Infection Control

The Mask Crusade

With airborne disease transmission is a growing concern, which type of disposable face mask offers the best protection?

Today, more than ever, airborne pathogens command our attention. The emergence of SARS has heightened our awareness of the threats posed by these agents. Respiratory protection from airborne pathogens has become crucial.

The disposable face mask has undergone important changes since its introduction many years ago. Filter materials and efficiencies have improved dramatically. Yet the wide range of types and styles of available masks, and variations in facial size and shape have created new concerns about end-user compliance and safety.

Traditional-Style Masks

Traditional rectangular masks with tie string attachments provide a fair degree of protection and adjustability. Elastic head bands and ear loops provide alternative attachment methods and tradeoffs involving convenience and performance.

In all these styles, breathing causes 'blow-by', where air flows around the perimeter of the mask instead of through the filter, allowing potential transmission of disease. The result can be infection of the user, or the patient (such as surgical wound infection).

Breathing also creates a 'bellows effect' causing the mask to contact the nose and mouth. Since filtration is never 100 per cent, there is another transmission risk to the user.

In addition, during inhalation when the mask is pulled against the mouth and nostrils, its effective area is reduced, increasing the effort required to inhale, causing fatigue and discomfort. Exhaled water vapor wets the mask, further increasing the discomfort and fatigue, as well as increasing the aforementioned contact risk.

Alternative Styles

Duckbill style masks reduce contact with the nose and mouth, however, they protrude to such an extent that downward vision is restricted. Furthermore, blow-by is not eliminated.

Cone style masks also prevent facial contact, but due to their rigid design the seal around the face is even less effective and blow-by is very common.

PFL(r)-style masks have features to prevent blow-by and prevent facial contact without restricting downward vision, and are by far the most effective in adjusting to facial contours as well as reducing the contact transmission risk.

NIOSH-certified respirators provide protection from specific hazards. For example, the N95 type respirator has been recommended by WHO and CDC to prevent the transmission of SARS. Some manufacturers offer NIOSH-certified surgeon's masks.

No two faces have the same size or shape. Users and administrators should choose their masks carefully. There is much at stake.

A Bright Future

Success in limiting the spread of disease will always depend on the cooperation of healthcare practitioners, manufacturers and consumers. There will be no single solution:

• Manufacturers must increase their knowledge of disease transmission and strive for continuous improvement of the materials, design and performance of their products.
• Agency certification standards and norms must be objective, repeatable and reproducible.
• Fit testing protocols, both qualitative and quantitative, need to be understood and practiced.
• Healthcare workers and administrators must continue to demand the best protection they can afford.

With increased knowledge we can all expect a bright future, and be better able to meet the needs of the healthcare community and the patient.

PFL is a registered trademark of Alpha Pro Tech.