The problem
The reason these machines are not recommended for use is that they aerosolise the virus and allow the viral particles to travel further and stick to many more surfaces as well as stay suspended in the air longer than when they are stuck to droplets. Because of that, they create a very hazardous environment for the medical staff (aerosol-generating procedure) and, if a room is not under negative pressure, they could also potentially travel through the ventilation to adjacent rooms and infect other people in the building who don’t have Covid-19.
Why is this all relevant?
Karmaflow filter is created to be a filtering system that deactivates as many of the virus particles as possible in the exhaled air from a Covid-19 patient and thereby make it much safer to use a BilevelPAP machine as a ventilator for a Covid-19 patient.
How is this done?
The exhaled air from a Covid-19 patient goes through the mask and into a tube lined with shortwave ultraviolet light (UV-C) LED-strip that is virucidal. This tube connects to a submerged filtering device inside and at the bottom of a container filled with Hypochlorous acid (HOCl is what the immune system (neutrophils) creates) that has a broad range of bactericidal and virucidal effects and can be used with a high predictability for disinfecting against the COVID-19 (1). This container can also be irradiated with UV-C light, both in the liquid part and in the part above the surface, if the liquid is something other than HOCl (this is because UV light might destabilise HOCl and impact its virucidal abilities).
The exhaled air is broken up by a nozzle into many small bubbles (similar to how you aerate an aquarium) that rise through the liquid and is thereby exposed to the virucidal properties of either HOCl or the UV-C light.
This air is then fed through another tube lined with UV-C light, and from here it can be feed into another loop with new container filled with HOCl or vented through a HEPA filter or even connected to a rooms exhaust ventilation if the room is negatively pressured.
Please see the schematic below for more detail.
Why UV-C?
The use of UV-C irradiation as a germicidal to inactivate airborne viruses has been known for a long time (2) and UV-C has been suggested, because it is a known process to mitigate the transmission of airborne viruses, to be used as a bioterrorism countermeasure (3).
Using UV-C to kill viruses is called Ultraviolet Germicidal Irradiation (UVGI) and it has been tested on many different viruses (ssRNA, ssDNA, dsRNA and dsDNA) where it has shown that ssRNA and ssDNA were more susceptible to UV inactivation (4). SARS-CoV-2 belongs to the broad family of viruses known as coronaviruses. It is a positive-sense single-stranded RNA (+ssRNA) virus, with a single linear RNA segment and a crown like appearance under an electron microscope (5).
The reason we are using so much UV-C LED inside the tubes is because the relative strength of UV-C to deactivate SARS-CoV-2 is not established. But what is known since before is that when RH goes up, so must the dose of UV-C to achieve the same effect. (6, 7)
Is this a complete machine/system?
No, it is not a complete system, but this is intended for inspiration so that others can adapt it and start using BiPAP/CPAP machines safely so that many more ventilators can be freed up for the most serious COVID-19 patients.
