Posted: 5/25/23

Q:  Any contraindication treating patient with patent foramen ovale?

A: In the general population 30% of individuals have a PFO. Individuals with a PFO have a slightly increased risk of decompression sickness (DCS). However, the risk of DCS for a patient undergoing hyperbaric oxygen treatment is zero. Thus, for patients undergoing HBO2 treatment the presence of a PFO is irrelevant. 

Posted: 5/19/23

Q: Radiation cystitis withOUT hematuria: One of our urologists would like to refer patients with incapacitating symptoms of radiation cystitis (frequency, urgency, etc) and evidence of "necrosis" on cystoscopy but no gross hematuria. He has anecdotal evidence that these symptoms improve with HBOT. Is there any support from the literature and /or would cystitis withOUT hematuria be covered by Medicare?

A:  From Dr. Helen Gelly, “CMS covers both codes N30.40 and N30.41.”   Please see linked excel spreadsheet for reference.

• Excel spreadsheet: Click Here

Posted: 5/1/23

Q:
Is the Biotronik Iperia 7 DR-T safe for HBO exposure? The manufacturer says: Hyperbaric oxygen therapy (HBOT) for patients with BIOTRONIK CRM devices is not recommended due to the potential for damage or impaired function of the implant after exposure. The physician should conduct a risk-benefit analysis if HBOT treatment is necessary. BIOTRONIK CRM devices are tested at various ambient pressures. The testing conditions vary between different device types and generations; however, device damage has never been experienced as a result of exposure to HBOT. The following product families have been tested in compliance with ISO 14708-2:2012: Edora, Enitra, Enticos, Evity pacemakers and CRT-Ps 40 cycles1 of ambient pressure up to 304 kPa (3.04 bar).

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

The UHMS HBO₂ Safety Committee is not able to endorse hyperbaric exposure of an implanted pacemaker or defibrillator that has not been pressure-tested by the manufacturer to at least the maximum intended treatment pressure.

However, this is a medical decision to be made by the Hyperbaric Medical Director with technical input and risk assessment from the Hyperbaric Safety Director. The manufacturer has indicated that while not tested, they are aware that their devices have been used, and that no adverse events have been reported. If your physician determines that the potential risks are warranted, we recommend that the decision is documented clearly in the patient’s chart and the patient is made aware of the potential risk of damage to the device caused by increased atmospheric pressure that could lead to failure of the device.

REFERENCES:

1. Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc. LINK

2. National Fire Protection Agency (NFPA). (2021). “NFPA 99 2021 Edition: Health Care Facilities Code.” Quincy, Massachusetts. LINK
3. Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Best Publishing Company. LINK

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.

Posted 4/26/2023

Q:
I work with monoplace chamber and am curious to know what the consensus is on whether or not to use alcohol prep pads for capillary finger stick procedures within the same room as the chamber prior to placing patient in for treatment? I understand the risk of alcohol inside the chamber, but my medical director and I cannot come up with a standard procedural policy as to why or why not we can or could not perform the test within the chamber room. Can someone provide the resource location or science stating the possibility of a 2x2 70% alcohol prep pad used on a single digit a few feet from the chamber may or may not have a potential risk of vapor contamination or contribute to a fire hazard? Thank you in advance.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

In the case of 70% isopropyl alcohol pads, this Committee recommends that there is thoughtful control over these items to ensure that they do not end up making their way into the chamber, as alcohol is prohibited in the Class B (monoplace) per NFPA 99 (2021):

14.3.1.6.2.3 Flammable liquids, gases, or vapors shall not be permitted inside any Class B chamber.

We are not aware of any code that would prohibit the use of alcohol prep pads in the room housing the chamber(s). However, this Committee recommends that the facility develops specific processes to this effect, and that pre-treatment safety checks are performed to ensure that the pads are always accounted for prior to commencement of treatments. The medical and safety directors for the facility have the responsibility to develop and enact policies and procedures for hyperbaric operations. It would be wise to consult with the local infection control, laboratory, and risk management teams as you decide the safe and proper practice for your facility.

On flammable vapors near, but not in the chamber:

Outside of the chamber and before the door closes, it may be possible to determine the relative time for alcohol and vapors to evaporate from the skin, thereby reducing the risk of introduction into the chamber. Many Committee members felt that fire risk in this instance is very negligible. Fire triangle: minimal fuel that evaporates over a short time, normobaric air, no heat source.

On alternative solutions:

Out of an abundance of caution with concern that pads may be inadvertently left in the chamber, some class B chamber facilities have removed all alcohol containing products, choosing to use aqueous-based soaps in dispensers, and Benzalkonium Chloride wipes in place of alcohol prep pads. In addition to this, some facilities chose to remove alcohol-containing caps on IV lines, reverting to “scrub the hub” methods. In the case of alcohol hand dispensers near the chambers, there is a risk of damage to the acrylic surfaces of the chamber if they come into direct contact with alcohol-based sanitizer. However, vapor damage to acrylic is very unlikely (See ASME/PVHO-2 mandatory appendix V, partial list of harmful substances and acceptable products).

Regarding source control of prohibited items:

If your facility chooses to use alcohol prep pads for capillary finger stick procedures within the same room as the chamber prior to treatment, we recommend that the alcohol prep pad is policed as part of a pre-treatment safety checklist to ensure that no prohibited items end up in the chamber. It is prudent to establish a process for maintaining repeatability that is acceptable to the safety director and medical director.

Considerations for Multiplace facilities:

Typically, pre-treatment glucose checks are done within the clinic in a nearby staging area. For glucose checks performed mid-treatment, at least two facilities have used the following process:

1. An unsealed cup containing one sealed alcohol prep pad, a pipette, and a lancet is passed through the medical lock of the multiplace chamber.
2. The sample is drawn into the pipette.
3. The cup and all contents are placed back into the medical lock and sent to the surface.
4. The sample is entered into the glucometer at the surface.

This is shown to be an effective way of bypassing in-chamber glucose tests, as some glucometers are not pressure compatible. The Hyperbaric Medical Director and Hyperbaric Safety Director should consult their infection control, laboratory, and risk management teams prior to instituting this as their process.

Respectfully,

The UHMS HBO2 Safety Committee

REFERENCES:

1. Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc. LINK
2. Undersea and Hyperbaric Medical Society, MEDFAQ Response, “Aerosolized Anti-fungal Spray,” Accessed 4/24/2024, LINK
3. Undersea and Hyperbaric Medical Society, MEDFAQ Response, “Protocol Regarding Purell Hand Sanitizer,” Accessed 4/24/2023, LINK
4. Undersea and Hyperbaric Medical Society, MEDFAQ Response, “IV Port Disinfection Caps in the Monoplace or Multiplace Hyperbaric Environment,” Accessed 4/24/2023, LINK
5. Undersea and Hyperbaric Medical Society, MEDFAQ Response, “Use of Alcohol Swabs in the Multiplace Hyperbaric Chamber,” Accessed 4/24/2023, LINK
6. National Fire Protection Agency (NFPA). (2021). “NFPA 99 2021 Edition: Health Care Facilities Code.” Quincy, Massachusetts. LINK
7. Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Best Publishing Company.

 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.

Posted: 2/227/2023

Q:
Can a home infusion system be used in a monoplace chamber? Patient has implanted port.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

Discovery

Upon further review, the device your patient has is an elastomeric pump – an AVANOS C-Series (C100020) Homepump. Upon reaching out to the manufacturer, it was discovered that the company tested a device of the same design many years ago (On-Q Pain infusion device). AVANOS identified that the design of the flow restrictor has not changed. The testing suggested that that the pump would behave as designed while under hyperbaric conditions. Regardless of this finding, the Safety Committee recommends that your Medical Director and Safety Director assess the safety of this device for your particular setting and decide whether or not to add the device to an “approved” or “approved with mitigation” list developed by your program.

Elastomeric Pumps in Hyperbaric Settings

We are aware of several published reports of the performance of other elastomeric pumps in hyperbaric settings. Some results show a safe delivery of the medications with no adverse outcomes. Other reports with a separate make and model show a slight decrease in delivery rate. The UHMS HBO₂ Safety Committee has responded to a similar question about the Braun Easypump several years ago. In your case, the information received by that manufacturer should provide some assurance that the pump will function as it was designed.

Response and General Approach to Equipment Evaluation

We would encourage you to first determine the necessity of the item for the time duration required to complete the therapy. Oftentimes, antibiotics may be delayed or briefly interrupted without negative outcomes. If it is possible and safe to delay either the HBO Therapy or the infusion, we would recommend this approach.

If you are considering the option to test this device for safe use within the hyperbaric environment, we can provide you with specific resources that may assist you in your evaluation process. This information not an

endorsement by the UHMS HBO2 Safety Committee for the use of this device in the hyperbaric environment. Rather, we hope that you will consider these suggestions in your individual approach:

• We strongly encourage a formal risk assessment of the device, with assistance from your hospital biomedical engineering group and perhaps your hospital safety or legal teams.
• If you discover that the device has been tested previously under hyperbaric conditions, we suggest that this may be utilized as validation of your final assessment, but we do not recommend that this is the entirety of device approval. Simply put, we recommend a formal risk assessment regardless of testing methods. (Exception: Modern ICD’s and Pacemakers are commonly tested by the manufacturer for function under pressure. Therefore, use under increased atmospheric conditions does not constitute an off-label use of those devices.)
• Consider reaching out to the manufacturer to learn more about the device, especially if there are limited performance details/specifications in the product manual.
• Try to gain an understanding of what types of stress the device was subjected to during the manufacturing and testing phase.
• You may wish to make the manufacturer aware of your intentions or you may remain anonymous.
• Regardless of the manufacturer’s response, there may be good reason for you to proceed with the evaluation, as this device may be vital to the continuum of care to the patient.
• It should be noted that any modifications to the device or use other than as recommended by the manufacturer risks voiding any warranty on the product.
• If evaluating a medical device, it is understood that few are intended to be used in the Multiplace hyperbaric environment. Therefore, consider that such use will likely fall into the FDA category of "Off-Label" and Investigational Use Of Marketed Drugs, Biologics, and Medical Devices “. You may also wish to review gov: Frequently Asked Questions about Medical Devices for more information.

NOTE: Regarding medical device evaluation, at least one major academic institution’s legal team with experience in medical device modification has approached the current FDA regulations in the following fashion:

“The program (modification and testing of medical devices for safe use in the hyperbaric environment) is not subject to FDA regulation. FDA regulates manufacturers and not the practice of medicine. Physicians are able to use FDA approved products other than under the labeled indications as long as the physician meets certain criteria. FDA’s statement on this off-label use is as follows:

“Good medical practice and the best interests of the patient require that physicians use legally available drugs, biologics and devices according to their best knowledge and judgment. If physicians use a product for an indication not in the approved labeling, they have the responsibility to be well informed about the product, to base its use on firm scientific rationale and on sound medical evidence, and to maintain records of the product's use and effects. Use of a marketed product in this manner when the intent is the "practice of medicine" does not require the submission of an Investigational New Drug Application (IND), Investigational Device Exemption (IDE) or review by an Institutional Review Board (IRB).”

We hope that this response will assist you in determining the best course of action for your program. Please do not hesitate to reach out to the UHMS HBO₂ Safety Committee if you have any follow-up questions.

Respectfully,

The UHMS HBO₂ Safety Committee

REFERENCES:

Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc.

Burman F, Sheffield R, Posey K. Decision process to assess medical equipment for hyperbaric use. Undersea Hyperb Med. 2009;36:137–44. PMID: 19462753.

Burnett, T., Bhalla, T., Sawardekar, A., & Tobias, J. D. (2011). Performance of the On‐Q pain infusion device during changes in environmental temperature. Pediatric Anesthesia, 21(12), 1231-1233.

Cooper, N (Email Correspondence), “C-Series Info,” AVANOS Corporation. Received 3/24/23

Dohgomori, H., Arikawa, K., Gushiken, T., & Kanmura, Y. (2002). Accuracy of portable infusers under hyperbaric oxygenation conditions. Anaesthesia and intensive care, 30(1), 25-28.

Lewis, I., Smart, D., Brown, B., & Baines, C. (2015). Performance of the Baxter Infusor LV10 under hyperbaric conditions. Diving Hyperb Med, 45, 37-41.

Millar, I. L. (2015). Hyperbaric intensive care technology and equipment. Diving Hyperb Med, 45(1), 50-56.

National Baromedical Society, “Flow Rate of the On-Q PainBuster under Hyperbaric Pressure,” Authored 7/19/2006.

National Fire Protection Agency (NFPA). (2021). NFPA 99 2021 Edition: Health Care Facilities Code. Quincy, Massachusetts. https://www.nfpa.org/

Perks, S., Blake, D. F., Young, D. A., Hardman, J., Brown, L. H., Lewis, I., & Pain, T. (2017). An assessment of the performance of the Baxter elastomeric (LV10) Infusor™ pump under hyperbaric conditions. Diving and Hyperbaric Medicine, 47(1), 33.

Radcliffe, J. J., & Spencer, I. (1994). Performance of the Baxter disposable patient‐controlled analgesia infusor under hyperbaric conditions. Anaesthesia, 49(9), 796-797.

Salman, D., Barton, S., & Nabhani-Gebara, S. (2013). Effect of environmental conditions on performance of elastomeric pumps. American Journal of Health-System Pharmacy, 70(13), 1100-1100.

Tobias, J. D., Johnson, G. A., & Patel, M. (2011). Performance of the On-Q pain infusion device during hyperbaric therapy. Anesthesia & Analgesia, 113(2), 275-277.

US Food and Drug Administration. (2014). “Off-label” and investigational use of marketed drugs, biologics, and medical devices: information sheet. Silver Spring, MD. LINK

Wang, J. (2013). Effect of environmental conditions on performance of elastomeric pumps--author's reply. American Journal of Health-system Pharmacy: AJHP, 70(13), 1100-1101.

Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Best Publishing Company.

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.

Posted: 4/7/2023

 Q: 
Any concerns with Fentanyl patch in monoplace chambers? Any risk of fire or effect on the delivery rate of fentanyl to the patient from pressure?

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

We understand that there are many hyperbaric programs that allow Fentanyl and other medication patches, in the Class B Monoplace environment, and some that do not. The decision of the Medical Director and Safety Director of your program to allow should be based on a risk assessment of the product. The chief concerns are flammability and the potential for increased medication uptake. 

With respect to the risk of fire, there is little data on the fire risk of transdermal patches. In an attempt to evaluate safety, Lavonas (2006) reviewed the results of a structured literature search, performed an analysis “of the potential for creating fire in the hyperbaric environment was performed using standard chemical and hazardous materials references and formulae at a range of appropriate pressure and FO2 values” and reviewed data from product manufacturers. The results of this study suggest the risk of fire from transdermal patches to be low in both multiplace and monoplace environments (Lavonas, 2006).

Regarding the potential risk of increased medication uptake, this concern is largely based in theory. There are no published evidence-based studies to suggest otherwise. Historically, the concern has been erratic or unpredictable drug absorption rates due to vasoconstriction and adiabatic temperature changes in the hyperbaric environment. One study that examined the effects of scopolamine patches on navy scuba divers found that “no unusual symptoms were seen as function of drug, pressure, or their interaction” (Schwartz, Curley, 1986).

Insight from the experience of our Safety Committee members:

• This question has come and gone for years. Many years ago we removed all patches. For the last 20+ years we have not. We have not observed problems.
• We have always removed them.
• It has been our practice to remove these patches.
• For patients hospitalized in our Intensive Care Unit (part of the Hyperbaric Center), we occasionally use patches with buprenorphine - without any adverse effects during HBOT.
• I cannot recall details, but once upon a time, I heard rumors that after a hyperbaric session in a multiplace chamber (in the other hyperbaric facility), there was red skin under the fentanyl patch, which was interpreted as skin burn due to increased temperature of the patch. Since then, we have been informing patients about this issue, asking them to observe local skin and the pharmacological effect of any patch (analgesic, nicotine, etc).
• I’ve heard the story of the multiplace chamber that got a nurse pregnant because her birth control patch didn’t work appropriately, and nobody told her about the issue while she worked in the chamber, but I’ve never seen this stated or reported in writing anywhere…just an anecdotal story.
• We’ve had no issues with transdermal patches that are gel-based at the dermal interface (e.g., Scopolamine)* or plastic membrane at the dermal interface (e.g., Fentanyl, Nicoderm CQ). The flammability risk was deemed low due to the sealing against the dermal surface and there have been no apparent dosing changes concurrent with HBO pressure changes.
• There is an August, 2014 article reporting two cases of no harm using daily removal (for HBO) and daily re-application of transdermal Fentanyl patches. (Pawasauskas & Perdrizet, 2014)
• I seem to remember receiving training somewhere that transdermal patches with foil dermal interfaces can have their pores altered such that an increased dose is delivered in hyperbaric conditions, but I can’t find that training or any examples of foil transdermal patches. I believe some of the estrogen birth control patches are of this type. There was a 2005 diving discussion board post about this and other transdermal patches with a response from DAN that indicated no dose change would be expected from pressure, but one could be expected from increased temperature water activities such as hot tubs. https://scubaboard.com/community/threads/ortho-evra-birth-control-patch-and-diving.83555/
• We talk about vasoconstriction and vasodilation due to the pressure, but few take into account the ambient temperatures which regulate drug absorption as well. I’m going to posit that these cancel each other . And, we do not prohibit patients with patches going out in 110F temp, or the other extreme 0F. There are no publish studies showing over/under dosing due to ambient temperatures.
• As long as the patient is not compromised on the daily pre-HBOT evaluation, I see no problem leaving the Fentanyl patch in place. I have heard all kinds of arguments for/against, but there isn’t one shred of evidence in the literature. Two articles: Lavonas found that these are not fire risks, and one other paper that removed patches every day and replaced with a fresh patch safely, which raises several other questions:
  • Who in your clinic can remove/replace drug elution patches?
  • What do you do with the patch you just removed? Do you replace the same patch after each treatment (these are 72-hr patches)
  • Who answers to the physician state board of dependent drugs for going through a patch every day?
• So, the answer will be whatever your habit is … without much science. Mine is … I left the patches in place. Never had a patient over-dose during any HBOT treatment.
• I don’t see any fire and clearly no mechanical issues. I checked a SDS and it indicates the product being non-flammable.
• We’ve allowed this patch for 10+ years with no reported adverse effects.

As indicated by the comments above, there is no consensus agreement. Fortunately, there are many studies and case reports available to assist program leaders in making the best decision for their particular practice. We encourage you to review these resources below.

Respectfully,

The UHMS HBO₂ Safety Committee

REFERENCES:

1. Lavonas, E.J. (2006). Safety analysis of transdermal medication delivery systems in the hyperbaric environment [Abstract]. Undersea and Hyperbaric Medical Society.
2. Schwartz, H.J.C., Curley, M.D. (1986). Transdermal scopolamine in the hyperbaric environment [Abstract].
3. Mikaili P, Moloudizargari M, Aghajanshakeri S. (2014). Treatment with topical nitroglycerine may promote the healing process of the diabetic foot ulcers. Medical Hypotheses, 83(2), 172-174. doi: 10.1016/j.mehy.2014.05.002.
4. Coto-Segura, P., Ingelmo, J., Alonso, T., Sanchez-Sambucety, P., Rodriguez-Prieto, M.A. (2007). Effectiveness of topical application of nitoglycerin spray to increase survival of cutaneous flaps and grafts. Actas Demosifilogr, 98, 291-5.
5. Coruh, A., Abaci, K., Gunay, G.K. (2004). Effect of topical nitroglycerine on the survival of ischemic flow-through venous flaps in rabbits. Journal of Reconstructive Microsurgery, 20(3):261-6.
6. Hotkar, M.S., Avachat, A.M., Bhosale, S.S., Oswal, Y.M. (2013). Preliminary investigation of topical nitroglycerin formulations containing natural wound healing agent in diabetes-induced foot ulcer. Internation Wound Journal, ISSN 1742-4801.
7. Pawasauskas, J., Perdrizet, G. (2014). Daily application of transdermal fentanyl patches in patients receiving hyperbaric oxygen therapy. Journal of Pain & Palliative Care Pharmacotherapy, 28, 226-232.
8. Williams, T. H., Wilkinson, A. R., Davis, F. M., & Frampton, C. M. (1988). Effects of transcutaneous scopolamine and depth on diver performance. Undersea biomedical research, 15(2), 89–98.
   
   

 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.

Posted: 3/24/2023

Q
What is current evidence-based recommendation regarding patients wearing soft contact lenses during HBOT? 

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

Gas-permeable contact lenses, both soft and hard styles, will not pose a risk for air trapping under the lens. There have been reports of hard contacts popping out of the eye or causing corneal edema, but these reports are decades old. Literature searches reveal no reports of issues with soft or hard contact lenses in the last 35 years.

Amongst our committee, we are not aware of any facilities that do not allow patients and inside attendants to wear soft and hard contact lenses in the chamber. We can report many years of successful diving, both in-water and in-chambers, without any complications.

REFERENCES:

1. Butler Jr, F. K. (1995). Diving and hyperbaric ophthalmology. Survey of ophthalmology, 39(5), 347-366.
2. Polse, K. A., & Mandell, R. B. (1971). Hyperbaric oxygen effect on corneal edema caused by a contact lens. Optometry and Vision Science, 48(3), 197-200.
3. Simon, D. R., & Bradley, M. E. (1980). Adverse effects of contact lens wear during decompression. JAMA, 244(11), 1213-1214.
4. Socks, J. F., Molinari, J. F., & Rowey, J. L. (1988). Rigid gas permeable contact lenses in hyperbaric environments. Optometry and Vision Science, 65(12), 942-945.

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.

Posted: 3/24/2023

Q:
In a multi-place chamber, with a treatment / dive profile of 2.0 ATA for 90 mins with a standard descent and ascent rate, what is the rationale of offering 15 mins of oxygen breathing at 2ATA (last 15 minutes of bottom time) for the inside tender followed by oxygen decompression (as opposed to air decompression)? This is one of the interventions that is being suggested to minimize DCS risk for the inside tender from one of the facilities. I cannot find any evidence / precedent to support this on a 2ATA for 90 mins dive profile. Even for consecutive dives with a surface interval of approximately 30-50 mins, there is no decompression obligation if US navy tables rev 7 (table 9-7 and 9-8) are followed for the treatment profile. I am being quoted a mix from a combination of US navy tables and nobendem tables to support this recommendation. However, I cannot find relevant and applicable evidence to support this. Is there any rationale to use this? One of the concerns I have from a medical standpoint is potential oxygen toxicity for the inside tender from regular exposure to at least one segment of hyperbaric oxygen 1-2 times a day on a daily basis. Kindly advise / opine. Thank you.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

We have had opportunity to clarify some of the questioner’s information above. The facility “standard” treatment table is an 8 to 10-minute compression to a gauge pressure of 33fsw/2 atmospheres absolute (ATA). Then follows 90 minutes of O₂ breathing by patients without air breaks. The Inside Attendant (IA) breathes chamber air for the entirety of the treatment. Finally, an 8 to 10-minute decompression. The total air exposure time for IA is 110 minutes (not the 90 minutes as stated in the above question).

IAs at this facility are allowed a repetitive exposure to the same profile for a second full treatment in a single day. The unit tries to separate the repetitive exposure by one treatment time, but there are times where the IA has finished the first treatment exposure and is recompressed for a second exposure with only a 60-minute surface interval.

The questions for the Safety Committee are as follows: Is there data to support O₂ breathing by the IA? What is the risk of Oxygen toxicity to the IA for 20 minutes of O₂ breathing at 2.0 ATA pressure? Another question arose during followup discussions with the questioner: What is the risk of Decompression Sickness (DCS) when the IA performs repetitive a back-to-back exposure with no O₂ breathing?

Limitations:

Our literature search will primarily include only references to IA DCS. We will try to limit the data to the 2 ATA specifications of this question, but be aware that some of the reviewed literature deals with 2.36 ATA pressures and that many multiplace chambers perform treatments at 2 ATA, 2.36 ATA, 2.5ATA, 2.8 ATA and sometimes greater as part of their daily routines. IA DCS exposure in this setting will over-estimate the risk of IA DCS in a chamber that strictly limits treatments to 2 ATA.

• There is no literature that addresses repetitive IA exposure in the same clinical day, and/or back-to-back repetitive exposures.
• Every exposure to increased pressure puts the IA at risk of DCS if flying or making an excursion to altitude. While the questioner does not state that this is a problem, we encourage the unit to have a policy/procedure for airline/altitude exposure within 12 to 24 hours after being an IA for hyperbaric treatments.

We will list several case reports and medical decision-making disasters for IAs, but these papers are for interest and not germane to the question at hand. Some of the case reports, while well within acceptable pressure limits, expose risks for DCS considering a patent foramen ovale (PFO), physical stress, caffeine use, age, obesity, dehydration, and other contributing factors.

Finally, we note that the hyperbaric chamber treatment profile is considered a “square profile” and may have potentially higher risk for DCS. This is true when attempting to compare a US Navy (or other wet diving table) to the exposure of a hyperbaric chamber treatment.  

Survey of the Literature:

Johnson-Arbor (2012) describes a case report of IA DCS in a 50-y/o man following a 40fsw wound healing treatment table. Of interest is that the unit did not require any oxygen breathing and had a total dive time of 120 minutes. The IA had participated in more than 200 exposures previously without incident. Following this episode, a transthoracic echocardiogram showed a large PFO with easy bubble shunting. The author suggests 10 to 20 minutes of oxygen breathing as a mitigation technique to decrease nitrogen load prior to chamber decompression.

Witucki, et. al. is a case series report of DCS and Oxygen toxicity between 1983 and 2011 at UCSD Hyperbaric Medicine Center. The IAs work in a mix of pressures from 2 – 6 ATA. Occupational guidelines for this facility limit one hyperbaric exposure within a 12-hour period. Any variation from that guideline is addressed on a case-by-case basis. A minimum of 6 hours surface interval is required for staffing a TT6 and 24 hours after a TT6A. Routine treatments in this facility are 2.4 ATA for 110 minutes (but might be longer or shorter based on clinical circumstances).

When studying the risk of DCS by IA, the UCSD group developed three time-based protocols for IA oxygen breathing: Protocol 1 was for a total treatment time (TTT) less than 80 minutes and requires no O2 breathing; Protocol 2 for TTT between 80 and 119 minutes requires 15 minutes of O₂ breathing; and Protocol 3 was between 120 and 139 minutes for 30 minutes of O₂ breathing. The incidence of IA DCS was zero for all three protocols (total exposures overall were 24,616 and most of these fit Protocol 2). There were no reported oxygen toxicity events for IAs.

Kot, et. al. describes a case report of IA DCS on a 2.5 ATA treatment protocol. According to Polish regulations, this profile (6 minutes compression, 70 minutes at pressure, and 6 minutes decompression) requires no oxygen breathing by the IA. The IA decompression schedules are determined by the same regulations for commercial diving operations. The authors conclude that any hyperbaric exposure is an operational risk for DCS.

Pougnet, et. al. performed a multi-center questionnaire review of DCS risk among IAs. The response rate of the survey was n=73. The time covered was approximately 10 years exposure for each respondent. Each respondent had approximately 200 hyperbaric exposures. The study reports 2 cutaneous DCS cases and 3 cases of DCS. By person, there was a 6.8% risk of DCS, but by exposures, the risk was 0.062%.

Perdrizet (2012), in a commentary paper for UHM Journal discusses limitations on reporting and true risk for IAs during hyperbaric exposure. While this paper does not address the question at hand it is well worth reading for a perspective into overall risk.

Clarke (2017) summarizes the existing literature regarding healthcare worker risk for DCS. We highly recommend this paper for your review. Clarke discusses risk of IA DCS and mitigation interventions by multiple institutions. Almost all of these have IA exposures at 2.36 ATA or higher (and/or in a mixed bag of pressures per IA over time). He discusses IA risk mitigation procedures at various institutions in the world.

There is a section (pg. 517) where 2 ATA exposure is discussed. The nitrogen risk (less than 120 minutes total treatment time) presents a smaller inert gas load. However, he does not address repetitive treatments in the same day. He concludes that adding a 10–20-minute period of oxygen breathing would be a conservative intervention.

One of the senior physicians in the UHMS Safety Committee shared personal information that may not have been published formally. During research for traumatic brain injury (TBI) and HBOT, one IA had been exposed to 2 ATA (at sea level) for 60 minutes (total treatment time) for 4 times in one day. This IA developed DCS and was treated. Using this case as a warning, they initiated O₂ breathing by the IA during the treatment profile.

Oxygen toxicity:

Of all the papers reviewed, there were no reports of oxygen toxicity among inside attendants.

Summary:

While there is available data that may be used to answer the question presented, there will be no clear consensus. We recommend conservative protection for the IA in a hyperbaric environment.

Oxygen is used at many facilities as a safety measure for inside attendants in multiplace chambers. This is done most often at the end of the treatment profile and during decompression. This practice has been called “zero time” as the nitrogen clock essentially stops when breathing oxygen at pressure. Since this practice is not scientifically validated, the use of oxygen should be considered an adjunct and not a sole mechanism to stop the bottom time. Some hyperbaric units continue to use the USN air diving tables as written and as if the IA was breathing air for the entire time, regardless of oxygen use or not. We raise this as an example of inadequate science for IA Oxygen breathing during hyperbaric exposure. In the examples given to answer this question, each unit has somewhat different solutions to the problem of IA DCS due to hyperbaric treatment pressures.

We have demonstrated that the use of oxygen breathing by the IA has shown to be an effective tool in lowering the risk of decompression sickness. We recommend that the unit apply the data presented with the needs of the individual clinic. There is no “one size fits all” solution for this question.

It is important to note that the USN tables are written for the Navy diver subjected to in-water exposures and cases of DCS within these tables are to be expected. The tables are not written for the IA in a hyperbaric air environment, noting that the IA may not be as physically fit as a Navy diver. We do not recommend “pushing” tables to the limits. We suggest always staying well below the limits set in the tables for the hyperbaric IA.

Respectfully,

The UHMS HBO₂ Safety Committee

REFERENCES:

1. Bell, J., Thombs, P. A., Davison, W. J., & Weaver, L. K. (2014). Decompression tables for inside chamber attendants working at altitude. Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc, 41(6), 505-513. LINK
2. Clarke, R. (2017). Health care worker decompression sickness: incidence, risk and mitigation. Undersea & Hyperbaric Medicine: Journal of The Undersea and Hyperbaric Medical Society, Inc, 44(6), 509-519.
3. Johnson-Arbor, K. (2012). Type II decompression sickness in a hyperbaric inside attendant. Undersea & Hyperbaric Medicine, 39(5), 915.
4. Kot, J., Lenkiewicz, E., Lizak, E., Góralczyk, P., & Chreptowicz, U. (2021). Spinal cord decompression sickness in an inside attendant after a standard hyperbaric oxygen treatment session. Diving and Hyperbaric Medicine, 51(1), 103.
5. Naval Sea Systems Command. (2016). US Navy Diving Manual (7th ed.). United States Navy Publication.
6. Pougnet, R., Pougnet, L., Lucas, D., Henckes, A., Loddé, B., & Dewitte, J. D. (2018). Health effects of hyperbaric exposure on chamber attendants: a literature review. International Maritime Health, 69(1), 58-62.
7. Perdrizet, G. A. (2012). Type II DCS in an inside hyperbaric attendant: commentary. Undersea & Hyperbaric Medicine, 39(5), 869.
8. UHMS HBO2 Safety Committee response to MEDFAQ, Accessed 2/28/2023, Originally published 2/2/2017.
9. Witucki, P., Duchnick, J., Neuman, T., & Grover, I. (2013). Incidence of DCS and oxygen toxicity in chamber attendants: a 28-year experience. Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc, 40(4), 345-350.
10. Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Best Publishing Company.
11. Zwart B. (1998) The “Nobendem” air/nitrox decompression profile calculator: a physiologic model extension based on the U.S. Navy standard air decompression tables. LINK

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.

Posted: 1/10/23

Q:
I am an active UHMS member and current medical director of an HBO facility accredited by UHMS, which is located within Portneuf Medical Center. We are planning to build a new HBO facility for 3 individual chambers. I would appreciate it if you could provide information about technical specifications on how to properly build it. Referral to architects, documents or any other valuable information is welcome. Thanks.

A:

I’d like to share the enclosed resources with you and point you towards the Facility Guidelines Institute’s 2022 Guidelines for Design and Construction of Hospitals. (Formerly an AIA guideline) https://www.fgiguidelines.org/

The enclosed documents contain a copy of the 2006, 2010 and 2014 guidelines as references for your information, but I would encourage you to follow the most current edition.

The UHMS Hyperbaric Facility Accreditation Manual is a great resource to prepare your facility with the Best Practice standards observed by the industry. Of course, the NFPA 99 Handbook is also a great reference that every Hyperbaric Facility should own. Finally, there is an older reference - 2004 UHMS Facility Design - that may still have relevance as it rightly concludes in the opening paragraph “there is no national standard for the design of a hyperbaric facility.” Another important factor to consider is that there may be various codes and statutes enforced by Authorities Having Jurisdiction in your area which will impact design. Of note, the State of Idaho has recently released the following statement regarding the construction of hyperbaric facilities: https://doi.idaho.gov/wp-content/uploads/ID/B23-01.pdf

I hope that these resources will assist your facility and I wish you the best of luck in this worthy endeavor. Please reach out to us if you have additional questions.

Regards,

Posted: /17/2023

 Q: 
Is there a protocol for post seizure related to oxygen toxicity? Should a seizure protocol be followed?

A:

I am not sure what the reader means by a “seizure protocol.” If this reference is to an in-patient, I would say yes that any nursing protocol for a seizure patients should be followed probably at least for 24 hours.

Usually, if the patient is an outpatient and the patient is neurologically intact and the seizure activity has stopped, they can be sent home with instructions to a family member to observe the patient more carefully for 24 hours. However, It has always been my policy to refer the outpatient to the ER immediately following the seizure. If the patient’s exposure in hyperbaric oxygen was only to 2.0 or 2.4 ATA, we would have to be concerned that a patient experiencing a seizure without a history of a seizure disorder, may have some reason to have a lower threshold for seizure activity and their workup should be accomplished in the same fashion as for any outpatient reporting to the ER with new onset of seizures. This workup would include blood chemistries including electrolytes and blood sugar as well as a CT scan. About 1/3 of adult patients who have a new onset of seizure disorder are found ultimately to have a brain tumor. Obviously, if the patient has a history of malignancy, the likelihood of a brain mass or masses would increase.

The other case that we would need to be considered is a patient with a known seizure disorder who has a seizure in the chamber during hyperbaric oxygen. Most often this sort of patient is found to not have their anti-convulsant drugs at adequate concentrations in the blood stream to suppress seizure activity. They may not be taking their anticonvulsants as prescribed. Blood tests can be done to assess the adequacy of most drugs. This type of patient should see their neurologist for determination of any changes in dosing or drug type. Interestingly, the most common anti-convulsant in adult patients, Dilantin (phenytoin), is not recommended in textbooks of hyperbaric medicine to suppress oxygen toxicity induced seizures. Barbiturates and benzodiazepines, however, are recommended along with some of the newer anticonvulsant dugs drugs.

Posted: 12/12/2022

Q:
Would it it be possible to email me a copy of the list of the Go / no-Go list of items for HBOT? Or is this an item that needs to be purchased? Would you please let me know? Thank you in advance.

A:

My name is Andrew Melnyczenko, Chair of the UHMS HBO2 Safety Committee. Your question was recently forwarded to me by the Executive Director of the UHMS, Mr. John Peters. The committee would be glad to assist you in answering your question, but please realize that the ultimate responsibility for these types of questions rests with the hyperbaric Medical Director and Safety Director of the associated hyperbaric facility.

As you may be aware, Go/No-Go lists are not universal. They will vary by chamber type and the scope of the facility. These lists are always subject to the risk assessments and decisions made by the local Safety Director and Medical Director of the hyperbaric program. The provision of such a list is not the duty of the UHMS HBO2 Safety Committee, as we cannot dictate the policy and practice of a hyperbaric program. However, the UHMS HBO2 Safety Committee has certainly provided an opinion on many different items in response to various MEDFAQ inquiries. MEDFAQs is a place where common questions related to hyperbaric oxygen therapy are submitted, reviewed by the appropriate UHMS committee, and posted as a benefit to the hyperbaric community.

It is important to note that the safety committee will always steer these responses toward the individual responsibility of the program’s Medical and Safety Director. We lean heavily on the process of risk evaluation and determination of the need for risk mitigation. This pattern is duplicated over and over again in many of our responses.

Perhaps the best examples of this are found within the following links:

1. https://www.uhms.org/resources/medfaqs-frequently-asked-questions-faq/safety-technical/162-item-approval.html?faq=467
2. https://www.uhms.org/resources/medfaqs-frequently-asked-questions-faq/safety-technical/162-item-approval.html?faq=381
3. https://www.uhms.org/resources/medfaqs-frequently-asked-questions-faq/safety-technical/162-item-approval.html?faq=194
4. https://www.uhms.org/resources/medfaqs-frequently-asked-questions-faq/safety-technical/162-item-approval.html?faq=143
5. (2021) NFPA 99, Chapter 14, Appendix A, A.14.3.1.6.4.3.

We hope that the information provided will assist you in answering your question. Please inform us if you have a more specific question about a particular item or topic. Thank you for reaching out to the UHMS and the UHMS HBO2 Safety Committee.

Sincerely,

Andrew Melnyczenko, BSHCA, CHT
Technical and Safety Director – Hyperbaric and Altitude Medicine, Division of Public Health, Infectious Diseases, and Occupational Medicine
Personal: (586) 612-3967
Office: (507) 538-5633
Pager: 127-00651
E-mail: melnyczenko.andrew@mayo.edu

Mayo Clinic
200 First Street SW
Rochester, MN 55905
mayoclinic.org

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.

Posted 1/6/2023

Q:

We have a patient with a failed flap. The patient presented today with dimethyl sulfoxide gel applied to the skin. Does this gel pose any risk to being in the chamber? Dimethyl Sulfoxide is a highly polar organic liquid that is used widely as a chemical solvent and a free radical scavenger. It shows a range of pharmacological activity including analgesia and anti-inflammation. Because of its ability to penetrate biological membranes, it is used as a vehicle for topical application of pharmaceuticals. Dimethyl sulfoxide appears as a clear liquid, essentially odorless. Closed cup flash point 192 °F. Vapors are heavier than air. Contact with the skin may cause stinging and burning and lead to an odor of garlic on the breath. An excellent solvent that can transport toxic solutes through the skin. High vapor concentrations may cause headache, dizziness, and sedation.

A:
The UHMS HBO₂ Safety Committee can provide guidance to assist your decision making the but cannot endorse a specific product for use. The ultimate responsibility for these types of questions rests with the Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility. We recommend that a proper risk assessment be performed by the HMD and HSD; with careful consideration given to the flammability, NFPA 704 rating of the material, amount, potential for vapor release, chamber volume, and the fuel load added to the environment.

In our review, we have found that Dimethyl Sulfoxide Gel (commonly known as DMSO) does appear to have some highly exothermic reactions to certain materials, and as you rightly point out, this product is classified as a flammable solvent. While ignition sources can be controlled in the monoplace hyperbaric setting, there is concern that the gel compound will produce vapors that could potentially ignite in the presence of oxygen under increased atmospheric pressure. In addition, this product would produce highly toxic products from combustion. The SDS clearly states that the product “May form flammable/explosive vapor-air mixture.”

You may also wish to consider the increased medical-legal risk to the patient and perhaps the care team involving the use of veterinary products that are not evaluated by the FDA for human use. The surgeon’s instructions for use that you shared with us indicate that this product should be reapplied every 2-3 hours, so there may be a window to remove the ointment during hyperbaric therapy.

REFERENCES:

1. Gaylord Chemical Company, L.L.C., “DMSO Health & Safety,” Accessed 12/21/2022 LINK
2. Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc.
3. National Fire Protection Agency (NFPA). (2021). NFPA 99 2021 Edition: Health Care Facilities Code. Quincy, Massachusetts.
4. SANCO Industries, Inc., “Safety Data Sheet: DMSO Gel,” Accessed 12/21/2022 LINK

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.

Posted: 12/2/2022

Q: We have been grandfathered in so our clinic is still in a billable area. But if we were to move our clinic what is the distance we have to be within from the hospital.

A: 250 yards

Posted: 11/29/2022

Q:
I am looking for guidelines on how often patient's HBOT hoods should be washed/cleaned over a 6-8 week M-F treatment program. The two previous facilities that I worked at required them to be washed/cleaned once a week.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility, with input and direction from your hospital’s Infection Control team.

We would recommend working closely with your hospital’s Infection Control team for guidance. Oxygen hood manufacturers are largely silent on recommending a particular frequency. For example, Amron International states the following in their User's Manual for the Amron Oxygen Treatment Hood 8891 Series:

“When worn multiple times by the same user, it is up to the facility protocol for determining how often and the best method for cleaning/disinfecting the product. One worn multiple times by different users, it is required that the hood be disassembled, cleaned, disinfected, dried, reassembled, and stored in a sealed bag prior to use by a new/different user.”

Because there is little guidance from the manufacturer, there are understandably many variations between Hyperbaric programs in their approach to the frequency of cleaning. Again, we would advise you to work with your Infection Control group to determine the best approach for your program. Of note, the World Health Organization published the following guidelines in the 2014 publication: “Infection Prevention and Control of Epidemic- and Pandemic-Prone Acute Respiratory Infections in Health Care.”

Annex I - Cleaning and disinfection of respiratory equipment

“Equipment used for respiratory therapy (e.g. items that come into contact with mucous membranes) is considered semicritical; such items should be cleaned and then receive at least high-level disinfection between patients. High-level disinfection of respiratory equipment takes place after cleaning, and is typically accomplished by chemical germicides or physical methods, as outlined below.”

It may be helpful to review the following feedback provided from several of our committee members:

• Where I worked, after every treatment, we used a disinfectant wipe to clean them.  When a patient finishes their series of treatment, we would disassemble the hood wash and high level disinfect before using on the next patient. 
• We also just clean as needed during their course of treatment. Once completed, we follow the manufacturers recommendations for reuse.
• In my experience we always give them a wipe with an approved product, and a proper clean when needed, for instance for any secretions or fluids etc.
• Follow the manufacturers recommendations for the and your facilities infection control procedure.
• Keep the hoods/masks labeled and separated from other patients’ equipment
• Clean daily and as necessary for patient care (visibly soiled not allowed) It could be argued that if there is no risk of cross contamination then maybe daily is too much, I think that may be a facility specific decision. Is there something in healthcare about disinfecting patient care equipment after each use?
• Terminal disinfection or disposal at the end of the patient’s course of treatments
• We recommend cleaning these prior to every use due to infectious disease control reasons, unless the hood/mask is dedicated to a patient who comes for treatments few times a week. In later case, we recommend cleaning once a week, unless needed otherwise.

REFERENCES:

Amron International. “Amron Oxygen Treatment Hood 8891 Series User Manual, Ver. 7.0,” Accessed 11/23/22

World Health Organization. (2014). Infection prevention and control of epidemic-and pandemic-prone acute respiratory infections in health care. World Health Organization.

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.
 

Posted: 10/25/2022

Q:
This practitioner called this AM asking about our thoughts on a patient in the monoplace chamber who was observed having static electricity buildup (hair was standing up during the treatment) despite the patient being grounded. They did stop the treatment and pulled the patient out of the chamber and tested all the spots recommended for the ohm's test and all were in range. Humidity is in the 40% range. They called Sechrist and all was as it should be, and this person is calling about what we know about it and make any necessary recommendations.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

The Committee understands your concern for patient safety, which should always be in the forefront of our minds as clinicians in the field of hyperbaric medicine. It is right and proper to ensure that the chamber and patient remain grounded. However, the situation you describe has occurred numerous times when certain conditions have been met, and there is a simple remedy that can be applied.

Medical-grade oxygen is generally a very dry gas. As humidity is the main factor in static generation, decreased humidity coupled with gas flow can cause an imbalance of electrons within the chamber. As dry gas flows along the cylindrical walls of the chamber, unbalanced electrons that surround very light objects can be drawn outward, and thus cause hair to “float” or “stand up”.

The Committee recommends the following actions if this phenomenon occurs:

1. a) Spray and wipe the acrylic (interior and exterior) with Novus^© 1 Plastic Clean & Shine.
2. b) Spritz the patient’s hair with clean water.

More information on static in the hyperbaric environment:

• The subject of static generation is one that should be understood well by operators of hyperbaric chambers. This topic was highlighted during the UHMS Scientific Meeting Safety Pre-Course in 2017. A third-party electrical engineering specialist, skilled in testing materials in oxygen-enriched environments was invited to be part of the panel. You may wish to review the entire content of their presentation here. The group expressed the following conclusions, (from slide #20):

The analysis of risk factors and associated data as a group suggests that the risk is mitigated in current HBO applications.

(This is) Supported by the successful history of use when implementing the current standard of safety. (e.g., NFPA 99, grounding straps, cleanliness, etc.)

• Another wonderful resource that may help you to better understand the factors surrounding static in the monoplace hyperbaric chamber is found in Sheffield and Burman’s article: “Static Electricity and Grounding in Hyperbaric Chambers.” We would encourage you to read through this article and take advantage of the 1 ‘Category A’ Continuing Education Credit offered by the NBDHMT through International ATMO.
• Some facilities have looked to add a humidifier to the room housing the chambers. However, as soon as the chamber door is closed, dry oxygen fills the cylinder. Humidity is likely to decrease throughout the treatment, so this solution may have limited effect. There is no code requirement for a humidifier in the room housing the chambers. The UHMS HBO2 Safety Committee responded to a question on this topic in 2015. LINK
• NFPA 77: Recommended Practice on Static Electricity (2019) is another pertinent resource that may offer valuable information on this topic. Of note, NFPA 77 has this to say regarding the application of humidity:

7.4 Charge Dissipation

7.4.2.3 - Humidification is not a cure-all for static electricity problems. Some insulators do not adsorb moisture from the air; therefore, high humidity will not noticeably decrease their surface resistivity. Examples of such insulators are uncontaminated surfaces of some polymeric materials, such as plastic piping, containers, and films, and the surface of petroleum liquids. These surfaces are capable of accumulating a static electric charge even when the atmosphere has a humidity of 100 percent.

• Movement will also "charge" the capacitor (in this case the human body), just like a balloon does when rubbed on carpeting, hair, etc. It is important to note that as long as the patient remains grounded and the ground has been verified, there should be little to no concern of the risk of fire. If connected to the ground, the accumulated charge will dissipate to the grounded chamber hull.
• Many chamber manufacturers recommend the use of an ohm meter (multimeter that reads ohms) to verify that the chamber hull is grounded to earth. LINK1 This device, as well as a wrist strap continuity tester can be used to verify that the wrist strap worn by the patient and grounding cord has continuity and is connected to the grounded chamber. LINK2

Relevant NFPA 99 references regarding electrostatic safeguards:

14.2.9.4.1.3 - The resistance between the grounded chamber hull and the electrical ground shall not exceed 1 ohm.

14.3.1.6.3.2 - In Class A and Class B chambers with atmospheres containing more than 23.5 percent oxygen by volume, electrical grounding of the patient shall be ensured by the provision of a high-impedance conductive pathway in contact with the patient's skin.

14.3.4.6 Electrostatic Safeguards

14.3.4.6.1 - Conductive accessories shall meet conductivity and antistatic requirements.

14.3.4.6.2 - Patient ground shall be verified in Class B chambers prior to each chamber operation.

14.3.4.6.3 - Patient ground shall be verified in Class A chambers prior 'to chamber operation whenever atmospheres containing more than 23.5 percent oxygen by volume are used.

14.3.4.6.4 - Chamber ground shall be verified to be in accordance with 14.2.9.4.1.3 for Class A and Class B chambers as part of the preventive maintenance program of the facility.

REFERENCES:

1. Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc.
2. International ATMO, Inc., “Static Electricity and Grounding in Hyperbaric Chambers,” Accessed 10/14/2022.
3. National Fire Protection Association. (2021). NFPA 99 2021 Edition: Health Care Facilities Code. Quincy, Massachusetts.
4. National Fire Protection Association. (2019). NFPA 77 2019 Edition: Recommended Practice on Static Electricity. Quincy, Massachusetts.
5. NOVUS Plastic Polish (Product). “NOVUS 1: Clean & Shine,” Accessed 10/14/2022.
6. Undersea and Hyperbaric Medical Society, MEDFAQ Response, “Humidity in the room housing monoplace chambers,” Accessed 10/14/2022.
7. Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Ch. 4.4 Electrical Systems, pg. 192-193. Best Publishing Company.
8. YouTube, “Perry Baromedical Proper Procedure for Patient Grounding,” Accessed 10/14/2022.
9. YouTube, “Sechrist Hyperbaric Chamber Ground Verification,” Accessed 10/14/2022.

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.

Posted: 10/11/2022

Q: 
Just wondering if the ejection fraction guidelines have changed, we have always followed the greater than 30%, or 25 to 30% if stable, would get cardiac clearance if needed, and what would be considered unstable? clearance if needed, and what would be considered unstable?

A:

Re: Left ventricular ejection fraction and hyperbaric oxygen:

This answer originates from Dr. Neil Hampson, M.D who is the retired long term medical director of the Virginia Mason Hyperbaric unit. Dr. Hampson is board certified in Internal Medicine, Pulmonary Medicine, Critical Care and Hyperbaric Medicine. Of course, in addition to the left ventricular ejection fraction, the patient’s recent cardiac history should be obtained and considered. If the patient has recently required medical intervention for cardiac failure issues especially if frequently recurrent, this factor should be included into the decision making in regard to the treatment with hyperbaric oxygen  for a non-emergent condition. It is always prudent to consult the patient’s cardiologist when there are concerns about the possibility of inducing congestive heart failure with hyperbaric oxygen treatments.

Here are Dr. Hampson’s recommendations:

Cardiac Screening for HBO_2: 

• History of cardiac disease – ask to see patient’s last CXR and review last echocardiogram report
• If echocardiogram is greater than one year old and was abnormal, repeat it
• If last echo of any age showed LVEF > 40%, repeat only if cardiac symptoms have progressed since that time
• If echocardiogram performed within one year shows:
• LVEF >30% Proceed with HBO2
• LVEF 20-30% Involve cardiology for optimization prior to considering HBO2
• LVEF <20% No routine HBO2

Posted: 10/14/22

Q: 
Hello, we have a patient status post radiation therapy and bilateral mastectomy. She currently has Natrelle silicone implants, and our department is curious to see if you have any previous studies on HBO therapy on a patient with such implants. We contacted the manufacturer (Abbvie), and they state: "No relevant information was identified". Thank you for your assistance.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

The UHMS HBO₂ Safety Committee is aware of many centers who have successfully delivered hyperbaric therapy to patients with fluid-filled and silicone-filled implants. Many, if not most hyperbaric programs no longer screen for these items. The rationale behind this conclusion is that fluid-filled, sealed objects are largely incompressible (Described in: Fluid Mechanics Fundamentals and Applications, 2013). Many of our committee members report years of repeated exposures to varying depths of pressure, both in patients and inside attendants.

However, the UHMS HBO2 Safety Committee is aware of a study (Grippaudo, 2002) regarding implant conformational changes after exposure to pressure with an implant containing a cohesive gel filling. It is our understanding is that newer generation implants are more likely to have this cohesive gel filling. There is potential that asymmetric pressure applied to these devices from capsular contractions may also cause rupture of an older device that is significantly weakened. This may cause cosmetic issues. You may wish to discuss this potential during the informed consent process.

Grippaudo (2002) – subjected breast implants to 40 simulated recreational dives. The goal was to determine if implants exposed to elevated pressure results in structural or conformational changes. Dive profiles were to 39m twice daily with an 8-hour surface interval between dives for a total of 20 days. Staged decompression was carried out in accordance with US Navy tables. Implants were inspected for integrity and CT scans were performed after all dives were completed. No shell ruptures were noted and no changes in volume were noted; however, conformational changes were noted in the cohesive gel implants with distortion remaining after 12 months.

There are several other comments provided by Committee members that may be of interest to you in determining your approach to these items:

• In a separate study, testing of a variety of FDA silicones used in implants for use in hydraulic systems within manned atmospheres have shown that these fluids load and offload gases slower than humans and are not chemically altered when exposed to pure oxygen. They are not an issue in HBO clinical operations from a gas exchange standpoint. (No source available)
• It is reported that pressure tolerance testing at Duke University was conducted on silicone-filled implants approximately 15-20 years ago. Pressure did not appear to damage the implants. (No source available)
• With regards to diving, the general recommendation we give is to allow some time after the surgery for the body to properly encapsulate the implants, as some BCD straps might put some lateral pressure at the site.
• We receive many questions related to tissue expanders. We have not noticed any issues with saline or silicone-based expanders as they generally will not be subject to Boyle’s Law. Theoretically, a patient might feel a little pressure on the site during compression, but I cannot say that a patient ever actually reported that symptom.
• One committee member reports having the Abbvie Natrelle silicone implants and has been an inside attendant many times without issue.
• As long as a bubble is not present, there would be no concern. It is improbable that patients would feel anything untoward during compression or decompression. Regarding tissue expanders, these are incrementally filled with normal saline. It is theoretically possible to have a bubble collection in these devices since more fluid is incrementally added by injection. However, I do not recall ever having a problem with HBOT even here.

REFERENCES:

1. Cengel, Y., & Cimbala, J. (2013). EBOOK: Fluid Mechanics Fundamentals and Applications (SI units). Chapter 2, pg. 44-46. McGraw Hill.
2. Divers Alert Network, ”Breast Implants and Diving”. (Accessed 10/10/2022)
3. Grippaudo, F. R., Minasi, P., Muratori, L., Rocco, M., Bruno, A., & Saracca, E. (2002). Mammary implants: laboratory simulation of recreational diving conditions. British journal of plastic surgery, 55(2), 120-123.

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.

Posted: 9/6/2022

Q:  

I work in a Hospital with two monoplace chambers. We are going to be running a 10-month old infant for hyperbaric treatment related to Hypospadias. Can the infant bring in a bottle with milk and/or pacifier? What about teething ring or soft toys? Can the infant wear a diaper with the Velcro removed and tape placed?

 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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

Regarding the items considered for allowance in the monoplace environment, the UHMS HBO₂ Safety Committee cannot approve a particular item for use in the chamber. We would offer the following suggestions:

Bottle filled with milk – Consider that the bottle will have to be properly ventilated. Evaluate if the opening on the tip is wide enough to vent the air space within the bottle.

Pacifier –  Consider that Boyle’s law will also have an impact on the size of the rubber bulb. Otherwise, this should not pose a significant risk. We would encourage you to pay attention to items that may fall between the gurney and the rails. Any loose item in the chamber can cause an obstacle upon removal of the patient. This may also lead to damage to the acrylic.

Teething Ring and soft toys – See note above on loose items. You should evaluate these items for potential risk to generate static, but the risk is likely to be minimal. Ensure that the patient and the chamber is properly grounded.

Diapers – Please refer to the UHMS HBO₂ Safety Committee’s previous answer on this topic. LINK

Your approach to the care of the infant during hyperbaric oxygen therapy is dependent upon the assessment of risk by your HMD and HSD. Several hyperbaric facilities have treated infants safely in the Monoplace Chamber. Some have assessed, and local policy dictates, that it is unsafe to leave an infant unattended and have applied the FDA’s provision to perform therapy under Off-Label practices, while under the supervision of a Physician and subject to certain, safety-based criteria. Others have adhered to the classification of the chamber occupancy and determined that the risk to the infant is greater with an occupant caregiver. The UHMS HBO2 Safety Committee does not support one decision over the other. We would suggest that you evaluate several factors prior to making this decision for your facility:

Considerations when treating an infant with an occupant caregiver in the monoplace setting:

• Please refer to the UHMS HBO2 Safety Committee’s previous answer on this topic. LINK

Considerations if treating an infant without an occupant caregiver in the monoplace setting:

There are several factors that may lead to this decision:

• Consider that the NFPA, the FDA, and the chamber manufacturer have recognized monoplace chambers as single occupancy.
• There is no interest by the HMD to authorize the off-label use of the medical device and assume the potential liability.
• The HMD and HSD deems that placing another individual inside the chamber will create unnecessary risk to both occupants by way of smothering caused by seizure or theoretical DCS risk if wrong gas is delivered.

When treating an infant/pediatric patient in the monoplace, consider the following:

• Consider the opportunity for ECG monitoring of this patient during therapy. Consider adding this capability to your chamber.
• Keep the stretcher in the flat position. Place hyperbaric-approved blankets surrounding the patient to prevent injury by rolling off.
• Offer the presence of a Neonatal Intensive Care (NICU) Nurse throughout therapy. Observe for signs of bradycardia and airway issues.
• Address the need for Pressure Equalization tubes. Older pediatric patients may not require this procedure if they are able to perform equalization techniques effectively.
• The presence of parents in the treatment room may be helpful in assuring that the patient is comfortable and safe.

REFERENCES:

Celebi, A. R. C., Kadayifcilar, S., & Eldem, B. (2015). Hyperbaric oxygen therapy in branch retinal artery occlusion in a 15-year-old boy with methylenetetrahydrofolate reductase mutation. Case reports in ophthalmological medicine, 2015.

Fok, T. F., Shing, M. K., So, L. Y., & Leung, R. K. W. (1990). Vascular Air Embolism‐Possible Survival. Acta Pædiatrica, 79(8‐9), 856-859.

Hsieh, W. S., Yang, P. H., Chao, H. C., & Lai, J. Y. (1999). Neonatal necrotizing fasciitis: a report of three cases and review of the literature. Pediatrics, 103(4), e53-e53.

Korambayil, P. M., Ambookan, P. V., Abraham, S. V., & Ambalakat, A. (2015). A multidisciplinary approach with hyperbaric oxygen therapy improve outcome in snake bite injuries. Toxicology International, 22(1), 104.

Liebelt, E. L. (1999). Hyperbaric oxygen therapy in childhood carbon monoxide poisoning. Current opinion in pediatrics, 11(3), 259-264.

Mader, J. T., Adams, K. R., Wallace, W. R., & Calhoun, J. H. (1990). Hyperbaric oxygen as adjunctive therapy for osteomyelitis. Infectious disease clinics of North America, 4(3), 433-440.

Marosek, N. J., (2019) Optimizing the pediatric hyperbaric oxygen therapy plan: Tandem therapy. UHMS Safety Pre-Course presentation.

Smith-Slatas, C. L., Bourque, M., & Salazar, J. C. (2006). Clostridium septicum infections in children: a case report and review of the literature. Pediatrics, 117(4), e796-e805.

Tsung, J. W., Chou, K. J., Martinez, C., Tyrrell, J., & Touger, M. (2005). An adolescent scuba diver with 2 episodes of diving-related injuries requiring hyperbaric oxygen recompression therapy: a case report with medical considerations for child and adolescent scuba divers. Pediatric emergency care, 21(10), 681-686.

Waisman, D., Shupak, A., Weisz, G., & Melamed, Y. (1998). Hyperbaric oxygen therapy in the pediatric patient: the experience of the Israel Naval Medical Institute. Pediatrics, 102(5), e53-e53.

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.

Posted: 8/26/22

Q: 
Is there any contraindication to treating a patient with a subarachnoid  hematoma stable over two CTH scans 12 hours apart and felt stable for home discharge by neurosurgery?

A:
The chair of the HBO2 Committee responded that there should not be any risk to this patient if treated with hyperbaric oxygen therapy. The SAH is a fluid-filled space and should not undergo any pressure-related changes. 

Posted: 9/19/22

Q: 

What are the current recommendations for activity restrictions (i.e. strenuous exercise), for inside attendants following a hyperbaric exposure (treatment)? Our standard profiles are 2.0ATA/ 105 minutes ABT, 2.4ATA/ 90 minutes ABT, 2.8ATA/ 85 min ABT, TT5, TT6, and 3.0ATA/ 85 min ABT.

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 Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) of your facility.

The UHMS HBO2 Safety Committee is aware of several programs which have instituted guidelines for inside attendants following a hyperbaric exposure. Unfortunately, there is no clear-cut answer to this question, but there are several references to consider. The safety committee will also offer the following comments from its members and our colleagues:

• In our department we have not set strict time limits.  We recommend using good judgment based on your normal workout history, with a 2–4-hour pre/post rest period as a baseline.  If you decide to work out, with a heavier than normal exercise regimen, your pre/post hyperbaric exposure time should be lengthened.
• Guideline information is shared and taught with all HBO staff, but we do not have a firm policy on this. For exceptional dives such as 5, 6, and 6A, they are given post-dive instructions. One item within the instructions expresses that they should avoid heavy activity for the next eight hours. But in all honesty, the practice of not exercising 4-6 hours pre or post dive has always been difficult to follow, especially for active tenders (regarding daily TT9 dives) as this would consume most of the day.
• A strict policy on exercise after compressed air exposure is problematic for several reasons. The recommendations used in our facility is listed below. I am not aware of published incident(s). Could this be a theoretical risk?

1.1.    NO STRENUOUS and/or JARRING EXERCISE AND NO COMPRESSED GAS DIVING:

1.1.1. Within 16 hours of completion of a single hyperbaric chamber pressurization.

1.1.2. Within 24 hours of completion of the last of multiple exposures (in one day) or single exposures over multiple days.

1.1.3. Within 48 hours of completion of an USN table 6 or any decompression profile with a USN group Z

Any deviation from this should be discussed beforehand (or as soon after as possible) with the Hyperbaric Medicine Staff physician. If there are any possible signs/symptoms of decompression sickness the Hyperbaric Medicine Staff Physician should be contacted as soon as possible.

• Matias Nochetto, MD “I don’t know any widely accepted standard recommendation for divers, and I am not aware of any for Inside Attendants. Common sense suggests that strenuous physical activity during decompression phase is not desirable. Where is the line to say it is ok is hard to answer; and a solid evidence-based answer might require a long and expensive research endeavor. The decompression stress imposed to an inside attendant tending treatments ranging from 2.0 ATA / 105 min to a fully extended USNTT6 is quite different. On the lighter ones (wound healing ones), I think it is reasonable to assume that for all practical purposes there is no more residual nitrogen after 12 hours. Moderate physical activity is probably acceptable long before that, but I don’t know of any tools to help us determine where that line is. Six hours? Four? I don’t know. Now if we talk about strenuous exercise, then I would recommend a longer interval. For those treatments imposing the highest decompression stress, I would definitively recommend no less than 12 hours and possibly more, like 18 or 24. Anything over 24 I think it is probably unnecessary. But one must consider that strenuous physical activity can take a big toll even on trained athletes, and any symptoms following exercise that followed a dive could represent a diagnostic challenge. Although a strenuous physical activity following a dive is not necessarily the same physiological insult as a hypobaric exposure following a dive, one could look at the Flying After Diving guidelines as a reference for a sensible approach. After all, the real question is how long should I wait to have a significant inert gas elimination to not be concerned about bubble formation when I add another stressor.”
• From Doc Vikingo, 03/2004: “The best advice is moderation. Stay well hydrated and warm. Avoid strenuous exercise of any type for 4 and 6 hours before and after diving, respectively, but remain mildly active between dives and for a while after the last dive.”

Exercise Before, During, and After Diving: Undercurrent 03/2004

• Madden, D., Lozo, M., Dujic, Z., & Ljubkovic, M. (2013): Recent studies have demonstrated the right-to-left passage of bubbles through intrapulmonary arterial-venous anastamoses (IPAVA) that allow blood to bypass the pulmonary microcirculation. These passages open up during exercise, and the aim of this study is to see if exercise in a postdiving period increases the incidence of arterialization….The safety of exercise after diving has been debated for some time. We have shown that exercise may directly contribute to arterialization. It may be concluded that exercise directly increases vulnerability to arterialization of VGE after diving. In some individuals, specifically those who have a low workload threshold for opening of IPAVA, it is possible that even relatively mild physical exertion associated with surface swimming at the end of a dive, climbing onto a boat, or walking with heavy gear on would be enough to provoke arterialization……Although many studies have shown that divers can arterialize with no DCS symptoms, there still remains a correlation between neurological DCS and the presence of arterial bubbles. Finally, subclinical levels of damage related to microemboli in the brain should not be ignored, especially in career divers.”

Exercise after SCUBA diving increases the incidence of arterial gas embolism | Journal of Applied Physiology

• “In general, the consensus amongst researchers is that exercise should be avoided within four to six hours before and after diving. Previously, this was set at 24 hours which was impractical.”

https://www.dansa.org/blog/2017/08/25/physical-exercise-before-during-after-a-dive

• Dr. Ernest Campbell: “If one were to put four restful hours between exercise and diving and six between diving and exercise, a diver should be in good shape in terms of absent bubbles.”

http://www.awoosh.com/DocVikingo/Exercise_and_DCS.htm

Based upon these responses, there does not seem to be a consensus agreement among the diving and hyperbaric community on this subject. The UHMS HBO2 Safety Committee recommends a local review of the literature among the Hyperbaric Medical Director (HMD) and Hyperbaric Safety Director (HSD) to determine the best course of action for your facility. Please keep in mind that any changes in your approach should be shared and documented with your hyperbaric team.

REFERENCES:

1. Burman, F. (2019). Risk Assessment Guide for Installation and Operation of Clinical Hyperbaric Facilities (6th ed.). San Antonio, TX: International ATMO, Inc.
2. DAN South Africa (08/25/2017), Article: “Physical Exercise Before, During & After A Dive,” Accessed 9/12/2022.
3. Doc Vikingo Diver’s Resource (2004), Article: “Exercise and Diving: When is it a Good Thing?” Accessed 9/12/2022.
4. Doc Vikingo – Undercurrent Online (03/2004), Article: “Exercise Before, During, and After Diving,” Accessed 9/12/2022.
5. Madden, D., Lozo, M., Dujic, Z., & Ljubkovic, M. (2013). “Exercise after SCUBA diving increases the incidence of arterial gas embolism.” Journal of Applied Physiology, 115(5), 716-722.
6. Workman, W. T., & Wood, J. S. (2020). Hyperbaric Facility Safety: A Practical Guide (2nd ed.). Best Publishing Company.

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.