle walk test, stair climbing and cardiopulmonary exercise test can be used as a functional assessment in the risk stratification of patients prior to lung resection. The BTS guidelines recommend that shuttle walk distances >400m or cardiopulmonary exercise testing VO_{2 max} >15mL/kg/min may be considered as cut-offs for good function.