We are in the process of opening a Wound Care and Hyperbaric’s clinic and were looking for a few documents to have on file.  We are wondering if you had a list of approved cleaners for the acrylic?

The UHMS safety committee can provide information but the ultimate responsibility for these types of questions is with the  safety director of your facility.

Regarding Approved cleaners for acrylic. 

• The manufacturers commonly specify what you can use to clean the acrylic windows on the monoplace and multiplace, Sechrist attached. We recommend that you contact the chamber manufacturer for their most current recommendation.
• The American Society of Mechanical Engineers, Safety Standard for Pressure Vessels for Human Occupancy: In-Service Guidelines, ASME-PVHO-2-2012 edition, Mandatory Appendices V, Partial list of harmful substances and acceptable products, pg 35, lists acceptable cleaners as well.  We recommend that you obtain this document for your library.
• Your facilities infection control needs to be engaged with this process, for example, the CDC recommends a 10% bleach solution for a C-Diff clean up.

Does the patient air mask and ground bracelet need to be disposed of after the patient finishes their HBO treatment cycle or can they be cleaned with disinfectant and used again?

Thank you for your question. The UHMS HBO2 safety committee can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the medical director and safety director of your facility.

Regarding:  Disposal or disinfection of the patient air break assembly and ground bracelet.

The instructions for use from the manufacture of the device, the facility’s infection prevention and control department policies, and hyperbaric medicine staff will all be utilized to determine the procedure based on the type of device used. The answer(s) will depend on the type of air break assembly and patient grounding device used, and the type of patient being treated. For example, if you are hospital based and have a patient that is in isolation your procedures will most likely be different that if you are an out-patient facility. 

1. If using a disposable mask and/or grounding bracelet: it is single patient use (label it for that patient, clean as per infection prevention and control policies and dispose of it at the end of the care plan).
2. If using a reusable air break assembly and/or grounding bracelet: have it cleaned per your institution’s cleaning procedures.
   1. With the demand valve style of air break mask, there is a recommendation that a bio-filter to be inserter between the oral/nasal mask or mouth piece and the demand valve. Consider issuing the re-usable oral/nasal mask or mouth piece to the patient for the duration of the patient care plan, then send the device to Central Sterilization before placing back into service for the next HBO₂

DISCLAIMER
Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet. If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility. Information provided on this forum is for general educational purposes only. It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

We have a patient who meets the treatment criteria for hyperbaric medicine however their home is infested with bed bugs. What recommendations can you make so that the chamber is not contaminated for the next patient?

Thank you for your question. The UHMS hyperbaric oxygen safety committee (SC) can provide information, but the ultimate responsibility for these types of questions is the medical director and safety director of your facility.

Regarding: The recommendations for avoiding a bed bug (Cimex lectularius) contamination in the hyperbaric chamber

The question does not identify what type of chamber it is. There are different concerns with monoplace and multiplace chambers. Addressing a bed bug contamination is not unique to hyperbaric chambers and we would encourage you to follow the infection control procedures of your institution. This is a serious issue, none of us want to be part of a hospital-acquired bed bug infestation, and we must protect our staff and other patients.  We encourage you to work with the chamber manufacturer to ensure any products used to clean the chamber are safe to use. We are aware of at least one facility that lost a monoplace chamber due to an exterminator using steam on the acrylic. The use of steam to clean a bed bug infestation in the monoplace chamber is not advised. ASME PVHO-1 acrylic is a low-temperature product and commonly rated for a minimum of around 50 degrees F and a maximum of about 125 degrees F, depending on design or manufacturer. Steam or cryogenics could be considered for a multiplace chamber if the acrylic windows are protected. Consider engaging social work/family support services and facility leadership to address the home issues.

 Things to consider:

• Bed bugs are not “jumpers,” they fall. For example, they do not jump from a patient to a gurney, instead they fall off the patient onto the gurney
• Two common items that transport bed bugs from the home to the hospital/clinic are wheelchairs and gurneys.
  • Patients that arrive via wheelchair or gurney should be transferred, if possible, to a clean hospital wheelchair or gurney.
    • The hospital wheelchair or gurney must be inspected and cleaned post use.
  • Have a patient change in a controlled room and place their belongings into a securable bag.
  • Inspect the patient’s dressing for bed bugs as they like to hide in folds and creases of linen and other materials.
  • Post-treatment; inspect the chamber with a high lumen flashlight. You are looking for black specs or moving bugs.
  • Post-treatment; don appropriate personal protective equipment to keep bugs from attaching to you, then enter the chamber and remove bugs by wiping and consider vacuuming the mattress, pillows, and area between the seal and acrylic. Remember – they do not jump.
  • Post-treatment; inspect the chamber mattress with a high lumen flashlight. You are looking for black specs or moving bugs. Also, examine the folds, creases, and zipper flaps of the mattress.
  • Post-treatment cleaning of the hyperbaric suite: The Hyperbaric Safety Director should be present to oversee the cleanup of the hyperbaric suite. Extreme care is to be used around the acrylic.
  • Cleaning solutions and disinfectants, approved for hyperbaric chambers, do not kill bed bugs. Instead, the best method of elimination from inside the chamber is by removal.
  • Inform the hospital cleaning staff or exterminators that steam cleaning is not to be performed on the chamber’s acrylic windows as steam will severely damage the acrylic.
  • Inform the hospital cleaning staff or exterminators that cryogenic fluids are not to be used on the chamber’s acrylic windows, as the extreme cold will damage the acrylic.
  • If possible, treat this patient in the last treatment block of the day; this will allow for the extending cleaning and inspection time without interfering with the other scheduled treatment times.
  • Also, ask the hospital’s exterminator for a protective mattress liner. For example, ActiveGuard®Mattress* Liner.
    • ActiveGuard is intended to be placed on a mattress and left on for eight weeks and up to two-years depending on the severity of infestation or presence of bed bugs.
    • ActiveGuard has a chemical that kills dust mites and bed bugs, but the liner itself will need to be evaluated by the HBO₂ Safety Director and Physician in Charge for acceptance during a treatment. One option is to place the liner on the mattress at the end of the day’s treatments and remove the linen just prior to the next day’s treatments.

*ActiveGuard is mentioned as this is the only mattress liner known to the UHMS SC as one that kills bed bugs.

DISCLAIMER
Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

I am a Registered Nurse/Hyperbaric Tech and we are preparing for a Joint Commission survey within the next few months and one of the questions that we might have to answer is how do we properly clean a chamber after a patient with CDIFF? Since we have never had a patient with this illness, we are unsure how to answer. We currently clean our chambers with Sani-Cloth HB, however CDIFF is not listed as one of the microorganisms that this particular product is effective against. I have heard from another sour

Thank you for your question. The UHMS hyperbaric oxygen safety committee (SC) can provide information but the ultimate responsibility for these types of questions is with the medical director and safety director of your facility.

Regarding: Cleaning the chamber after a patient with Clostridium Difficile (Cdiff).

The type of chamber was not identified in the question. There are different concerns with the monoplace and multiplace chambers. You are correct in stating that the Sani-Cloth HB is not effective in killing the Cdiff spore. The Centers for Disease Control (CDC) recommends a 10% bleach solution as an effective way to kill the spore. 

Regardless of the type of chamber we encourage the facility to work with their infection control and risk departments to develop a procedure that works for the types of chamber(s) utilized and types of patients treated. It is not just the chambers, a procedure should cover all contact surfaces, BP cuffs, thermometers, stethoscopes, handwashing, care of the linen, (do you allow adult diapers),  etc. Consider what you define as a Cdiff exposure, is the infection active and is the patient on medication for it?

The Center for Disease Control and the Environmental Protection Agency have published several articles stating that it is more important to “mechanically wipe or remove the organisms than to kill the organisms.” This method has been used by hyperbaric facilities for decades with no adverse events reported.

To kill the spore use a bleach solution at a concentration approved by the chamber/acrylic manufacturer.  Always check with the chamber manufacturer regarding what approved products they recommend. Several chamber manufactures do allow hypo-chlorite solutions such as the 10% bleach mixture to come into contact with their acrylic windows. The ASME PVHO-2 lists a 10% hypochlorite solution as one of the approved cleaners for acrylic. Attached is a copy of Appendix 19A and 19C of Jerry Stachiw’s book, Handbook of Acrylics. It shows bleach, no-crazing after 12-hrs duration and 2000 psi flex stress. The solution concentration that he used however, was extremely dilute. The unstressed situation was 10% concentration with no effect after one-year.

The primary concern between the mechanical scrubbing of the chamber with a detergent to remove the spore and using bleach to kill the spore after a Cdiff exposure, is the ventilation. It is much easier to use the bleach wipes in the multiplace than the monoplace due to the size and ability to ventilate the multiplace chamber atmosphere. There have been reported incidents of staff exposure to bleach causing respiratory problems, not only in hyperbaric facilities but in environmental services and employees caring for swimming pools. 

Considerations include:

1. Work with your Infection Control and the Environment of Care Committee
2. There are known respiratory concerns for staff (and patients) when using bleach and adequate personal protection equipment must be provided. 
3. Note contact time, the solution used must be allowed adequate “wet” time to kill the spore. The directions for use will describe the minimum time, 4 minutes, 5 minutes, and so on.
4. Follow up with a fresh water rinse. (Don’t let the bleach solution stand to long without rinse). Bleach will leave a film on the acrylic that will need to be removed. This requires additional time and effort to insure the acrylic is clean and optically clear.
5. Understand items/issues from ASME/PVHO-2-2016 ("Section 2" and "Mandatory Appendix V, Partial List of Harmful Substances and Acceptable Products")  It also gives information on other issues when using cleaners.
   1. Temperature considerations.
   2. Chamber should not be under pressure.
   3. Application material (soft cloth, etc.)
   4. Apply solution to soft cloth first, not directly on acrylic.
   5. No power buffers.
   6. Don't fixate on just the active ingredients. (perfumes, colorants, etc. can also be contraindicated)

ARTICLES OF INTEREST:

• LINK LIBRARY FOR LABORATORIES, HOSPITALS & OTHER INSTITUTIONS
  Nosocomial Infections: C. Difficile
  Sodium Hypochlorite Bleach for The Control And Prevention of Clostridium difficile in Healthcare Facilities
• Sechrist: CARE AND DISINFECTION OF THE CHAMBER AND GURNEY
• Appendix 19A: Effect of Cleaners and Disinfectants on stress crazing initiation
• Perry: Approved Clensers
• Clostridium difficile (CDI) Infections Toolkit

DISCLAIMER
Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

Have the protocals for cleaning the chambers and disinfection changed in light of the COVID-19 outbreak?

Date Posted: 3/17/2020

Question: Have the protocals for cleaning the chambers and disinfection changed in light of the COVID-19 outbreak?

Thank you for your question. The UHMS HBO₂ safety committee (UHMS-SC)  can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the Medical Director and Hyperbaric Safety Director (MD & HSD) of your facility.

The UHMS-SC directs all hyperbaric practices to follow the guidance of the Centers for Disease Control (CDC) along with guidance from the Hyperbaric Chamber Manufacturer, State and local health agencies, and your hospital infection prevention and control group. All of these sources will impact the decision for your practice. Your choice should be a decision made between the MD & HSD of your program. The UHMS-SC can provide guidance based upon existing literature available to the public, but does not endorse a particular product or procedure.

The CDC has released a list of items as identified by the Environmental Protection Agency (EPA) that can be utilized for disinfection, stating that:

“Products with EPA-approved emerging viral pathogens are expected to be effective against COVID-19 based on data for harder to kill viruses. Follow the manufacturer’s instructions for all cleaning and disinfection products (e.g., concentration, application method and contact time, etc.).”

It is important to note that many of the items within the EPA’s list may be unsafe to utilize on acrylic surfaces. It is important to reach out to your specific chamber manufacturer for further guidance. In all cases, it is important to follow the guidance of the product’s manufacturer for application and contact time.

For non-acrylic surfaces, The UHMS-SC advises you follow the guidance of your hospital’s infection prevention and control department to identify a particular product that is known to be effective against COVID-19.

Regarding protocols for cleaning chamber surfaces, hyperbaric facilities should follow the protocols set forth by their institution. Dr. Jim Chimiak, Medical Director at the Divers Alert Network states: “There are no special recommendations that we are aware of for chamber attendants or for disinfection of the hyperbaric chamber and BIBs in light of the COVID-19 pandemic. The usual disinfection protocols are more than sufficient to kill COVID-19, in the unlikely event that it would be present.”

References:

EPA.gov, “List N: Disinfectants for Use Against SARS-CoV-2,” Accessed 3/17/2020

https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2

Sechrist Industries, “CARE AND DISINFECTION OF THE CHAMBER AND GURNEY,” Accessed 3/17/2020

https://sechristusa.com/wp-content/uploads/2018/09/Approved-Chamber-Disinfectants.pdf

Perry Baromedical, “PERRY GUIDANCE ON COVID-19,” Accessed 3/17/2020

https://perrybaromedical.com/uncategorized/perry-guidance-on-covid-19/

Divers Alert network, “DAN ENCOURAGES DIVERS AND DIVE OPERATORS TO PROPERLY DISINFECT DIVE GEAR,” Accessed 3/17/2020

https://www.diversalertnetwork.org/news/dan-encourages-divers-and-dive-operators-to-properly-disinfect-dive-gear

Respectfully,

The UHMS Safety Committee

 DISCLAIMER

Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

It seems that COVID-19 has now reached the shores of Europe in full swing and although the UK has left Europe, Europeans are still plentiful in the UK and UK travellers and visitors are exposed to this new virus. What PPE has been tested to be safe under pressure? What cleaning products would be recommended after treating an infected patient? .

Date Posted: 3/17/2020

Thank you for your question. The UHMS HBO₂ safety committee (UHMS-SC)  can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the Medical Director and Hyperbaric Safety Director (MD & HSD) of your facility.

The UHMS-SC directs all hyperbaric practices to follow the guidance of the Centers for Disease Control (CDC) along with guidance from the Hyperbaric Chamber Manufacturer, State and local health agencies, and your hospital infection prevention and control group. All of these sources will impact the decision for your practice. Your choice should be a decision made between the MD & HSD of your program. The UHMS-SC can provide guidance based upon existing literature available to the public, but does not endorse a particular product or procedure.

The CDC has released a list of items as identified by the Environmental Protection Agency (EPA) that can be utilized for disinfection, stating that:

“Products with EPA-approved emerging viral pathogens are expected to be effective against COVID-19 based on data for harder to kill viruses. Follow the manufacturer’s instructions for all cleaning and disinfection products (e.g., concentration, application method and contact time, etc.).”

It is important to note that many of the items within the EPA’s list may be unsafe to utilize on acrylic surfaces. It is important to reach out to your specific chamber manufacturer for further guidance. In all cases, it is important to follow the guidance of the product’s manufacturer for application and contact time.

For non-acrylic surfaces, The UHMS-SC advises you follow the guidance of your hospital’s infection prevention and control department to identify a particular product that is known to be effective against COVID-19.

Regarding protocols for cleaning chamber surfaces, hyperbaric facilities should follow the protocols set forth by their institution. Dr. Jim Chimiak, Medical Director at the Divers Alert Network states: “There are no special recommendations that we are aware of for chamber attendants or for disinfection of the hyperbaric chamber and BIBs in light of the COVID-19 pandemic. The usual disinfection protocols are more than sufficient to kill COVID-19, in the unlikely event that it would be present.”

References:

EPA.gov, “List N: Disinfectants for Use Against SARS-CoV-2,” Accessed 3/17/2020

https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2

Sechrist Industries, “CARE AND DISINFECTION OF THE CHAMBER AND GURNEY,” Accessed 3/17/2020

https://sechristusa.com/wp-content/uploads/2018/09/Approved-Chamber-Disinfectants.pdf

Perry Baromedical, “PERRY GUIDANCE ON COVID-19,” Accessed 3/17/2020

https://perrybaromedical.com/uncategorized/perry-guidance-on-covid-19/

Divers Alert network, “DAN ENCOURAGES DIVERS AND DIVE OPERATORS TO PROPERLY DISINFECT DIVE GEAR,” Accessed 3/17/2020

https://www.diversalertnetwork.org/news/dan-encourages-divers-and-dive-operators-to-properly-disinfect-dive-gear

Respectfully,

The UHMS Safety Committee

 DISCLAIMER

Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

We started our Hyperbaric Chamber Service in Hong Kong in September 2018 and was running both elective and emergency cases smoothly. In view of NCoV in Hong Kong, though we screened patients for the treatment, there is concern of infection control issue to the inside attendants. I was wondering if Surgical Mask could be used inside multichamber with treatment pressure of 2.4ATA and duration of 125 minutes. There would be meeting with the Hyperbaric Director, Bio-engineering and Technologist week later

Posted: 3/18/2020

MEDFAQ Question: We started our Hyperbaric Chamber Service in Hong Kong in September 2018 and was running both elective and emergency cases smoothly.   In view of NCoV in Hong Kong, though we screened patients for the treatment, there is concern of infection control issue to the inside attendants.  I was wondering if Surgical Mask could be used inside multichamber with treatment pressure of 2.4ATA and duration of 125 minutes.  There would be meeting with the Hyperbaric Director, Bio-engineering and Technologist week later and I would like to seek expert opinion in this perspective.

Thank you for your question. The UHMS HBO₂ Safety Committee can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the Medical Director and Hyperbaric Safety Director (HSD) of your facility.

Users of many products that are considered for use in the hyperbaric environment are not likely to receive permission from the manufacturer, just as clothing manufacturers will not usually “approve” items for hyperbaric exposure. This decision is often left to the end-user of the product.

There are no obvious mechanical or physiological risks that present with using such a device inside a chamber. The only risk of concern would then be fire.

Perceivably, in a 21% oxygen (AIR) environment, the risk of synthetic fabrics may be reduced compared to the 100% oxygen environment where individuals are required to be grounded. However, due to the increased safety risk to the inside attendant of NOT wearing the mask, it would be reasonable to allow the mask into the chamber for the inside attendant/s to use, provided that the oxygen concentration is limited to less than 23.5% oxygen and the atmosphere is ventilated per NFPA 99, Chapter 14 (2018) 14.2.4.1.1 – 14.2.4.1.2. Also, the mask will quickly become humid as a result of the attendant’s respiration, further reducing the possibility of combustion.

It is suggested that a proper risk assessment be initiated by the HSD or coordinator of your hyperbaric program. A risk assessment procedure found in section A14.3.1.6.4.3 of NFPA 99 is written for hyperbaric wound dressings, but the process is useful for other items as well. The HSD should consider using this risk assessment process when deciding which materials may be allowed in the hyperbaric environment. Furthermore, section 14.3.1.6.4.4 calls for written approval by the HSD and the Medical Director for allowance of items normally prohibited. In all cases, it is important to follow the guidance of federal, state and local health agencies and your hospital infection prevention and control group.

For your convenience, the National Fire Protection Association offers a public read-only version of NFPA 99 (2018). You may access this document by visiting the following site:

https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=99

Respectfully,

The UHMS Safety Committee

 DISCLAIMER

Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

What is the risk of airborne droplet transmission from the exhaust of a Monoplace chamber? What elements of risk mitigation (i.e. filters, distance, exhaust location) should be considered?

Date:       5/5/2020

Question: What is the risk of airborne droplet transmission from the exhaust of a Monoplace chamber? What elements of risk mitigation (i.e. filters, distance, exhaust location) should be considered?

Answer:  Thank you for your question. The UHMS HBO2 safety committee can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the medical director and safety director of your facility.

It must first be known that the UHMS Safety Committee cannot definitively answer your specific question of risk without knowing a myriad of factors surrounding the construction of your facility’s exhaust system. Other factors such as the height of the exhaust, wind, temperature, humidity, and variations in ventilation rate may impact the ability of the droplets to travel the length of the exhaust. Even with these factors, we assume there may remain an element of uncertainty, as serial cultures and viral concentration measurements in several locations would be necessary to validate any mitigation measures. In any case, we would encourage you to work with your chamber manufacturer, infection prevention specialists and facilities management teams to determine the best course of action.

We encourage you to review these additional comments from the committee that may assist you in the risk assessment ⁽¹⁾ and decision-making process:

• There is speculation that the droplets will likely salt out on the inside of the exhaust pipe.
• The exhaust point is typically found on the rooftop of a building, and should not be considered a serious concern, as the location is usually a great distance from the general population.
• Monoplace chambers have moisture and particulate filtration on the supply side to protect pneumatic gauges, regulators and valves (PVHO-1, 4-4.3). On the exhaust side, PVHO-1 requires a screen to prevent exhaust blockage, and NFPA 99, 14 14.2.11.2.4 calls for the installation of a 0.3cm² screen to protect the exhaust endpoint. Neither of these items would serve as filters in the infection control sense.
• If the user were to add exhaust-side filters of the same materials used in the N95 respirator, there would be a risk to the chamber’s ability to ventilate and decompress capably. Any attempt to modify the existing exhaust system should be done only with approval of the chamber manufacturer. Alterations like these would also require testing of the decompression capability and documentation describing the testing measures used, along with approval from the manufacturer. The measure is possible, but may be seen as excessive, as this measure is not a current requirement concerning the delivery of Hyperbaric Oxygen to patients with other highly infectious diseases.
• It is noted that sea-level negative pressure rooms within hospitals require the point of exhaust, without HEPA filtration, to be 25 feet away from potentially contacting the general population (Ventilation of Healthcare Facilities - ASHRAE Standard 170).
• Other factors include particulate size. The Diver’s Alert Network has investigated this to understand the effectiveness of face masks and the output of compressed breathing air filter systems. The particles range from 4µm down to 0.5µm. From the research found on virus particles (not specifically SARS CoV2), 42% of particles were smaller than 1µm. Here is one source. To quote: “RNA was detected in coughs from 38 (81%) of the 47 subjects who had flu. The RNA was found in 35% of particles larger than 4 microns in diameter, 23% of particles 1 to 4 microns in diameter, and 42% in particles smaller than 1 micron.” Compressed air filters don’t really remove particles smaller than 1µm. However, the N95 respirator can remove up to 95% of particles as small as 0.3 µm. 99.5% for particles down to 0.75µm.
• Transmission of droplets: there would need to be some studies, but firstly the air/oxygen leaving the chamber is going to be cooler due to the pressure drop from chamber pressure to the 1 psi regulated outlet pressure (adiabatic cooling from the pressure change and some Joule-Thompson cooling from orifices in the flow path). We have actually seen this when decompressing a monoplace chamber rapidly – ice forming at the exhaust screen. This will/should cause droplets to fall out faster and rest on the piping (and associated pressure controls in the exhaust system). Secondly, the longer they travel, the more of them are going to fall out – friction on the piping, temperature, impact at the bends and so on; however, some particles will likely make it to the exhaust outlet. Lastly, this argument is with respect to droplets and does not address airborne transmission. Droplets, which have greater mass, will be more likely to settle at some stage due to the gravitational effects.
• Exhaust outlet concerns: Physical distancing of at least 6 feet is generally accepted; however this may be insufficient as some claim these droplets can exist in the air for up to 30 minutes before dropping. Additionally, temperature and turbulence will affect these results as will the exit speed of the droplets and wind effects which may carry them further. A higher temperature at the exit will also serve to keep them from coalescing.
• It is perceived that a safe distance from the exhaust point could be 30 feet. This is based upon comments from infectious disease specialists including Dr. Anthony Fauci, who stated that in extreme cases, sneezing in patients with significant viral loading can project particles into the air up to 27 feet. A typical monoplace chamber exhaust ranges from 85 to 400 lpm, and human exhalation may deliver 6 – 25 lpm (rest to active). In the chamber you’d expect a dilution of 6/85 at the minimum flow rates. Ventilating the chamber at 250 lpm may provide a dilution of approximately 3%. This in combination with the adiabatic and Joule-Thompson cooling, and the length of the exhaust piping (which if it has any metallic section is going to cause the droplet to stick to the wall more easily), would make it highly unlikely for someone to be significantly exposed.
• It is likely that the exhaust from a monoplace chamber is akin to hospital HVAC exhaust due to its general location (rooftops in most instances). Because of this, there should be minimal exposure to patients, staff or the public at large. If the facility and the safety director have done their due diligence and ensured that NFPA-99 guidelines have been followed for installation of the chamber exhaust, then there should be minimal risk due to this distancing. While the intent of NFPA-99 regarding exhaust requirements was for fire safety, they also serve to help mitigate infection control risks.

14.2.11.2* Exhaust from all classes of chambers shall be piped outside of the building.

14.2.11.2.1 Each Class B chamber shall have an independent exhaust line.

14.2.11.2.2 The point of exhaust shall not create a hazard.

14.2.11.2.3 The point of exhaust shall not allow reentry of gases into the building.

References

Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities. San Antonio, TX: International ATMO, Inc.

The American Society of Mechanical Engineers. (2019). ASME PVHO-1-2019: Safety Standard for Pressure Vessels for Human Occupancy. Two Park Avenue, New York, NY

National Fire Protection Agency (NFPA). (2018). NFPA 99 2018 Edition: Health Care Facilities Code. Quincy, Massachusetts.

N Engl J Med (2020). “Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1,” April 16, 2020, 382:1564-1567, DOI: 10.1056/NEJMc2004973

Bourouiba, L. (2020), “Turbulent Gas Clouds and Respiratory Pathogen Emissions: Potential Implications for Reducing Transmission of COVID-19,” Published online March 26, 2020, Journal of the American Medical Association, doi:10.1001/jama.2020.4756

Lindsley, W. (2010). “Measurements of Airborne Influenza Virus in Aerosol Particles from Human Coughs,” November 30, 2010, PLOS One, https://doi.org/10.1371/journal.pone.0015100

American Society of Heating, Refrigeration, and Air-Conditioning Engineers (2017), “Ventilation of Healthcare Facilities - ASHRAE Standard 170 -2017,” American Society of Heating, Refrigeration, and Air-Conditioning Engineers, www.ashrae.org

Respectfully,

The UHMS Safety Committee

DISCLAIMER

Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet.  If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility.  Information provided on this forum is for general educational purposes only.  It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

I am seeking clarification on the frequency of terminal clean for monoplace chambers with regards to Covid. I independently implemented a terminal clean policy after each treatment in our monoplace chambers once Covid became a concern in the US. However, I am finding that this practice is putting my staff at risk for injury due to the strenuous and repetitive action required to clean the acrylic. With 6 chambers we are cleaning several times a day rather than the usual once a week for each chamber. We hav

Posted: 9/15/2020

Q:  
I am seeking clarification on the frequency of terminal clean for monoplace chambers with regards to Covid. I independently implemented a terminal clean policy after each treatment in our monoplace chambers once Covid became a concern in the US. However, I am finding that this practice is putting my staff at risk for injury due to the strenuous and repetitive action required to clean the acrylic. With 6 chambers we are cleaning several times a day rather than the usual once a week for each chamber. We have not had any of our HBOT patients present with symptoms of Covid nor have any been positive. To get to the point: What is the recommendation for a terminal clean on monoplace chambers for patients who are asymptomatic or negative – that do not present with a concern for Covid?

A:
Thank you for your question. The UHMS HBO2 Safety Committee can provide information to assist you in answering your question, but the ultimate responsibility for these types of questions rests with the Medical Director and Safety Director of your facility.

The HBO₂ Safety Committee recommends that the monoplace chamber interior is cleaned after each patient use with the proper cleansing agents identified within the references below and in accordance with your local infection control advisors. We consider these to be universal precautions (similar to the disinfection of a hospital room, blood pressure cuff or exam table). This action provides protection for patients and staff who may come into contact with infectious organisms.

You may wish to consider the following elements of risk identified by several of our safety committee members:

• We recommend replacing the linen and fresh patient garments between each patient therapy.
• An extra duty cycle of detail cleaning should be done on a regular basis, (i.e. polish the acrylic, external surfaces, eliminate dust, etc.)
• The risks to staff should be considered, as bleach is a known respiratory irritant and cleaning with a hydrochloride solution after a C-Diff exposure is a good example of the need for PPE for your staff.
• Some members identified the need to focus on the contact areas of the chamber (i.e. rails, contact points of the mattress and pillow, air break assembly, and any surfaces that patients or staff may have contacted).
• Consider that exhalation and aerosolized droplets is the main spreader of the COVID-19 virus, and most monoplace chambers are designed with a unidirectional flow from head to foot. Since the exhaust travels one-way, droplets cannot circulate back through the outlet system. Therefore the areas of greatest concern are where the next patient could touch something that was touched or breathed upon by a previous patient.
• It is logical to inform patients to try not to touch the acrylic tube and then their faces as a mitigating measure to reduce the risk of transmission.
• COVID-19 infection by contact is rare – certainly versus inhalation – and is usually countered with good hand-hygiene and surface cleansing prior to the start of therapy (excluding alcohol-based agents).

References and Related Works:

• UHMS HBO2 Safety Committee Response to MEDFAQ – “Have the protocols for cleaning the chambers and disinfection changed in light of the COVID-19 outbreak?” Date Posted: 3/17/2020, Undersea and Hyperbaric Medical Society
• UHMS Guidelines for infection control, patient treatment, and staff safety considerations related to Hyperbaric Oxygen Therapy (HBO2) in monoplace and multiplace hyperbaric chambers during the novel coronavirus disease (COVID-19) outbreak, Published March 2020, Undersea and Hyperbaric Medical Society
• UHMS HBO2 Safety Committee Response to MEDFAQ – “What is the risk of airborne droplet transmission from the exhaust of a Monoplace chamber? What elements of risk mitigation (i.e. filters, distance, exhaust location) should be considered?” Date Posted: 8/16/2017, Undersea and Hyperbaric Medical Society
• UHMS HBO2 Safety Committee Response to MEDFAQ – “Cleaning the chamber after a patient with Clostridium Difficile (Cdiff)” Date Posted: 8/16/2017, Undersea and Hyperbaric Medical Society
• Mize J, Hamm T, “Cleaning and Disinfection of Hyperbaric Oxygen Monoplace Chamber,” Published 2/13/20, Accessed 9/3/20, Wound Reference, Inc.
• https://sechristusa.com/wp-content/uploads/2018/09/Approved-Chamber-Disinfectants.pdf
• https://perrybaromedical.com/uncategorized/perry-guidance-on-covid-19/
• https://perrybaromedical.com/guidelines-for-cleaning-your-hyperbaric-chamber/
• Centers for Disease Control, “Guideline for Disinfection and Sterilization in Healthcare Facilities,” May, 2019, Accessed 9/3/20
• Centers for Disease Control, “CDC updates COVID-19 transmission webpage to clarify information about types of spread,” May 22nd, 2020, Accessed 9/14/20

Respectfully,

The UHMS HBO₂ Safety Committee

DISCLAIMER
Neither the Undersea and Hyperbaric Medical Society (UHMS) staff nor its members are able to provide medical diagnosis or recommend equipment over the internet. If you have medical concerns about hyperbaric medicine you need to be evaluated by a doctor licensed to practice medicine in your locale, which can provide you professional recommendations for hyperbaric medicine based upon your condition. The responsibility of approving the use of equipment resides with the physician and safety director of the facility. Information provided on this forum is for general educational purposes only. It is not intended to replace the advice of your own health care practitioner and you should not rely upon it as though it were specific medical advice given to you personally.

I work for a charitable therapy centre in the UK providing hyperbaric oxygen therapy. We operate a small, multi place (6 person) mild dose (maximum 2atm) compression chamber where the oxygen is delivered on demand via breathing apparatus. We are looking for some expert advice on the safe decontamination/ disinfection of such a chamber using a bio fogging method. Would you have any information that you please share with us regarding the safe and appropriate bio fogging of hyperbaric chambers or know of w

Posted: 1/19/2021

Q:
I work for a charitable therapy centre in the UK providing hyperbaric oxygen therapy. We operate a small, multi place (6 person) mild dose (maximum 2atm) compression chamber where the oxygen is delivered on demand via breathing apparatus. 

We are looking for some expert advice on the safe decontamination/ disinfection of such a chamber using a bio fogging method. Would you have any information that you please share with us regarding the safe and appropriate bio fogging of hyperbaric chambers or know of who may be able to help? 

A:
Good evening! We are not aware of any fogging agents that have been approved for hyperbaric applications, and we recommend you research the EUBS and UHMS recommendations for updates.

https://www.uhms.org/resources/medfaqs-frequently-asked-questions-faq/safety-technical/161-infection-prevention.html?faq=409
https://www.uhms.org/images/Safety-Articles/ECHM-position-on-HBOT-and-COVID-19-16th-March-2020_1.pdf