Hyperbaric oxygen therapy Villanueva E, Johnston R, Clavisi O, Burrows E, Bernath V, Rajendran M, Wasiak J, Fennessy P, Anderson J, Harris A, Yong K

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1 Hyperbaric oxygen therapy Villanueva E, Johnston R, Clavisi O, Burrows E, Bernath V, Rajendran M, Wasiak J, Fennessy P, Anderson J, Harris A, Yong K Authors' objectives To assess the effectiveness of hyperbaric oxygen therapy (HBOT). Searching Several electronic databases were searched from 1966 to 1999; the search terms were reported. Also searched were the internet sites of Health Technology Assessment groups and the Database of Randomised Controlled Trials in Diving and Hyperbaric Medicine (DORCTHIM). Textbooks, book chapters and references were also checked. Studies were restricted to those reported in English. Study selection Study designs of evaluations included in the review Controlled studies were eligible for inclusion. Uncontrolled studies or those without a comparison group were excluded. Specific interventions included in the review Studies that assessed HBOT delivered in either a monoplace or multiplace chamber compared with procedures not using HBO, including standard or conventional therapy, normobaric oxygen or placebo, were eligible for inclusion. The frequency and duration of HBOT varied considerably across the studies. Participants included in the review Studies of participants with the following indications were included: thermal burns; diabetic wounds including diabetic gangrene and diabetic foot ulcers; non-diabetic wounds and decubitus (or pressure) ulcers; soft tissue infections including necrotising fasciitis, Fournier's gangrene and necrotising arachnidism; actinomycosis; soft tissue radionecrosis; osteomyelitis; osteoradionecrosis; skin graft survival; multiple sclerosis and cerebral palsy; cardiovascular conditions including acute myocardial infarctions, cerebrovascular disease, and peripheral obstructive arterial disease; soft tissue injuries including acute ankle sprains and crush injuries; facial paralysis (Bell's palsy); cluster and migraine headaches; Legg-Calve-Perthes disease (necrosis of the femoral head); sudden deafness and acoustic trauma; Crohn's disease; osteoporosis; cancer; and carbon monoxide poisoning. Studies that assessed participants with decompression illness, gas embolism, gas gangrene, cyanide poisoning, head trauma, cerebral oedema, acquired brain injury, cognitive impairment, senile dementia, glaucoma, keratoendotheliosis, human immunodeficiency virus infection, anaemia from exceptional blood loss, insulin dependent diabetes mellitus, facial neuritis, arthritis, spinal injuries and non-union fractures were excluded. Outcomes assessed in the review No inclusion criteria were specified for the outcome measures. The specific outcomes assessed varied widely according to the different indications. How were decisions on the relevance of primary studies made? The authors stated that a team of reviewers assessed the studies for inclusion. Assessment of study quality The quality of the studies was assessed according to methods of randomisation (adequate, unclear, inadequate, none), blinding, and the reporting of losses to follow-up. The studies were then classified according to the hierarchy of the National Health and Research Council revised hierarchy of evidence grading (see Other Publications of Related Interest). The authors did not state how many reviewers performed the quality assessment. Page: 1 / 5

2 Data extraction Two independent reviewers extracted the data, with any disagreements being resolved through discussion and consensus. The odds ratios (ORs) or weighted mean differences (WMDs), along with the number of adverse events, were extracted. Methods of synthesis How were the studies combined? The studies were grouped according to participant indications and, where appropriate, the ORs or WMDs were pooled in a meta-analysis using a random-effects model. Where significant heterogeneity was detected between the studies, a narrative synthesis of the studies was used. How were differences between studies investigated? Where studies were found to be clinically heterogeneous, statistical heterogeneity was assessed using the Q statistic (P=0.10) and sensitivity analysis. In addition, Galbraith diagrams and L'Abbe plots were generated to assess any further differences. Results of the review The authors stated that 80 studies were included in the review. However, the results of only 65 studies were reported, as where there was systematic review evidence available for an indication, this was reported in preference to the results of primary studies included in the review. Sixty-five studies with more than 5,856 participants were reported: 2 systematic reviews, 38 randomised controlled trials (RCTs), 21 comparative studies, 3 comparative studies with historical controls, and 1 case series. This section summarised the main findings of the review; for more specific details the reader is referred to the relevant sections of the report. Thermal burns (8 studies): the studies were clinically and methodologically heterogeneous. Overall, there was little evidence to support the use of HBOT for this indication. Diabetic wounds (5 studies): the studies were clinically and statistically homogeneous. The results showed that major amputations were less likely in diabetic patients with chronic ulceronecrotic lesions who were treated with HBOT than in patients receiving comparison therapies. It was also found that HBOT promoted wound healing and reduced the length of hospital stay, although it also increased the risk of minor amputations. Non-diabetic wounds (1 study): based on the results of one small study, there was some evidence that treatment with HBOT was associated with decreases in the area of chronic, non-diabetic wounds. Necrotising soft tissue infections (2 studies): the studies were clinically and methodologically heterogeneous. The results from one of the studies indicated that HBOT was associated with significant increases in overall survival. The results from the other study failed to reach significance for this outcome, and indicated that HBOT was associated with more operations and debridements. Necrotising fasciitis (3 studies): the studies were small, clinically heterogeneous, and provided little information about the HBOT. There was little evidence from any of the included studies to support the use of HBOT for this indication. Fournier's gangrene (1 study): survival was significantly better in patients who received HBOT than in those who received the comparison therapy alone. The results were based on a small retrospective cohort study. Osteomyelitis (1 study): there were no significant differences between the group treated with HBOT and the comparison group in terms of length of hospitalisation, clinical outcome or risk of recurrence. Osteoradionecrosis (2 studies): one study assessed prevention and the other assessed the treatment of osteoradionecrosis. The results of the study examining prevention showed that HBOT was more effective than penicillin in the prevention of osteoradionecrosis. The study that assessed treatment showed that patients who were Page: 2 / 5

3 treated with HBOT had significantly less failed implants and a higher survival rate in comparison with controls. Skin graft survival (2 studies): both studies were poorly reported in terms of the patient population and comparison interventions. Therefore, no conclusions could be drawn regarding the effectiveness of HBOT for either myocutaneous flaps or split skin grafts. Acute myocardial infarction (2 studies): neither of the studies provided evidence to support the use of HBOT for acute myocardial infarction. The studies either failed to find any benefit on major end points or suffered from flaws in the study design. Cerebrovascular disease (2 studies): the results of the studies were conflicting and assessed only a small number of end points. Therefore, no evidence was found to support the use of HBOT in cerebrovascular disease. Peripheral obstructive arterial disease (1 study): only one small trial was identified. The study did not provide any evidence of benefit with HBOT in patients with peripheral obstructive arterial disease. Soft tissue injuries (acute ankle sprains and crush injuries) (2 studies): one study assessed patients with acute ankle sprains and one patients with crush injuries. The results of the former (ankle sprains) indicated no treatment benefit with adjunctive HBOT. The second small trial of patients with crush injuries of the lower limbs showed that HBOT benefited patients in terms of decreased surgical intervention, but not in terms of decreased healing time. Cluster headaches (2 studies): two small, poor-quality studies showed some benefit of HBOT compared with the comparison therapy in relation to pain relief and physiochemical outcomes. Migraine headaches (2 studies): both studies were small. Therefore, further research is needed to provide conclusive evidence of any treatment benefit with HBOT for this indication. Facial paralysis (1 study): only one small study was included. The results provided some evidence of a benefit of HBOT in patients with moderate to severe facial paralysis of less than 1 week in duration. Sudden deafness and acoustic trauma (4 studies): the studies provided conflicting evidence of any treatment benefit with HBOT within this indication. Head and neck cancer (9 studies): the studies were clinically and methodologically heterogeneous. The results provided no support for there being any treatment benefit of HBOT in patients with head and neck cancer. Cervical cancer (6 studies): no conclusions could be drawn regarding the effectiveness of HBOT in conjunction with radiotherapy for cervical cancer. Bladder cancer (4 studies): the studies provided conflicting results on any survival benefit with HBOT in conjunction with radiotherapy for bladder cancer. Lymphomas (1 study): the results indicated some benefits of HBO exposure in the treatment of lymphomas. However, the study was small and of poor methodological quality. Lung cancer (1 study): this study provided no evidence of a treatment benefit of HBOT in patients with lung cancer. Neuroblastoma (1 study): one small, poor-quality study showed some evidence of an effect of HBOT in patients with neuroblastoma. Adverse events: those recorded that were associated with HBOT were myopia, barotraumas, oxygen toxicity, claustrophobia and decompression illness. Cost information Yes. The authors reported that based on a cost of AUS$6,941 per treatment course, monoplace HBOT could be costeffective in the treatment of diabetic wounds and necrotising soft tissue infections. They also reported that for Page: 3 / 5

4 osteoradionecrosis, HBOT may cost an estimated AUS$28,480 per case avoided. Authors' conclusions There was evidence of effectiveness for HBOT in diabetic wounds, and limited evidence of effectiveness in the prevention of osteoradionecrosis, crush injuries, cluster and migraine headaches, and facial paralysis. Insufficient or conflicting evidence was found for the indications of thermal burns, non-diabetic wounds, necrotising soft tissue infections, treatment of osteoradionecrosis, skin graft survival, cerebrovascular disease, peripheral obstructive arterial disease, sudden deafness, cancer of the head and neck, cervical cancer, bladder cancer, lymphoma and neuroblastoma, carbon monoxide poisoning, necrotising arachnidism, actinomycosis, soft tissue radionecrosis, cerebral palsy, Crohn's disease, Legg-Calve-Perthes disease and osteoporosis. There was a lack of evidence of any beneficial effect in multiple sclerosis, osteomyelitis, acute myocardial infarction, acute ankle sprains and lung cancer. CRD commentary This was a broad review, but the question was clearly defined in terms of the participants, interventions and study designs. Several sources were searched for relevant studies, but only English language articles were included. This means that other studies might have been missed. Efforts were made to minimise reviewer bias and errors in the study selection and data extraction processes. However, it was not reported how many reviewers were involved in the assessment of study quality. The quality of the studies was adequately assessed, and the results of the quality assessment were discussed in the text. Sufficient study details were provided to allow the reader to assess whether the authors' conclusions are consistent with the evidence reviewed. The use of both meta-analyses and a narrative synthesis, dependent upon the heterogeneity of the studies, was appropriate. Differences between the studies were also thoroughly explored. Overall, this was a thorough review and the authors' conclusion appears robust. Implications of the review for practice and research The authors did not state any implications for practice or further research. Bibliographic details Villanueva E, Johnston R, Clavisi O, Burrows E, Bernath V, Rajendran M, Wasiak J, Fennessy P, Anderson J, Harris A, Yong K. Hyperbaric oxygen therapy. Canberra, ACT, Australia: Medicare Services Advisory Committee. Assessment report; MSAC applications Original Paper URL Other publications of related interest National Health and Medical Research Council. A guide to the development, implementation and evaluation of clinical practice guidelines. Canberra: The Council; Indexing Status Subject indexing assigned by CRD MeSH Hyperbaric Oxygenation AccessionNumber Date bibliographic record published 31/05/2006 Page: 4 / 5

5 Powered by TCPDF ( Date abstract record published 31/05/2006 Record Status This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn. Page: 5 / 5