With 19 million patients passing through the system every year, the average hospital is a hive of activity. But people sitting in the waiting room waiting to be treated often become a source of infection themselves until they recover. Pathogens spread from patients like pawns across the squares of the hospital chess board. Can the hospital team stop its opponents? And what role does the ambient air play in this process?
The rules of the game are simple. Depending on how the pathogens are transmitted, they can advance across different fields. The target is the patients in the operating room. During surgery, their natural protective barriers are open. Pathogens are thus able to enter the areas of the body where they cause disease particularly easily. The hospital team has to try to stop them. On your mark, get set, go!
Atishoo! The die is cast. At speeds of up to 160 kilometers per hour, a patient in the waiting room emits a cloud of tiny spittle droplets, which serve as a means of transport for pathogens from the throat or respiratory tract. And with that, our first player moves up a square. The influenza virus, or the real flu. The 80 to 120 nanometer small viruses are protected by the liquid envelope, ejected from the throat – directly onto the patient’s hand.
All squares are now occupied. Alongside the new arrivals, the pawns of Rota, Noro and Adenoviruses are already in the game. These viruses cause diarrheal diseases. Poor hand hygiene can allow them to adhere to the infected person’s hand. It is precisely this lack of hygiene that allows them to advance up the board. Because the patient – ignoring the need to disinfect the contaminated hand – stands up to shake his doctor’s hand. In this encounter, the pathogens can migrate from the patient’s hand to that of the doctor. This move is referred to as a contact or smear infection. Thanks to this person-to-person transmission, influenza has almost reached its destination. If the doctor now takes part in an operation, the pathogens have won.
However, well-trained hospital staff know the dangers of direct contact. The Robert Koch Institute (RKI) estimates that around 90 percent of pathogens are transmitted via the hands. After contact with rooms or patients that are likely to be contaminated, hospital staff therefore pay particular attention to their hand hygiene. Surgical hand disinfection avoids spreading pathogens over the body and thoroughly cleans the forearms. In this way, the staff not only protect patients, but also themselves. For the pawns in the influenza game, it’s all over at this point. But at the start, more influenza viruses have sneaked onto the playing field unnoticed.
Droplets have managed to get past the hand in the fine spray mist. With a size of between 5 and 100 micrometers, they have entered the room air through the gaps between the fingers. Once again, it’s one move ahead for influenza, and the game starts all over again. While particles around 100 micrometers sink to the ground after only about six seconds, particles one-tenth the size can remain in the air for as long as ten minutes. Accelerated by the sneeze, you can thus infect people within a radius of about one to two meters. This is an important characteristic of the pawns. When influenza viruses reach the respiratory tract play area, they can infect the doctor and be exhaled by her. This is a direct path to the operating room and is referred to as droplet infection. Effectively, only filtration protects against airborne particles. Fortunately, our patient’s doctor is wearing a face mask.
Medical masks such as the Collectex mask from Freudenberg Filtration Technologies can effectively filter droplets from the air we breathe. The special structure of the three-layer polypropylene filter medium reduces the penetration of droplets. Even the smallest droplets get caught in the fine web of the nonwovens like flies in a spider’s web. With a filter efficiency of at least 98 percent, viral pawns don’t stand a chance.
Our doctor is therefore protected from infection. However, the actual purpose of the mask is to protect the patient. If contamination has previously occurred in the respiratory tract of the treating staff, the mask prevents further spread. In this way, transmission to the patient is stopped at two points. The playing area is blocked and influenza has now lost its second player as well.
The last chance for influenza and things are getting exciting again. Some of the pawns are surrounded by droplets smaller than 5 micrometers called aerosols. These can remain in the air for up to 30 hours and travel long distances, depending on how they are circulated. In the process, the water around the viruses increasingly evaporates until only a droplet core remains. These airborne particles can enter the ventilation system and occupy a lot of squares on the board very quickly.
The clinic’s final move is the ventilation and air-conditioning system. The air filters installed in it are a true defense against viral adversaries. They protect patients from infection, they protect against pathogenic microorganisms, and they filter out non-disease-causing particles that serve as transport vehicles for pathogens, such as droplets.
That’s no easy challenge. After all, the aerosol pawns are minute particles. To effectively protect the operating room play area, a HEPA-13 high-efficiency particulate air filter needs to be installed in addition to the usual two-stage filter systems for coarse to fine particles. These filter out as much as 99.9 percent of even the smallest particles, which measure as little as 0.3 micrometers. This means that the air handling unit succeeds in capturing even the last of the influenza pawns.
The hospital team has won and ensured that patients are protected.
But effective air filtration systems consume a lot of energy too. Efficient filter solutions are essential to keep energy consumption and CO2 emissions as low as possible, and consequently also costs. Viledon filter solutions are effective in reducing pressure drop and increasing energy efficiency. With customized filtration solutions, our team will ensure that the hospital team always comes out on top in our virus game.
In other words, checkmate – thanks to Freudenberg filter systems.