COPD pathophysiology Flashcards
Pink puffer (Pp) and blue bloater (Bb)
Pp’s suffer mostly from emphysema
Bb’s suffer mostly from chronic bronchitis
How can COPD be diagnosed?
Confirm using post-bronchodilator spirometry (FEV1/FVC <0.7)
Rule out alternatives using chest x ray, ecg and blood tests
Patients should be >35yrs have one of the following symptoms:
- SOB on exertion
- chronic cough
- regular sputum production
- frequent chest infections
- wheeze
The GOLD standard for post-bronchodilator spirometry
1) Mild-FEV1>80%
2) Moderate- FEV1= 50-80%
3) severe- FEV1= 30-50%
4) Very severe- FEV1<30%
What are the aims of COPD treatment?
Reduce breathlessness
Reduce exacerbation frequency
Reduce hospitalisation
The damage caused by COPD is irreversible hence most treatment is aimed at slowing down the progress of the disease
What is the mMRC?
The modified Medical Research Council
A scale used to measure shortness of breath
What is CAT?
The COPD assessment test
How does the GOLD 2017 ABCD assessment tool work?
C and D=
A= mMRC=0-1, CAT<10, 0-1 exacerbations (not leading to hospitalisation)
B= mMRC>2, CAT>10, 0-1 exacerbations (not leading to hospitalisation)
C= mMRC=0-1, CAT<10, >2 exacerbations or 1 exacerbation leading to hospitalisation
D= mMRC>2, CAT>10, >2 exacerbations or 1 exacerbation leading to hospitalisation
NICE guidance
If FEV>50% then offer LABA or LAMA
If FEV<50% then offer LABA+ICS/LAMA
If COPD stable, have FEV1>50% are on a LABA and still are SOB and/or have frequent exacerbations then consider LABA+ICS combo inhaler or LABA+LAMA if ICS not tolerated
Give LAMA+LABA+ICS if still SOB despite LABA/ICS treatment
NICE recommends Roflumilast (PDE4 inhibitor) if symptoms do not improve despite triple therapy and FEV1<50%
Other things to consider with patients on multiple therapy
ICS is associated with increased risk of pneumonia
LAMA/LABA is preferred to LABA/ICS in the most recent global guidelines for COPD as they tend to have a greater clinical effect
Patient on two inhaled drugs may benefit from a combo inhaler as they are more convenient
Trimbow triple therapy inhaler
Delivers 100mcg beclometasone, 6mcg formeterol and 9mcg glycopyrrolate
Has extra fine particles (on avg. 1.1microns) as it gives a more potent effect for beclometasone (100mcg extra fine=250mcg non-extrafine)
What is an acute excerbations?
Worsening of patient condition from stable state that is acute in onset and may warrant additional treatment
Results in SOB, worsening cough, increased sputum, change in sputum colour
How can exacerbations be reduced?
Improved inhaler technique
Take flu vaccines, pneumococcal jab
Educate on signs and symptoms
Emergency antibiotics/steroids to be kept at home
Oxygen treatment for COPD
Possible lengthening of life seen in severe COPD
Very little clinical effect seen in mild-moderate COPD
Patients who have type 2 respiratory failure should carry 24-28% Venturi mask and an oxygen alert card detailing oxygen to be given and target O2 sat
What is respiratory failure?
Where Pa02<8kPa (hypoxia) or PaCO2>6.7kPa (hypercapnia)
Hypoxia is known as type 1 resp. failure
Hypercapnia is type 2 resp. failure
COPD patients require controlled oxygen treatment as they may retain CO2 which could contribute to hypercapnia
The 4 steps in the role of a pharmacist in COPD
1) Education on signs and symptoms
2) Early diagnosis
3) Management and support during disease
4) Follow up sessions and meds optimisation
