By Dr. Lon W. Keim
Imagine being at risk of losing one of your feet.
That’s what a mother of seven from Kuwait with advanced diabetes mellitus recently faced before coming to Nebraska Medicine and the University of Nebraska Medical Center, through the assistance of the Office of International Healthcare Services.
She presented with a problem wound involving her right foot, now threatened by potential amputation. Her management was further complicated by the need of dialysis three times per week for her end stage renal disease.
Years ago Dr. Jefferson Davis and Dr. Thomas Hunt coined the term “problem wounds,” which they defined as wounds which simply do not heal as they should.
Through their experience and research they determined that a common denominator of problem wounds is tissue hypoxia or oxygen deprivation. Tissue hypoxia is commonly a result of three factors: inadequate oxygen in the blood, insufficient regional blood flow, or most often – focal oxygen demand exceeds delivery. That is the metabolic demands of the wound exceed oxygen delivery from the available blood supply.
Accordingly, the body’s inherent defense mechanisms – the ability to fight infection, generate new blood vessels, build tissue, create strength, provide coverage – are forced to function in an oxygen deficient environment. Thus a problem wound, like the one the woman from Kuwait experienced, is created.
Re-establishment of local regional blood flow through vascular enhancement procedures such as arthrectomies, angioplasties, stent placement, and bypass procedures is the essential cornerstone of initial management.
Hyperbaric Oxygen Therapy (HBO) also has been found to be a useful adjunct in selected patients who tissue oxygenation is not improved to accepted levels by revascularization procedures The patient is entirely enclosed in a monoplace chamber and breathes 100 percent oxygen at pressures greater than 1.0 atmospheric pressure absolute (ATA).
With increased pressure, the amount of oxygen physically dissolved in the blood is increased. This increased oxygen pressure in plasma enhances diffusion from existing vasculature and improves regional wound tissue oxygen tensions.
The increased oxygen tension will not make a normal wound heal faster, but allows an otherwise compromised wound to heal through improved white cell function, enhanced antibiotic effectiveness, promotion of micro-vessel growth and collagen formation. It should be emphasized that HBO is not a substitute for adequate debridement or appropriate antibiotics, adequate nutrition, or local wound care.
Prior to coming to Nebraska, the mother from Kuwait had been evaluated by clinicians in Europe who believed nothing further could be done with amputation being the next most likely course of action. She was subsequently referred to Nebraska Medicine where vascular surgeons were able to improve her distal vascular circulation through angioplasties and stent placement.
Subsequent transcutaneous oxygen assessment confirmed marginal tissue oxygen tensions that reversed with Hyperbaric Oxygen Therapy, thereby justifying further treatment with HBO. While continuing her dialysis three times a week, through a series of HBO treatments at 2.4 ATA for 90 minutes each, local wound care, and pressure off loading, her wound oxygen tensions improved, allowing her wound to heal to a degree it was believed she could be safely discharged and return to Kuwait with her limb intact.
It should be emphasized that her recovery was the result of a team effort that included: skilled surgeons, gifted interventional radiologists, talented infectious disease expertise, attentive nurses, ongoing dialysis support, pressure off loading, aggressive nutritional support, and hyperbaric oxygen therapy.
The Hyperbaric Unit at Nebraska Medicine is equipped with four monoplace chambers capable of treating patients at pressures up to 3.0 ATA. The unit is staffed by hyperbaric trained critical care nurses, and is located immediately adjacent to an ICU. As such, the Nebraska Medicine specialists are capable of both treating walk-in outpatients as well as those requiring intensive critical care support. Although available 24/7 for emergent conditions, the unit routinely runs four shifts a day, with the majority of patients treated once daily five days a week.
HBO is viewed as the primary treatment for only three conditions: (1) acute carbon monoxide intoxication, (2) decompression sickness (bends), and air emboli (air bubbles within the vascular system).
For all other conditions, HBO is viewed as adjunctive therapy to the traditionally accepted mandates of care: adequate debridement and wound care, pressure off loading, edema control, nutrition, wound care, appropriate antibiotics, etc.
The following conditions have been approved and are endorsed by the Undersea and Hyperbaric Medicine Society (UHMS) as appropriate for treatment with HBO: (1) Clostridial myonecrosis – gas gangrene, (2) Necrotizing Soft Tissue Infections, (3) Refractory Chronic Osteomyelitis, (4) Compromised Flaps & Grafts, (5) Diabetes Mellitus – with lower extremity problem wounds refractory to conventional management for > 30 days, Wagner III-IV, (6) Delayed Radiation Injury – to Soft Tissues and Bone including radiation cystitis, radiation caries, colorectal radiation enteritis, or any chronic non-resolving chronic wound within a prior area of radiation, (7) Crush Injury – Skeletal Muscle Compartment Syndromes, (8) Intracranial Abscess, (9) Idiopathic Sudden Sensorineural Hearing Loss, (10) Exceptional Blood Loss Anemia, and (11) Thermal Burns.
The risks and side effects associated with HBO therapy are few. They include: confinement anxiety; barotrauma to the ears sinuses and potentially the lungs; fire (controlled by rigid adherence to strict safety protocols), rare oxygen induced seizures; and occasional transient reversible changes in vision. All in all, it is extremely well tolerated with minimum risks.