The Duet Device

Have you seen an Acapella Duet before? This is another one of those things I wish I could hand out to maybe half of my patients.

  • A Duet device is a special kind of Positive Expiratory Pressure (PEP) that provides resistive oscillatory pressure to exhalation which promotes increased lung volumes due to re-inflation of collapsed airways, but in addition to positive pressure reinflation, it also allows for the nebulization of medications simultaneously.
  • Typically given by RT while a person is hospitalized to increase efficacy and effectiveness of nebulizer treatments, however, patients are not typically instructed on how to use them independently. Or, if they are, they don’t remember by the time they get home or to their next facility.
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Patients who benefit from Duet use:

Cystic Fibrosis
Chronic Bronchitis
Pre/Post Lung Transplant

Or anyone doing nebulizer treatments. However, nebulizer treatments are not being recommended for patients with COVID-19, unless they are in a closed environment (like a negative pressure room with only medical professionals in attendance) as nebulizers aerosolize viral particles into the air.

What does the evidence say about using PEP with nebulizers? Does it actually work?

  • In Cystic Fibrosis patients, nebulized medication deposition decreased but distribution increased when a duet device was used.
  • In Asthma patients, nebulized medication deposition increased and distribution increased, specifically to the middle and lower thirds of the lungs when a duet device was used.
  • Use of PEP in patients with COPD reduces post-exercise dyspnea and increases length of time the patient is able to participate in exercise. PEP also reduces dynamic hyperinflation, even at only 5cm of H2O of pressure.
  • In healthy subjects, tracers were used and researchers found that using PEP with nebulized medications improves membrane permeability (diffusion) of the medications. They also found that higher pressure were tolerable, from 10-20 cm of H2O.
  • As we discussed in this blog post, there is no evidence informed protocol for PEP use yet.

How to Set Up the Nebulizer with the Duet for treatments:

As more patients are coming home from acute care after COVID-19, and hopefully testing negative, some will continue to require ongoing treatment for the damage done to their lungs. This may be in the form of nebulized medications once they are no longer carrying the virus.

To improve your patients ability to participate in physical activity or exercise, they should be performing their nebulizer treatments at least 15-20 minutes before activity. This may mean that you need to instruct them how to do this and them as them to make sure it is done before you see them for the next visit. This gives the medications (typically bronchodilators) time to do their job: open up the airways to improve ventilation, and hopefully diffusion, and hopefully perfusion.

I always request duet devices for my patients who are running nebulizer treatments, if I feel they also need airway clearance or dynamic hyperinflation management. Have you ever used duet devices? Tell me about it in the comments!

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Albuquerque, I. M., Cardoso, D. M., Masiero, P. R., Paiva, D. N., Resqueti, V. R., Fregonezi, G. A., & Menna-Barreto, S. S. (2016). Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals. Jornal brasileiro de pneumologia : publicacao oficial da Sociedade Brasileira de Pneumologia e Tisilogia42(6), 404–408.

Alcoforado, L, et al. (2013). Evaluation of lung function and deposition of aerosolized bronchodilators carried by heliox associated with positive expiratory pressure in stable asthmatics: A randomized clinical trial. Volume 107, Issue 8, Pages 1178–1185;

Laube, B, et al. (2005). Positive Expiratory Pressure Changes Aerosol Distribution in Patients with Cystic Fibrosis. Respiratory Care, 50 (11) 1438-1444

Padkao, T., Boonsawat, W., & Jones, C. U. (2010). Conical-PEP is safe, reduces lung hyperinflation and contributes to improved exercise endurance in patients with COPD: a randomised cross-over trial. Journal of physiotherapy56(1), 33–39.

Ubolsakka-Jones C, Pongpanit K, Boonsawat W, Jones DA. Positive expiratory pressure breathing speeds recovery of postexercise dyspnea in chronic obstructive pulmonary disease. Physiother Res Int. 2019;24(1):e1750. doi:10.1002/pri.1750

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