Key Insights On Using Hyperbaric Oxygen For Wounds

   If values continue to be low and patients have a diagnosis for which HBOT would be covered, Dr. Fife performs in-chamber TcPO2 studies. As she notes, outcome studies suggest that 84 percent of diabetic foot ulcers with in-chamber values >200 mmHg are likely to respond to HBOT. Dr. Fife says treatment can be at 2.0 ATA or greater as long as in-chamber TcPO2 values are >200 mmHg.6 Dr. Fife says it is not clear whether the same in-chamber values are predictive of success for arterial ulcers or failing flaps. The average number of treatments for a DFU is around 35, says Dr. Fife. She notes that if patients fail to demonstrate benefit after 20 treatments, then HBOT should stop.

   Q: In your experience, what is the main barrier to treatment with HBOT?

   A: Dr. Suzuki notes one contraindication is untreated pneumothorax. However, Dr. Fife adds that one can treat pneumothorax if it is vented. Dr. Suzuki asks patients to refrain from getting the treatment when they have sinus congestion as high pressure may exacerbate the symptoms. If the patient is having a hard time clearing the ears during HBOT, both he and Dr. Fife suggest putting pressure equalization tubes in the patient’s ears.

   Dr. DellaCorte adds that ear barotrauma due to chamber pressure and claustrophobia are other barriers to treatment. Dr. Fife notes another relative contraindication includes pulmonary air trapping (chronic obstructive pulmonary disease). Patients with COPD are at risk for pulmonary barotrauma and Dr. Fife says one must decide whether it is safe for these patients to undergo HBOT. Patients with uncontrolled seizures are not recommended for HBOT, according to Dr. Fife.

   Dr. Suzuki’s patients sometimes complain of logistical problems since the ideal HBOT occurs Monday through Friday for 20 days, meaning four weeks of commitment. For out-of-town patients (commuting for an hour or longer) or dialysis patients, he recommends treatment three times a week (on non-dialysis days). Outcome data suggest that regular attendance to therapy affects whether patients benefit, according to Dr. Fife.7 She adds that therapy five days per week can be difficult for chronically ill patients.

   Dr. Suzuki refutes the claim that patients on VAC therapy (KCI) cannot be in the chamber. He says as long as the HBOT technicians know how to disconnect and reconnect the suction hose to keep the machine outside of the chamber, patients using VAC therapy can successfully undergo treatment with HBOT.

   Drs. DellaCorte and Fife note the barrier of insurance coverage. Although it is likely that non-diabetic patients with ischemia would benefit, Dr. Fife says in the absence of acute arterial insufficiency, a failing flap or osteomyelitis, patients whose only diagnosis is chronic arterial disease do not meet current coverage guidelines.

    “This is unfortunate since there are no other interventions likely to prevent limb loss if revascularization has failed to sufficiently increase tissue oxygen levels,” explains Dr. Fife.

   Research has shown that HBOT is cost effective in comparison to amputation and increases quality of life years.8,9 Dr. Fife notes the cost benefit of HBOT is enhanced by proper patient selection. Patients are best referred before tissue loss has progressed to the point where amputation is inevitable, says Dr. Fife. She notes that transcutaneous oximetry can be useful in screening out patients who are likely to get well without HBOT or patients who cannot be helped.

   Dr. Fife says one should not use HBOT as an alternative to proper revascularization. She says those on dialysis or those who have a transplant are less likely to benefit from HBOT, but are also less likely to benefit from any other intervention.

   Dr. Fife maintains that HBOT must be under the supervision of a properly trained advanced care practitioner who can manage complications.

    “When hyperbaric treatment is used in conjunction with standard wound care, researchers have demonstrated improved results in the healing of difficult or limb-threatening wounds in comparison to routine wound care alone,” she says.

Comments

Dear Editor,

In regards to your recent article, Key Insights On Using Hyperbaric Oxygen For Wounds, published in Volume 23, January 1, 2010:

Dr. Kazu Susuki’s and Dr. Caroline E. Fife’s concerns over equalization of pressure in patients’ middle ears and sinuses during compression is certainly an important one. Middle ear squeeze has been recognized as the most common complication in hyperbaric oxygen therapy. Likewise, as noted by Dr. Michael DellaCorte, pulmonary barotrauma resulting from impaired elimination of gas from the lungs of patients with COPD during decompression is another complication with potentially serious consequences relating to the effects of Boyle’s Law.

What is not mentioned in this discussion, however, is that methods to significantly reduce the incidence of middle ear barotrauma during compression, and to more effectively manage patients with COPD during decompression, have been developed. Dr. Benton P. Zwart of the U.S. Air Force investigated the consequences of pressure change conducted with a constant rate of volume change over time rather than a constant rate of pressure change over time.2 He reported that this approach significantly reduced the incidence of middle ear barotrauma and would, as a result of the same physical principles, make decompression safer for patients with COPD, emphysema, and asthma.

While implementing the pressure-change protocols investigated by Zwart on chambers with manual pneumatic control systems, and even rudimentary electronic control systems, is impractical, they have been implemented during both compression and decompression on chambers with computer-based automatic control systems. Feedback on the practical use of these methods over a number of years has confirmed Zwart’s findings.

Very truly yours,

Russell E. Peterson, Ph.D.
Technical Director
Environmental Tectonics, Corporation
Biomedical Systems
Southampton, Pennsylvania
www.etcbiomedical.com

1 Vrabec JT, Pirone C, Goble S, Mader JT. Middle ear barotrauma from hyperbaric oxygen therapy: Severity,
prevention and management. In: Mueller PHJ, Pirone C, Barach P, eds. Patient safety: Prevention and treatment of complications in hyperbaric medicine. Kensington, Maryland: Undersea and Hyperbaric Medical Society, Inc., 2002:107-113.

2 Zwart BP. The "smooth ride" profile: Development, implementation, and evaluation of a hyperbaric chamber descent and ascent based on a constant rate of volume change with time. Davis Hyperbaric Laboratory Report, Brooks AFB, Texas, 1998.

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