An investigation into the efficiency of disposable face masks.

Abstract

SUMMARY Disposable face masks used in hospitals have been assessed for the protection afforded the patient and the wearer by challenges of simulated natural conditions of stress. Operating theatre masks made of synthetic materials allow the wearer to breathe through the masks, and these have been shown to protect the patient well but the wearer slightly less. Cheaper paper masks are worn for ward duties, and of these only the Promask protected the area in front of the wearer: air does not pass through this mask, expired air is prevented from passing forward, and the wearer breathes unfiltered air. All the other paper masks tested allowed many bacteria-laden particles to pass through them.Masks are worn for fewer ward procedures than 20 years ago, but most nursing authorities still recommend their use on the wards during the performance of many aseptic techniques even though this may be unnecessary.' If they are used they must provide the safeguard for which they are worn, which is to prevent the nasopharyngeal organisms of the wearer infecting a patient. In a study spread over three years, nasopharyngeal carrier rates of Staphylococcus aureus varied between 29%0 and 42% among personnel in an operating suite, and it has been noted how many times people touch their noses and thus contaminate their hands.3Masks worn by hospital staff to restrict the flow of potential pathogens from their mouths or noses are of two types, both of which are disposable. Those used during minor procedures, such as wound dressings, are usually made of paper and are not suitable for the prolonged wear necessary in an operating theatre, where more expensive masks made of one of various synthetic materials are worn; these should fit snugly over the face and cover the mouth and nose so that the wearer breathes filtered air in and out freely.

Post spinal meningitis and asepsis

“…This may be a consequence of the type of ventilation in the operating room, as a reduction in bacterial shedding was observed in rooms with laminar airflow but not in conventionally ventilated rooms (52). Non‐woven tissue or glass fibres are superior to linen or paper masks (53). The use of an adaptable soft mask, avoiding mask wiggling, changing masks between each patient and close shaving is recommended (51).…”

Issues Affecting Respirator Selection for Workers Exposed to Infectious Aerosols: Emphasis on Healthcare Settings

“…A 1941 study evaluating surgical masks made of either gauze or muslin concluded that they were inadequate for protecting wounds because bacteria-containing particles passed through the filter material and around the edges of the masks (Hirshfeld & Laube, 1941). Subsequent studies, in which not only surgical masks made of gauze and muslin but also ones made of paper, foam, and synthetic materials were evaluated, resulted in filter efficiencies ranging from the teens to nearly 100% (Brosseau, McCullough, & Vesley, 1997;Ford & Peterson, 1963;Ford, Peterson, & Mitchell, 1967;Miller, 1973Miller, , 1995Rogers, 1980). The findings of other studies in which surgical masks were evaluated (with some reported to have highly efficient filters) have emphasized that a secure face seal is essential for preventing infectious particles from escaping (as well as entering) at a mask's edges (Ha'eri & Wiley, 1980;Johnson, Martin, & Resnick, 1994;Pippin, Verderame, & Weber, 1987;Tuomi, 1985).…”

Postoperative wound infections and surgical face masks: A controlled study

“…One year later, his assistant Hfibener published a study showing that wearing a face mask diminished droplet spread from the mouth of a test person [2]. After this, many studies [3][4][5][6][7] have been published comparing different surgical face masks and how to wear them. The history of the use of face masks as told by Rockwood and O'Donoghue [8] is impressive and they speak in favor of the use of face masks in the operating room.…”