Hyperbaric Oxygen Use in Wound Healing

Different methods exist to enhance healing. And with hyperbaric treatment, even the most complex and pervasive wounds can benefit.

The air we breathe is approximately 21% oxygen, 78% nitrogen, and small amounts of other gases such as carbon dioxide, hydrogen, and neon. Hyperbaric oxygen therapy (HBO or HBOT) is a treatment where patients breathe in near 100% oxygen in a pressurized environment.

Indications

According to the Undersea and Hyperbaric Medical Society, there are 14 approved indications for hyperbaric treatment:

1. Air or gas embolism
2. Carbon Monoxide poisoning
3. Gas gangrene
4. Crush injury/compartment syndrome
5. Decompression sickness
6. Arterial insufficiencies
7. Severe anemia
8. Intracranial abscess
9. Necrotizing soft tissue infections
10. Refractory osteomyelitis
11. Delayed radiation injury (soft tissue and bone necrosis)
12. Compromised grafts and flaps
13. Acute thermal burn injury
14. Idiopathic sudden sensorineural hearing loss

The use of hyperbaric treatment in wound healing falls under the indication of necrotizing soft tissue infection, such as a Wagner grade 4 or 5 diabetic ulcer. Refractory osteomyelitis is also an indication for hyperbaric use in wound treatment.

Using hyperbaric treatment

The average atmospheric pressure at sea level is one atmosphere absolute, or one ATA. During an HBOT session, the patient is usually under two to three atmospheres absolute of pressure. Each additional ATA from sea level is the equivalent of 33 feet of sea water. For example, if a patient is receiving hyperbaric treatment at two ATA, it is as if they are 33 feet underwater.

Most HBOT sessions are provided in a single-person (monoplace) chamber made of a transparent, plastic material. The patient lies on a gurney that slides in and out of the chamber. The patient and hyperbaric technician can communicate via a two-way intercom system and can easily see one another.

Typical HBOT sessions last 90 minutes, and treatment time starts once the patient reaches the prescribed “depth” or ATA ordered by the provider. Standard “travel” time (how long it takes to reach the prescribed ATA and how long it takes to return to one ATA at the end of treatment) depends on the rate of compression and decompression. The rate is set by the hyperbaric technician to be a safe and tolerable level for the patient.

Hyperbaric treatment at outpatient facilities typically delivers 30 to 40 treatments daily Monday through Friday. However, some acute care settings can treat patients daily or even twice per day as their condition requires.

How it works

Wounds need oxygen and nutrients to heal. The increased pressure of oxygen during HBO treatment may increase and improve oxygen in the blood supply to damaged tissues. It reduces tissue edema, promotes angiogenesis, stimulates cells, and improves the immune system by strengthening white blood cells.

According to the National Library of Medicine, a 40-patient study was performed using HBO therapy as an adjunctive treatment in complex wound care. After completion of a treatment series, 77.5% of patients’ wounds healed. Wound size reduction was noted after five treatments with the largest reduction in size occurring within the first 10 treatments.

6 challenges of using hyperbaric treatment

1. HBOT can be costly. Depending on the patient’s insurance, prior authorization may be necessary. Proving medical necessity can be time consuming, and even after approval, the patient may still have significant copays.
2. Some patients may find it difficult to tolerate the ear pressure during compression and decompression. The sensation is like being in an airplane or traveling up and down a mountain. The HBOT technician can assist most patients in techniques to clear their ears, but some patients may need to see an ear, nose, and throat (ENT) provider to prescribe appropriate medications or tube placement.
3. If a patient with a lower leg or foot wound has stenosis of the lower leg arteries, an evaluation by a vascular provider is important. A vascular surgeon may be able to perform a procedure to improve blood flow to the wound. Patients with significant stenosis should have their blood flow optimized prior to starting HBO therapy.
4. Patients with claustrophobia may find that they are unable to tolerate HBO therapy. Anxiety can often be talked through with the HBO tech or anxiolytic medications may be prescribed.
5. Compliance with pressure relief of qualifying foot wounds is essential for healing. No amount of hyperbaric treatment can heal a wound that is not compliant with appropriate offloading. Likewise, nutrition deficiencies will need to be corrected prior to beginning therapy, as proper nutrition is essential.
6. Missing HBOT sessions can be a big challenge. Patients who miss treatments are unlikely to receive the full benefit of HBOT. The decision to continue treatment with a patient who misses multiple appointments should be discussed by the treatment team.

Complications

Although HBOT complications are not common, they can be serious. The following complications highlight situations that wound care clinicians may encounter.

• Ear injuries: This can result from the increased pressure during treatment. The pressure may cause fluid to leak and the eardrum to rupture if the patient does not effectively clear their ears or ignores ear discomfort.
• Cardiopulmonary concerns: Cardiopulmonary clearance should be obtained prior to beginning treatment, and patients with certain lung diseases should not receive hyperbaric treatment. In addition, pacemakers and ICDs must be approved for HBO therapy by the manufacturer. Working closely with a patient’s cardiologist or pulmonologist is sometimes necessary.
• Temporary vision impairments: A small number of HBO patients may develop temporary changes in their eyesight such as blurry vision and nearsightedness. This is due to the normal metabolic processes of increased oxygen intake. These symptoms normally resolve themselves, but severe or ongoing symptoms should be evaluated by an ophthalmologist.
• CNS oxygen toxicity seizures: This condition is rare at normal clinical treatment levels of two to three ATA. Even so, all patients are monitored throughout each HBO session. A thorough medical exam and review of medications should be completed prior to a patient’s first treatment and maintained to monitor for changes.
• Flammable items in the hyperbaric chamber: All accredited hospital or outpatient hyperbaric facilities have safety checklists in place. Each patient receives a safety screening prior to beginning each session. This screening reviews the list of prohibited items in the chamber to reduce the rare but serious risk of fire.

Within the past 20 years, hyperbaric treatment has become widely available. Used properly, and for approved conditions, HBOT can be a helpful adjunctive treatment in complex wound care.