The use of Asthma adjunts lecture for medical students

1. CLINICAL SKILLS
Year 2 2012

2. At the end of this session, the student will be expected to:
 Define peak expiratory flow and interpret PEF readings
for adults and children on charts
 Describe how to use a peak flow meter, used in
assessment of lung function in patients eg to assess the
presence and reversibility of bronchospasm, and in
monitoring of patients on therapy
 Be able to explain the use of a metered dose inhaler to a
patient commencing inhaled treatment for the first time
 Be able to explain the indications for and use of a spacer
device

3.  Simplest, quickest and cheapest test of lung function.
 Often the only one available in general practice.
 PEF is the maximum rate of air, expressed in litres per
minute, which the patient forcibly exhales in 10
milliseconds, starting from full inhalation.
 When the airways narrow, PEFR (peak expiratory flow
rate) falls.

4. Predicted PEF
 For each patient, predicted peak flow is worked out from a chart of
predicted values for patients of similar characteristics (ht, age ,sex, race
and wt).
 In adults, this depends on their sex, age and height.
 We can then compare the actual PEF of the patient with the predicted PEF.
 In children a predicted peak flow measurement depends on height until the
age of approximately 10 or11yrs, when gender is then taken into
consideration too (puberty -> increased strength).
 Results nearest to 100% of the predicted value are the most normal, and
results over 80% are often considered normal.

7. Explain and demonstrate to the patient what he
is required to do:
 i.e. take a deep breath in, then blow out as hard and
fast as possible into the peak flow meter, with the lips
sealed firmly around the mouthpiece.
 The best of 3 attempts is recorded.
(Note-the peak flow meter has a disposable
mouthpiece, which is changed prior to use by each
patient)

9. Use of MDI's transformed asthma management, particularly with regard to the role of
steroids in asthma.
 They have overcome the serious toxic effects that were previously experienced with
prolonged oral steroids.
 Standard MDI's are the most widely used delivery system as they are both effective and
easily portable.
 Used to administer corticosteroids e.g Becotide, bronchodilators (Beta-stimulants e.g
Astavent=Salbutamol) and anti- cholinergics (e.g Atrovent).
 Important to note, a 4mg Salbutamol tablet produces an equivalent effect in the lungs to
200mcg of inhaled Salbutamol, but the risk of side-effects e.g. headaches, tremors or GI
disturbance is directly proportional to the overall dose, hence the inhaled route is infinitely
better.
 Disadvantage - The technique of inhalation is difficult especially in the elderly, young
children less than 5yrs of age and in arthritic patients.

10. 1) Explain the procedure to the patient and demonstrate what is to
be done so as to ensure the patient gets the full benefit of the
treatment.
2) Check expiry date.
3) Shake well.
4) Hold upright.
5) Co-ordinate inhalation with pressing the canister down.
6) Wait a few seconds before the next inhaled metered dose.

12.  Many different spacer devices available.
 Principle of spacers is that the medication is ejected into the chamber before the patient
inhales.
 Gives several advantages over the standard metered dose inhaler:
1) No need to co-ordinate actuation of the canister with inhalation. Hence suitable for use
in children and patients with poor inhalation technique.
2) No direct impact of cold aerosol particles on the back of the throat, makes some people
on MDI's cough or gag.
3) Larger drug particles, which otherwise get deposited in the mouth and throat, are
instead deposited in the chamber. Hence reduces incidence of oral thrush
( Candidiasis) in patients on inhaled steroids.
Spacers are best suited for patients who receive all their treatment at home e.g. the
elderly and young children- They are fitted with a mouthpiece or a facemask for
very young babies.

15.  National Asthma Guidelines (KEH Asthma Clinic)
 Illustrations from the National Respiratory Training
Centre, Warwick
 Latest updates by Drs Reina Abraham/ Matthews
and clinicians 2012

16.  Oxygen therapy
 Nebulisation
 Basic airway management
 Adult endotracheal intubation