Difference between bts and nice guideline on asthma management?
in the 3rd step: Leukrotiene receptor antagonist (BTS) e.g. montelukast is used instead of LABA (nice)
BTS guideline with asthma management
BTS/Sign Guidelines on Diagnosis
- High probability of asthma clinically: Try treatment
- Intermediate probability of asthma: Perform spirometry with reversibility testing
- Low probability of asthma: Consider referral and investigating for other causes
Nice guideline for asthma diagnosis
ICE recommend assessment and testing at a “diagnostic hub” to establish a diagnosis. They specifically advise not to make a diagnosis clinically and require testing:
First-line investigations:
- Fractional exhaled nitric oxide
- Spirometry with bronchodilator reversibility
If there is diagnostic uncertainty after first line investigations these can be followed up with further testing:
- Peak flow variability measured by keeping a diary of peak flow measurements several times per day for 2 to 4 weeks
- Direct bronchial challenge test with histamine or methacholine
Dyspnoea scale
- Grade 1 – Breathless on strenuous exercise
- Grade 2 – Breathless on walking up hill
- Grade 3 – Breathless that slows walking on the flat
- Grade 4 – Stop to catch their breath after walking 100 meters on the flat
- Grade 5 – Unable to leave the house due to breathlessness
Diagnosis of COPD
Clinical presentation + spirometry
- FEV1 <80%
- FEV1/FCV <70%
The overall lung capacity is measured by forced vital capacity (FVC) and their ability to quickly blow air out is measured by the forced expiratory volume in 1 second (FEV1).
The severity of the airflow obstruction in COPD can be graded using the FEV1:
Long term managment of COPD
- SABA
- if no asthmatic features: give combined LABA + LAMA
In more severe cases additional options are:
- Nebulisers (salbutamol and/or ipratropium)
- Oral theophylline
- Oral mucolytic therapy to break down sputum (e.g. carbocisteine)
- Long term prophylactic antibiotics (e.g. azithromycin)
- Long term oxygen therapy - SEVERE COPD where they get chronic hypoxia, polycythaemia, cyanosis
ABG
- Raised Co2 makes the blood pH more acidotic by breaking down carbonic acid
- Raised bicarbonate means: they chronically retain CO2 and their kidneys have responded by producing more bicarbonate to balance the acidic CO2
- Low po2 indicates respiratory failure/hypoxia
In acute exacerbation of COPD, there are x levels of CO2
Rising levels of co2 and the kidneys cant keep up with it.
This can lead to type 2 respiratory failure: High CO2, low oxygen
Target 02 saturations in COPD
- If retaining CO2 aim for oxygen saturations of 88-92% titrated by venturi mask
- If not retaining CO2 and their bicarbonate is normal (meaning they do not normally retain CO2) then give oxygen to aim for oxygen saturations > 94%
Treatment of acute exacerbation of COPD
