1. Scintigraphic Assessment of Radio-Aerosol Pulmonary Deposition With the Acapella Positive Expiratory Pressure Device and Various Nebulizer Configurations
Brian K. Walsh, RRT-NPS, RRT-ACCS, RPFT, FAARC
Boston Children’s Hospital and
Harvard Medical School

2. Background
There are several components to optimal delivery of medications to the pulmonary system
Breathing patterns – including muscle weakness
Diameter of the airway – mucus, inflammation, bronchospasm or maybe a combination
Inhaled medications can promote hydration, reduce viscosity, bronchodilate and aide in mucociliary clearance
Has become an acceptable adjunct

3. Background
Bronchial hygiene therapy involves noninvasive and invasive techniques to assist with mobilization and clearance.
Two modalities are:
Positive expiratory pressure (PEP)
High frequency oscillatory PEP
PEP – to stabilize the airways, preventing collapse and possibly improving collateral ventilation

4. Moving Stenosis and Collateral Ventilation
Walsh, Resp Care, 2011; 56;9
McCool, Chest 2006;129;250

5. Oscillatory PEP
May have the added benefit of dislodging thick secretions and decrease mucus viscoelasticity
Acapella high-frequency oscillatory PEP produces oscillations during EXHALATION by the use of a magnetic valve that creates intermittently occlusions.
5 pressure settings at approximately 13 Hz
Not position dependent / two flow range devices

6. Research Question
Proximal placement of nebulizer would be superior to manufacture recommended (distal) and equal to nebulizer alone
Recommended
Hypothesis
Control
Conflicts of interest are properly disclosed on page 329.

7. Methods Randomized crossover clinical trial
Approved by research committee
Subjects
Non-smoking, healthy males, no lung disease, years with normal spirometry
Procedure
SVN run at 7 L/min with 3.6um +/- 2.2um MMAD with 4 mL of saline and technetium-99m-labeled diethylene triamine penta-acetic acid (25mCi) and nebulized over 9 mins
Randomized to 3 different configurations

8. Procedure Continued Via mouth piece with subjects seated upright
Breathing patterns were standardized with deep breaths and inspiratory pauses
Immediately after administration scintigraphy was performed
Lung images were divided into regions of interest

9. Lung Regions of Interest

10. Scintigraphy
Most commonly used for the diagnosis of pulmonary embolism via ventilation/perfusion scan. Less commonly used to evaluation lung transplants and right to left shunts.

11. Results Enrolled 14 males, but only 10 completed
Mean age was 24.4 (2.2)
BMI 22.6 (2.6)
Spirometry normal
Deposition was similar in the right and left lungs
There was less total deposition in configuration A than B or C

12. Lung Deposition Total Lung
Recommended
Experiment
Control

13. Lung Deposition Upper, Middle and Lower
Recommended
Experiment
Control

14. Lung Deposition Central, Intermediate and Peripheral

15. Discussion
Despite the Acapella appearing to be a nice reservoir the distal placement likely creates impaction of larger particles
Internal mechanisms within the Acapella create turbulent or transitional flow that increase the deposition of larger particles in the device
Some evidence that MMAD is reduced due to a filtering effect

16. Discussion
Recommended – Demonstrating a large amount of aerosol depositing within the Acapella
Proximal placement (Experiment) – Demonstrating a large amount of aerosol within the mouth piece and valve

17. Discussion PEP in general may play a role in aerosol delivery
Some findings supportive
Some findings within SD
Some findings consistent with prolonged expiratory phases that may allow lower inspired drug delivery compared to normal breathing with periodic inspiratory holds
Maybe they should have used a breath actuated nebulizer??

18. Discussion
Lung deposition was not statically different however trends were noticed
Normal distribution of ventilation were consistent with results.
Limitation
These were normal subjects who do not exhibit the same breathing or flow pattern
They didn’t describe or measure minute ventilation during the administration

19. Editorial by Dr. Berlinski The Order of the Factors Affects a Product
Combining therapies is attractive
Is marketed to reduces time
Yet, can increase cost or reduce effectiveness by reducing aerosol delivery by 70%
Limitations discussed regarding normal subjects, however concluded that it would likely be the same in lung diseased patients
Order of therapies may matter
Some have recommended a certain order of therapies in the past

20. Conclusions
Placing the nebulizer distal to the oscillatory PEP device decreased intrapulmonary deposition, compared to proximal placement, and compared to nebulizer alone.
Three possible take home messages:
You could say more data is needed to go against manufacturers recommendations
You could apply the SVN at the proximal (mouth piece) of the oscillatory PEP device when therapy time is considered a factor
You could # 2 to all patients who require the combination of therapies

21. What you cannot conclude…
The experimental placement and combined therapy is superior to SVN alone
BAN would be better

22. Review and Comments