COPD Flashcards
how do muscarinic antagonists work?
SAMA/ LAMA mechanism: competitive inhibition of muscarinic receptors on bronchiole smooth muscle. By antagonising Ach action, this prevents increase for intracellular calcium which causes bronchodilation.
why are SAMA/ LAMA used more in COPD than asthma?
- More benefits in COPD
- Can be nebuliser in severe exacerbations of asthma
- Only by inhalation (dry powder/ aerosol) or nebuliser (caution for glaucoma)
how long does LAMA effect last?
24hrs
what are the side effects of LAMA?
- Side effects: dry mouth, in men- difficulty passing urine
why are LAMA and LABA used together?
further benefits – better lung function, improved symptoms, better exercise tolerance.
what therapy is not recommended as monotherpay within COPD?
ICS - modest effect in relieving breathlessness/ lung function
what are the side effects of corticosteroids?
glaucoma, central fat deposition, osteoporosis, increased risk of infection, hirsutism, peptic ulcer, increased appetite, emotional disturbances, hypotension, hypokalaemia
what is the action of theophylline/ aminophylline?
vasodilator, anti-inflammatory, contributes to immunomodulatory actions
what is aminophylline hydrolysed to?
rapidly hydrolysed after absorption from gut to theophylline
what are the side effects of theophylline/ aminophylline?
- GI- nausea, vomiting, diarrhoea
- CNS stimulation – insomnia, irritability, occasional seizures at high plasma concentrations
what does theophylline/ aminophylline react with?
many antibiotics
before nebulising a breathlessness patient who isnt responding to therapy what should you check?
inhaler technique
when are mucolytic used?
used in patients with chronic productive cough with thick vicious sputum
what is contra indicated with mucolytic medication?
history of peptic ulcer
define acute exacerbating COPD?
sustained or worsening symptoms from usual stable state, which is beyond day to day variations with acute onset
what are the non defining symptoms of acute exacerbating asthma?
- symptoms may include: increased SoB, increased cough, increased sputum production and change in sputum colour
what is the management of exacerbated COPD?
- oxygen
- steroids – 30mg for 7-14mg
- bronchodilators- salbutamol/ ipratropium
- antibiotics – purulent sputum – amoxicillin, doxycycline, clarithromyocin
- aminophylline
- consider rescue packs on discharge – personal care plan
- end stage – opioids/ benzodiazepines
which COPD can take prophylatic AB?
those who do not smoke
what primarily causes COPD?
smoking
describe COPD
COPD: predominately caused by smoking and characterised by airflow obstruction that is not fully reversible, does not change markedly over several months and is usually progressive
- Exacerbations often occur where there is rapid and sustained worsening of symptoms beyond normal day to day variations and require change in treatment.
what are the symptoms of COPD?
wheezing, lip pursing, chronic productive cough, barrel chest, dyspnoea, prolonged expiratory time, bronchitis – increased sputum, digital clubbing
what are the clinical features of COPD?
Clinical features: easily fatigued, frequent resp infections, use of accessory muscles for normal breathing, orthopneic, cor pulmonale (later in disease), thin appearance
what is emphysema?
alveolar destruction - alot bigger hence less SA
how quick can hypoxia occur?
seconds/ minutes
how long does it take to have respiratory acidosis?
hours
how long does it take for metabolic compensation?
days
what is normal Pa of O2?
10.6-13.4
what is normal PaCO2?
4-6kPa
what is normal bicarbonate levels?
22-26mmol/L
how do you assess an ABG reading?
- Look at pH – acidosis or alkalosis
- What caused it? Resp first. If high CO2 – more acidic (lower pH – respiratory acidosis). If low CO2 – more alkaline (higher pH – respiratory alkalosis)
- Is there any compensatory? Check bicarb – higher – metabolic alkalosis, if lower than metabolic acidosis
- Compensatory takes time to occur – so can judge how long this has occurred for