Classification of surgical masks

2020-03-03 13:59:51 administrator 20

According to performance characteristics and scope of application, surgical masks can be divided into: surgical protective masks, surgical masks, ordinary surgical masks.

1. Surgical protective mask

Medical protective mask is suitable for the medical personnel and related personnel of the airborne respiratory infectious disease protection, is a kind of closed self-priming filter type medical protective equipment, high protection grade, especially suitable for clinical activities by airborne or close contact in patients with respiratory tract infection disease transmission by droplets when worn. Can filter the particles in the air, blocking droplets, blood, body fluids, secretion droplets, etc. belong to disposable products. Surgical masks block most pathogens such as bacteria and viruses, and the WHO recommends anti-particulate masks for health workers to prevent viral infections in the air in hospitals. [2]

Surgical protective masks meet the technical requirements of gb19083-2003, and important technical indicators include filtration efficiency of non-oily particles and airflow resistance. Specific indicators are as follows: [3]

1) filtration efficiency: under the condition of air flow rate (85±2) L/min, the filtration efficiency of the aero median diameter (0.24±0.06) m sodium chloride aerosol is not less than 95%, which is in conformity with N95 (or FFP2) and above. An infectious agent less than 5 m in diameter that can block airborne transmission or close contact with an infectious agent transmitted by droplets.

2) inspiratory resistance: under the above flow conditions, inspiratory resistance shall not exceed 343.2pa (35mmH2O).

3) if the sample is sprayed to the mask under 10.9kpa (80mmHg) pressure, the inside of the mask should not show such technical indicators as penetration.

4) the mask must be fitted with a nose clip made of a flexible material with a length of >8.5cm.

5) the synthetic blood was sprayed into the mask sample with 10.7kpa (80mmHg) pressure, and there should be no infiltration inside the mask.

2. Surgical mask

Surgical masks are suitable for the basic protection of medical personnel or related personnel, as well as the protection to prevent the spread of blood, body fluids and spatter during invasive operation. They are of medium protection level and have certain respiratory protection performance. Mainly in a clean environment with a cleanliness of less than 100,000, operating room work, nursing patients with low immune function and body cavity puncture and other operations to wear. Surgical masks can block most bacteria and some viruses, preventing medical staff from getting infected, and also preventing the exhalation of microorganisms carried by medical staff directly, posing a threat to patients undergoing surgery. Surgical masks require a filtration efficiency of more than 95 percent for bacteria. Disposable surgical masks should also be issued to suspected respiratory patients to prevent the risk of infection to other hospital staff and to reduce the risk of cross-infection, but not as effective as surgical masks. [4]

It conforms to yy0469-2004 "technical requirements for surgical masks", and the important technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance. Specific indicators are as follows:

1) filtration efficiency: under the condition of air flow rate (30±2) L/min, the filtration efficiency of the median aerodynamic diameter (0.24±0.06) m sodium chloride aerosol should not be less than 30%.

2) bacterial filtration efficiency: under specified conditions, the filtration efficiency of staphylococcus aureus aerosol with an average particle diameter of (3±0.3) × m should not be less than 95%; The filtration rate of bacteria should be ≥95%. The filtration rate of non-oily particles should be ≥30%.

3) respiratory resistance: under the filter efficiency flow condition, the inspiratory resistance shall not exceed 49Pa, and the expiratory resistance shall not exceed 29.4pa. When the pressure difference between the two sides of the mask is △P of 49Pa/cm, the gas velocity should be ≥264mm/s.

4) nose clip and mask belt: the mask should be equipped with a nose clip, which is made of a malleable material. The length of the nose clip should be greater than 8.0cm. The mask belt should be easy to wear, and the rupture strength at the connection point between each mask belt and the mask body should be greater than 10N.

5) penetration of synthetic blood: after 2ml of synthetic blood is sprayed to the outer side of the mask with 16.0kpa (120mmHg) pressure, no penetration should occur to the inner side of the mask.

6) flame retardant performance: the mask material should be non-flammable material, and the flame of the mask after leaving the flame is less than 5s.

7) residual ethylene oxide: for masks sterilized with ethylene oxide, the residual ethylene oxide should be less than 10 g/g.

8) skin irritation: the primary irritation index of mask materials should be no more than 0.4, and there should be no allergic reaction.

9) microbial index: the total bacterial colony is no more than 20CFU/g, and coliform, pseudomonas aeruginosa, staphylococcus aureus, hemolytic streptococcus and fungi shall not be detected. [5]

3. Regular surgical mask

Common surgical mask is used to block the mouth and nasal spillage, can be used in general medical environment disposable health care, the lowest level of protection. Suitable for general health care activities, such as sanitary cleaning, liquid, clean sheets yuan, or pathogenic microorganisms other than the particles such as pollen barrier or protection.

Comply with the relevant registration product standards (YZB), the general lack of particles and bacteria filtration efficiency requirements, or filtration efficiency requirements for particles and bacteria under medical surgical masks and medical respirator, for only 0.3 mu m diameter of aerosol reach 20.0% - 25.0% of the protective effect, short of filtration efficiency of particles and bacteria, can not effectively stop the pathogen invasion through respiratory tract, cannot be used for clinical invasive operation, also cannot have protective effect on particles and bacteria, virus, limited to dust particles or aerosols play a mechanical barrier.