Hyperbaric Oxygen Therapy for Pets–What’s The Evidence?

I recently participated in a couple of discussions on a veterinary web forum about hyperbaric oxygen therapy (HBOT) and evidence-based medicine. This technique is being heavily promoted with confident claims of scientifically proven benefits.  I thought, then, that I would take a look at the evidence.

What Is It?
Hyperbaric oxygen therapy involves placing patients in an airtight chamber and raising the atmospheric pressure and oxygen level so that oxygen is dissolved in the blood and delivered to tissues at higher levels than possible in normal atmospheric conditions. It is the treatment of choice for decompression sickness (The Bends) associated with SCUBA diving, but it is also recommended for numerous other medical indications. The Undersea and Hyperbaric Medical Society list 14 indications for which they consider the evidence sufficient to recommend HBOT.

What’s the Evidence?
When pressed, advocates acknowledged that there is virtually no clinical trial data in companion animal or food animal species to support HBOT for specific indications. This should automatically make any recommendations of HBOT tentative at best, and the therapy should essentially be considered experimental.

There is a large amount of in vitro and animal model research suggesting potential benefits of HBOT for a wide range of conditions, and proponents cite this as justification for putting HBOT chambers in veterinary practices and treating patients. Certainly, this evidence suggests HBOT is plausible and worth investigating. I have heard wacky theories for why HBOT should work (one vet once told me it was so successful because it recreated the state of the Earth’s atmosphere before the Biblical flood, when people lived hundreds of years). However, there are sound physiological rationales for the concept supported by good preclinical evidence.

Unfortunately, such pre-clinical research also has significant limitations and is often not consistent with the results of subsequent clinical trials for many therapies. It is necessary but not sufficient for making clinical decisions, and it is primarily intended to suggest that a new therapy is plausible and might work, not to prove that it does work in the real world. We often have to make the best of a bad business and rely on such evidence when there is nothing better, but any recommendations based purely on pre-clinical research must be made cautiously and with appropriate caveats, something HBOT advocates rarely do.

Most of the animal model studies are in rats, mice, and, to a lesser extent, guinea pigs and rabbits. There are a few experimental studies in dogs, cats, and horses (see Veterinary Studies  below). Most of these involve wounds or skin flaps and grafts, and they are by no means universally positive.

Another source evidence frequently used in veterinary medicine when there are no good veterinary studies is clinical trial data from humans. There is significant risk in extrapolation across species lines, but it is an inevitable and important part of veterinary medicine given the reality of limited resources to support target-species clinical trial research. One advocate of HBOT claims that we can have confidence in the value of HBOT because there are many controlled studies in the human literature showing the benefits of hyperbaric oxygen therapy for many conditions.

One outstanding review of the evidence for wound care, tissue trauma, and neurological disease, commissioned for the Washington State Health Care Authority, has recently been published.

It identifies moderate quality evidence to support the use of HBOT for aiding the healing of chronic wounds in diabetics, late radiation tissue injury, multiple sclerosis symptoms, and possibly in affecting mortality (though not long-term function) in traumatic brain injury. The evidence is of poor quality and inconclusive or not supportive for most other indications evaluated.

I have also taken a quick look at other systematic reviews of HBOT (primarily produced by the Cochrane Collaboration, though there are several from other sources) for the last 5 years. This is the most reliable assessment of the balance of the human clinical trial evidence, and it establishes what degree of confidence we should or should not have in the use of HBOT for specific problems (in humans, of course; again direct extrapolation to veterinary patients often changes the picture significantly)

These reviews are listed below. Again, they provide pretty good (though not always strong or consistent) support for adjunctive use of HBOT in treating wounds (in humans, of course). The evidence is fair to poor for other indications.

Is It Safe?
There is little data on the safety of HBOT in companion animals. One protocol was studied in 3 dogs in Japan and appeared to achieve oxygenation targets without obvious side effects.

(Hiroki YANAGISAWA, Eiichi KANAI, Hideki KAYANUMA, Takuo SHIDA, Tsunenori SUGANUMA. Hyperbaric Air Therapy in Dogs for Clinical Veterinary Medicine: A Basic Study. J. Vet. Med. Sci. 73(10): 1351–1354, 2011). However, there is really very little controlled data on possible risks in most companion animal species.

 

The Washington State review provides a nice evaluation of safety data (again in humans) for HBOT, which suggests that it is generally pretty safe but that there are common minor side effects and less common serious side effects.

 

The overall evidence suggests that harms associated with HBOT are generally mild and self-limiting. The majority of reported harms include barotrauma, temporary visual disturbances, and, more rarely, oxygen toxicity. Occasional reports of seizures represent the most serious side effects. The Medical Services Advisory Committee (MSAC) of Australia reported an overall harms incidence rate of 6.3%; 17% incidence of general pain or discomfort during decompression; 4.8% incidence of ear pain; 1.5% incidence of tympanostomy tube placements; 0.9% incidence of persistent ocular changes; 0.6% incidence of ear barotrauma; 0.34% incidence of abdominal pain; and 0.1% incidence of claustrophobia.

Notable indication-specific harms found in the literature include the following:

 ·         Among patients with LRTI, there were reports of ear pain (16% in a trial of 150 patients), transient myopia (3% in one study 8% in another), and confinement anxiety (1.7%).

 ·         Pooled data from 2 trials reported severe pulmonary complications (defined as either, rising oxygen requirements and infiltrates in chest x-ray or cyanosis and hyperpnoea so severe as to imply “impending hyperoxic pneumonia”) among 13% of TBI patients receiving HBOT compared with none in the control groups (RR, 15.57; 95% CI, 2.11-114.72).

 ·         One study reported ear problems among 47% of children with cerebral palsy receiving HBOT versus 22% among controls (P significant but value not reported). Another study reported a 12% seizure rate and found that 35% of patients reported ear problems.

 ·         Another reported that 8% of 50 children stopped treatment due to adverse events, including seizures, and one other study reported 1 seizure in an observational study of 230 patients. 

·         Among patients with MS, a 2011 Cochrane Collaboration review reported 77 patients (55%), across 4 trials, suffered temporary deterioration in visual acuity in the HBOT group versus 3 patients (2.3%) in the sham group (OR, 24.87; 95% CI, 1.44-428.5; NNT, 1; 95% CI, 1-2).

Of course, the most dramatic risk seen in veterinary use of HBOT is the catastrophic explosion of the oxygen chamber. This happened in Florida last year, and both the patient and one of the veterinary staff were killed. While this is clearly a problem with the administration of HBOT, not the technique itself, it is a risk that has to be factored in to any assessment of the pros and cons of the practice.

 

Bottom Line
HBOT is a biologically plausible therapy with substantial in vitro and animal model research to support possible benefits in a variety of conditions. There is, however, almost no clinical trial evidence to support its use in companion animal species. Justification of veterinary use of HBOT comes only from extrapolation from basic principles, pre-clinical research, anecdote, and extrapolation from research in humans, so this should be viewed as an unproven, experimental veterinary therapy.

There are a few indications for which the human clinical trial research provides at least a moderate degree of confidence that HBOT is effective. There are many others for which there is only limited and low-quality evidence and no clear conclusion can be drawn. Not all uses validated in humans are relevant to veterinary use, and most veterinary applications have not been directly studied in people. Overall, the evidence is strongest for adjunctive use of HBOT to facilitate healing of chronic wounds not resolving with standard therapies.

HBOT is generally quite safe, but there are both minor and serious potential adverse effects, and there is some risk associated with the use of the equipment.

Everyone will interpret this evidence differently in light of their own understanding of how research evidence should be integrated into clinical decision making. For my part, it suggests to me that HBOT is a promising therapy for a variety of indications but not clearly demonstrated effective for very many even in humans, and the veterinary evidence is too weak to be very useful in making recommendations. I would certainly like to see more and better research evidence before there is widespread use of this technique.

Companion Animal Studies

1.      Baumwart, C. A.Doherty, T. J.Schumacher, J.Willis, R. S.Adair, H. S., IIIRohrbach, B. W. Effects of hyperbaric oxygen treatment on horses with experimentally induced endotoxemia. American Journal of Veterinary Research. 2011 72 9 1266-1275

Objective – To determine the effectiveness of preinduction hyperbaric oxygen treatment (HBOT) in ameliorating signs of experimentally induced endotoxemia in horses. Animals – 18 healthy adult horses. Procedures – Horses were randomly assigned to 1 of 3 equal-sized treatment groups to receive normobaric ambient air and lipopolysaccharide (LPS), HBOT and LPS, or HBOT and physiologic saline (0.9% NaCl) solution. Horses were physically examined, and blood was obtained for a CBC and to determine concentration or activity of plasma tissue necrosis factor-?, blood lactate, and blood glucose before the horses were treated with HBOT and then intermittently for 6 hours after administration of LPS or physiologic saline solution. Results – All LPS-treated horses developed signs and biochemical and hematologic changes consistent with endotoxemia. Treatment with HBOT significantly ameliorated the effect of LPS on clinical endotoxemia score but did not significantly improve other abnormalities associated with endotoxemia. Conclusions and Clinical Relevance – The protective effect of HBOT was minimal, and results did not support its use as a treatment for horses prior to development of endotoxemia.

2.      Holder, T. E. C.Schumacher, J.Donnell, R. L.Rohrbach, B. W.Adair, H. S. A. Effects of hyperbaric oxygen on full-thickness meshed sheet skin grafts applied to fresh and granulating wounds in horses. American Journal of Veterinary Research. 2008 69 1 144-147

Objective – To determine the effects of hyperbaric oxygen therapy (HBOT) on full-thickness skin grafts applied to fresh and granulating wounds of horses. Animals – 6 horses. Procedures – On day 0, two 4-cm-diameter circular sections of full-thickness skin were removed from each of 2 randomly selected limbs of each horse, and two 4-cm-diameter circular skin grafts were harvested from the pectoral region. A skin graft was applied to 1 randomly selected wound on each limb, leaving the 2 nongrafted wounds to heal by second intention. On day 7, 2 grafts were harvested from the pectoral region and applied to the granulating wounds, and wounds grafted on day 0 were biopsied. On day 14, 1 wound was created on each of the 2 unwounded limbs, and the wounds that were grafted on day 7 were biopsied. All 4 ungrafted wounds (ie, 2 fresh wounds and 2 wounds with 1-week-old granulation beds) were grafted. The horses then received HBOT for 1 hour daily at 23 PSI for 7 days. On day 21, the grafts applied on day 14 were biopsied. Results – Histologic examination of biopsy specimens revealed that grafts treated with HBOT developed less granulation tissue, edema, and neovascularization, but more inflammation. The superficial portion of the graft was also less viable than the superficial portion of those not treated with HBOT. Conclusions and Clinical Relevance – The use of HBOT after full-thickness skin grafting of uncompromised fresh and granulating wounds of horses is not indicated.

3.      Kerwin, S. C.Lewis, D. D.Elkins, A. D.Oliver, J. L.Hosgood, G.Pechman, R. D., Jr.Dial, S. L.Strain, G. M. Effect of hyperbaric oxygen treatment on incorporation of an autogenous cancellous bone graft in a nonunion diaphyseal ulnar defect in cats. American Journal of Veterinary Research. 2000 61 6 691-698

12 mature cats were used to determine whether hyperbaric oxygen treatment (HBOT) would affect incorporation of an autogenous cancellous bone graft in diaphyseal ulnar defects. Bilateral non-union diaphyseal ulnar defects were created in each cat. An autogenous cancellous bone graft was implanted in 1 ulnar defect in each cat, with the contralateral ulnar defect serving as a non-grafted specimen. Six cats were treated by use of hyperbaric oxygen at 2 atmospheres absolute for 90 min once daily for 14 days, and 6 cats were not treated (control group). Bone labelling was performed, using fluorochrome markers. Cats were killed 5 weeks after implanting, and barium sulfate was infused to evaluate vascularization of grafts. Ulnas were evaluated by use of radiography, microangiography, histological examination, and histomorphometric examination. Radiographic scores did not differ between treatment groups. Microangiographic appearance of grafted defects was similar between groups, with all having adequate vascularization. Differences were not observed between treated and non-treated groups in the overall histological appearance of decalcified samples of tissue in grafted defects. Mean distance between fluorescent labels was significantly greater in cats given HBOT than in non-treated cats. Median percentage of bone formation in grafted defects was significantly greater in cats given HBOT. Hyperbaric oxygen treatment increased the distance between fluorescent labels and percentage of bone formation when incorporating autogenous cancellous bone grafts in induced non-union diaphyseal ulnar defects in cats, but HBOT did not affect revascularization, radiographic appearance or qualitative histological appearance of the grafts.

4.      Hosgood, G.Hodgin, E. C.Strain, G. M.Lopez, M. K.Lewis, D. D. Effect of deferoxamine and hyperbaric oxygen on free, autogenous, full-thickness skin grafts in dogs. American Journal of Veterinary Research. 1995 56 2 241-247

Free, autogenous, full thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine 10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight,i.v.), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, i.v.). All dogs (DEF-HES/HBO and HES/HBO treated) were exposed to 60 minutes of hyperbaric oxygen (HBO) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in HES/HBO treated dogs (mean + SD; 13.3 + 21.3%; median, 3.0%) than in DEF-HES/HBO treated dogs (64.7 + 39.2%; 88.3%). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs. Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of DEF-HES/HBO treated dogs. These cells were also observed in the dermis, and in some viscera of DEF-HES/HBO treated dogs. Deferoxamine appeared to attenuate the detrimental effect of HBO and HES on survival of free skin grafts. It is concluded that the clinical use of HBO and DEF-HES is not recommended because it failed to improve the survival of free skin grafts.

5.      Kerwin, S. C.Hosgood, G.Strain, G. M.Vice, C. C.White, C. E.Hill, R. K. The effect of hyperbarbic oxygen treatment on a compromised axial pattern flap in the cat. Veterinary Surgery. 1993 22 1 31-36

A pedicile skin flap based on the caudal superficial epigastric artery was created in 12 cats. The artery was ligated and the vein left intact. Six cats were treated with hyperbaric oxygen at 2 atm absolute for 90 minutes daily for 14 days, starting the day after surgery. Skin flap colour was significantly better in the treated cats on days 1, 2, and 3. The amount of exudate was significantly less in the treated cats on day 3. There was no difference in the amount of swelling between treated and nontreated control cats. Although 5 of 6 of the treated cats had 100% skin flap survival, there was no significant difference in total flap survival between treated and nontreated control cats.

Systematic Reviews of HBOT for Wounds in Humans

1.      Systematic review of the effectiveness of hyperbaric oxygenation therapy in the management of chronic diabetic foot ulcers.

Liu R, Li L, Yang M, Boden G, Yang G. Mayo Clin Proc. 2013 Feb;88(2):166-75. doi: 10.1016/j.mayocp.2012.10.021.
Thirteen trials (a total of 624 patients), including 7 prospective randomized trials, performed between January 1, 1966, and April 20, 2012, were identified as eligible for inclusion in the study. Pooling analysis revealed that, compared with treatment without HBO, adjunctive treatment with HBO resulted in a significantly higher proportion of healed diabetic ulcers (relative risk, 2.33; 95% CI, 1.51-3.60). The analysis also revealed that treatment with HBO was associated with a significant reduction in the risk of major amputations (relative risk, 0.29; 95% CI, 0.19-0.44); however, the rate of minor amputations was not affected (P=.30). Adverse events associated with HBO treatment were rare and reversible and not more frequent than those occurring without HBO treatment (P=.37).

This meta-analysis reveals that treatment with HBO improved the rate of healing and reduced the risk of major amputations in patients with diabetic foot ulcers. On the basis of these effects, we believe that quality of life could be improved in selected patients treated with HBO.

 

2.      Hyperbaric oxygen therapy for treating chronic wounds

Kranke P, Bennett MH, Martyn-St James M, Schnabel A, Debus SE
April 18, 2012
This review update of randomised trials found that HBOT seems to improve the chance of healing diabetes-related foot ulcers and may reduce the number of major amputations in people with diabetes who have chronic foot ulcers. In addition this therapy may reduce the size of wounds caused by disease to the veins of the leg, but the review found no evidence to confirm or refute any effect on other wounds caused by lack of blood supply through the arteries or pressure ulcers.

 

3.      A systematic review of the effectiveness of interventions in the management of infection in the diabetic foot.

Peters EJ, Lipsky BA, Berendt AR, Embil JM, Lavery LA, Senneville E, Urban?i?-Rovan V, Bakker K, Jeffcoate WJ. Diabetes Metab Res Rev. 2012 Feb;28 Suppl 1:142-62. doi: 10.1002/dmrr.2247.
There was no improvement in infection outcomes associated with hyperbaricoxygen therapy.

 

4.      Hyperbaricoxygen therapy: solution for difficult to heal acute wounds? Systematic review.
Eskes AM, Ubbink DT, Lubbers MJ, Lucas C, Vermeulen H. World J Surg. 2011 Mar;35(3):535-42. doi: 10.1007/s00268-010-0923-4.
We included five trials, totaling 360 patients. These trials, with some methodologic flaws, included different kinds of wound and focused on different outcome parameters, which prohibited meta-analysis. A French trial (n = 36 patients) reported that significantly more crush wounds healed with HBOT than with sham HBOT [relative risk (RR) 1.70, 95% confidence interval (CI) 1.11-2.61]. Moreover, there were significantly fewer additional surgical procedures required with HBOT (RR 1.60, 95% CI 1.03-2.50), and there was significantly less tissue necrosis (RR 1.70, 95% CI 1.11-2.61). In one of two American trials (n = 141) burn wounds healed significantly quicker with HBOT (P < 0.005) than with routine burn care. A British trial (n = 48) compared HBOT with usual care. HBOT resulted in a significantly higher percentage of healthy graft area in split skin grafts (RR 3.50, 95% CI 1.35-9.11). In a Chinese trial (n = 145) HBOT did not significantly improve flap survival in patients with limb skin defects. HBOT, if readily available, appears effective for the management of acute, difficult to heal wounds. 

 

5.      Hyperbaric oxygen therapy for acute surgical and traumatic wounds
Eskes A, Ubbink DT, Lubbers M, Lucas C, Vermeulen H
February 16, 2011
This review did not find any high quality research evidence showing that HBOT is beneficial for wound healing. Two poor quality studies suggested benefits associated with HBOT. The first in patients with crush injuries, showed improved wound healing and fewer adverse outcomes. The second reported improved survival of split skin grafts. A third trial reported no benefits associated with HBOT for skin grafts.

Further, better quality research is needed to determine the effects of HBOT on wound healing.

 

6.      Hyperbaricoxygen therapy for wound healing and limb salvage: a systematic review.

Goldman RJ. PM R. 2009 May;1(5):471-89. doi: 10.1016/j.pmrj.2009.03.012.

This article is a systematic review evaluating published clinical evidence of the efficacy of hyperbaricoxygen therapy (HBOT) for wound healing and limb salvage… The author evaluated 620 citations, of which 64 reported original observational studies and randomized controlled trials (RCTs) on HBOT and healing outcomes. All citations with 5 subjects were selected for full text review (44 articles) and evaluated according to GRADE criteria for high, medium, low, or very low level of evidence. A Cochrane review identified 1 additional study with a low level of evidence….For patients with diabetic foot ulcers (DFU) complicated by surgical infection, HBOT reduces chance of amputation (odds ratio [OR] 0.242, 95% CI: 0.137-0.428) (7 studies) and improves chance of healing (OR 9.992, 95% CI: 3.972-25.132) (6 studies)…HBOT is associated with remission of about 85% of cases of refractory lower extremity osteomyelitis, but an RCT is lacking to clarify extent of effect. There is a high level of evidence that HBOT reduces risk of amputation in the DFU population by promoting partial and full healing of problem wounds. There is a moderate level of evidence that HBOT promotes healing of arterial ulcers, calciphylactic and refractory vasculitic ulcers, as well as refractory osteomyelitis. There is a low to moderate level of evidence that HBOT promotes successful “take” of compromised flaps and grafts.

Systematic Reviews for Other Indications in Humans

Systematic review of agents for the management of gastrointestinal mucositis in cancer patients.
Gibson RJ, Keefe DM, Lalla RV, Bateman E, Blijlevens N, Fijlstra M, King EE, Stringer AM, van der Velden WJ, Yazbeck R, Elad S, Bowen JM; Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Support Care Cancer. 2013 Jan;21(1):313-26. doi: 10.1007/s00520-012-1644-z. Epub 2012 Nov 10.
…the panel suggests the use of hyperbaricoxygen as an effective means in treating radiation-induced proctitis.

 

Does hyperbaric oxygen therapy improve the survival and quality of life in patients with traumatic brain injury?
Bennett MH, Trytko B, Jonker B
December 12, 2012
The effectiveness of HBOT on the recovery of brain-injured patients is uncertain. There is also concern regarding potential adverse effects of the therapy, including damage to the ears, sinuses and lungs from the effects of pressure, temporary worsening of short-sightedness, claustrophobia and oxygen poisoning.

In an attempt to address the uncertainty surrounding the use of HBOT, the authors of this review identified all studies which were randomized controlled trials investigating the effects of HBOT in traumatically brain-injured people of all ages.

The authors found seven eligible studies involving 571 people. The combined results suggest that HBOT reduces the risk of death and improves the level of coma; however, there is no evidence that these survivors have an improved outcome in terms of quality of life. It is possible, therefore, that the overall effect of hyperbaric oxygen is to make it more likely that people will survive with severe disability after such injuries. The authors conclude that the routine use of HBOT in brain-injured patients cannot be justified by the findings of this review.

Due to the small number of trials with a limited number of people, it is not possible to be confident in the findings. Further large, high quality trials are required to define the true extent of benefit from HBOT.

 

Using oxygen at high pressure (in a compression chamber) for the treatment of broken bones
Bennett MH, Stanford RE, Turner R
November 14, 2012
This review found no evidence from randomised trials to support or refute the use of hyperbaric oxygen therapy to avoid or treat poorly healing broken bones. However, in this update, we found three ongoing randomised trials that are likely to provide some evidence to inform on the use of hyperbaric oxygen therapy in the future.

 

Hyperbaric oxygen therapy for vascular dementia
Xiao Y, Wang J, Jiang S, Luo H
July 11, 2012
This review included one randomised controlled trial of poor methodological quality involving 64 patients with VaD who were also taking donepezil. Safety assessment was not mentioned at all. Although the authors reported cognitive benefit, this trial alone cannot be taken as evidence of efficacy. Further well-designed randomised controlled trials are needed.

 

Ghanizadeh A.  Hyperbaricoxygen therapy for treatment of children with autism: a systematic review of randomized trials.
Med Gas Res. 2012 May 11;2:13. doi: 10.1186/2045-9912-2-13.
The electronically search resulted in 18 title of publications. Two studies were randomized, double-blind, controlled-clinical trials. While some uncontrolled and controlled studies suggested that HBO therapy is effective for the treatment of autism, these promising effects are not replicated. Therefore, sham-controlled studies with rigorous methodology are required to be conducted in order to provide scientific evidence-based HBO therapy for autism treatment.

 

Hyperbaric oxygen therapy (HBOT) for the treatment of the late effects of radiotherapy
Bennett MH, Feldmeier J, Hampson N, Smee R, Milross C
May 16, 2012
We found some evidence that LRTI affecting the head, neck and lower end of the bowel can be improved with HBOT. There is little evidence for or against benefit in other tissues affected by LRTI. Our conclusions are based on 11 randomised trials with a limited number of patients. Further research is needed.

 

High pressure oxygen breathing during radiotherapy for cancer treatment
Bennett MH, Feldmeier J, Smee R, Milross C
April 18, 2012
Breathing oxygen while at raised pressure in a closed chamber (hyperbaric oxygen or HBO) may increase the effectiveness of radiotherapy and thus improve mortality and reduce tumour regrowth. We found some evidence that people with head and neck cancer are less likely to die within five years if they are treated this way, and evidence that regrowth of tumour at the original site is less likely for head and neck, and cervical cancer. However, Hyperbaric oxygen therapy (HBOT) may only be effective when radiotherapy is given in an unusually small number of sessions, each with a relatively high dose. HBOT does not appear to work for other cancers studied. Our conclusions are based on 19 randomised trials with over 2000 patients.

 

Hyperbaricoxygen treatment for inflammatory bowel disease: a systematic review and analysis.
Rossignol DA. Med Gas Res. 2012 Mar 15;2(1):6. doi: 10.1186/2045-9912-2-6.
Thirteen studies of HBOT in Crohn’s disease and 6 studies in ulcerative colitis were identified….Twelve publications reported using HBOT in animal models of experimentally-induced IBD… Although most publications reported improvements with HBOT, some studies suffered from limitations, including possible publication and referral biases, the lack of a control group, the retrospective nature and a small number of participants.

HBOT lowered markers of inflammation and oxidative stress and ameliorated IBD in both human and animal studies. Most treated patients were refractory to standard medical treatments. Additional studies are warranted to investigate the effects of HBOT on biomarkers of oxidative stress and inflammation as well as clinical outcomes in individuals with IBD.

 

A systematic review of interventions to enhance the healing of chronic ulcers of the foot in diabetes.
Game FL, Hinchliffe RJ, Apelqvist J, Armstrong DG, Bakker K, Hartemann A, Löndahl M, Price PE, Jeffcoate WJ. Diabetes Metab Res Rev. 2012 Feb;28 Suppl 1:119-41. doi: 10.1002/dmrr.2246.
The present report is an update of the earlier IWGDF systematic review, but the conclusion is similar: that with the exception of HBOT and, possibly, negative pressure wound therapy, there is little published evidence to justify the use of newer therapies. This echoes the conclusion of a recent Cochrane review and the systematic review undertaken by the National Institute for Health and Clinical Excellence Guidelines Committee in the UK. Analysis of evidence presents considerable difficulties in this field particularly as controlled studies are few and the majority are of poor methodological quality.

 

High pressure (hyperbaric) oxygen therapy for Bell’s palsy
Holland NJ, Bernstein JM, Hamilton JW
February 15, 2012
Our searches revealed no trials that met the inclusion criteria for the review. We found very low quality evidence from one trial to suggest that hyperbaric oxygen therapy might be beneficial for moderate to severe Bell’s palsy. The quality of evidence from this trial was very low because the assessors of facial function were aware of which treatment each participant had been given, which introduces a high risk of bias. There is therefore no high quality evidence on which to base conclusions about the efficacy of hyperbaric oxygen therapy in Bell’s palsy.

 

Hyperbaric oxygen therapy, which involves people breathing pure oxygen in a specially designed chamber, for the treatment of multiple sclerosis
Bennett MH, Heard R
August 10, 2011
The review of nine trials found no consistent evidence that HOBT can improve disability or modify the progression of MS. There is little need for further research.

 

Hyperbaric oxygen may reduce the risk of dying, the time to pain relief and the chance of adverse heart events in people with heart attack and unstable angina
Bennett MH, Lehm JP, Jepson N
August 10, 2011
We first searched the literature in 2004 and most recently in June 2010, finding one further study. Overall,we found some evidence that people with ACS are less likely to die or to have major adverse cardiac events, and to have more rapid relief from their pain, if they receive hyperbaric oxygen therapy as part of their treatment. However, our conclusions are based on six relatively small randomised trials (five of which included only patients with confirmed heart muscle death). While HBOT may therefore reduce the risk of dying, time to pain relief and the chance of adverse heart events in people with heart attack and unstable angina, more work is still needed to be sure that HBOT should be recommended.

 

There is insufficient evidence to support the use of hyperbaric oxygen for treatment of patients with carbon monoxide poisoning
Buckley NA, Juurlink DN, Isbister G, Bennett MH, Lavonas EJ
April 13, 2011
the review of published trials found conflicting, potentially biased, and generally weak evidence regarding the usefulness of hyperbaric oxygen for the prevention of neurological injury.

 

Hyperbaric oxygen as an additional treatment for malignant otitis externa
Phillips JS, Jones SEM
February 16, 2011
The review found no trials to demonstrate that the addition of hyperbaric oxygen therapy offers a better outcome than the treatments alone. Further research is required.

 

Efficacy of pre- and postirradiation hyperbaricoxygen therapy in the prevention of postextraction osteoradionecrosis: a systematic review.
Fritz GW, Gunsolley JC, Abubaker O, Laskin DM. J Oral Maxillofac Surg. 2010 Nov;68(11):2653-60. doi: 10.1016/j.joms.2010.04.015. Epub 2010 Aug 19.
Most of the studies had a small sample size, lacked specific inclusion and exclusion criteria, did not report the interval between radiation and extraction, and provided limited information on the method of extraction. There was also variation in HBO protocols, radiation dosage, the use of antibiotics, and the use of adjunctive cancer therapy.

On the basis of the best available evidence, there is currently insufficient information to show that the use of HBO reduces the incidence of osteoradionecrosis in irradiated patients requiring tooth extraction.

 

Hyperbaric oxygen therapy for delayed onset muscle soreness and closed soft tissue injury
Bennett MH, Best TM, Babul-Wellar S, Taunton JE
June 16, 2010
Our review included nine small trials, involving a total of 219 participants. Two trials compared HBOT versus sham therapy on ankle sprain and knee sprain respectively. Neither trial provided sufficient evidence to determine if HBOT helped people with these injuries. The other seven trials examined the effect of HBOT on muscle injury following unaccustomed exercise. There was no evidence that HBOT helped people with muscle injury following unaccustomed exercise, but some evidence that people given HBOT had slightly more pain. Further research on HBOT is not a high priority given the variety of other treatment interventions available.

 

Normal pressure oxygen therapy and hyperbaric oxygen therapy for migraine and cluster headaches
Bennett MH, French C, Schnabel A, Wasiak J, Kranke P
October 7, 2009
In our review, we found some weak evidence to suggest that HBOT helps people with acute migraine headaches and possibly cluster headaches, and that NBOT may help people with cluster headache. We found no evidence that either can prevent future attacks. Because many migraines can be treated simply with appropriate drug therapy, further research is needed to help choose the most appropriate patients (if any) to receive HBOT.

 

Little evidence that burns patients benefit from hyperbaric oxygen therapy
Villanueva E, Bennett MH, Wasiak J, Lehm JP
October 7, 2009
The review found only two randomised trials, with only a limited number of patients. There was no consistent benefit from HBOT, but one trial did suggest an improvement in healing time. Overall, there is little evidence to support or refute the use of HBOT for burns patients. More research is needed.

 

Hyperbaric oxygen therapy for acute ischaemic stroke
Bennett MH, Wasiak J, Schnabel A, Kranke P, French C
October 7, 2009
There is little evidence that stroke patients benefit from hyperbaric oxygen therapy….Our review found only six randomised trials involving 283 participants. Too few patients have been studied to say whether or not HBOT decreases the chance of dying and only three trials suggested any improvement in the ability to do everyday tasks. Overall, there is currently little evidence to support the use of HBOT for stroke patients.

 

Interventions for replacing missing teeth: hyperbaric oxygen therapy for irradiated patients who require dental implants
Esposito M, Grusovin MG, Patel S, Worthington HV, Coulthard P
October 8, 2008
We could only identify one study including a limited number of patients. This study suggested that the use of hyperbaric oxygen (HBO) therapy for patients who require dental implants after radiotherapy is of no apparent clinical benefit….More reliable studies are needed to provide the final answer to this question.

 

 

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8 Responses to Hyperbaric Oxygen Therapy for Pets–What’s The Evidence?

  1. v.t. says:

    Thanks for this, skeptvet.

    Now, my question is, how can advocates possibly recommend HBOT when even human studies and trials show side effects that many cannot possibly be measured in companion animals (just an example among many, earaches). This begs some sort of regulation and strict control of HBOT, especially since there is limited and even less evidence of efficacy and safety in companion animals. How do advocates sleep at night, when their patients can’t tell them how they feel (potential side effects, and owners don’t know what to monitor for, nor recognize)!

  2. Art says:

    Has UF really started a controlled hbot study? If so where did the money to fund it come from and could the study be registered like it would be in human medicine studies?
    Art Malernee dvm

  3. skeptvet says:

    I have heard that there is a study going on at UF, but I don’t have any details about it.

    Registration of clinical studies is not currently available for veterinary research because there is no registry. EBVMA is looking into what would be involved in starting one, but no specific plans yet.

  4. Art says:

    I went to get some required by law continuing education that was paid for by a hbot chamber maker for pets only. The speaker promoted chambers for stroke cases. I see that human chamber makers cannot do that.
    See
    http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/ucm191710.htm
    Art Malernee Dvm

  5. Pingback: New Studies Show Hyperbaric Oxygen Therapy Helps Treat Concussion, but no more than Placebo Treatment | The SkeptVet

  6. Melanie says:

    My 16 lb. Terrier had two HBOT sessions two days apart last week. She had trouble walking after the second treatment ( for wounds) and a crusty circle on the upper and lower lids around both eyes which is still present. 12/8/2015

    I have not read in this website of any side effect of this nature using HBOT. Is this a new procedure for vets?

  7. skeptvet says:

    HBOT is not widely used in veterinary medicine, so many vets have no experience with it. And as the article indicates, there is little direct clinical research on the benefits or the risks in pets, so it’s hard to know if the symptoms your pet had were related to the HBOT or not. This is part of why more research is needed before this practice becomes widespread.

  8. Art Malernee dvm says:

    Not widely used>>
    The deal is they put the hbot chamber in your office and you split the money it makes 50/50 with the hbot maker. I am not sure if they do that deal with the Florida vet school.
    See
    http://www.hvmed.com/#!florida-hvm-chambers/cbzd

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