COPD Flashcards
What are some of the other names for COPD?
- Chronic airflow limitation (CAL)
- Chronic obstructive lung disease (COLD)
- Chronic obstructive airway disease (COAD)
- Obstructive lung disease (OLD)
What is COPD?
- Progressive airflow limitation
- Not fully reversible
- Abnormal inflammatory response
What is the gold standard for diagnosing, assessing and monitoring COPD?
Spirometry - FEV1 is the best predictor of mortality
What spirometry values are indicative of COPD?
- FEV1/FVC ratio < 70%
- FEV1 < 80% predicted after bronchodilator medication
What are the characteristics of mild COPD?
- FEV1: 60-80% predicted
- Few symptoms, no effect with ADL
- No complications
What are the characteristics of moderate COPD?
- FEV1 40-59% predicted
- Increasing dyspnoea
- Increasing limitation on ADL
- Consider sleep apnoea
What are the characteristics of severe COPD?
- FEV1 < 40% predicted
- Dyspnoea on minimal exertion
- ADLs severely affected
- Complications include severe hypoxaemia, hypercapnia, pulmonary hypertension, heart failure
What conditions contribute to COPD?
- Chronic bronchitis
- Emphysema
- Asthma
What causes an obstructive defect?
- Partial occlusion of airway lumen
- Inflammation of airway wall/bronchial smooth muscle constriction
- Destruction of lung parenchyma (tissue surrounding conducting airways)
What are the characteristics of chronic bronchitis?
- Patient coughs on most days at least 3 consecutive months for at least 2 years
- Blue bloaters presentation common
What are the characteristics of pulmonary emphysema?
- Permanent enlargement of airspaces distal to terminal bronchioles
- Destruction of parenchyma
- Collapsed airways
- Pink puffers
What are some of the signs and symptoms of COPD?
- Breathlessness
- Cough/sputum production
- Wheeze
- Chest pain
- Weight loss
- Depression
- Muscular weakness
- Osteoporosis
What are the risk factors for COPD?
- Genes
- Tobacco smoke
- Occupational dusts
- Air pollution
- Asthma
- SES
How many pack years are associated with approx 80% of COPD patients?
History of at least 20 pack years
1 pack year = 20 cigarettes per day for 1 year
What are some of the evidence-based treatments for optimising function in COPD?
- Bronchodilators
- Pulmonary rehabilitation
- Prevention/treatment of osteoporosis
- Treatment of hypoxaemia & pulmonary hypertension
- Surgical approach for some patients
What is the normal pressure for pulmonary circulation?
25/10mmHg
What is hypoxic pulmonary vasoconstriction?
- Produced by smooth muscles cells in pulmonary arterioles
- Can improve V/Q matching
- Can increase the strain on the right side of the heart
What factors in COPD lead to increased pulmonary artery pressures and right heat failure/strain?
- Loss of vascular surface due to loss of lung parenchyma
- Compression of vascular bed due to hyperinflation
- Hyperviscosity of blood due to polycythemia
- Left ventricular failure
- Vessel changes due to inflammation
- Pulmonary embolism
- Hypoxic vasoconstriction
What are the indications for home O2 in COPD?
- Nocturnal O2 (SpO2 <88%)
- Role in exercise as supplement
- Arterial PaO2 < 55mmHg on room air at rest/awake
- Daytime PaO2 55-59mmHg & evidence of organ damage/heart failure
What are some of the evidence-based treatments for preventing deterioration in COPD?
- Smoking cessation
- Treatment of nicotine dependence
- Influenza immunisation
- Mucolytic medications
- Long term oxygen therapy
What are some of the exacerbations of COPD?
- Increased dyspnoea
- Increased sputum volume/purulence (pus)
- Increased cough
- Increased wheeze
- Fever
- URTI
What are some of the causes of COPD exacerbations?
- Respiratory infection (50%)
- Congestive cardiac failure (25%)
- Unknown causes (25%)
What are some of the evidence-based treatments for managing exacerbations in COPD?
- Early diagnosis/treatment
- Inhaled bronchodilators
- Systemic corticosteroids
- Antibiotics
- Controlled O2 delivery
Why is residual volume higher in COPD patients?
- Hyperinflation of the lungs due to loss of elastic recoil, enlarged spaces
- Unable to exhale as much air due to airways collapsing during expiration (destroyed parenchyma = floppy)
- Leaves higher residual volume (gas trapping)
What are the indications of hyperinflation?
- Barrel shaped chest
- Upper chest pattern of breathing
- Little lower chest expansion
- CXR: Lung fields larger/blacker, diaphragm flatter, ribs more horizontal
What is dynamic pulmonary hyperinflation (DPH)?
- Compensatory strategy in response to airflow limitation
- Results in increased end-expiratory lung volume above predicted RV
- Decreases airway resistance allowing increase RR
- Occurs during exercise
What are the disadvantages of DPH?
- Altered chest wall compliance
- Mechanical disadvantage of respiratory muscles
What is the effect of hyperinflation on the diaphragm?
- Length-tension relationship of fibres altered
- Decreased zone of apposition
- Medial orientation of fibres
- Decreased curvature
- Acts as fixator against abdominal contents
What is pulmonary rehabilitation?
- 8-12 week program of supervised exercise/education specific to COPD
- Improves dyspnoea, exercise tolerance, QOL
What is the impact dyspnoea in COPD?
- Lack of fitness
- Immobility
- Social isolation
- Depression
What is inspiratory muscle training (IMT)?
- Resisted breathing on inspiration
- One-way spring-loaded valve
- Mouth piece & nose clip
- Resistance 9-41cmH2O (threshold)
What intensity does IMT require to be effective in endurance athletes?
High intensity (> 50% max)
What results have been found from IMT in endurance athletes?
- Increased inspiratory muscle strength (MIP - maximum inspiratory pressure)
- Increased exercise performance
What are the mechanisms of improvement with IMT in endurance athletes?
- No change in lung volumes
- Increased diaphragm thickness
- Increased limb perfusion (e.g. more blood to legs)
- Decreased lactate (muscles require less O2)
- Decreased neural drive
- Decreased perceived exertion in breathing
What is the evidence for IMT in COPD?
- Increased inspiratory muscle strength/endurance
- Decreased dyspnoea
- Improved exercise tolerance
- Improved QOL
- Additional benefits to pulmonary rehab
- Reduced hospitilisation days
What are the training parameters for patients in the acute illness phase (ICU, mechanical ventilation)?
- 5 days/week
- 5 sets of 6 breaths, rests in between (50% MIP, just able to complete 6th breath)
What are the training parameters for patients with stable chronic COPD?
- 3 days/week for minimum 8 weeks initially
- > 30 % MIP
- 2 mins on : 1 min off for 30 mins
- Maintenance: 2 sessions/week forever
Who is IMT for?
Acutely:
- COPD/long term ICU patients
- Main problem is dyspnoea
Long term:
- Stable COPD
- Addition to pulmonary rehab
- Or if can’t attend pulmonary rehab
What is maximum inspiratory pressure (MIP) a measure of?
Inspiratory muscle strength
What are the contraindications/precautions to IMT in chronic COPD?
- Recent undrained pneumothorax
- History of recurrent spontaneous pneumothorax
- Large bullae on CXR (big conjoined spaces, no elastic tissue, risk of pneumothorax)
- Marked osteoporosis with history of spontaneous rib fractures
- Lung surgery within last 12 months (speak to surgeon, negotiate)
