Case 10 - COPD Flashcards
Which COPD patients should be offered long term oxygen therapy?
Very severe airflow obstruction (FEV1 <30%) Cyanosis Polycathemia - increased Hb in blood Peripheral oedema Raised JVP O2 saturations <92% on air PO2 <7.3kPa
What is the stepwise management of COPD?
1st line - SABA or SAMA (short acting muscarinic antagonist)
2nd line - FEV1 >50% LABA or LAMA
2nd line - FEV<50% LABA + inhale corticosteroid in combination inhaler
3rd line - oral theophylline used in people who cannot tolerate inhaler therapy
What is the most common organism which causes infective exacerbations of COPD?
Haemophilus influenzae ?
Streptococcus pneumoniae ?
What are the NICE guidelines for the management of an exacerbation of COPD?
Increase frequency of bronchodilator use (consider nebs)
Give prednisolone 30mg for 7-14 days
Give oral antibiotics ‘if sputum is purulent’ or clinical signs of pneumonia - amoxicillin or tetracycline or clarithromycin
What are the hallmark symptoms of COPD?
Shortness of breath
Chronic cough
Sputum production
What is the difference between type I respiratory failure and type II respiratory failure?
Type I - where PaO2 <8kPa, indicates infection, oedema or shunt
Type II - where as well as reduced oxygen, PaCO2 > 7. This can indicate gas trapping, such as in COPD and asthma
What is the pathological process that leads to type II respiratory failure in COPD?
In COPD the elastic recoil of the lungs is lost, causing gas trapping and reduced excretion of CO2
Excess CO2 increase the acid levels and lower the pH
How is acidosis in COPD compensated for?
The kidneys are stimulated to reabsorb more bicarbonate which acts as a base and neutralises the carbonic acid, restoring pH back to normal
What are the clinical features of hypercapnia?
Dilated pupils Bounding pulse Hand flap Myoclonus - jerky muscles Confusion Drowsiness Coma
What is normal pH?
7.35-7.45
What is normal pCO2?
4.7 - 6.9kPa
What X-Ray changes might be seen that suggest COPD?
Flattened diaphragms Horizontal ribs Hyperinflated lungs - >6 anterior ribs seen above diaphragm Smaller heart size Nipple shadows
What is the p pulmonale sign on an ECG and what does it indicate in someone with COPD?
Where the p waves are “peaked” in amplitude
This represents right atrial enlargement - indicates cor pulmonale
What are the major complications of COPD?
Acute exacerbations Polycythaemia (increased Hb) Cor pulmonale Pneumothorax (due to ruptured bullae) Lung carcinoma
What is CPAP
Continuous positive airway pressure
Applies mild air pressure on a continuous basis to keep the airways continuously open in people who are not able to breathe spontaneously on their own
Why do you have to be careful giving too much oxygen to patients with type II respiratory failure?
These patients have a higher risk of retaining CO2 - if you give too much oxygen then they will produce more CO2 which will be trapped
Target oxygen salts are therefore lower for COPD patients
When is long term home oxygen therapy (LTOT) indicated in patients with COPD?
When PaO2 <7.3kPa on air
How is the severity of COPD classified and what are the stages?
Mild - FEV1 >80% predicted
Moderate - FEV1 50-79% predicted
Severe - FEV1 30-49% predicted
Very Severe - FEV1 <30% predicted
When are antibiotics indicated in COPD?
Increased sputum levels
Fever - temp >38 degrees
Raised inflammatory markers - e.g, high neutrophils
What are the contraindications for NIV (non invasive ventilation)?
Pneumothorax
Vomiting - due to high risk of gastric aspiration
Confusion or GCS <8
Facial trauma/deformity
Recent gastro-oesophageal surgery (positive pressure could go into stomach and cause increased risk of perforation)
