An integrative approach to thoracic diseases includes hyperbaric oxygen therapy and other modalities. 

Thoracic diseases I commonly encounter in New Zealand include pleural effusions, pneumothorax, trauma, asthma, pneumonia, neoplasia and congestive heart failure. (Pleural effusions are often due to infections, rodenticide toxicity, and less often chylothorax). Being an integrative veterinary practice, we combine the “best of both worlds”, making use of conventional veterinary medicine and surgery, as well as complementary therapies, to ensure our patients are treated with the least invasive means to achieve the best possible outcome. We aim to improve and sustain our patients’ quality of life as well as give our clients peace of mind, with our comprehensive approach.

Patients frequently present as unstable, with tachypnoea, dyspnoea, hypoxia or cyanosis and collapse. Primary care to stabilize the patient involves a number of mainstream treatments including oxygen, thoracocentesis, placement of a chest drain, surgery, fluid support, and medications such as antimicrobials, diuretics and others. Complementary therapies that I find helpful to assist with the stabilization of a patient include flower essences (Rescue Remedy or Emergency Essence, the Australian version) to help take the edge off stress and anxiety; homotoxicological medicines that can be injected, such as Traumeel, which helps regulate inflammation and promote healing; acupuncture and aquapuncture (the injection of agents into acupuncture points) to promote healing; and intravenous vitamin C, which supports immune system function, aids in the resolution of infections, reduces free radical damage, has been shown to induce apoptosis in some neoplastic cells, and assists with tissue healing.

Once a diagnosis has been reached and the patient is stable, a treatment plan is strategized. In addition to the above modalities, we are also able to offer Hyperbaric Oxygen Therapy (HBOT). The pros and cons of these different options are evaluated and then presented to clients, taking into account their preferences, which could include financial considerations.

Because we have had so much success with HBOT in our clinic, this article will focus on the benefits of this therapy.

Introduction to hyperbaric oxygen therapy

HBOT has been used in human medicine since the beginning of the 20th century. Based on sound scientific principles, it is an accepted treatment modality for several conditions, including non-healing wounds, compromised skin grafts, refractory infections, gas gangrene, crush injuries, carbon monoxide poisoning, and thermal burns.

The hyperoxygenation provided by HBOT facilitates the optimization of a number of physiological processes. It assists in the resolution of infection (directly and indirectly), supports neovascularization, enhances osteoblast and osteoclast activity, and stimulates tissue regeneration. Additionally, some research suggests it may be of benefit in heart disease and in halting the progression of certain neoplastic conditions.

Extensive scientific information, as well as controlled studies (probably more than for many of our better-known conventional treatment modalities), support the use of HBOT, and many have been conducted with animal subjects in order to justify use in humans. Basically, any ischaemic condition may benefit from this form of therapy, either alone or in conjunction with conventional therapies.

Physiology and applications of HBOT

In a pressurized chamber, humans and animal patients breathe 100% oxygen. Under this increased pressure (usually two atmospheres), the partial pressure of oxygen is greatly increased in the body, leading to increased carriage of oxygen by hemoglobin, but most importantly the dissolution of oxygen in the plasma (a 12 to 15 fold increase), which is carried to areas that may be too poorly perfused with oxygen to heal efficiently under normal circumstances. This raised level of oxygen remains in the tissues for up to four hours post treatment, and healing activity is promoted.

Hyperoxygenation facilitates the oxidative white blood cell-killing mechanism and improves basic leukocyte function. Growth of anaerobic bacteria such as clostridia and pseudomonas is inhibited, thereby limiting the production of deadly toxins and aiding in the resolution of clostridial cellulitis and myonecrosis. Together with this action, the activity of aminoglycocides and other antimicrobial agents is enhanced (their transport across the bacterial cell wall is oxygen dependent), making HBOT a very useful adjunctive treatment modality for chronic and deep infections.

Neovascularization is supported by HBOT as it provides the necessary pO2 to support collagen deposition, angiogenesis and capillary budding. Vasoconstriction is induced by hyperoxic conditions, and the reduction in blood fl ow together with the restoration of endothelial integrity decreases edema formation while still achieving sufficient oxygenation of tissues.

Since the diffusion of oxygen into tissues is often impaired by edema, scar tissue and vessel damage, HBOT is an effective means of delivering oxygen to target tissues as it overcomes these barriers. The amount of oxygen reaching superficial tissues is easily quantified in humans using transcutaneous measurements, making this a useful non-invasive tool for wound assessment and its likely response to treatment with HBOT.

A number of human and animal studies have shown the effects of HBOT on malignant tumors using a variety of treatment protocols. Just fewer than half of these studies showed a regression in tumor growth; half showed no effect, and a few showed apparently enhanced tumor progression. The different protocols used, as well as the type of tumor being treated, may have influenced the results. Animal studies using HBOT to treat sarcomas reported the most beneficial effects. HBOT used in combination with radiotherapy or chemotherapy has been shown to be more successful in controlling or reversing tumor growth.

HBOT complications

Oxygen toxicity inducing neurological symptoms is rare, but may occur when pressures higher than three atmospheres are used for prolonged periods. One potential negative effect of hyperoxygenation is the formation of oxygen-derived free radicals, although these may be counteracted with the administration of antioxidants. Additionally, HBOT augments host cell enzyme activity to assist in the degradation of free radicals, minimizing their negative effects.

Potential complications of HBOT include tympanic membrane rupture and generalized discomfort because of the increased pressure. Development of pneumothorax due to the presence of lung bullae is also possible, so a thorough examination, especially of the patient’s thorax, should be conducted before therapy is begun. Unstable patients should not be treated.

In most hyperbaric facilities, there is a time lag involved in directly accessing an animal being treated (due to the need to safely decompress), so HBOT should not be used to treat unstable animals unless an attendant is in the chamber with the patient.

Use in the clinic

Clinical experience suggests that most animals tolerate the hyperbaric chamber without the need for sedatives, and experience very little discomfort for the duration of therapy. Treatment generally lasts 60 to 90 minutes (usually 15 minutes of compression, 60 minutes at the desired pressure, and 15 minutes of decompression), and may be done once or twice a day depending on the severity of the condition being treated. The number of treatments required is also dependent on the nature of the condition, but animals typically respond very well to between one and five sessions, although up to ten may be required for severe conditions.

While HBOT may make a significant difference to a patient’s survival and quality of life, it is not always practical (especially for an unstable animal) or affordable (see the case studies below). As with many conditions, there is not necessarily a “magic bullet” when it comes to managing thoracic disease. However, a holistic approach – addressing the animal’s diet and lifestyle, and making use of appropriate treatments that integrate drugs and nutraceuticals – provides a variety of possibilities for treating thoracic issues.

Case studies

BEANIE is a 12-year-old male Fox Terrier. He was presented for a third opinion regarding a chronic cough, after a specialist diagnosed allergic or infectious lower airway disease. He had been treated with a variety of medications, including antihistamines, doxycycline, fenbendazole and others, but none helped improve his condition.

HBOT was recommended if he didn’t improve with initial supportive treatments that included vitamin C, grapeseed extract (proanthocyanidins) and a Heel remedy.

Beanie’s cough improved significantly and has been subsequently well managed, so there was no need for other therapies.

MAGGIE, a two-year-old FS Kelpie, had eaten rodenticide five days prior to presentation with a cough, white mucus membranes, crackles on auscultation of the lung field, and melena. A cell count revealed a regenerative anemia consistent with the blood loss associated with anticoagulant toxicity.

Vitamin K therapy was instituted immediately.

Maggie became severely lethargic within 12 hours and was treated with HBOT that evening. By the following morning, her demeanor had improved significantly, and she was bright and responsive. Another session of HBOT was repeated the following day, and she went on to make a full recovery.

JACK, a two-year-old MN Border Collie Cross, had trauma leading to a pneumothorax, with a collapsed left lung and subcutaneous emphysema.

He was stabilized with intravenous fluids, thoracocentesis, a pressure bandage, aspiration of air pockets, intravenous vitamin C, Traumeel and NSAIDS. HBOT wasn’t to be used in this instance because of the pneumothorax.

Aside from small remaining pockets of subcutaneous air, there was a marked improvement within 24 hours, and Jack made a full recovery.

MUNTER, a one-and-a-half-year-old MN Pomeranian, had a history of chronic lethargy. A diagnostic workup with radiographs revealed pleural effusion of unknown duration. Thoracocentesis showed noncoagulating blood and the cell count confirmed regenerative anemia consistent with rodenticide toxicity.

Vitamin K therapy was initiated along with HBOT, daily for three days. Each session of HBOT was followed by a marked improvement in Munter’s demeanor. He made a full recovery.

MARLEY, a five-year-old MN Burmese Cat, presented with a pyothorax; 200 ml fluid was aspirated by thoracocentesis. A chest drain was put in place with high dose intravenous vitamin C (2.5 grams BID) as well as antibiotics based on culture and sensitivity.

Marley’s fractiousness compromised the chest drain position so it was removed. His response to therapy (probably the Vitamin C) was profound and Marley was treated as an outpatient with full recovery.

ISIS, a male Bengal and a patient of Dr. Christina Chambreau, presented at age five with severe asthma. He had a mild chronic cough since eight weeks that was nonresponsive to any conventional treatments. One-and-a-half years prior to presentation, Isis was given his annual vaccines and the first of two suggested FIP vaccines (he was an indoor cat owned by a 75-year-old man). Hours later, Isis was on oxygen with blue lips and severe asthma. Multiple medications prevented severe attacks, but Isis continued with mild coughs, became lethargic and could tolerate no decrease in medicines. One month of homeopathic treatment with Thuja as the drugs were tapered off resulted in a deep healing. He lived another 15 years, had no more respiratory problems and only one episode of rodent ulcer.

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