Clinical Sciences: COPD Overview

Clinical Sciences: Medical and Neurological conditions Chronic Obstructive Pulmonary Disease (COPD)

• COPD is a medical condition characterized by persistent airflow limitation, typically progressive.
• Key cause of COPD is smoking.
• COPD involves narrowing of the respiratory tract due to long-term damage to the respiratory system.
• COPD causes symptoms like hypoxia (low oxygen), breathlessness, and coughing.
• No cure exists, and the condition typically worsens over time.
• Early treatment and quitting smoking can improve COPD symptoms.

Intended Learning Outcomes

• Students should understand the normal respiratory process.
• Students should understand what COPD is.
• Students should understand the pathology of COPD.
• Students should understand the clinical course of COPD.
• Students should understand the features of COPD.
• Students should understand the assessment of COPD.
• Students should understand COPD management (pharmacological and non-pharmacological).

Healthy Lungs vs. COPD Lungs

• Healthy lungs have open, clear bronchioles and alveoli (air sacs).
• COPD lungs show narrowed and blocked bronchioles and damaged alveoli, filled with mucus.

Obstructive Chronic Bronchitis

• In obstructive chronic bronchitis, airway size decreases by 20-25%.
• Thick, sticky mucus blocks the airways instead of clearing.
• Inflammation and swelling in the airways further narrow them.

Emphysema

• Emphysema damages lung tissue of alveoli, impacting air sac shape and reducing gas exchange surface area.
• Air cannot be effectively expelled during exhalation, becoming trapped.

Spirometry

• Spirometry measures lung function by quantifying the volume of air a person can exhale.
• Maximum inhalation is followed by forceful exhalation.
• Measurements like FEV1 and FVC provide indicators to assess COPD.

Terminology about Lung Function Tests

• FEV1: Forced Expiratory Volume in one second.
• FVC: Forced Vital Capacity (total volume of air exhaled in one forced breath).
• FEV1/FVC ratio: Fraction of air exhaled in the first second to the total exhaled.
• VC: Vital Capacity (total volume of air exhaled in a full breath).
• FEV6: Forced Expiratory Volume in six seconds (often approximated the FVC).
• EELV: End Expiratory Lung Volume.
• DH: Dynamic Hyperinflation: fixed increase of EELV above normal/resting value during exertion.

Obstructive Pattern

• In an obstructive pattern, FEV1 and FVC are lower than normal, and the FEV1/FVC ratio is below 0.7.

Bronchodilator Reversibility Test

• Spirometry becoming normal after bronchodilator use indicates it is NOT COPD but likely asthma in most cases.
• In COPD, post-bronchodilator FEV1/FVC stays below 0.7.
• Change in FEV1 less than 12% and <200mL post-bronchodilator usually indicates COPD.
• Change greater than 12% and >200mL indicates Asthma.

What is Asthma?

• Asthma is a reversible airway obstruction caused by airway inflammation.
• Increased response in airways to variety of stimuli occurs.
• Symptoms include: diffuse wheezing, dyspnea (difficulty in breathing), and cough.

Differential Diagnosis: COPD and Asthma

• COPD onset is usually mid-life (around 50 years old)
• Asthma onset is often in childhood
• COPD symptoms progress slowly, whereas asthma symptoms are more variable.
• COPD patients typically have a history of smoking.
• Common signs in asthma patients may include allergy, rhinitis, and eczema, as well as family history of asthma.

Classification of Severity of Airflow Limitation in COPD

• COPD severity classified based on FEV1 percent predicted values, categorized into 4 stages: Mild, Moderate, Severe, and Very Severe.

Assessment of Symptoms

• COPD Assessment Test (CAT): An 8-item measure assessing health status impairment in COPD.

• (http://catestonline.org)

• This 8 item test can be used to help assess breathing with patients with COPD.

• Modified British Medical Research Council (mMRC): A questionnaire used to evaluate breathlessness intensity.

Additional Investigations

• Chest X-ray: Helpful in excluding alternative diagnoses or presence of other conditions.
• Lung volumes and diffusing capacity: Help characterize severity but aren't mandatory for management.
• Oximetry and ABG: Used for assessing oxygen saturation and need for supplemental oxygen.
• Exercise testing: Shows exercise impairment and predicts prognosis. This can include a 6-minute walk test or a more comprehensive lab-based exercise test.

Exacerbations

• Exacerbations are acute changes in symptoms (dyspnea, cough, sputum) that require treatment changes.
• Symptoms include worsening shortness of breath, increased sputum volume or purulence, and/or signs of upper respiratory infection (URTI) or other systemic responses.

Risk of Exacerbations

• Risk of exacerbations assessed with history of exacerbations and spirometry tests.
• Two or more past-year exacerbations OR FEV1 <50% of predicted values are indicators of high risk of exacerbations.
• Common causes include viral or bacterial infections and environmental factors (temperature, air quality).

Quit Smoking

• Cessation of smoking is crucial for COPD management to lessen symptoms and slow disease progression.
• Pharmacotherapy and nicotine replacement therapy can increase long-term smoking abstinence rates.

Pathology for Acute Exacerbation of COPD

• Respiratory infections (viruses or bacteria) and pollutants are common triggers for acute exacerbation in COPD.
• Inflammation, bronchoconstriction, and mucus production increase and impair respiratory airflow.

Respiratory Tract

• Diagrams of the Respiratory Tract are shown outlining the major structures relevant to COPD.

Definition of COPD

• COPD is a common, preventable, and treatable disease characterized by persistent airflow limitation that is typically progressive.
• It involves an enhanced chronic Inflammatory response within the airways and lungs caused by noxious particles or gases.

Features of COPD

• Airflow obstruction is typical, usually progressive and not completely reversible.
• COPD is often associated with clinical diseases like chronic bronchitis or emphysema.
• There are often associated systemic manifestations, muscle wasting and comorbidities (e.g., cor pulmonale).
• Symptoms often include cough, sputum production, and dyspnea.

Problems for people with COPD (ICF)

• Long-term O2 insufficiency can damage organs and muscles. This can affect overall well-being.
• COPD limits breathing exercises and daily activities, including activities of daily living (ADL).
• Related environmental factors, such as living situations and perceived social support, also affect individuals with COPD.

Treatment of COPD

• Medication, such as bronchodilators, can help improve COPD symptoms.
• Inhaled corticosteroids may be needed, especially when FEV1 <60% predicted, to reduce symptoms and exacerbations
• Long-term oxygen therapy may be necessary in more severe cases.
• Pulmonary rehabilitation programs help cope with everyday life including tasks such as bathing, dressing, etc

Bronchodilators

• Bronchodilators are key medications to manage COPD symptoms.
• Bronchodilators are prescribed as needed or regularly to prevent or reduce symptoms.
• Treatment choice depends on the patient's response to different types of bronchodilators.
• Types include beta2 agonists, anticholinergics, and combinations.
• Long-acting inhaled bronchodilators are often used for convenient symptom relief and are effective in preventing exacerbations.

Inhaled Corticosteroids

• Inhaled corticosteroids improve COPD symptoms and lung function.
• They lower the frequency of exacerbations in COPD patients with FEV1 less than 60% predicted.
• Use of inhaled corticosteroids has a potential increased risk of pneumonia.
• Withdrawal from inhaled corticosteroids may worsen symptoms.

Combined Formulations for Quick Relief and Prevention

• Combined formulations such as beta2 agonist + anticholinergic are used for quick relief.
• COPD-specific combined formulations like bronchodilator + corticosteroid are used for prevention of COPD symptoms.

Summary of Inhaled Medications for COPD

• Summary table lists common inhaled medications for COPD, categorized by their function (reliever or preventer), main components, and dosage form.

Home Oxygen Therapy (HOT)

• HOT is a low flow or high flow oxygen delivery system for individuals needing supplemental oxygen.
• It's sometimes needed for patients with severe COPD or other conditions.

Use of Home O2 Therapy LONG TERM

• Long-term oxygen use is indicated for chronic hypoxemia (low blood oxygen levels).
• Criteria for long term oxygen include exertion-induced desaturation, demonstrated compliance and improvement in activity levels and quality of life.

Use of Home O2 Therapy SHORT TERM

• Short-term use of HOT may be necessary for COPD patients not meeting long-term criteria, and needing short-term oxygen management. This is sometimes used for patients who need palliative care from COPD.
• Patient may have persistent desaturation even at rest.

Indications for Long Term Oxygen Therapy (LTOT)

• LTOT is indicated for chronic, stable COPD with low oxygen levels, and may require certain blood tests.
• Criteria include a stable course of COPD under medical management and low oxygen levels in the blood.

Dosage and Use of Home O2

• Dosage and usage of HOT varies by patient condition and needs.
• Patients may require continuous or intermittent use for different purposes.