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COPD Physiology The lungs are filters Filter in oxygen Filter out - PDF document

11/4/2014 Stan Kellar, MD Chief of Clinical Affairs, BH NLR Pulmonary Medicine Sleep Medicine COPD Physiology The lungs are filters Filter in oxygen Filter out carbon dioxide (Vascular filter, not part of this discussion) 1


  1. 11/4/2014 Stan Kellar, MD Chief of Clinical Affairs, BH NLR Pulmonary Medicine Sleep Medicine COPD Physiology • The lungs are filters • Filter in oxygen • Filter out carbon dioxide • (Vascular filter, not part of this discussion) 1

  2. 11/4/2014 Physiology • Ventilation • Perfusion • Diffusion Anatomy Inspiration/Expiration 2

  3. 11/4/2014 INSPIRATION Passive Expiration Forced Expiration 3

  4. 11/4/2014 Respiratory bronchiole Tethering 4

  5. 11/4/2014 Normal Conducting System Alveoli • Surface area equivalent to that of a tennis court. • Very thin. Alveolar and capillary surface 5

  6. 11/4/2014 Perfusion • Low pressure bed, PA pressure 30/10. • Approximately 6 billion capillaries in human lung, or about 2000 per alveolus. • Under normal (resting) conditions there is little or no flow to the apices, a waterfall effect. Ventilation/Perfusion • Under normal circumstances the V/Q (ventilation to perfusion) ratio is 1. • This is altered with decreased perfusion (PE) or decreased ventilation (obstructive lung disease or infiltrative diseases). Transportation O2 • Primarily by hemoglobulin. • Very little dissolved in plasma. 6

  7. 11/4/2014 Transportation of CO2 • 10% dissolved in plasma. • 20 % carried by Hemoglobin. • 70% in form of bicarbonate. • CO2 dissociation curve linear. COPD • Chronic airflow limitation • Airway inflammation • Affects more than 6% of the population • Third leading cause of death in US • Preventable • Treatable COPD • Chronic bronchitis ‐ chronic productive cough for three months in two successive years • Emphysema ‐ permanent enlargement of airspaces distal to the terminal bronchioles, loss of alveolar walls • “Asthma” ‐ Reversible airflow limitation 7

  8. 11/4/2014 Emphysema Causes • Smoking ‐ Duration and Amount. PACK YEARS • Threshold? About 25 pack years • Smoking • Smoking • Biomass fuel in developing countries Incidence • Overall 6.3% USA • Higher in men, lower education level and socioeconomic groups • Incidence increases with increasing age • 3 rd to 6 th leading cause of death 8

  9. 11/4/2014 RISK BY AGE Pathology • Airway limitation ‐ inflammation • Goblet cell hyperplasia • Mucus plugging • Loss of airway tethering • Loss of airway rigidity • Bronchospasm Normal Airway 9

  10. 11/4/2014 Airway narrowing Symptoms • Shortness of breath • Cough, with or without sputum • Wheezing • Chest tightness Dyspnea • Lung disease • Heart disease • Circulatory problems • Neuromuscular diseases • Therefore not all dyspnea is due to lung diseases 10

  11. 11/4/2014 Wild Cards • ACID REFLUX • 25% of patients with significant reflux have no reflux symptoms • Another 25% underestimate the degree of reflux • Patients with symptoms have 2x rate of exacerbations • Deconditioning Physical Findings • Wheezing • Decreased breath sounds • Crackles in bases • Diminished heart sounds • Barrel ‐ shaped chest • Tobacco stained finger tips • Clubbing is rare Chest X ‐ ray • Normal • Hyperinflation • Bullae • Flattened hemi ‐ diaphragms • Basilar scarring • Unexpected disease ‐ pneumothorax, lung cancer 11

  12. 11/4/2014 Hyperinflation Pneumothorax Spirometry • FEV1 ‐ effort dependent • FVC ‐ effort and time dependent, more than 6 seconds • FEV1/FVC ratio ‐ less than 70% • Peak flow ‐ useful for trends, very effort dependent 12

  13. 11/4/2014 G lobal initiative on chronic O bstructive L ung D isease • GOLD 1: Mild (FEV1 >80% Pred.) • GOLD 2: Moderate (FEV1 50 ‐ 80% Pred.) • GOLD 3: Severe (FEV1 30 ‐ 50% Pred.) • GOLD 4: Very severe (FEV1 < 30% Pred.) COPD Assessment Test OK < 10 Modified Medical Research Council Guide • Please Check Line That Applies to You Grade 0: I only get short of breath with strenuous exercise. ___ • Grade 1: Short of breath hurrying or up slight incline. ___ • Grade 2: I walk slower on level ground as similar aged individuals • or I stop to rest when walking on my own. ___ • Grade 3: I stop for breath when walking 100 meters or after a • few minutes. ___ • Grade 4: I am too breathless to leave the house or I am • breathless dressing or undressing. ___ • 13

  14. 11/4/2014 RISK • Related to history of exacerbations • Group A: Low risk, less symptoms ‐ GOLD 1 ‐ 2 and 0 ‐ 1 exacerbations • Group B: Low risk, More symptoms – GOLD 1 ‐ 2 and 0 ‐ 1 exacerbations • Group C: High risk, Less symptoms – GOLD 3 ‐ 4 and > 2 exacerbations • Group D: High risk, More symptoms ‐ GOLD 3 ‐ 4 and > 2 exacerbations Exacerbations • Increased dyspnea • Increased cough • Sputum production • +/ ‐ fever • +/ ‐ chest pain – chest tightness Exacerbation Treatment • Steroids, oral or IV • Antibiotics, oral or IV • Additional bronchodialators • Hospitalization • Non ‐ invasive ventilation • Ventilation • Over 7% do not return to baseline 14

  15. 11/4/2014 Smoking Cessation • Without help/nicotine replacement ‐ 10% • With help/nicotine replacement ‐ 50 ‐ 60% • ASK – ADVISE – ASSESS – ASSIST ‐ ARRANGE • Chantix • Nicotine, Give enough • Too much nicotine causes nausea Decreased airflow + smoking • Progressive lung disease • 25 times normal risk for heart attack or stroke • 8 times risk for lung, laryngeal, esophageal, stomach, kidney, bladder, oral and pancreatic cancer • Cessation rapidly reduces the risk of cardiovascular complications 15

  16. 11/4/2014 Medications: Short acting Rescue • Beta agonists, MDI or nebulizer (albuterol) • Techniques • Spacers • Cost • Intended for rescue • Primary side effects cardiac arrhythmia (tachycardia) and tremor Medications: Short acting Rescue • Anticholinergics, MDI or nebulizer (Atrovent) • Short acting • Rescue • Costs • Adverse effects rare, dryness Medications: Long acting • Beta agonists, MDI and nebulizer • Foradil and Serevent are the primary single agents with MDI • Perforomist and Brovana are the nebulized forms • Almost never used alone • Increased risk of death in asthma patients when use alone (Black Box Warning) 16

  17. 11/4/2014 Medications: Long acting • Anticholinergics, MDI • Spiriva and Tudorza • Cost Medications: Inhaled Steroids • MDI and nebulizer • Controversy • Single agents, Flovent, Asmanex, Qvar, Pulmicort • Anti ‐ inflammatory • Adverse effects ‐ oral thrush, hoarseness, possible osteoporosis, increased risk of pneumonia Medications: Steroids/Beta agonists • MDIs • Advair Discus and MDI • Symbicort • Dulera • Breo, new, fluticasone and vilanterol 17

  18. 11/4/2014 Medication: LABA + LA Anticholinergic • Anoro, new Medications: Steroids • Anti ‐ inflammatory • Oral prednisone or Medrol • Dose and length of treatment controversial • IV for hospitalized patients, dose and length of treatment controversial • Adverse effects – Hyperglycemia, thrush, increased risk of infection, osteoporosis, weight gain, myopathy Medications: Phosphodiesterase ‐ 4 Inhibitors • Daliresp – anti ‐ inflammatory • Frequent side effects with nausea, vomiting, diarrhea, generalized aches, loss of appetite 18

  19. 11/4/2014 Medication: Theophyllins • Moderate bronchodialator • Toxicity is dose related • Adverse effects – nausea, vomiting, headaches, seizures • Blood levels altered by other medications, both up and down Special Consideration • Alpha ‐ 1 Antrypsin Deficiency • Earlier emphysema with a basilar predominance • Replacement available • Testing is free Vaccinations • Yearly flu immunization • Pneumococcal vaccine for patients 65 years and older 19

  20. 11/4/2014 Oxygen • Improve mortality • Improve dyspnea • Improve quality of life • Improve cognition • Cost – over $500/mo., 1 million patients in USA at a cost of over 2 billion dollars Oxygen • PaO2 , 55 mmHg or saturation, 89% at rest • PaO2 , 60 with cor pulmonale, right heart failure or HCT > 55 • O2 saturation less than 89 % for more than 5 minutes with sleep (Look for OSA) • Pao2 < 55 or saturation <88 with exercise • In COPD patients check ABGs on O2 to check PaCO2 ANN Internal Med 1980; 93:391 20

  21. 11/4/2014 Lancett 11981; 1:681 Oxygen • No benefit for saturations > 92% • Increase in PaCO2 (Hypoventilation) • Absorptive atelectasis • Hyper ‐ oxemia can result in decreased free water clearance • Facial burns especially in patients with facial hair • Fall risk with the tubing • NO SMOKING RISK • Related to history of exacerbations • Group A: Low risk, less symptoms ‐ GOLD 1 ‐ 2 and 0 ‐ 1 exacerbations • Group B: Low risk, More symptoms – GOLD 1 ‐ 2 and 0 ‐ 1 exacerbations • Group C: High risk, Less symptoms – GOLD 3 ‐ 4 and > 2 exacerbations • Group D: High risk, More symptoms ‐ GOLD 3 ‐ 4 and > 2 exacerbations 21

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