COPD Flashcards
(25 cards)
What two clinical features characterise COPD?
- chronic bronchitis
- emphysema
What are the RFs for COPD?
- smoking
- occupational exposure (dust, silica)
Define chronic bronchitis
Productive cough >3m (2+ years)
What is the pathophysiology of emphysema?
Inflammatory response to tobacco smoke tips balance of enzymes towards elastases.
- destruction of alveolar wall = loss of elastic recoil (airways collapse on exhalation)
- trapped air in alveoli = hyperinflation
- impaired gas exchange (hypoxaemia & CO2 retention)
What is a-1 antitrypsin deficiency?
AD disorder - a1-antitrypsin insufficient to inhibit neutrophil elastase as sequestered in the liver
= accumulation of elastase in lungs & damage to lung parenchyma
- COPD early onset (<45) esp in smokers
- liver cirrhosis
What are the classic symptoms of COPD?
- SOBOE
- chronic productive cough (smoking hx)
- wheeze / chest tightness
- RTI exacerbation
What clinical findings indicate COPD on examination?
- target sats 88-92%
- pursed lip breathing & tripoding
- WL (accessory muscle use)
- barrel chest, hyper resonance, expiratory wheeze
- cyanosis (chronic hypoxaemia)
- cor pulmonale signs
What are the clinical signs of cor pulmonale?
PHTN -> RHF
- COPD etc
- raised JVP
- peripheral oedema
- hepatomegaly
How is COPD diagnosed?
PFTs (spirometry)
- FVC/FEV1 ratio
- non-reversible after bronchodilator (<12% increase in FEV1)
- air trapping = increased TLC & RV
What is FVC?
Forced vital capacity
= Max air expired after max inspiration
What is FEV1?
Forced expiratory volume (1s)
= max expiration in 1s
What are the target sats for COPD & CO2 retainers?
88-92%
Which is reduced more in COPD: FVC or FEV1?
FEV1
FEV1/FVC ratio = <70% of expected (for age, gender, height, weight)
When is it appropriate to screen for a-1 antitrypsin deficiency?
- <45
- no RFs for COPD
- FHx COPD
- unexplained liver disease
What organisation dictates the pathways for COPD management?
BTS - British Thoracic Society
What conservative therapies exist for COPD management?
- smoking cessation clinics/apps
- vaccinations (annual flu & pneumococcal)
- pulmonary rehab
- education programmes
- long-term O2Tx
- treat comorbidities
When is domiciliary oxygen appropriate for COPD patients?
ABG:
- sats <88%
- PaO2 <55mmHg
+RHF or raised Hct:
- sats <90%
- PaO2 <60mmHg
Why are the target sats for COPD lower?
Hypoxaemia needed to stimulate respiratory drive to breathe out excess CO2
Necessary to preserve shunting:
- vasoconstriction in hypoxia to shunt blood to better ventilated regions
What is a crucial modifiable risk factor for poor COPD management to screen for when producing a care plan?
Ability to use an inhaler
- coordination
- understanding
- technique
What symptoms are indicative of a COPD exacerbation?
- more severe SOB & work of breathing
- cough
- purulent sputum / greater sputum volume
What can cause a COPD exacerbation?
- RTIs
- HF
- PE
- medications: B-blockers, opioids, NSAIDs, MTX
How is an exacerbation of COPD diagnosed?
- low sats
CXR - effusion, oedema
ABG - worsening hypercapnia
ECG - MAT
What is MAT on an ECG?
Multifocal Atrial Tachycardia
- rapid, irregular, narrow QRS
- 3 different P-wave morphologies
(Complication of hypoxia as competing atrial foci, caused by B-agonists that act on B-1 receptors in heart = arrhythmias)
How is COPD exacerbation managed?
- O2 Tx - nasal cannula/venturi
- Metered-dose inhalers + spacers / nebulisers - SABA + SAMA
- Cortiicosteroids - IV methylpred / oral pred (5-7d)
- Abx
- mechanical ventilation if ARDS