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Back to Basics Review: Respirology in Under Two Hours. Nha Voduc MD FRCPC Original Presentation by Jen Block MD FRCPC. April 8, 2011. The Plan. Pulmonary Function Testing Asthma COPD Sleep Apnea Pleural Effusion Lung Cancer. Spirometry: Measurement of Airflow.
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Back to Basics Review: Respirology in Under Two Hours Nha Voduc MD FRCPC Original Presentation by Jen Block MD FRCPC April 8, 2011
The Plan... • Pulmonary Function Testing • Asthma • COPD • Sleep Apnea • Pleural Effusion • Lung Cancer
1. Take as deep a breath as possible2. Blast out the air into spirometer3. Continue exhaling for several more seconds UpToDate
Flow Volume Loop TLC RV
Interpretation • Upper Airway Abnormalities • Obstructive Lung Disease • Restrictive Lung Disease
Upper Airway Abnormalities • Variable extrathoracic obstruction impairs inspiratory flow more than expiratory flow -- negative pressure during inspiratory “sucks in” (narrows) airway • Variable intrathoracic obstruction impairs expiratory flow more than inspiratory flow -- positive intrathoracic pressure compresses in airway ERJ 2005; 26: 948-968
Obstructive Lung Disease • FEV1/FVC is <70% and • FEV1 < 80% (or < 2 standard deviations) • “scooped out” • lung volumes may show Hyperinflation or “gas trapping” (increased residual volume) ERJ 2005; 26: 948-968
Restrictive Lung Disease • TLC < 80% (or < 2 standard deviations) • normal FEV1/FVC ratio • Neuromuscular, Chest wall, Interstitial Lung disease ERJ 2005; 26: 948-968
Asthma • Pathophysiology • Diagnosis • Chronic Management • Acute Management
Asthma: Definition • paroxysmal or persistent symptoms (dyspnea, chest tightness, wheeze, cough) • variable airflow limitation and airway hyper-responsiveness • due to inflammation
Comprehensive Asthma Management • Suspect asthma and confirm diagnosis • Education • Assess severity • Avoid / control triggers and environmental modification • Medications for chronic disease • Assess control • Management plan for exacerbation • Regular follow-up
Asthma Diagnosis: Requirements PFTs • If FEV1 is low, try to increase it using a short-acting bronchodilator (reversibility) • ≥12% and ≥180 ml improvement in FEV1 from baseline 15 minutes after the use of an inhaled short-acting bronchodilator
Asthma Diagnosis • If FEV1 is normal, try to see if airways are hyperresponsive by giving an irritant (methacholine challenge)
Comprehensive Asthma Management • Suspect asthma and confirm diagnosis • Education • Assess severity • Avoid / control triggers and environmental modification • Medications for chronic disease • Assess control • Management plan for exacerbation • Regular follow-up
Relievers – Short Acting Beta-Agonists • SABAs for acute relief • ‘rescue’ medication used as needed • MDI salbutamol (Ventolin) • dry powder terbutaline (Bricanyl) • Frequent use of SABA indicates poor control • Regular use associated with tachyphylaxis
Inhaled Corticosteroids (ICS) • Anti-inflammatory ICS mainstay of therapy • Prevent symptoms, improve PFTs, decrease hyper-responsiveness, reduce morbidity
Inhaled Corticosteroids – How do they work? • Like steroids produced endogenously by adrenal cortex • Anti-inflammatory – inhibit production of cytokines, which: • reduces eosinophil infiltration • inhibits macrophage function • reduces production of leukotrienes
ICS Adverse Effects • thrush • dysphonia • osteoporosis • decreasedgrowth velocity (?) • glaucoma • cataracts • adrenal insufficiency
Long Acting β2-Agonists (LABAs) • add if not controlled by moderate dose ICS • better than doubling ICS • “not recommended as maintenance monotherapy” • Increased mortality! • doesn’t replace SABAs • salmeterol (Serevent), formoterol (Oxeze)
Combination LABA / ICS Products • Salmeterol/fluticasone (Advair) MDI and diskus • Budesonide/formoterol (Symbicort) turbuhaler
Leukotriene Receptor Antagonists (LTRAs) • Second or third choice medication or in patients who can’t take ICS • Montelukast (Singulair) • Oral medication • Use in patients with: • symptoms despite LABA/ICS • ASA sensitivity, nasal polyps • exercise-induced asthma
IgE Antagonists: Omalizumab (Xolair) • Monoclonal antibodies block action of IgE on mast cell • Effective if IgE levels are only slightly elevated (500-1200) • Monthly injection • Extremely expensive • Use if frequent need for oral steroids despite optimum conventional Rx and patient has drug plan or $$$
Comprehensive Asthma Management • Suspect asthma and confirm diagnosis • Education • Assess severity • Avoid / control triggers and environmental modification • Medications for chronic disease • Assess control • Management plan for exacerbation • Regular follow-up
Assess Control • Both physicians and patients over-estimate their degree of control (many patients are much worse than they think they are)
Comprehensive Asthma Management • Suspect asthma and confirm diagnosis • Education • Assess severity • Avoid / control triggers and environmental modification • Medications for chronic disease • Assess control • Management plan for exacerbation • Regular follow-up
Asthma Exacerbation • ABC’s • include RR, O2 sats, assess work of breathing, wheezing • history: • Diagnosis • Environmental triggers • Previous exacerbations/admissions/intubations • Treatment history • Compliance • Inhaler technique • Other medical illnesses or medications
Asthma Exacerbation • short-acting beta-agonists ie. salbutamol (Ventolin) • short-acting anti-cholinergics ie. ipratropium (Atrovent) • systemic anti-inflammatory therapy • oral = prednisone • intravenous = solumedrol • very severe: MgSO4, intubation, anesthetic
COPD • Definition • Constrast from asthma • Pathophysiology • Diagnosis • Chronic Management • Acute Management
COPD Definition • respiratory disorder largely caused by smoking characterized by: • progressive, partially reversible airway obstruction • hyperinflation • systemic manifestations • increasing frequency and severity of exacerbations
COPD Risk Factors • Host Factors: • genetics (alpha-1-antitrypsin deficiency) • bronchial hyper-responsiveness • Environmental Factors: • smoking • childhood viral infections • occupational & environmental exposures
Pathophysiology - Airflow Obstruction • alveoli and support structures are destroyed • decreased elastic recoil • lack of tethering gives airway collapse • airway compression by adjacent overdistended lung units • mucosal inflammation and secretions
Pathophysiology - Hyperinflation • expiratory flow limitation in COPD results in air trapping • end-expiratory lung volumes are increased • further hyperinflation with exercise (increased respiratory rate results in decreased expiratory time) • decreased inspiratory capacity a major cause of dyspnea • Increased load on inspiratory muscles
COPD Diagnosis • do not screen asymptomatic individuals • assess symptomatic patients with spirometry • post-bronchodilator FEV1/FVC ratio less than 0.7
Education - Effects of Smoking on FEV1 Mortality Benefit BMJ 2008; 336: 598-600.
Education • “Tobacco is the only legal consumer product that kills one third to one half of those who use it as intended by its manufacturers, with its victims dying on average 15 years prematurely” • - World Health Organization
What Can You Do? • 2007: 19% of adult Canadians are active smokers • smoking cessation advice • even brief advice increases chances of patients quitting • Personalized, direct but non-judgmental message • www.gosmokefree.ca • www.smokershelpline.ca • nicotine replacement therapy • many different types • any form of NRT increases chances of quitting vs. control • buproprion, varenicline
Other Prevention • vaccination: • flu vaccine yearly • pneumococcal vaccine q5years
Short-Acting Bronchodilators • Even patients with “fixed” airflow obstruction can have good clinical response to bronchodilators even if FEV1 changes very little • Reduces hyperinflation, reduces dyspnea and increases exercise capacity
Short-Acting Bronchodilators • anti-cholingergics: ipatropium (Atrovent) • dry mouth • glaucoma if sprayed into eye • urinary retention • β2-agonists: salbutamol (Ventolin) • tachycardia, palpitations • sleeplessness, tremor • improves PFTS, dyspnea and exercise performance