BACKGROUND: Chronic wounds are common and present a health problem with significant effect on quality of life. Various pathologies may cause tissue breakdown, including poor blood supply resulting in inadequate oxygenation of the wound bed. Hyperbaric oxygen therapy (HBOT) has been suggested to improve oxygen supply to wounds and therefore improve their healing.
OBJECTIVES: To assess the benefits and harms of adjunctive HBOT for treating chronic ulcers of the lower limb.
SEARCH METHODS: For this second update we searched the Cochrane Wounds Group Specialised Register (searched 18 February 2015); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015, Issue 1); Ovid MEDLINE (1946 to 17 February 2015); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, 17 February 2015); Ovid EMBASE (1974 to 17 February 2015); and EBSCO CINAHL (1982 to 17 February 2015).
SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing the effect on chronic wound healing of therapeutic regimens which include HBOT with those that exclude HBOT (with or without sham therapy).
DATA COLLECTION AND ANALYSIS: Three review authors independently evaluated the risk of bias of the relevant trials using the Cochrane methodology and extracted the data from the included trials. We resolved any disagreement by discussion.
MAIN RESULTS: We included twelve trials (577 participants). Ten trials (531 participants) enrolled people with a diabetic foot ulcer: pooled data of five trials with 205 participants showed an increase in the rate of ulcer healing (risk ratio (RR) 2.35, 95% confidence interval (CI) 1.19 to 4.62; P = 0.01) with HBOT at six weeks but this benefit was not evident at longer-term follow-up at one year. There was no statistically significant difference in major amputation rate (pooled data of five trials with 312 participants, RR 0.36, 95% CI 0.11 to 1.18). One trial (16 participants) considered venous ulcers and reported data at six weeks (wound size reduction) and 18 weeks (wound size reduction and number of ulcers healed) and suggested a significant benefit of HBOT in terms of reduction in ulcer area only at six weeks (mean difference (MD) 33.00%, 95% CI 18.97 to 47.03, P < 0.00001). We identified one trial (30 participants) which enrolled patients with non-healing diabetic ulcers as well as venous ulcers ("mixed ulcers types") and patients were treated for 30 days. For this "mixed ulcers" there was a significant benefit of HBOT in terms of reduction in ulcer area at the end of treatment (30 days) (MD 61.88%, 95% CI 41.91 to 81.85, P < 0.00001). We did not identify any trials that considered arterial and pressure ulcers.
AUTHORS' CONCLUSIONS: In people with foot ulcers due to diabetes, HBOT significantly improved the ulcers healed in the short term but not the long term and the trials had various flaws in design and/or reporting that means we are not confident in the results. More trials are needed to properly evaluate HBOT in people with chronic wounds; these trials must be adequately powered and designed to minimise all kinds of bias.
It's hard to know what people in the field know or don't know or think they know. Mixed results with a mix of ulcers complicated by a variety of underlying pathology. Diabetics surely have arterial disease as well as neuropathy playing roles. Venous stasis and arterial insufficiency are often combined. Finding a hperbaric oxygen center can be expensive. As noted, results are a mixed bag. If hyperbaric oxygen is easily available and the ulcer is non-healing, it may be worth a trial short term for diabetic ulcers and longer term for venous ulcers and mixed. This clearly does not preclude standard care for these lesions which, if properly applied and adhered to may do the job without the oxygen.
Another example of a possibly interesting therapy, with a 'clever' rationale, which has not been well studied, but is already in use in many institutions. This meta-analysis shows that there are no solid data to prove or refute the usefulness of this therapy, and that the very few results at hand are not of a sufficient methodological quality. It gives some clues to the planification of future clinical trials on this therapy, for example the importance of the choice of a well-defined population (venous ulcer vs arterial ulcer), or the comparator therapy (sham vs usual care).