1. AEROSOL DELIVERY DEVICES
Ma. Henrietta O. de la Cruz, M.D.

2. Educational components of Asthma Treatment Strategies
Teaching and monitoring the inhalation technique of drugs is important.
Short courses of oral corticosteroids are occasionally needed.
All persons with asthma should avoid exposure to high allergen concentrations (Gøtzsche et al., 2004) [B] and, for example, sensitizing chemicals at work.
Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) should be used cautiously, as 10 to 20% of patients with asthma are allergic to these drugs.
Smoking may wreck the results of asthma care.
Develop an ACTION PLAN for self management
The treatment should be tailored for each patient according to the severity of the disease and modified flexibly step-by-step. Self-management of drug dosing is encouraged (written instructions!).
Allergen immunotherapy may help some patients (Abramson, Puy, & Weiner, 2003; Malling, 1998) [A].

3. Why inhalation therapy?
Oral
Slow onset of action
Large dosage used
Greater side effects
Not useful in acute
symptoms
Inhaled route
Rapid onset of action
Less amount of drug used
Better tolerated
Treatment of choice
in acute symptoms

4. Particle deposition

5. Uses of Aerosols Diagnostic use bronchial aerosol challenge
THERAPEUTIC
COPD and Asthma
Beta2-Adrenergic agonists
anticholinergic drugs
steroids
cromolyn sodium
Alveolar diseases
emphysema (recombinant alpha1- antitrypsin)
interstitial lung diseases (steroids, questionable reports)
Abnormalities of the Mucociliary Transport System
reduce tenacious mucus
widely applied in clinical practice but may have little scientific basis
Diagnostic use
bronchial aerosol challenge
measurement of dimensions of airways and alveoli
ventilation scintigraphy
mucociliary clearance
alveolar particulate clearance

6. Therapeutic Uses of Aerosols
Immunization and Lung infections
pseudomonas infection in cystic fibrosis
pneumocystis infection in HIV infection
Systemic drug delivery
inhaled analgesia with fentanyl or morphine
nasal sprays for calcitonin, oxytocin

7. Aerosol delivery equipment
small volume nebulizers
large volume nebulizers
metered dose inhalers
dry powder inhaler
continuous therapy nebulizers
auxiliary spacing devices
*other specialized aerosol delivery equipment to reduce mass median aerodynamic diameter of 2- 5 um

8. MDI: metered dose inhaler
Using your MDI correctly:
Remove the cap from the mouthpiece and shake the MDI well.
Exhale slowly though pursed lip.
Hold the inhaler upright and place it in front of your mouth.  Keep your mouth slightly open. 
Breathe in deeply (and at the same time) press the inhaler between your thumb and forefinger.  This forces the medication from the inhaler in a “puff” that you then inhale into your lungs.
Remove the inhaler from your mouth, holding your breath counting to 10. Then exhale slowly through pursed lips. 
Most inhaler instructions ask you to take two puffs. You need to wait about two minutes before taking the second puff, using the same technique as described in steps 1, 2, 3 and 4 above.

10. Laryngeal deposit with MDI
45-95% of the drug impacts in the oropharyngeal region
only 5-25% reaches the lower airways
regional deposition depends on:
specific drug and MDI
inhalation pattern and airway geometry
hand-breath coordination
deposition improves dramatically if a holding chamber is used
inertia due to mass cause particles to continue their present trajectory rather than follow curvature of airways
impaction is proportional to:
velocity
diameter of particle
sharpness of airway turns
inverse of airway radius
impaction is dominant in the major and segmental bronchi for rapidly inhaled particles greater than 4 um

11. MDI vs Nebulizer 4-12 puffs by MDI with spacer achieves same
degree of bronchodilation
as one 2.5 mg nebulized
treatment of albuterol
MDI with spacer are
cheaper & faster delivery

13. Spacers and Holding Chambers
reduction of drug deposition in the oropharynx to 3-35% (from 45-95%)
minimizes local side effects of steroids
amount of systemic drug uptake via the stomach and intestine is reduced by 40-80%
demands of coordination when using a spacer are minimal
asthmatic infant
elderly

14. Dry Powder Devices

15. Powder Devices
Dry powder inhalers (DPI’s) are breath activated, multidose or single dose, portable devices containing a drug
in general, they deliver a greater amount of drug as small respirable particles (<5-6um) if inhalation flow rate is high
only few patients above 6y.o. are unable to create large enough flow rates

16. Aerosol Generation and Delivery: Powder Devices
the usual deposition pattern is % in the oropharynx and % in the lungs (not very different from pMDI’s)
deposition rates vary according to the types of DPI
turbuhaler is among the most efficient, having a lung deposition of 25-35%

17. HOW TO USE TURBOHALERS Unscrew and lift off the cover.
Hold the inhaler upright with the grip downwards.To load the inhaler with a dose, turn the grip as far as it will go in both directions, listening for a click. Do not hold the mouthpiece when you load the inhaler. 
Breathe out. Do not breathe out through the mouthpiece.
Place the mouthpiece gently between your teeth, close your lips and inhale forcefully and deeply through your mouth. 
Remove the inhaler from your mouth before breathing out.
If more than one dose has been prescribed, repeat steps 2-5. Replace the cover. 
Rinse your mouth out with water. Do not swallow. 

18. Mechanisms: Sedimentation
depends on the terminal velocity of a particle under the influence of gravity
terminal velocity is proportional to:
density of particle
diameter of particle
enhanced by breath- holding or slow steady breathing

19. Comparison between MDI & DPI
High velocity aerosols
Requires hand breath co- ordination
Delivery of medicines independent of external factors
Time consuming to teach
Requires deep& slow breathing only
Aerosol velocity depends on inspiratory flow rate
No hand breath co- ordination needed
Delivery of medication largely dependent on external factors
Easy to teach
Requires high inspiratory flow>28L/min

20. Deposition%
Loss in air
Apparatus GI
Lung
MDI DPI Nebulizer

21. SMALL VOLUME NEBULIZERS
PORTABLE MODEL SVN

22. Aerosol Generation and Delivery: Nebulizers
solutions or suspensions of drugs can be aerosolized via nebulizers
nebulizers are driven ultrasonically or by compressed air
most of the drug is retained in the nebulizer, and only about 2-10% reaches the lower airways
Nebulizers require few
instructions, less
supervision & coordination
& maybe preferred by the
Patient
new brands work only during inspiration, so loss from aerosolization during expiration is reduced

23. Mechanisms of Aerosol Deposition
Inertial impaction
Sedimentation
Diffusion
Electrostatic precipitation
Interception

24. Mechanisms: Diffusion
important mechanism for deposition of particles <0.5um in diameter
extremely small particles are displaced by the random bombardment of gas molecules and collide with the airway walls
does not account for much of the deposition of therapeutic aerosols

25. Choice of inhalation therapy
Infants Nebulizer
Children
< 4 years Nebulizer
4 year DPI/MDI/Spacer
7 years DPI/MDI
Adults MDI/DPI
Acute episodes Nebulizer

26. Hazards of therapy Bronchospasm Over hydration
Overheating of inspired gases
Delivery of contaminated aerosol
Tubing condensation draining into the airway
Malfunction of device and/or improper technique may result in underdosing.
improper technique (inappropriate patient use) overdosing.
Complications of specific pharmacologic agent may occur.
CFC: affect the environment by its effect on the ozone layer

27. INFECTION CONTROL: MEDICATIONS:
Universal Precautions for body substance isolation.
SVN and LVN are for single patient use or should be subjected to high-level disinfection between patients.
Published data establishing a safe use-period for SVN and LVN are lacking; however they probably should be changed or subjected to high-level disinfection at approximately 24-hour intervals.
MEDICATIONS:
Medications should be handled aseptically.
Tap water should not be used as the diluent.
Medications from multidose sources in acute care facilities must be handled aseptically and discarded after 24 hours.
MDI accessory devices are for single patient use only. Cleaning of accessory devices is based on aesthetic criteria.
There are no documented concerns with contamination of medication in MDI canisters.

28. Patient Education in the Clinic
Explain nature of the disease (i.e. inflammation)
Explain action of prescribed drugs
Stress need for regular, long-term therapy
Allay fears and concerns
Peak flow reading
Treatment diary / booklet

29. Patient Education Consider issuing a peak flow meter & giving
appropriate education on
peak flow monitoring
Review or develop a
written plan for managing relapses
Review the patient’s understanding of the
causes of exacerbations, correct uses of medication & actions to be taken for
worsening symptoms or peak flow measurement

30. Self Management Plan Keep it simple
If your PEFR falls below 50-80% of your personal best start taking your oral steroids.
Or if you start waking at night with symptoms or develop a cough on exertion.

32. Assessment of efficacy
Proper technique applying device
Patient response to or compliance with procedure
Objectively measured improvement (eg, increased FEV1 or peak flow)

33. Demonstration