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Dr Gerard Meachery

Dr Gerard Meachery. The objectives of the pre-anaesthetic assessment . Evaluate the patient’s medical condition from medical history, physical examination, investigations and, when appropriate, past medical records Optimise the patient’s medical condition for anaesthesia and surgery

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Dr Gerard Meachery

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  1. Dr Gerard Meachery

  2. The objectives of the pre-anaesthetic assessment • Evaluate the patient’s medical condition from medical history, physical examination, investigations and, when appropriate, past medical records • Optimise the patient’s medical condition for anaesthesia and surgery • Determine and minimise risk factors for anaesthesia • Plan anaesthetic technique and peri-operative care • Develop a rapport with the patient to reduce anxiety and facilitate conduct of anaesthesia • Inform and educate the patient about anaesthesia, peri-operative care and pain management • Obtain consent for anaesthesia

  3. Guidelines on the radical management of patients with lung cancer • Lim E, Baldwin D, Beckles M, et al. Thorax 2010, 65 Suppl III, iii1-iii27 • A joint initiative by the British Thoracic Society and the Society for Cardiothoracic Surgery in Great Britain and Ireland undertaken to update the 2001 guidelines for the selection and assessment of patients with lung cancer who can potentially be managed by radical treatment

  4. Guidelines on the radical management of patients with lung cancer • 2.1.3 Assessment of lung function • 43. Offer surgical resection to patients with low risk ofpostoperative dyspnoea. [C] • 44. Offer surgical resection to patients at moderate to high riskof postoperative dyspnoea if they are aware of and accept therisks of dyspnoea and associated complications. [D] • 47. Consider using shuttle walk testing as functional assessmentin patients with moderate to high risk of postoperativedyspnoea using a distance walked of >400 m as a cut-off forgood function. [C] • 48. Consider cardiopulmonary exercise testing to measure peakoxygen consumption as functional assessment in patients withmoderate to high risk of postoperative dyspnoea using >15 ml/kg/min as a cut-off for good function. [D]

  5. Guidelines on the radical management of patients with lung cancer • 49. RR Further studies with specific outcomes are required to define the role of exercise testing in the selection of patients for surgery • 51. Avoid taking pulmonary function and exercise tests as sole surrogates for quality of life evaluation. [C]

  6. Pulmonary Function Testing

  7. Categorise PFTs according to specific purposes Identify at least one indication for spirometry, lung volumes, and diffusing capacity Obstructive and restrictive ventilatory defects Relate respiratory history to indications for performing pulmonary function tests Objectives

  8. Pulmonary Function Testing • Establish baseline lung function and evaluate the presence or absence of lung disease • Evaluate symptoms of dyspnoea • Evaluate if the lung disease is primarily an obstructive, restrictive or mixed ventilatory defect • Quantify the respiratory impairment and monitor the extent of known disease on lung function • Monitor effects of therapies used to treat respiratory disease

  9. Pulmonary Function Testing • Evaluate operative risk • Perform surveillance for occupational-related lung disease • Evaluate disability or impairment • Assess for reversible components to optimise a patient’s clinical status

  10. Spirometry • Forced expiratory volume in 1 second (FEV1) • Volume exhaled in the first second of an FVC manoeuvre • (forced exhalation from maximal inspiration) • Vital capacity (VC) • Total volume exhaled by a exhalation from maximal inspiration • Can be a forced exhalation (FVC) or a relaxed exhalation (RVC) – best one taken as VC • FEV1/VC • Ratio between FEV1 and VC

  11. Pulmonary Function Testing • In normal spirometry, FVC, FEV1, and FEV1 -to-FVC ratio are above the lower limit of normal • The lower limit of normal is defined as the result of the mean predicted value (based on the patient's sex, age, and height)

  12. Spirometry

  13. Reduction in FEV1 • Airway obstruction is the most common cause of reduction in FEV1 • Airflow obstruction may be secondary to Bronchospasm (Asthma/ COPD) Airway inflammation (Asthma/ COPD/ Bronchiectasis) Loss of lung elastic recoil (Emphysema) Increased secretions in the airway (Bronchitis/ Bronchiectasis/ Infection)

  14. Assessing reversibility in airway obstruction • Response of FEV1 to inhaled bronchodilators is used to assess the reversibility of airway obstruction (Post Bronchodilator challenge) • Methacholine Challenge – used to assess possible underlying asthma, (ie reversible airway obstruction). Baseline lung function may be normal when the patient is clinically stable.

  15. Assessing reversibility in airway obstruction • Gibson Resp Med • 12% or 200ml

  16. Reversible Airway Obstruction

  17. Reversible Airway Obstruction

  18. Indications for Lung Volume Tests • Diagnose or assess the severity of restrictive lung disease • Differentiate between obstructive and restrictive disease patterns • Assess the response to therapy • Make preoperative assessments of patients with compromised lung function

  19. Static lung volumes • Total lung capacity (TLC) • Total volume of air in the lungs at the end of an maximal inspiration • Residual volume (RV) • Volume of air remaining in the lungs at the end of a maximal expiration • Functional residual volume (FRC) • Volume of air remaining in the lungs at the end of tidal expiration

  20. Lung Volumes

  21. Reduction in FVC • A reduced FVC on spirometry in the absence of a reduced FEV1 -to-FVC ratio suggests a restrictive ventilatory defect • An inappropriately shortened exhalation during spirometry can (and often does) result in a reduced FVC (i.e. Patient effort is important)

  22. Causes of Abnormal Lung Volumes • Raised TLC • COPD esp. emphysema • Transiently raised during an asthma exacerbation or in the recovery phase of an asthma exacerbation • Increased RV • Airways disease (air-trapping), e.g. asthma or emphysema • Reduced TLC/ FVC/ RV • Restrictive defect (intrapulmonary or extrapulmonary)

  23. Diffusion Capacity/ Transfer Factor • The diffusing capacity is a measure of the conductance of the CO molecule from the alveolar gas to Haemoglobin in the pulmonary capillary blood • CO (and oxygen) must pass through the alveolar epithelium, tissue interstitium, capillary endothelium, blood plasma, red cell membrane and cytoplasm before attaching to the Haemoglobin molecule

  24. Diffusion Capacity

  25. Indications for Diffusion Capacity • Evaluate or follow the progress of parenchymal/ interstitial lung disease • Evaluate pulmonary involvement in systemic disease • Evaluate obstructive lung disease • Quantify disability associated with interstitial lung disease • Evaluate pulmonary hemorrhage

  26. Diffusion capacity • TLCO = transfer factor for the lung for carbon monoxide i.e. Total diffusing capacity for the lung • Same as DLCO • KCO = transfer coefficent i.e. Diffusing capacity of the lung per unit volume, standardised for alveolar volume (VA) • VA = Lung volume in which carbon monoxide diffuses into during a single breath-hold technique

  27. Abnormal Diffusion Capacity • Low TLC • Low TLCO • Low/normal KCO • = Intrapulmonary restrictive defect • Interstitial lung diseases • Pulmonary oedema • High TLC • Low TLCO • Low KCO • emphysema

  28. Abnormal Diffusion Capacity • Low TLCO • but high/N KCO • = extrapulmonary restrictive defect • Obesity • Neuromuscular disease (respiratory muscle weakness) • Pleural disease e.g. effusion, thickening, tumor • Skeletal deformity • Post pneumonectomy

  29. Abnormal Diffusion Capacity • Normal/raised TLCO • Raised KCO • Asthma • Pulmonary haemorrhage

  30. Obstructive Lung Disease Chronic Obstructive Pulmonary Disease (COPD) Chronic Bronchitis “Excessive mucus production, with a productive cough on most days, for at least 3 months for 2 years or more.” Emphysema Primarily caused by cigarette smoking. Alpha -1-antitrypsin deficiency Environmental pollutants

  31. Working Definition of COPD Chronic obstructive pulmonary disease (COPD) is characterised by airflow obstruction. The airflow obstruction is usually progressive, not fully reversible and does not change markedly over several months. The disease is predominantly caused by smoking. Airflow obstruction is defined as a reduced FEV1 (forced expiratory volume in 1 second) and a reduced FEV1/FVC ratio (where FVC is forced vital capacity), such that FEV1 is less than 80% predicted and FEV1/FVC is less than 0.7. (www.nice.org.uk/CG012NICEguideline)

  32. Chronic Obstructive Pulmonary Disease (COPD) Characterized by: • Dyspnoea at rest or with exertion • Productive cough • Barrel-chest (↑AP to Transverse diameter) • Chest percussion: Hyper resonant • Chest auscultation: Breath sounds distant or absent • Chest X-Ray • Flattened diaphragms • Hyperinflated lung fields/ bullae

  33. Emphysema Spirometry Reduction in FEV1 Reduction in FEV1/ VC ratio Lung Volumes Increased lung volumes (“air trapping”) Diffusing Capacity Reduced

  34. Obstructive Lung Disease Asthma Airway obstruction is characterized by inflammation of the mucosal lining of the airways, bronchospasm and increased airway secretions Reversible airway obstruction

  35. Obstructive Lung Disease Asthma Triggers Exercise/ Cold air Allergic agents Pollens, house dust mite, animal dander, moulds Non-allergic agents Viral infections, environmental pollutants, medication, food additives, emotional upset Occupational exposure Cotton/ wood dusts, grains, metal salts, insecticides

  36. Obstructive Lung Disease Asthma During Attacks Peak Flow (PEF) is reduced/ Hypoxia Response to bronchodilators Spirometry Reduced FEV1 Lung Volumes Increased (Hyperinflation) Diffusion Capacity Normal During stable state: Spirometry may be normal

  37. Causes of Restrictive Spirometry • Pulmonary fibrosis • Pleural effusion • Pleural tumors • Lung resection (lobectomy/ pneumonectomy) • Diaphragm weakness or paralysis • Neuromuscular disease • Kyphoscoliosis • Obesity • Inadequate respiration secondary to pain • Congestive heart failure • Ascites • Pregnancy

  38. Restrictive Lung Disease Idiopathic Pulmonary Fibrosis Or secondary to Treatment with bleomycin, cyclophosphamide, methotrexate or amiodarone Autoimmune diseases: Rheumatoid arthritis, systemic lupus erythematousus (SLE), scleroderma Sarcoidosis Pneumoconiosis Silicosis – Silica dust Asbestosis – Asbestos fibers

  39. Restrictive Lung Disease Idiopathic Pulmonary Fibrosis Increasing exertional dyspnoea Dry cough Finger clubbing Inspiratory crackles on auscultation Chest X-Ray Interstitial infiltrates are visible Honeycombing pattern

  40. Restrictive Lung Disease Idiopathic Pulmonary Fibrosis Spirometry Reduced VC Lung volumes Reduced TLC/ RV Diffusion capacity Reduced

  41. Diseases of Chest Wall and Pleura Disorders involving the chest wall or pleura of the lungs result in restrictive ventilatory defects on pulmonary function testing. But, lung parenchyma is not affected.

  42. Spirometry Reduced FEV1 and FVC Lung Volumes Reduced TLC Diffusion Capacity Reduced KCo Normal Diseases of Chest Wall and Pleura

  43. Obstructive v. Restrictive

  44. Mixed Picture Bronchiectasis Pathologic and irreversible dilatation of the bronchi, resulting from destruction of the bronchial wall by severe, repeated infections and inflammation

  45. Bronchiectasis Post infective: Whooping cough/ TB Genetic: Cystic Fibrosis/ Primary Cliliary Dyskinesia (PCD) Immunodeficiency

  46. Bronchiectasis Dyspnoea Significant productive cough Purulent, foul smelling sputum Haemoptysis Frequent pulmonary infections Chronically unwell Chest X-Ray / CT Scan Airway Dilation

  47. Airway Function Tests Flow Volume Loop (FVL)

  48. Airway Function Tests Flow Volume Loop (FVL)

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