Acute Conditions
Acute conditions including injuries sustained due to trauma to the legs or body, nervous system damage and surgical trauma (incisions), benefit from HBOT.
The general principal behind HBOT is that hyper-oxygenation reduces tissue swelling and enhances oxygen delivery to injured tissues by increasing the amount of dissolved oxygen in the plasma. Increasing oxygen aids in salvaging damaged tissue that would otherwise be lost from necrosis.
Chronic Conditions
Chronic conditions including poor healing wounds or wounds that involve a large surface area; bone infections; internal abscesses or other infections that result in tissue destruction, loss of blood supply, and necrosis, also benefit from HBOT. Acute injuries or inflammatory processes may progress to the chronic state if left untreated or are undiscovered until an advanced state. Using HBOT for these circumstances enhances normal body processes, such as stimulation of new blood vessel growth (angiogenesis), enhancing leukocyte ability to kill bacteria, stimulation of production of connective tissue cells (fibroblasts) and connective tissue (collagen).
Veterinary HBOT is an Adjunct to Other Therapies
Important factors in healing any wound or infection are, of course, an accurate diagnosis, along with selection of appropriate medical therapy. HBOT enhances the effectiveness of antibiotics and other treatments as well as their ability to reach the desired target destination. Several problems have been identified in horses where the application of HBOT would be useful are:
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Wounds (traumatic, surgical, etc)
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Traumatic injuries with soft tissue swelling
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Skin, muscle, tendinous or ligamentous injury
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Severe muscle swelling
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Post-injection reactions (Clostridial myositis)
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Spider bites
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Bone infection
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Bone and soft tissue healing after orthopedic procedures
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Head and spinal injury
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Hypoxic-ischemic encephalopathy (birth asphyxia or dummy foal syndrome)
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Chronic infections
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Lung and abdominal abscesses
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Intestinal diseases
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Gastric ulcer healing
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Colitis
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Prevention of ischemia reperfusion injury post colon torsion
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Any intestinal ischemic injury
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Laminitis or founder
Wound Applications for HBOT
Animal HBOT is effective for many types of wounds including massive degloving injuries to the lower leg, large surface wounds from trauma, injection reactions, spider bites and pressure sores from prolonged recumbency as with debilitated animals or neonatal foals. HBOT decreases tissue swelling and therefore salvages damaged tissues when used in the case of traumatic injuries. In the case of chronic wounds, HBOT assists the epithelium covering the wound and stimulates fibroblast production of collagen.
Bone Infections
Situations where bone infections can occur in horses include the following:
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Complication of bacterial septicemia in foals
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Complication following joint injections
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Complication following orthopedic surgery in foals or adults
The pathophysiology of bone infection involves the following:
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Bacteremia (blood borne bacteria) or local invasion
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Bacterial localization in sinusoidal capillaries
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Suppurative inflammatory response within the medullary space
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Destruction of capillary structure
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Increased intraosseous pressure
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Decreased tissue partial pressure of oxygen (pO2)
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Necrosis of tissue
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Destruction of supportive structure and growth centers
Along with the above, the following alterations occur to impair the bone’s ability to respond:
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Impaired blood flow
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Tissue hypoxia
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Tissue necrosis and destruction
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Ineffective leukocyte function
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Impaired antibiotic delivery
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Impaired antibiotic function (as many antibiotics require specific amounts of oxygen to be effective)
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Poor bone “wound” healing
Uses of HBOT in bone infections include the following:
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Increased diffusion of oxygen from the blood vessels
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Enhancement of neovascularization (angiogenesis)
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Stimulation of collagen production to build new bone
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Improvement of blood flow by reduction of edema via vasoconstriction
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Enhancement of leukocyte ability to kill bacteria
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Enhancement of delivery and activity of antibiotics
Applications of Veterinary HBOT for Chronic Infectious Processes
Internal abscesses may occur in the lungs (Rhodococcus equi) or in the abdomen (Rhodococcus equi, Streptococcus equi) and are rarely diagnosed early in the course of the disease. When these abscesses are diagnosed, there is a thick-walled fibrous connective tissue capsule surrounding them that impairs antibiotics from reaching the affected area.
This results in prolonged antibiotic treatment often with no resolution of the illness at a high cost to the owner and potentially fatal consequences for the animal. HBOT enhances the effectiveness of antibiotics and other treatments as well as their ability to reach the desired target destination.
HBOT for Neurologic Injuries
Head and spinal trauma often result in severe loss of body function. The Neurologic deficits are thought to result from swelling of tissue within a confined space, the loss of blood and oxygen supply and the sequential biochemical effects of these on the nervous tissue.
Hypoxic-ischemic encephalopathy, a common syndrome in foals (often termed the “dummy foal syndrome”), is considered to be related to the loss of blood flow and/or oxygen at some point during the birthing process. Any of the above mentioned problems benefit from the application of HBOT in an effort to reduce the swelling of tissue and salvage the injured nervous tissue.
Other Applications for Animal Hyperbaric Oxygen
Veterinary HBOT can be used for training injuries in equine athletes. The beneficial effects would include reduction of tissue swelling, reduction of pain associated with swelling and inflammation, and enhancement of the connective tissue repair process.