The Mechanical and Aerospace Engineering Department at Carleton University, Ottawa, Canada, studied the effect of Vacuum Flowrate on Mask Efficiency with the EXHALO™ Shield. The poster was presented at the Canadian Society of Respiratory Therapists Annual Conference in May 2021.


The EXHALO™ Shield is a new innovative device from Solutions in Critical Care designed to minimize and manage the release of airborne contaminants and aerosol particles upon patient exhalation.


The study was conducted using computational fluid dynamics modeling of the EXHALO™ Shield in conjunction with an oxygen mask. Researchers observed the release of 1000 2.5 micron particles (the optimal particle size for lung deposition).  They used varying flowrates of 0, 10, 50 and 100 L/min. The flowrates represent the various vacuum systems used in hospitals ranging from portable suction units to full-wall vacuums. Inlet boundary conditions mimicked an 11 L/min breathing rate.

Vacuum Flowrate Particles on Mask % Particles Removed % Particles Released %
0 L/min 3.5 0.2 96.3
10 L/min 6.4 35.3 58.3
50 L/min 5.9 71.8 22.3
100 L/min 5.3 93.9 0.8
EXHALO Shield Study Diagram
Click to enlarge diagram of particle trajectories with velocities.


Particle-mass dispersion is reduced in this simulated model with the addition of the EXHALO™ Shield. The dispersion is further reduced by increasing the flowrate of the vacuum suction line. The EXHALO™ Shield could provide support in combatting the ongoing COVID-19 pandemic by mitigating the release of aerosols produced by patients receiving oxygen therapy or other aerosol-generating medical procedures.

Click here to view the poster.

Exhalo Shield Study Conclusion


  • Works with more than 18 different masks, including adult and pediatric oxygen, aerosol and tracheostomy masks
  • Transparent, lightweight
  • Single patient use
  • Latex and BPA free
Exhalo product picture side angle

To learn more about the EXHALO™ Shield, call 888-891-1200 or email us to be connected to a local sales representative.

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