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, FAARCBoston Children’s Hospital and

Harvard Medical School

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

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

Moving Stenosis and Collateral Ventilation

McCool, Chest 2006;129;250Walsh, Resp Care, 2011; 56;9

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

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.

Methods• Randomized crossover clinical trial• Approved by research committee• Subjects– Non-smoking, healthy males, no lung disease, 18-30

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

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

Lung Regions of Interest

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.

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

Lung Deposition Total Lung

RecommendedExperimentControl

Lung DepositionUpper, Middle and Lower

RecommendedExperimentControl

Lung DepositionCentral, Intermediate and Peripheral

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

DiscussionA.Recommended – Demonstrating a

large amount of aerosol depositing within the Acapella

B.Proximal placement (Experiment) – Demonstrating a large amount of aerosol within the mouth piece and valve

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??

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

Editorial by Dr. BerlinskiThe 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

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:1. You could say more data is needed to go against

manufacturers recommendations2. You could apply the SVN at the proximal (mouth piece)

of the oscillatory PEP device when therapy time is considered a factor

3. You could # 2 to all patients who require the combination of therapies

What you cannot conclude…

• The experimental placement and combined therapy is superior to SVN alone

• BAN would be better

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