Medical protective clothing, low-pressure ward, virus detection laboratory ...
Battlefront frontiers, they guard the paramedics
With the development of the new coronavirus pneumonia epidemic, more and more medical personnel have rushed to the forefront to protect people's health and safety with their dedication. The "human-to-human" virus transmission mode caused the epidemic to rag and caused public panic.
As the first-line medical personnel who have the most contact with people infected with the new coronavirus, they are often the "number one target" for viral infection. How to ensure the personal safety of front-line medical personnel is an unavoidable issue. So, in this battle with the new crown virus, what protection methods are silently guarding the safety of frontline medical staff and assisting them to resist the constant attack of the virus?
Medical protective clothing: the most commonly used and effective armor
In the field of frequent "confrontation" with the new crown pneumonia virus, medical protective clothing is undoubtedly the most direct and effective protective "armor" for medical personnel.
Medical protective clothing refers to protective clothing used by medical personnel and people entering specific medical and health areas. Its main role is to isolate bacteria, harmful ultra-fine dust, acid and alkali solutions, electromagnetic radiation, etc., to ensure personnel safety and keep the environment clean. Medical protective clothing has a variety of classifications, and can be divided into four categories according to the purpose and use occasion: the first is the familiar "white coat", which is the protective clothing worn by medical staff in their daily work; the second is surgery Clothing is specially designed for medical staff to work in the operating room; the third type is isolation clothing, which is worn when medical personnel are in contact with patients, family members visiting patients, etc .; the fourth type of protective clothing is for medical emergency, Clothing worn by personnel entering special areas such as infectious disease areas and electromagnetic radiation areas.
According to different uses and occasions, the materials used in protective clothing have strict standards, among which medical protective clothing has the requirement of "three rejections and one antibody". The so-called "three-rejection and one-antibody" means that the medical protective clothing must be able to resist the entry of water, alcohol, and oil stains, and must be able to effectively resist static electricity.
How do medical protective clothing achieve "three rejections and one resistance"? Researcher Jin Xiangyu of Donghua University explained that the key is that the materials used to make medical protective clothing are “different”. Micro / nano-level medical and health protection nonwoven materials are made by compounding different materials, such as polyethylene / polypropylene spunbond nonwoven fabric and breathable microporous film or other nonwoven fabrics. The woven fabric is made of breathable microporous film, and it can also be made of wood-spun composite spunlace nonwoven fabric.
The performance of protective clothing materials also has strict standards, including protective (sealing), wearability, safety and health.
Protective (sealing) requirements require protective clothing to have a liquid barrier function. Key parts of protective clothing, such as left and right front plackets, left and right arms, and back positions, must be impervious to water, resistant to hydrostatic pressure not lower than 1.67 kPa; resistant to synthetic blood The penetrability is not lower than level 2. "If synthetic blood acts on the protective clothing at a pressure of 1.75 kPa, it is required to be inaccessible for 5 minutes; at the same time, the outer side of the protective clothing has a water level of not less than level 3. In addition, it is necessary to prevent the penetration of microparticles and key parts And the filtration efficiency of non-oily particles at the joints is not less than 70%. "Jin Xiangyu said.
Wearability requires sufficient strength and dimensional stability of the protective clothing. "During the tensile test, the breaking strength of the protective clothing is not less than 45 Newtons, and the elongation at break is not less than 30%." Jin Xiangyu said that for the wearing comfort, the protective clothing materials also have a moisture permeability requirement.
Safety and hygiene require that the protective clothing itself is non-toxic, does not irritate the skin, and is resistant to mold growth.
Negative pressure isolation ward: a stronghold against viruses
During the SARS period in 2003, the World Health Organization stressed that hospitals must have negative pressure wards to treat SARS patients. Over the years, various design and management studies for negative pressure wards have proved the same conclusion: it is a perfect emergency medical treatment system for public health emergencies, controls the source of infection, cuts off the transmission channels, and provides safety protection for medical staff and patients. place.
The so-called negative pressure isolation ward means that the atmospheric pressure in the ward is different from the atmospheric pressure in the outer area. Generally, the pressure inside the ward is lower than the outside pressure, so that the air inside can not get out, and only the outside air can enter. This can prevent the virus contained in the air in the ward from being discharged to the outside area, reducing the risk of infection in the entire hospital.
"Negative pressure ward is a medical facility for the treatment of highly contagious respiratory patients. It has strict functional zoning and work processes." Shandong Zibo Runchun Air Conditioning Purification Equipment Co., Ltd. has successively been Shandong Weifang Second People's Hospital, Hebei Xingtai People's Hospital, etc. Many hospitals construct negative pressure wards. The company ’s chairman Su Xunpan told reporters that the function of negative pressure isolation wards for infectious diseases is mainly two points. One is to use the principle of negative pressure to isolate pathogenic microorganisms. Discharge after treatment, without polluting the environment. Second, through ventilation and reasonable air flow organization, the concentration of pathogenic microorganisms in the ward is diluted, so that medical personnel are in a favorable wind direction, and medical personnel are protected at work.
Due to the special requirements of the infectious disease treatment workflow, the design and construction of negative pressure wards have certain particularities. Negative pressure wards are divided into process isolation and air isolation. Process isolation is achieved by controlling the flow of personnel items in the building plane. Air isolation is achieved through clean ventilation technology to form pressure gradients in various areas to prevent the spread of germs.
"The isolation ward is equipped with three doors such as the preparation room, the front room, and the isolation room. The front room design of the ward and the preparation room can avoid the leakage of infectious gas in the ward when the person enters and exits. The leakage of infectious gas indoors needs to ensure that the air pressure in the isolation ward is always lower than the air pressure in the front chamber, so that the airflow does not leak into the corridor. "Su Xunpan added that the negative pressure isolation ward of infectious diseases includes a set of Air purification device and two exhaust air purification devices. The air supply purification device is composed of a air supply cabinet and a coarse, medium and high efficiency filter device, and the filtration efficiency is 99.99%. The exhaust air purification device is composed of an exhaust cabinet and a coarse-effect and medium-efficiency filter device, and the filtration efficiency is 99.99%. At the same time, the low-voltage ward also needs to be ventilated by DC air conditioning to dilute the pathogen content. The minimum air exchange rate in the ward should be more than 6 times per hour.
Virus testing laboratory: about subsequent disposal
Since the outbreak of the new coronavirus, samples of suspected cases have been sent to the laboratory for testing every day. The laboratory test results are related to the patient's subsequent treatment plan, and are also closely related to the medical staff.
At present, the laboratory biosafety level of new coronavirus detection is mostly level two. Wu Jian, director of the Biosafety Secondary Laboratory (p2 laboratory) of Guangzhou Customs International Travel Health Care Center, told reporters that according to the protective measures taken by the operating biological factors, the laboratory's biosafety level is divided into first, second, and third. Level 4 and Level 4, the level of protection is the lowest, and level 4 is the highest.
Wu Jian introduced that the biosafety secondary laboratory is suitable for the detection of pathogenic bacteria, viruses and other microorganisms that can cause human or animal diseases, but such microorganisms generally do not pose a serious hazard to humans, animals or the environment, and spread The risks are limited. Operating in different levels of laboratories, technicians also need to achieve the appropriate level of protection. Nucleic acid testing of the new coronavirus is performed in a biosafety secondary laboratory, but testers need personal protection in a biosafety tertiary laboratory, namely medical protective masks, medical protective clothing, goggles or protective screens, double-layered latex gloves , Medical protective caps, waterproof boot covers, etc.
The samples tested in the laboratory are most likely to come from people infected with the new coronavirus. Will the testing in the laboratory pose a risk of infection to the testers or pollute the environment around the laboratory? "This need not be too worrying, it is related to the laboratory design." Wu Jian said that the biosafety secondary laboratory needs to have a negative pressure system and be equipped with a secondary biosafety cabinet. The normal operation of the biosafety cabinet can effectively ensure that the biohazard factor aerosols that are operated will not leak out of the biosafety cabinet; the negative pressure system ensures that the biohazard factor aerosols that are operated in this experimental area will not spread to the laboratory Outside the area, it is discharged through the filter at the end of the negative pressure system, which also ensures the safety of the large environment outside the laboratory.
Of course, all facilities and equipment need human operation. Wu Jian said that well-trained technicians and strict laboratory biosafety operating standards are the prerequisites for all facilities and equipment to effectively play a protective role.
Intern Ge Junxia reporter Chen Yu