What is COPD
A disease characterised by airflow obstruction which is usually progressive and irreversible. It encompasses emphysema and chronic bronchitis
How is obstruction defined diagnostically in respiratory disease
FEV1 less than 80% and FEV1/FVC ratio less than 0.7
How do you diagnose bronchitis
It is a symptomatic diagnosis - sputum production for >3 months of the year, for >1 year
How do you diagnose emphysema
It is a histological diagnosis, dilatation of the air spaces distal to the terminal bronchioles
What are the causes of COPD
Smoking Atmospheric pollution (most common worldwide) - may play a role Alpha-1 Antitrypsin deficiency - a rare cause of emphysema
What might a patient with COPD complain of
SOB
Cough with sputum
Wheeze
Does COPD cause clubbing
No
What signs might you see on a COPD patient
Use of accessory muscles Pursed lip breathing Asterixis - if CO2 retention Reduced cricosternal distance - hyperexpansion Reduced chest expansion Reduced breath sounds
*May be coarse crackles if infective exacerbation
Why might you do an ECG on a COPD patient
To look for signs of right ventricular hypertrophy
What oxygen saturations are you aiming for in an acutely ill COPD patient
88-92%
How would you give oxygen in the acute setting to a COPD patient
Use either a 24% or 28% venturi mask and oxygen at 4L/min
What is the criteria for long term oxygen therapy for a COPD patient
If PaO2 less than 7.3 and patient is stable (more than 5 weeks since last exacerbation)
Non-smoker (long term)
What important investigations should be done to investigate COPD?
Bedside- culture MCS
ABG
Imaging: CXR- hyperexpansion, bullae, ruling out malignancy, infective exacerbation or other lung disease
Pulmonary function tests
What is the medical management for chronic COPD?
3 steps:
- Relievers- short acting beta agonists e.g Atrovent
- LABA e.g. Spiriva/long acting muscarinic antagonist
- Combination with steroids e.g. Seretide
Why are steroids avoided where possible in Copd?
Expensive
Increased risk pneumonia
What is the management of an acute exacerbation of COPD?
Controlled O2 therapy
Nebulised bronchodilators
Steroids: IV hydrocortisone, followed by 7-14 days oral prednisolone
Abx: doxycycline
NIV: if no response and severe hypercapnic respiratory failure: pH less than 7.35
Aminophylline IV- if no response
What are the most common causative pathogens for an acute infective exacerbation of COPD?
Strep pneumonia
Haemophilus influenza
Moraxella cattarhalis
