Presentation on theme: "Scintigraphic Assessment of Radio-Aerosol Pulmonary Deposition With the Acapella Positive Expiratory Pressure Device and Various Nebulizer Configurations."— Presentation transcript:
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
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;250 Walsh, 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 Recommended Experiment Control
Lung Deposition Upper, Middle and Lower Recommended Experiment Control
Lung Deposition Central, 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
Discussion A.Recommended – Demonstrating a large amount of aerosol depositing within the Acapella A.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. 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
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 recommendations 2.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