THE ADVANTAGES OF USING FILTERS IN CPAP EQUIPMENT

GENERAL GUIDELINES

Common Household Contaminants

Indoor Air Quality• Looking back at the previous slide we can see that there are a number of

contaminants present in the average household that affects the occupants general indoor air quality. The higher levels of these contaminants increase allergies and place additional strain on respiratory function.

• Larger particles such as pet dander, plant dust and the dry skin are generated from within the household and are typically not filtered by a conventional HVAC system. Smaller particles such as viruses, bacteria, tobacco smoke and other fine particulate – are harmful to the occupants and generally not filtered by any HVAC system available presently.

• The OEM filters on most CPAP devices available through Carefusion are high efficiency, ultra fine quality and filter out many of these smaller as well as larger particulates.

• The following 6 slides contain information on general air filtration principles .

PRINCIPLES OF AIR FITLRATION

• Mechanical air filters remove particles from the air stream because particles come into contact with the surface of fibers in the filter media and adhere to the fibers.

• The mechanisms by which the particles come into contact with the fibers in the filter media are Straining (sieving), Interception, Diffusion, Inertial seperation and Electrostatic attraction. The first of these mechanisms applies mainly to mechanical filters and is influenced by particle size. Electrostatic filtration is obtained by charging the media as a part of the manufacturing process.

STRAINING

• Occurs when the opening between the media members (fibers, screen mesh, corrugated metal, etc.) is smaller than the particle diameter of the particle the filter is designed to capture. This principle spans across most filter designs, and is entirely related to the size of the particle, media spacing, and media density.

INTERCEPTION

• In order to be intercepted, a particle must come within a distance from a fiber of one radius of itself. The particle thus makes contact with the fiber and becomes attached. The interception mechanism can be contrasted with the impaction mechanism in that a particle which is intercepted is smaller and its inertia is not strong enough to cause the particle to continue in a straight line. It therefore follows the air stream until it comes into contact with a fiber.

DIFFUSION• Occurs when the random (Brownian) motion of a particle causes that particle to

contact a fiber. As a particle vacates an area within the media, by attraction and capture, it creates an area of lower concentration within the media to which another particle diffuses, only to be captured itself. To enhance the possibility of this attraction, filters employing this principle operate at low media velocities and/or high concentrations of microfine fibers, glass or otherwise. The more time a particle has in the "capture zone", the greater the surface area of the collection media (fibers), the greater the chances of capture. Filter manufacturers have two distinct methods of addressing this principle — employ more square footage of fine glass-mat type media or employ less square footage of high lofted glass media.

INTERIAL SEPERATION• Uses a rapid change in air direction and the principles of inertia to separate mass

(particulate) from the air stream. Particles at a certain velocity tend to remain at that velocity and travel in a continuous direction. This principle is normally applied when there is a high concentration of course particulate, and in many cases as pre-filtration mode to higher efficiency final filters.

ELECTROSTATIC ATTRACTION• Filters utilizing large diameter fiber media rely on electrostatic charges to increase

their efficiency of fine particle removal. Large diameter fiber media is normally chosen due to low cost and air flow resistance. However, these filters often lose their electrostatic charge over time because the particles captured on their surface occupy charged sites, thereby neutralizing their electrostatic charge.

• The majority of the CPAP Filters Carefusion offers, encompass this principle.

Mechanical and Electrostatic filters

• As mechanical filters load with particles over time, their collection efficiency and pressure drop typically increase. Eventually, the increased pressure drop significantly inhibits airflow, and the filters must be replaced. For this reason, pressure drop across mechanical filters is often monitored because it indicates when to replace filters.

• Conversely, electrostatic filters, which are composed of polarized fibers, may lose their collection efficiency over time or when exposed to certain chemicals, aerosols, or high, relative humidity. Pressure drop in an electrostatic filter generally increases at a slower rate than it does in a mechanical filter of similar efficiency.

• Thus, unlike the mechanical filter, pressure drop for the electrostatic filter is a poor indicator of the need to change filters. When selecting an HVAC filter, you should keep these differences between mechanical and electrostatic filters in mind because they will have an impact on your filter’s performance (collection efficiency over time), as well as on maintenance requirements (change-out schedules).

TOP CPAP MODEL FILTER PROPERTIES

• CPAP blows room air into the airway at a known and prescribed pressure. This provides pneumatic support for the airway and treats Obstructive Sleep Apnea

• Blowing room air into the airway can entrain allergens and particles which can irritate the airway tissue and interfere with treatment. This is why filters are so important.

• CareFusion has conducted bio compatibility testing on all filter materials to ensure compliance with the highest possible standards of care.

• It is a vital part of CPAP use, that the filters be changed regularly and monitored to ensure effective filtration

• To order CareFusion CPAP Filters contact TiaraSales@carefusion.com