Hyperbaric oxygen therapy for late radiation tissue injury

BACKGROUND

This is the third update of the original Cochrane Review published in July 2005 and updated previously in 2012 and 2016. Cancer is a significant global health issue. Radiotherapy is a treatment modality for many malignancies, and about 50% of people having radiotherapy will be long-term survivors. Some will experience late radiation tissue injury (LRTI), developing months or years following radiotherapy. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based on the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of complications following surgery and radiotherapy.

OBJECTIVES

To evaluate the benefits and harms of hyperbaric oxygen therapy (HBOT) for treating or preventing late radiation tissue injury (LRTI) compared to regimens that excluded HBOT.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 24 January 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. survival from time of randomisation to death from any cause; 2. complete or substantial resolution of clinical problem; 3. site-specific outcomes; and 4.

ADVERSE EVENTS

Our secondary outcomes were 5. resolution of pain; 6. improvement in quality of life, function, or both; and 7. site-specific outcomes. We used GRADE to assess certainty of evidence.

MAIN RESULTS

Eighteen studies contributed to this review (1071 participants) with publications ranging from 1985 to 2022. We added four new studies to this updated review and evidence for the treatment of radiation proctitis, radiation cystitis, and the prevention and treatment of osteoradionecrosis (ORN). HBOT may not prevent death at one year (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.47 to 1.83; I2 = 0%; 3 RCTs, 166 participants; low-certainty evidence). There is some evidence that HBOT may result in complete resolution or provide significant improvement of LRTI (RR 1.39, 95% CI 1.02 to 1.89; I2 = 64%; 5 RCTs, 468 participants; low-certainty evidence) and HBOT may result in a large reduction in wound dehiscence following head and neck soft tissue surgery (RR 0.24, 95% CI 0.06 to 0.94; I2 = 70%; 2 RCTs, 264 participants; low-certainty evidence). In addition, pain scores in ORN improve slightly after HBOT at 12 months (mean difference (MD) -10.72, 95% CI -18.97 to -2.47; I2 = 40%; 2 RCTs, 157 participants; moderate-certainty evidence). Regarding adverse events, HBOT results in a higher risk of a reduction in visual acuity (RR 4.03, 95% CI 1.65 to 9.84; 5 RCTs, 438 participants; high-certainty evidence). There was a risk of ear barotrauma in people receiving HBOT when no sham pressurisation was used for the control group (RR 9.08, 95% CI 2.21 to 37.26; I2 = 0%; 4 RCTs, 357 participants; high-certainty evidence), but no such increase when a sham pressurisation was employed (RR 1.07, 95% CI 0.52 to 2.21; I2 = 74%; 2 RCTs, 158 participants; high-certainty evidence).

AUTHORS' CONCLUSIONS

These small studies suggest that for people with LRTI affecting tissues of the head, neck, bladder and rectum, HBOT may be associated with improved outcomes (low- to moderate-certainty evidence). HBOT may also result in a reduced risk of wound dehiscence and a modest reduction in pain following head and neck irradiation. However, HBOT is unlikely to influence the risk of death in the short term. HBOT also carries a risk of adverse events, including an increased risk of a reduction in visual acuity (usually temporary) and of ear barotrauma on compression. Hence, the application of HBOT to selected participants may be justified. The small number of studies and participants, and the methodological and reporting inadequacies of some of the primary studies included in this review demand a cautious interpretation. More information is required on the subset of disease severity and tissue type affected that is most likely to benefit from this therapy, the time for which we can expect any benefits to persist and the most appropriate oxygen dose. Further research is required to establish the optimum participant selection and timing of any therapy. An economic evaluation should also be undertaken.

Effect of enriched oxygen inhalation on lower limb skin temperatures in diabetic and healthy humans: a pilot study

INTRODUCTION

Measurement of skin temperature with infrared thermometry has been utilised for assessing metabolic activity and may be useful in identifying patients with ulcers suitable for hyperbaric oxygen treatment and monitoring their treatment progress. Since oxygen promotes vasoconstriction in the peripheral circulation, we hypothesised that oxygen administration may lower skin temperature and complicate the interpretation of temperatures obtained. This pilot study investigated the effect of oxygen administration on lower limb skin temperature in healthy subjects and diabetic patients.

METHODS

Volunteers were recruited from healthy staff members (n = 10) and from patients with diabetic foot ulcers (n = 10) at our facility. Foot skin surface temperatures were measured by infra-red thermometry while breathing three different concentrations of oxygen (21%, 50% and 100%).

RESULTS

Skin temperature changes were observed with increasing partial pressure of oxygen in both groups. The mean (SD) foot temperatures of diabetic patients and healthy controls at air-breathing baseline were 30.1°C (3.6) versus 29.0°C (3.7) respectively, at FiO₂ 0.5 were 30.1°C (3.6) versus 28.5°C (4.1) and at FiO₂ 1.0 were 28.3°C (3.2) versus 29.2°C (4.3). None of these differences between groups were statistically significant.

CONCLUSIONS

Data from this small study may indicate a difference in thermal responses between healthy subjects and diabetic patients when inhaling oxygen; however, none of the results were statistically significant. Further investigations on a larger scale are warranted in order to draw firm conclusions.

Hyperbaric oxygen for sudden hearing loss: Influence of international guidelines on practice in Australia and New Zealand

INTRODUCTION

Idiopathic sudden sensorineural hearing loss (ISSHL) is an otolaryngologic emergency. The Undersea and Hyperbaric Medicine Society (UHMS) revised practice guidelines in 2014 adding ISSHL to approved indications. This study investigated whether the UHMS guidelines influenced referral and practice in Australia and New Zealand.

METHODS

Retrospective review of 319 patient referrals in two time periods (five years prior to addition of ISSHL to indications (T-PRE) and three years post (T-POST)).

RESULTS

Seven of eight participating hyperbaric facilities provided data down to the level of the indication for HBOT for analysis. In T-PRE 136 patients were treated with HBOT for ISSHL, representing between 0% and 18% of the total cases to each facility. In the T-POST period 183 patients were treated for ISSHL, representing from 0.35% to 24.8% of the total patients in each facility. Comparison between the two periods shows the proportion of patients treated with ISSHL among all indications increased from 3.2% to 12.1% (P < 0.0009). One facility accounted for 74% (101/136) of ISSHL patients receiving HBOT in T-PRE and 63% (116/183) in T-POST. ISSHL case load at that facility increased from 18% to 24.8% (P = 0.009) after the UHMS guideline publication. Three of the seven units had a significant increase in referrals after the guideline change.

CONCLUSION

There remains equipoise regarding HBOT in the management of ISSHL. Only three out of seven units had a significant increase in ISSHL patients after the UHMS guidelines publication. Without well controlled RCTs to develop guidelines based on good evidence this is unlikely to change and practice variation will continue.

Adjunctive hyperbaric oxygen treatment for necrotising soft-tissue infections: A systematic review and meta-analysis

INTRODUCTION

Surgical intervention, broad-spectrum antibiotics and intensive care support are the standard of care in the treatment of necrotising soft-tissue infections (NSTI). Hyperbaric oxygen treatment (HBOT) may be a useful adjunctive treatment and has been used for almost 60 years, but its efficacy remains unknown and has not been systematically appraised. The aim was to systematically review and synthesise the highest level of clinical evidence available to support or refute the use of HBOT in the treatment of NSTI.

METHODS

The review was prospectively registered (PROSPERO; CRD42020148706). MEDLINE, EMBASE, CENTRAL and CINAHL were searched for eligible studies that reported outcomes in both HBOT treated and non-HBOT treated individuals with NSTI. In-hospital mortality was the primary outcome. Odds ratio (ORs) were pooled using random-effects models.

RESULTS

The search identified 486 papers of which 31 were included in the qualitative synthesis and 21 in the meta-analyses. Meta-analysis on 48,744 patients with NSTI (1,237 (2.5%) HBOT versus 47,507 (97.5%) non-HBOT) showed in-hospital mortality was 4,770 of 48,744 patients overall (9.8%) and the pooled OR was 0.44 (95% CI 0.33-0.58) in favour of HBOT. For major amputation the pooled OR was 0.60 (95% CI 0.28-1.28) in favour of HBOT. The dose of oxygen in these studies was incompletely reported.

CONCLUSIONS

Meta-analysis of the non-random comparative data indicates patients with NSTI treated with HBOT have reduced odds of dying during the sentinel event and may be less likely to require a major amputation. The most effective dose of oxygen remains unclear.

An observational trial to establish the effect of hyperbaric oxygen treatment on pelvic late radiation tissue injury due to radiotherapy

INTRODUCTION

Rates of pelvic cancer are growing globally with around half of these patients receiving radiotherapy. In a small proportion, radiotherapy results in significant late radiation tissue injury (LRTI) to surrounding tissue, most commonly affecting the bladder and bowel mucosa. We conducted a combined prospective and retrospective observational trial to establish the effectiveness of hyperbaric oxygen treatment (HBOT) in improving the symptoms and signs of LRTI in these patients.

METHODS

Fifty-two patients were included after receiving radiotherapy for cancers of the bowel, bladder, cervix, prostate or vulva. They received HBOT at 203-243 kPa (2.0-2.4 atmospheres absolute (atm abs)) for 90 minutes with the median number of treatments being 30 (IQR 1). Late effects normal tissues - subjective, objective, management, analytic (LENT-SOMA) scores were recorded before and after treatment.

RESULTS

The mean LENT-SOMA scores before and after HBOT were 11.7 (SD 5.3) and 8.1 (5.1) respectively. This reduction in score of 3.7 (95% CI 2.6 to 4.8) was statistically significant (P < 0.001). For radiation cystitis the mean reduction was 3.7 (95% CI 2.4 to 5.0, P < 0.001) and for radiation proctitis was 3.8 (95% CI 1.4 to 6.1, P = 0.004). There were no significant adverse effects recorded.

CONCLUSIONS

Hyperbaric oxygen treatment may be an effective and safe treatment for pelvic late tissue radiation injury.

South Pacific Underwater Medicine Society guidelines for cardiovascular risk assessment of divers

The South Pacific Underwater Medicine Society (SPUMS) diving medical for recreational scuba divers was last reviewed in 2011. From 2011 to 2019, considerable advancements have occurred in cardiovascular risk assessment relevant to divers. The SPUMS 48th (2019) Annual Scientific Meeting theme was cardiovascular risk assessment in diving. The meeting had multiple presentations updating scientific information about assessing cardiovascular risk. These were distilled into a new set of guidelines at the final conference workshop. SPUMS guidelines for medical risk assessment in recreational diving have subsequently been updated and modified including a new Appendix C: Suggested evaluation of the cardiovascular system for divers. The revised evaluation of the cardiovascular system for divers covers the following topics: 1. Background information on the relevance of cardiovascular risk and diving; 2. Defining which divers with cardiovascular problems should not dive, or whom require treatment interventions before further review; 3. Recommended screening procedures (flowchart) for divers aged 45 and over; 4. Assessment of divers with known or symptomatic cardiovascular disease, including guidance on assessing divers with specific diagnoses such as hypertension, atrial fibrillation, cardiac pacemaker, immersion pulmonary oedema, takotsubo cardiomyopathy, hypertrophic cardiomyopathy and persistent (patent) foramen ovale; 5. Additional cardiovascular health questions included in the SPUMS guidelines for medical risk assessment in recreational diving; 6. Updated general cardiovascular medical risk assessment advice; 7. Referencing of relevant literature. The essential elements of this guideline are presented in this paper.

The myopic shift associated with hyperbaric oxygen administration is reduced when using a mask delivery system compared to a hood - a randomised controlled trial

INTRODUCTION

A temporary myopic shift is a well-recognized complication of hyperbaric oxygen treatment (HBOT). Oxidation of proteins in the crystalline lens is the likely cause. Direct exposure of the eye to hyperbaric oxygen may exacerbate the effect. Our aim was to measure the magnitude of the myopic shift over a course of HBOT when using two different methods of oxygen delivery.

METHODS

We conducted a randomised trial of oxygen delivery via hood versus oronasal mask during a course of 20 and 30 HBOT sessions. Subjective refraction was performed at baseline and after 20 and 30 sessions. We repeated these measurements at four and 12 weeks after completion of the course in those available for assessment.

RESULTS

We enrolled 120 patients (mean age 57.6 (SD 11.2) years; 81% male). The myopic shift was significantly greater after both 20 and 30 sessions in those patients using the hood. At 20 treatments: refractory change was -0.92 D with hood versus -0.52 D with mask, difference 0.40 D (95% CI 0.22 to 0.57, P < 0.0001); at 30 treatments: -1.25 D with hood versus -0.63 with mask, difference 0.62 D (95% CI 0.39 to 0.84, P < 0.0001). Recovery was slower and less complete in the hood group at both four and 12 weeks.

CONCLUSIONS

Myopic shift is common following HBOT and more pronounced using a hood system than an oronasal mask. Recovery may be slower and less complete using a hood. Our data support the use of an oronasal mask in an air environment when possible.

Is there a role for hyperbaric oxygen therapy in the treatment of refractory wounds of rare etiology?

INTRODUCTION

Delayed wound healing indicates wounds that have failed to respond to more than 4-6 weeks of comprehensive wound care. Wounds with delayed healing are a major source of morbidity and a major cost to hospital and community healthcare providers. Hyperbaric oxygen therapy (HBOT) is a treatment designed to increase the supply of oxygen to wounds and has been applied to a variety of wound types. This article reviews the place of HBOT in the treatment of non-healing vasculitic, calcific uremic arteriolopathy (CUA), livedoid vasculopathy (LV), pyoderma gangrenosum (PG) ulcers.

METHODS

We searched electronic databases for research and review studies focused on HBOT for the treatment of delayed healing ulcers with rare etiologies. We excluded HBOT for ulcers reviewed elsewhere.

RESULTS

We included a total of three case series and four case reports including 63 participants. Most were related to severe, non-healing ulcers in patients with vasculitis, CUA, LV, and PG. There was some evidence that HBOT may improve the healing rate of wounds by increasing nitric oxide (NO) levels and the number of endothelial progenitor cells in the wounds. HBOT may also improve pain in these ulcers.

CONCLUSION

We recommend the establishment of comprehensive and detailed wound care registries to rapidly collect prospective data on the use of HBOT for these problem wounds. There is a strong case for appropriately powered, multi-centre randomized trials to establish the true efficacy and cost-effectiveness of HBOT especially for vasculitis ulcers that have not improved following immunosuppressive therapy.

Mortality After Paclitaxel-Coated Device Use in Dialysis Access: A Systematic Review and Meta-Analysis

Purpose: To report the risk of all-cause mortality in patients who underwent dialysis access treatment using paclitaxel-coated devices compared with percutaneous transluminal angioplasty (PTA) with an uncoated balloon. Materials and Methods: A systematic review and meta-analysis of randomized controlled trials were performed to investigate the mortality outcomes associated with paclitaxel-coated devices in the treatment of patients with a failing dialysis access (last search date February 28, 2019). The primary endpoint was all-cause mortality. This analysis included 8 studies comparing paclitaxel-coated balloon (PCB) angioplasty (n=327) and PTA (n=331) in the treatment of failing dialysis access. None investigated paclitaxel-coated stents. Mortality data were pooled using a random effects model. Statistical heterogeneity was evaluated with a chi-square test and the I2 statistic. Summary statistics are expressed as relative risk ratios (RR) with a 95% confidence interval (CI). Results: At the pooled mean follow-up of 13.5 months (median 12, range 6–24) all-cause mortality was similar in the PCB group (13.8%) compared with PTA (11.2%; RR 1.26, 95% CI 0.85 to 1.89, p=0.25; I2=0%). Subgroup analysis, stratified according to length of follow-up, confirmed that there were no statistically significant differences in mortality at short- and midterm follow-up [6-month (8 studies): 5.2% vs 4.8%, RR 1.24, 95% CI 0.62 to 2.47, p=0.55; 12-month (6 studies): 6.3% vs 6.0%, RR 1.06, 95% CI 0.43 to 2.63, p=0.90; and 24-month (3 studies): 19.0% vs 13.5%, RR 1.38, 95% CI 0.90 to 2.12, p=0.14). Conclusion: The analysis found no difference in short- to midterm mortality among patients treated with a drug-coated balloon compared with PTA. With proven benefit and no evidence of harm, the authors recommend ongoing use of PCB for the failing dialysis access.

Evidence brief: hyperbaric oxygen therapy (HBOT) for traumatic brain injury and/or post-traumatic stress disorder

This report is a product of the VA Evidence-based Synthesis Program. The purpose is to provide "timely and accurate syntheses of targeted healthcare topics …. to improve the health and healthcare of Veterans". The authors have made a comprehensive search and analysis of the literature and make recommendations to assist clinicians in dealing with veterans suffering from either traumatic brain injury (TBI) or post-traumatic stress disorder (PTSD). The report is timely and of great potential impact given the vigorous and lengthy debate among hyperbaric physicians and lay people determined to find an answer for the large numbers of veterans deeply affected with some combination of PTSD and post-concussion dysfunction. The authors lament the evidence on using hyperbaric oxygen treatment (HBOT) for TBI/PTSD has been "controversial, widely debated, and potentially confusing." Unfortunately, this report will not improve that situation. The report is as much a political document as it is evidence-based. That politics are involved is apparent from the outset with the statement "The ESP Coordinating Center is responding to a request from the Center for Compassionate Innovation (CCI)…" The report fails to further illuminate the situation than the many thousands of words already spent on summarising the evidence. Let me save you some time and get to the quick of this report. The authors (rightly) highlight the fact that uncontrolled case series and a randomised, controlled trial (RCT) without blinding or a sham control all suggest HBOT may be of benefit for these Veterans. Somewhat disappointingly, well-controlled, blinded RCTs using a sham exposure to 1.2 or 1.3 ATA breathing air fail to confirm any such benefit. While the conventional interpretation of these data is that there is no reliable evidence of an effect of HBOT, proponents have responded by postulating these control exposures are not 'sham' because they are clinically active. Any putative mechanism remains unknown and unproven outside the context of this clinical area. These exposures just happen to be about equipotent with true HBOT. With this accurate summary, the authors conclude that any effect of HBOT is as yet unclear. They suggest that in Veterans who have not responded to other therapeutic options, the use of HBOT is "reasonable". This conclusion allows for a similar recommendation for any unproven therapeutic option where there is no clearly effective treatment available and is, to this reviewer, unacceptable. While any putative mechanism for low-pressure air exposure owes more to magical thinking than physics, physiology or therapeutics, this is an argument the authors of this report seem to have accepted at some level. The proponents of HBOT have an obligation to both show the greater effectiveness of HBOT than a functional sham and to demonstrate a plausible mechanism. Until then, the strongest recommendation that should be made is that the 'sham' therapy can be used until the case is proven. It is not clear why the proponents of HBOT do not advocate this, given the 'efficacy' seems roughly equal with HBOT. Logic determines one cannot prove a negative. This reviewer agrees it is not possible to definitively prove trivial pressure exposures breathing air may have a comparable effectiveness in treating TBI/PTSD as true HBOT. Using the principle of Occam's razor it seems far more likely any apparent effectiveness is the result of a participation effect in both groups. In my view, the authors of this report have taken an easy option in allowing that HBOT use is reasonable. The tragedy is potentially the waste of time, money and hope this may bring to the very Veterans the authors are charged to serve. I have discussed this issue in more detail previously in the pages of this journal.

The use of drug-eluting stents in infrapopliteal arteries: an updated systematic review and meta-analysis of randomized trials

INTRODUCTION

Endovascular treatment below-the-knee is safe and effective but limited by poor patency. Coronary drug-eluting stents (DES) may play a role in providing mechanical scaffolding and deliver anti-proliferative drug to the site of vascular barotrauma to reduce the incidence of restenosis. Our aim was to evaluate and compare the use of contemporary DES with standard endovascular-therapies for atherosclerotic disease of infrapopliteal arteries.

EVIDENCE ACQUISITION

We performed a meta-analysis of randomized controlled trials comparing DES with conventional treatment for symptomatic peripheral artery disease (search date 30 August 2017). The primary endpoint was primary patency. Secondary endpoints were freedom from target lesion revascularization (TLR), major amputation, sustained Rutherford class improvement and mortality.

EVIDENCE SYNTHESIS

We identified 7 trials enrolling 801 randomly assigned patients (392 DES, 409 control). At the median follow-up of 12-months DES improved rates of primary patency (OR 3.49, 95%CI 2.38-5.12, I2=0%, P<0.00001), freedom from TLR (OR 2.19, 95%CI 1.30-3.69, I2=38%, P=0.003), major amputation (OR 0.56, 95%CI 0.31-0.99, I2=0%, P=0.049), and Rutherford class improvement (OR 1.62, 95%CI 1.01-2.59, I2=65%, P=0.046), but not mortality (OR 1.05, 95%CI 0.68-1.62; I2 =0%, P=0.91) compared to control. Subgroup analysis of primary patency favoured DES coated in sirolimus analogues compared to paclitaxel (Test for subgroup differences, Chi2=6.51, df=1, P=0.01, I2=84.6%).

CONCLUSIONS

At midterm follow-up DES significantly improved rates of primary patency, re-intervention, Rutherford class improvement and major amputation for the treatment of atherosclerotic disease of infrapopliteal arteries compared to control therapy, with no effect on patient survival. Stents coated in sirolimus analogues were more effective than paclitaxel.

Assessment of hyperbaric patients at risk of malnutrition using the Malnutrition Screening Tool - a pilot study

BACKGROUND

Nutritional assessment and support is essential for wound management. The hyperbaric oxygen clinic is a unique outpatient service where chronically unwell patients present daily for hyperbaric oxygen treatment (HBOT) over several weeks, allowing time for effective nutritional intervention. This is the first study to examine the prevalence of those at risk of malnutrition in a cohort of hyperbaric medical patients.

METHODS

A prospective study was undertaken over six months. Following consent, 39 enrolled patients had the Malnutrition Screening Tool and Baseline Characteristic Collection Form completed. Those at risk of malnutrition were given an option to be assessed by a dietitian to complete a Subjective Global Assessment (SGA). At the completion of treatment, the patients completed a questionnaire.

RESULTS

Twelve of the 39 patients screened were at risk of malnutrition using our screening process. Of these, all the patients with available SGA results were diagnosed with moderate to severe malnutrition. Patients receiving HBOT for non-healing wounds and osteoradionecrosis were most at risk of malnutrition.

CONCLUSION

The prevalence of patients being at risk of malnutrition in our hyperbaric medical service was about one in three. Malnutrition screening should be part of routine patient assessment in order to ensure patients receive timely nutritional intervention. This may improve wound healing.

The effectiveness of hyperbaric oxygen therapy for healing chronic venous leg ulcers: A randomized, double-blind, placebo-controlled trial

Over 30% of venous leg ulcers do not heal despite evidence-based treatment. This study aimed to determine the effectiveness of Hyperbaric Oxygen Therapy (HBOT) as an adjunct treatment for nonhealing venous leg ulcers. A randomized, double-blind, parallel group, placebo-controlled trial was undertaken in three hyperbaric medicine units. Adults with a venous leg ulcer, Transcutaneous Oxygen Measurement indicative of a hypoxic wound responsive to oxygen challenge, and without contraindications for HBOT; were eligible. Of 84 eligible patients, 10 refused and 74 enrolled. 43 participants achieved over 50% ulcer Percent Area Reduction (PAR) after four weeks of evidence-based care and were thus excluded from the intervention phase. Thirty-one participants were randomized to either 30 HBOT treatments (100% oxygen at 2.4 atmospheres absolute (ATA) for 80 minutes), or 30 "placebo" treatments, receiving a validated "sham" air protocol, initially pressurized to 1.2ATA, then cycled between 1.05-1.2ATA for eight minutes before settling at 1.05ATA. The primary outcome was numbers in each group completely healed. Secondary outcomes were ulcer PAR, pain and quality of life, 12 weeks after commencing interventions. The participants' mean age was 70 years (standard deviation (SD) 12.9) and median ulcer duration at enrolment was 62 weeks (range 4-3120). At 12 weeks, there was no significant difference between groups in the numbers completely healed. The HBOT intervention group had a mean of 95 (SD 6.53) ulcer PAR, compared to 54 (SD 67.8) mean PAR for the placebo group (t = -2.24, p = 0.042, mean difference -40.8, SE 18.2) at 12 weeks. HBOT may improve refractory healing in venous leg ulcers, however patient selection is important. In this study, HBOT as an adjunct treatment for nonhealing patients returned indolent ulcers to a healing trajectory.

Epidural analgesia versus patient-controlled intravenous analgesia for pain following intra-abdominal surgery in adults

BACKGROUND

Intravenous patient-controlled analgesia (IVPCA) with opioids and epidural analgesia (EA) using either continuous epidural administration (CEA) or patient-controlled (PCEA) techniques are popular approaches for analgesia following intra-abdominal surgery. Despite several attempts to compare the risks and benefits, the optimal form of analgesia for these procedures remains the subject of debate.

OBJECTIVES

The objective of this review was to update and expand a previously published Cochrane Review on IVPCA versus CEA for pain after intra-abdominal surgery with the addition of the comparator PCEA. We have compared both forms of EA to IVPCA. Where appropriate we have performed subgroup analysis for CEA versus PCEA.

SEARCH METHODS

We searched the following electronic databases for relevant studies: Cochrane Central Register of Controlled Trials (CENTRAL) (2017; Issue 8), MEDLINE (OvidSP) (1966 to September 2017), and Embase (OvidSP) (1988 to September 2017) using a combination of MeSH and text words. We searched the following trial registries: Australian New Zealand Clinical Trials Registry, ClinicalTrials.gov, and the EU Clinical Trials Register in September 2017, together with reference checking and citation searching to identify additional studies.We included only randomized controlled trials and used no language restrictions.

SELECTION CRITERIA

We included all parallel and cross-over randomized controlled trials (RCTs) comparing CEA or PCEA (or both) with IVPCA for postoperative pain relief in adults following intra-abdominal surgery.

DATA COLLECTION AND ANALYSIS

Two review authors (JS and EY) independently identified studies for eligibility and performed data extraction using a data extraction form. In cases of disagreement (three occasions) a third review author (MB) was consulted. We appraised each included study to assess the risk of bias as outlined in Section 8.5 of the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE to assess the quality of the evidence.

MAIN RESULTS

We included 32 studies (1716 participants) in our review. There are 10 studies awaiting classification and one ongoing study. A total of 869 participants (51%) received EA and 847 (49%) received IVPCA. The EA trials included 16 trials with CEA (418 participants) and 16 trials with PCEA (451 participants). The studies included a broad range of surgical procedures (including hysterectomies, radical prostatectomies, Caesarean sections, colorectal and upper gastrointestinal procedures), a wide range of adult ages, and were performed in several different countries.Our pooled analyses suggested a benefit with regard to pain scores (using a visual analogue scale between 0 and 100) in favour of EA techniques at rest. The mean pain reduction at rest from waking to six hours after operation was 5.7 points (95% confidence interval (CI) 1.9 to 9.5; 7 trials, 384 participants; moderate-quality evidence). From seven to 24 hours, the mean pain reduction was 9.0 points (95% CI 4.6 to 13.4; 11 trials, 558 participants; moderate-quality evidence). From 24 hours the mean pain reduction was 5.1 points (95% CI 0.9 to 9.4; 7 trials, 393 participants; moderate-quality evidence). Due to high statistical heterogeneity, no pooled analysis was possible for the estimation of pain on movement at any time. Two single studies (one using CEA and one PCEA) reported lower pain scores with EA compared to IVPCA at 0 to 6 hours and 7 to 24 hours. At > 24 hours the results from 2 studies (both CEA) were conflicting.We found no difference in mortality between EA and IVPCA, although the only deaths reported were in the EA group (5/287, 1.7%). The risk ratio (RR) of death with EA compared to using IVPCA was 3.37 (95% CI 0.72 to 15.88; 9 trials, 560 participants; low-quality evidence).A single study suggested that the use of EA may result in fewer episodes of respiratory depression, with an RR of 0.47 (95% CI 0.04 to 5.69; 1 trial; low-quality evidence). The successful placement of an epidural catheter can be technically challenging. The improvements in pain scores above were accompanied by an increase in the risk of failure of the analgesic technique with EA (RR 2.48, 95% CI 1.13 to 5.45; 10 trials, 678 participants; moderate-quality evidence); the occurrence of pruritus (RR 2.36, 95% CI 1.67 to 3.35; 8 trials, 492 participants; moderate-quality evidence); and episodes of hypotension requiring intervention (RR 7.13, 95% CI 2.87 to 17.75; 6 trials, 479 participants; moderate-quality evidence). There was no clear evidence of an advantage of one technique over another for other adverse effects considered in this review (Venous thromboembolism with EA (RR 0.32, 95% CI 0.03 to 2.95; 2 trials, 101 participants; low-quality evidence); nausea and vomiting (RR 0.94, 95% CI 0.69 to 1.27; 10 trials, 645 participants; moderate-quality evidence); sedation requiring intervention (RR 0.87, 95% CI 0.40 to 1.87; 4 trials, 223 participants; moderate-quality evidence); or episodes of desaturation to less than 90% (RR 1.29, 95% CI 0.71 to 2.37; 5 trials, 328 participants; moderate-quality evidence)).

AUTHORS' CONCLUSIONS

The additional pain reduction at rest associated with the use of EA rather than IVPCA is modest and unlikely to be clinically important. Single-trial estimates provide low-quality evidence that there may be an additional reduction in pain on movement, which is clinically important. Any improvement needs to be interpreted with the understanding that the use of EA is also associated with an increased chance of failure to successfully institute analgesia, and an increased likelihood of episodes of hypotension requiring intervention and pruritus. We have rated the evidence as of moderate quality given study limitations in most of the contributing studies. Further large RCTs are required to determine the ideal analgesic technique. The 10 studies awaiting classification may alter the conclusions of the review once assessed.

Consensus guideline: Pre-hospital management of decompression illness: expert review of key principles and controversies

(Mitchell SJ, Bennett MH, Bryson P, Butler FK, Doolette DJ, Holm JR, Kot J, Lafère P. Pre-hospital management of decompression illness: expert review of key principles and controversies. Diving and Hyperbaric Medicine. 2018 March;48(1):45е.doi.10.28920/dhm48.1.45-55.) Guidelines for the pre-hospital management of decompression illness (DCI) had not been formally revised since the 2004 Divers Alert Network/Undersea and Hyperbaric Medical Society workshop held in Sydney, entitled "Management of mild or marginal decompression illness in remote locations." A contemporary review was initiated by the Divers Alert Network and undertaken by a multinational committee with members from Australasia, the USA and Europe. The process began with literature reviews by designated committee members on: the diagnosis of DCI; first aid strategies for DCI; remote triage of possible DCI victims by diving medicine experts; evacuation of DCI victims; effect of delay to recompression in DCI; pitfalls in management when DCI victims present at hospitals without diving medicine expertise and in-water recompression. This was followed by presentation of those reviews at a dedicated workshop at the 2017 UHMS Annual Scientific Meeting, discussion by registrants at that workshop and, finally, several committee meetings to formulate statements addressing points considered of prime importance to the management of DCI in the field. The committee placed particular emphasis on resolving controversies around the definition of "mild DCI" arising over 12 years of practical application of the 2004 workshop's findings, and on the controversial issue of in-water recompression. The guideline statements are promulgated in this paper. The full workshop proceedings are in preparation for publication.

Hyperbaric oxygenation for tumour sensitisation to radiotherapy

BACKGROUND

Cancer is a common disease and radiotherapy is one well-established treatment for some solid tumours. Hyperbaric oxygenation therapy (HBOT) may improve the ability of radiotherapy to kill hypoxic cancer cells, so the administration of radiotherapy while breathing hyperbaric oxygen may result in a reduction in mortality and recurrence.

OBJECTIVES

To assess the benefits and harms of administering radiotherapy for the treatment of malignant tumours while breathing HBO.

SEARCH METHODS

In September 2017 we searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library Issue 8, 2017, MEDLINE, Embase, and the Database of Randomised Trials in Hyperbaric Medicine using the same strategies used in 2011 and 2015, and examined the reference lists of included articles.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing the outcome of malignant tumours following radiation therapy while breathing HBO versus air or an alternative sensitising agent.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of and extracted data from the included trials.

MAIN RESULTS

We included 19 trials in this review (2286 participants: 1103 allocated to HBOT and 1153 to control).For head and neck cancer, there was an overall reduction in the risk of dying at both one year and five years after therapy (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.70 to 0.98, number needed to treat for an additional beneficial outcome (NNTB) = 11 and RR 0.82, 95% CI 0.69 to 0.98, high-quality evidence), and some evidence of improved local tumour control immediately following irradiation (RR with HBOT 0.58, 95% CI 0.39 to 0.85, moderate-quality evidence due to imprecision). There was a lower incidence of local recurrence of tumour when using HBOT at both one and five years (RR at one year 0.66, 95% CI 0.56 to 0.78, high-quality evidence; RR at five years 0.77, 95% CI 0.62 to 0.95, moderate-quality evidence due to inconsistency between trials). There was also some evidence with regard to the chance of metastasis at five years (RR with HBOT 0.45 95% CI 0.09 to 2.30, single trial moderate quality evidence imprecision). No trials reported a quality of life assessment. Any benefits come at the cost of an increased risk of severe local radiation reactions with HBOT (severe radiation reaction RR 2.64, 95% CI 1.65 to 4.23, high-quality evidence). However, the available evidence failed to clearly demonstrate an increased risk of seizures from acute oxygen toxicity (RR 4.3, 95% CI 0.47 to 39.6, moderate-quality evidence).For carcinoma of the uterine cervix, there was no clear benefit in terms of mortality at either one year or five years (RR with HBOT at one year 0.88, 95% CI 0.69 to 1.11, high-quality evidence; RR at five years 0.95, 95% CI 0.80 to 1.14, moderate-quality evidence due to inconsistency between trials). Similarly, there was no clear evidence of a benefit of HBOT in the reported rate of local recurrence (RR with HBOT at one year 0.82, 95% CI 0.63 to 1.06, high-quality evidence; RR at five years 0.85, 95% CI 0.65 to 1.13, moderate-quality evidence due to inconsistency between trials). We also found no clear evidence for any effect of HBOT on the rate of development of metastases at both two years and five years (two years RR with HBOT 1.05, 95% CI 0.84 to 1.31, high quality evidence; five years RR 0.79, 95% CI 0.50 to 1.26, moderate-quality evidence due to inconsistency). There were, however, increased adverse effects with HBOT. The risk of a severe radiation injury at the time of treatment with HBOT was 2.05, 95% CI 1.22 to 3.46, high-quality evidence. No trials reported any failure of local tumour control, quality of life assessments, or the risk of seizures during treatment.With regard to the treatment of urinary bladder cancer, there was no clear evidence of a benefit in terms of mortality from HBOT at one year (RR 0.97, 95% CI 0.74 to 1.27, high-quality evidence), nor any benefit in the risk of developing metastases at two years (RR 2.0, 95% CI 0.58 to 6.91, moderate-quality evidence due to imprecision). No trial reported on failure of local control, local recurrence, quality of life, or adverse effects.When all cancer types were combined, there was evidence for an increased risk of severe radiation tissue injury during the course of radiotherapy with HBOT (RR 2.35, 95% CI 1.66 to 3.33, high-quality evidence) and of oxygen toxic seizures during treatment (RR with HBOT 6.76, 96% CI 1.16 to 39.31, moderate-quality evidence due to imprecision).

AUTHORS' CONCLUSIONS

We found evidence that HBOT improves local tumour control, mortality, and local tumour recurrence for cancers of the head and neck. These benefits may only occur with unusual fractionation schemes. Hyperbaric oxygenation therapy is associated with severe tissue radiation injury. Given the methodological and reporting inadequacies of the included studies, our results demand a cautious interpretation. More research is needed for head and neck cancer, but is probably not justified for uterine cervical or bladder cancer. There is little evidence available concerning malignancies at other anatomical sites.

Pre-hospital management of decompression illness: expert review of key principles and controversies

Guidelines for the pre-hospital management of decompression illness (DCI) had not been formally revised since the 2004 Divers Alert Network/Undersea and Hyperbaric Medical Society workshop held in Sydney, entitled "Management of mild or marginal decompression illness in remote locations". A contemporary review was initiated by the Diver's Alert Network and undertaken by a multinational committee with members from Australasia, the USA and Europe. The process began with literature reviews by designated committee members on: the diagnosis of DCI; first aid strategies for DCI; remote triage of possible DCI victims by diving medicine experts; evacuation of DCI victims; effect of delay to recompression in DCI; pitfalls in management when DCI victims present at hospitals without diving medicine expertise and in-water recompression. This was followed by presentation of those reviews at a dedicated workshop at the 2017 UHMS Annual Meeting, discussion by registrants at that workshop and finally several committee meetings to formulate statements addressing points considered of prime importance to the management of DCI in the field. The committee placed particular emphasis on resolving controversies around the definition of "mild DCI" arising over 12 years of practical application of the 2004 workshop's findings, and on the controversial issue of in-water recompression. The guideline statements are promulgated in this paper. The full workshop proceedings are in preparation for publication.

Primary Non-Hodgkin's Lymphoma of the Orbit

Between 1954 and 1980, 9 patients with non-Hodgkin's lymphoma of the orbit were treated at the Regional Radiotherapy Centre, Mount Vernon Hospital. Following radiotherapy complete local regression of the tumour was seen in every case. Three patients subsequently developed recurrent disease which proved fatal in two cases. The overall 5 year survival was 89%.

Hyperbaric oxygen therapy for late radiation tissue injury

BACKGROUND

Cancer is a significant global health problem. Radiotherapy is a treatment for many cancers and about 50% of people having radiotherapy will be long-term survivors. Some will experience late radiation tissue injury (LRTI) developing months or years later. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based upon the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of problems following surgery.

OBJECTIVES

To assess the benefits and harms of HBOT for treating or preventing LRTI.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 11), MEDLINE, EMBASE, DORCTIHM and reference lists of articles in December 2015. We also searched for ongoing trials at clinicaltrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of the relevant trials using the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and extracted the data from the included trials.

MAIN RESULTS

Fourteen trials contributed to this review (753 participants). There was some moderate quality evidence that HBOT was more likely to achieve mucosal coverage with osteoradionecrosis (ORN) (risk ratio (RR) 1.3; 95% confidence interval (CI) 1.1 to 1.6, P value = 0.003, number needed to treat for an additional beneficial outcome (NNTB) 5; 246 participants, 3 studies). There was also moderate quality evidence of a significantly improved chance of wound breakdown without HBOT following operative treatment for ORN (RR 4.2; 95% CI 1.1 to 16.8, P value = 0.04, NNTB 4; 264 participants, 2 studies). From single studies there was a significantly increased chance of improvement or cure following HBOT for radiation proctitis (RR 1.72; 95% CI 1.0 to 2.9, P value = 0.04, NNTB 5), and following both surgical flaps (RR 8.7; 95% CI 2.7 to 27.5, P value = 0.0002, NNTB 4) and hemimandibulectomy (RR 1.4; 95% CI 1.1 to 1.8, P value = 0.001, NNTB 5). There was also a significantly improved probability of healing irradiated tooth sockets following dental extraction (RR 1.4; 95% CI 1.1 to 1.7, P value = 0.009, NNTB 4).There was no evidence of benefit in clinical outcomes with established radiation injury to neural tissue, and no randomised data reported on the use of HBOT to treat other manifestations of LRTI. These trials did not report adverse events.

AUTHORS' CONCLUSIONS

These small trials suggest that for people with LRTI affecting tissues of the head, neck, anus and rectum, HBOT is associated with improved outcome. HBOT also appears to reduce the chance of ORN following tooth extraction in an irradiated field. There was no such evidence of any important clinical effect on neurological tissues. The application of HBOT to selected participants and tissues may be justified. Further research is required to establish the optimum participant selection and timing of any therapy. An economic evaluation should be undertaken.

Normobaric and hyperbaric oxygen therapy for the treatment and prevention of migraine and cluster headache

BACKGROUND

Migraine and cluster headaches are severe and disabling. Migraine affects up to 18% of women, while cluster headaches are much less common (0.2% of the population). A number of acute and prophylactic therapies are available. Hyperbaric oxygen therapy (HBOT) is the therapeutic administration of 100% oxygen at environmental pressures greater than one atmosphere, while normobaric oxygen therapy (NBOT) is oxygen administered at one atmosphere. This is an updated version of the original Cochrane review published in Issue 3, 2008 under the title 'Normobaric and hyperbaric oxygen for migraine and cluster headache'.

OBJECTIVES

To examine the efficacy and safety of normobaric oxygen therapy (NBOT) and hyperbaric oxygen therapy (HBOT) in the treatment and prevention of migraine and cluster headache.

SEARCH METHODS

We updated searches of the following databases up to 15 June 2015: CENTRAL (the Cochrane Library), MEDLINE, EMBASE, and CINAHL. For the original review we searched the following databases up to May 2008: CENTRAL, MEDLINE, EMBASE, CINAHL, DORCTIHM, and reference lists from relevant articles. We handsearched relevant journals and contacted researchers to identify trials.

SELECTION CRITERIA

Randomised controlled trials comparing HBOT or NBOT with one another, other active therapies, placebo (sham) interventions, or no treatment in participants with migraine or cluster headache.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data and assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

In this update, we included 11 trials with 209 participants. Five trials (103 participants) compared HBOT versus sham therapy for acute migraine, three trials compared NBOT to sham therapy or ergotamine tartrate for cluster headache (145 participants), two trials evaluated HBOT for cluster headache (29 participants), and one trial (56 participants) compared NBOT to sham for a mixed group of headache. The risk of bias varied considerably across these trials but in general trial quality was poor to moderate. One trial may not have been truly randomised and two included studies were reported as abstracts only. Seven trials did not indicate allocation concealment or randomisation method. Notably, 10 of the 11 trials used a sham comparator therapy and masked the outcome assessor to allocation.We pooled data from three trials, which suggested that HBOT was effective in relieving migraine headaches compared to sham therapy (risk ratio (RR) 6.21, 95% CI 2.41 to 16.00; 58 participants, three trials). The quality of evidence was low, having been downgraded for small crossover studies with incomplete reporting. There was no evidence that HBOT could prevent migraine episodes, reduce the incidence of nausea and vomiting, or reduce the requirement for rescue medication. There was no evidence that HBOT was effective for the termination of cluster headache (RR 11.38, 95% CI 0.77 to 167.85; P = 0.08) (one trial), but this trial had low power.NBOT was effective in terminating cluster headache compared to sham in a single small study (RR 7.88, 95% CI 1.13 to 54.66), but not superior to ergotamine administration in another small trial (RR 1.17, 95% CI 0.94 to 1.46; P = 0.16). A third trial reported a statistically significant difference in the proportion of attacks successfully treated with oxygen (117 of 150 attacks were successfully treated with NBOT (78%) versus 30 of 148 attacks treated with NBOT (20%)). The proportion of responders was consistent across these three trials, and suggested more than 75% of headaches were likely to respond to NBOT.No serious adverse events during HBOT or NBOT were reported.

AUTHORS' CONCLUSIONS

Since the last version of this review, two new included studies have provided additional information to change the conclusions. There was some evidence that HBOT was effective for the termination of acute migraine in an unselected population, and some evidence that NBOT was similarly effective in cluster headache. Given the cost and poor availability of HBOT, more research should be done on patients unresponsive to standard therapy. NBOT is cheap, safe, and easy to apply, so will probably continue to be used despite the limited evidence in this review.

Hyperbaric oxygen therapy for acute coronary syndrome

BACKGROUND

Acute coronary syndrome (ACS), includes acute myocardial infarction and unstable angina, is common and may prove fatal. Hyperbaric oxygen therapy (HBOT) will improve oxygen supply to the threatened heart and may reduce the volume of heart muscle that perishes. The addition of HBOT to standard treatment may reduce death rate and other major adverse outcomes.This an update of a review previously published in May 2004 and June 2010.

OBJECTIVES

The aim of this review was to assess the evidence for the effects of adjunctive HBOT in the treatment of ACS. We compared treatment regimens including adjunctive HBOT against similar regimens excluding HBOT. Where regimens differed significantly between studies this is clearly stated and the implications discussed. All comparisons were made using an intention to treat analysis where this was possible. Efficacy was estimated from randomised trial comparisons but no attempt was made to evaluate the likely effectiveness that might be achieved in routine clinical practice. Specifically, we addressed:Does the adjunctive administration of HBOT to people with acute coronary syndrome (unstable angina or infarction) result in a reduction in the risk of death?Does the adjunctive administration of HBOT to people with acute coronary syndrome result in a reduction in the risk of major adverse cardiac events (MACE), that is: cardiac death, myocardial infarction, and target vessel revascularization by operative or percutaneous intervention?Is the administration of HBOT safe in both the short and long term?

SEARCH METHODS

We updated the search of the following sources in September 2014, but found no additional relevant citations since the previous search in June 2010 (CENTRAL), MEDLINE, EMBASE, CINAHL and DORCTHIM. Relevant journals were handsearched and researchers in the field contacted. We applied no language restrictions.

SELECTION CRITERIA

Randomised studies comparing the effect on ACS of regimens that include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three authors independently evaluated the quality of trials using the guidelines of the Cochrane Handbook and extracted data from included trials. Binary outcomes were analysed using risk ratios (RR) and continuous outcomes using the mean difference (MD) and both are presented with 95% confidence intervals. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

No new trials were located in our most recent search in September 2014. Six trials with 665 participants contributed to this review. These trials were small and subject to potential bias. Only two reported randomisation procedures in detail and in only one trial was allocation concealed. While only modest numbers of participants were lost to follow-up, in general there is little information on the longer-term outcome for participants. Patients with acute coronary syndrome allocated to HBOT were associated with a reduction in the risk of death by around 42% (RR: 0.58, (95% CI 0.36 to 0.92), 5 trials, 614 participants; low quality evidence).In general, HBOT was well-tolerated. No patients were reported as suffering neurological oxygen toxicity and only a single patient was reported to have significant barotrauma to the tympanic membrane. One trial suggested a significant incidence of claustrophobia in single occupancy chambers of 15% (RR of claustrophobia with HBOT 31.6, 95% CI 1.92 to 521).

AUTHORS' CONCLUSIONS

For people with ACS, there is some evidence from small trials to suggest that HBOT is associated with a reduction in the risk of death, the volume of damaged muscle, the risk of MACE and time to relief from ischaemic pain. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. The routine application of HBOT to these patients cannot be justified from this review.

Hyperbaric oxygen therapy for chronic wounds

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.

Adjunctive hyperbaric oxygen for necrotizing fasciitis

BACKGROUND

Hyperbaric oxygen therapy (HBOT) involves the therapeutic administration of 100% oxygen in a pressure chamber at pressures above one atmosphere absolute. This therapy has been used as an adjunct to surgery and antibiotics in the treatment of patients with necrotizing fasciitis with the aim of reducing morbidity and mortality.

OBJECTIVES

To review the evidence concerning the use of HBOT as an adjunctive treatment for patients with necrotizing fasciitis (NF). Specifically, we wish to address the following questions.1. Does administration of HBOT reduce mortality or morbidity associated with NF?2. What adverse effects are associated with use of HBOT in the treatment of individuals with NF?

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE Ovid (1966 to September 2014); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) Ovid (1982 to September 2014); EMBASE Ovid (1980 to September 2014); and the Database of Randomised Controlled Trials in Hyperbaric Medicine (DORCTHIM, M Bennett) (from inception to September 2014). In addition, we performed a systematic search of specific hyperbaric literature sources. This included handsearching of relevant hyperbaric textbooks; hyperbaric journals (Hyperbaric Medicine Review, South Pacific Underwater Medicine Society Journal, European Journal of Underwater and Hyperbaric Medicine, Aviation Space and Environmental Medicine Journal); and conference proceedings of the major hyperbaric societies (Undersea and Hyperbaric Medical Society, South Pacific Underwater Medicine Society, European Underwater and Baromedical Society, International Congress of Hyperbaric Medicine).

SELECTION CRITERIA

We included all randomized and pseudo-randomized trials (trials in which an attempt at randomization has been made but the method was inappropriate, for example, alternate allocation) that compared the effects of HBOT with the effects of no HBOT (no treatment or sham) in the treatment of children and adults with necrotizing fasciitis.

DATA COLLECTION AND ANALYSIS

We planned independent data collection by two review authors using standardized forms.

MAIN RESULTS

We found no trials that met the inclusion criteria.

AUTHORS' CONCLUSIONS

This systematic review failed to locate relevant clinical evidence to support or refute the effectiveness of HBOT in the management of necrotizing fasciitis. Good quality clinical trials are needed to define the role, if any, of HBOT in the treatment of individuals with necrotizing fasciitis.

Hyperbaric medicine and the placebo effect

The placebo in medicine has a long and interesting history. Despite the widespread use of placebo medication and sham interventions in clinical research, surprisingly little is known about how placebos work. There is evidence the administration of placebo preparations can induce measurable changes in physiology including the production of endorphins. Placebos usually involve some form of deception, but have been shown to work even when their lack of 'active' ingredients is declared to the patient. The relevance of the nature of placebo effects has become a central debate in the field of hyperbaric medicine with the recent suggestion that 131 kPa of air may be an active therapeutic intervention rather than a convenient and convincing sham. This paper discusses the nature of placebo and participation effects and the implications for hyperbaric oxygen therapy if low-pressure air is regarded as therapeutic.

Unestablished indications for hyperbaric oxygen therapy

Unestablished indications are conditions in which systematic clinical use of hyperbaric oxygen treatment (HBOT) is not supported by adequate proof of benefit. HBOT is vulnerable to use in many such conditions for various reasons, perhaps the most important being that a placebo or participation effect may create an impression of efficacy. The systematic use of HBOT in unestablished indications raises ethical concerns about provision of misleading information, giving false hope, and taking payment for therapy of doubtful benefit. Any practice perceived as unethical or unscientific has the potential to draw the wider field into disrepute. Of substantial contemporary relevance is the use of HBOT in treatment of various forms of chronic brain injury; in particular, cerebral palsy in children and the sequelae of mild traumatic brain injury in adults. There are now multiple, randomised, blinded, sham-controlled trials of HBOT in both indications. None of these studies showed benefit of HBOT when compared to sham control, though the sham and HBOT groups often both improved, indicating that a placebo or participation effect influenced outcomes. These results almost certainly explain those of open-label trials (lacking sham controls) in which HBOT frequently seems beneficial. Advocates for HBOT in chronic brain injury claim that the sham treatments (usually 1.3 ATA pressure exposure whilst air breathing) in the blinded trials are actually active treatments; however, the same dose of oxygen can be achieved at 1 ATA breathing 27% oxygen. To counter this argument, advocates also claim that the extra 0.3 ATA of pressure is somehow independently beneficial, but this notion has limited biological plausibility and there is little supporting evidence. Chronic brain injuries remain unestablished indications at this time and, in our opinion, should not be systematically treated with HBOT.

Hyperbaric oxygen therapy for acute ischaemic stroke

Background Most cases of stroke are caused by impairment of blood flow to the brain (ischaemia), which results in a reduction in available oxygen and subsequent cell death. It has been postulated that hyperbaric oxygen therapy (HBOT) may reduce the volume of brain that will die by greatly increasing available oxygen, and it may further improve outcomes by reducing brain swelling. Some centres are using HBOT routinely to treat people with stroke. This is an update of a Cochrane Review first published in 2005.Objectives To assess the effectiveness and safety of adjunctive HBOT in the treatment of people with acute ischaemic stroke.Search methods We searched the Cochrane Stroke Group Trials Register (last searched April 2014), the Cochrane Central Register of Controlled Trials(CENTRAL) (April 2014), MEDLINE (1966 to April 2014), EMBASE (1980 to April 2014), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to April 2014), the Database of Randomised Controlled Trials in Hyperbaric Medicine(DORCTIHM) (searched April 2014) and the reference lists of articles.We handsearched relevant publications and contacted researchers to identify additional published and unpublished studies.Selection criteria Randomised controlled trials (RCTs) that compared the effects of adjunctive HBOT versus those of no HBOT (no treatment or sham).Data collection and analysis Three review authors independently extracted data, assessed each trial for internal validity and resolved differences by discussion.Main results We included 11 RCTs involving 705 participants. The methodological quality of the trials varied. We could pool data only for case fatalities. No significant differences were noted in the case fatality rate at six months in those receiving HBOT compared with the control group (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.34 to 2.75, P value 0.96). Four of 14 scale measures of disability and functional performance indicated improvement following HBOT, for example, the mean Trouillas Disability Scale score was lower with HBOT (mean difference (MD) 2.2 point reduction with HBOT, 95% CI 0.15 to 4.3, P value 0.04), and the mean Orgogozo Scale score was higher (MD 27.9 points, 95% CI 4.0 to 51.8, P value 0.02).Authors' conclusions We found no good evidence to show that HBOT improves clinical outcomes when applied during acute presentation of ischaemic stroke. Although evidence from the 11 RCTs is insufficient to provide clear guidelines for practice, the possibility of clinical benefit has not been excluded. Further research is required to better define the role of HBOT in this condition.

Randomized controlled trials in diving and hyperbaric medicine

Randomized controlled trials (RCTs) are widely accepted as the most appropriate methodology available for the investigation of health interventions. This is because of the low potential for systematic bias and the ability to assume causality. Well-designed RCTs, often modified by the addition of blinding participants to the treatment allocated, greatly assist physicians and funding agencies in deciding on the most effective and cost-efficient methods available to prevent and treat ill health. One of the problems for hyperbaric physicians is the widely scattered nature of the evidence, making retrieval and appraisal problematic. This review assembles the randomized evidence in order to assist practitioners, discusses the nature of randomized trials and explores approaches to designing and performing powerful and convincing trials in this area. It is extracted from the UHMS Report Hyperbaric Oxygen Therapy Indications.

Hyperbaric oxygen therapy for the adjunctive treatment of traumatic brain injury

BACKGROUND

Traumatic brain injury is a common health problem with significant effect on quality of life. Each year in the USA approximately 0.56% of the population suffer a head injury, with a case fatality rate of about 40% for severe injuries. These account for a high proportion of deaths in young adults. In the USA, 2% of the population live with long-term disabilities following head injuries. The major causes are motor vehicle crashes, falls, and violence (including attempted suicide). Hyperbaric oxygen therapy (HBOT) is the therapeutic administration of 100% oxygen at environmental pressures greater than 1 atmosphere absolute (ATA). This involves placing the patient in an airtight vessel, increasing the pressure within that vessel, and administering 100% oxygen for respiration. In this way, it is possible to deliver a greatly increased partial pressure of oxygen to the tissues. HBOT can improve oxygen supply to the injured brain, reduce the swelling associated with low oxygen levels and reduce the volume of brain that will ultimately perish. It is, therefore, possible that adding HBOT to the standard intensive care regimen may reduce patient death and disability. However, a concern for patients and families is that using HBOT may result in preventing a patient from dying only to leave them in a vegetative state, entirely dependent on medical care. There are also some potential adverse effects of the therapy, including damage to the ears, sinuses and lungs from the effects of the pressure and oxygen poisoning, so the benefits and risks of the therapy need to be carefully evaluated.

OBJECTIVES

To assess the effects of adjunctive HBOT for traumatic brain injury.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL and DORCTHIM electronic databases. We also searched the reference lists of eligible articles, handsearched relevant journals and contacted researchers. All searches were updated to March 2012.

SELECTION CRITERIA

Randomised studies comparing the effect of therapeutic regimens which included HBOT with those that did not, for people with traumatic brain injury.

DATA COLLECTION AND ANALYSIS

Three authors independently evaluated trial quality and extracted data.

MAIN RESULTS

Seven studies are included in this review, involving 571 people (285 receiving HBOT and 286 in the control group). The results of two studies indicate use of HBOT results in a statistically significant decrease in the proportion of people with an unfavourable outcome one month after treatment using the Glasgow Outcome Scale (GOS) (relative risk (RR) for unfavourable outcome with HBOT 0.74, 95% CI 0.61 to 0.88, P = 0.001). This five-point scale rates the outcome from one (dead) to five (good recovery); an 'unfavourable' outcome was considered as a score of one, two or three. Pooled data from final follow-up showed a significant reduction in the risk of dying when HBOT was used (RR 0.69, 95% CI 0.54 to 0.88, P = 0.003) and suggests we would have to treat seven patients to avoid one extra death (number needed to treat (NNT) 7, 95% CI 4 to 22). Two trials suggested favourably lower intracranial pressure in people receiving HBOT and in whom myringotomies had been performed. The results from one study suggested a mean difference (MD) with myringotomy of -8.2 mmHg (95% CI -14.7 to -1.7 mmHg, P = 0.01). The Glasgow Coma Scale (GCS) has a total of 15 points, and two small trials reported a significant improvement in GCS for patients treated with HBOT (MD 2.68 points, 95%CI 1.84 to 3.52, P < 0.0001), although these two trials showed considerable heterogeneity (I(2) = 83%). Two studies reported an incidence of 13% for significant pulmonary impairment in the HBOT group versus 0% in the non-HBOT group (P = 0.007).In general, the studies were small and carried a significant risk of bias. None described adequate randomisation procedures or allocation concealment, and none of the patients or treating staff were blinded to treatment.

AUTHORS' CONCLUSIONS

In people with traumatic brain injury, while the addition of HBOT may reduce the risk of death and improve the final GCS, there is little evidence that the survivors have a good outcome. The improvement of 2.68 points in GCS is difficult to interpret. This scale runs from three (deeply comatose and unresponsive) to 15 (fully conscious), and the clinical importance of an improvement of approximately three points will vary dramatically with the starting value (for example an improvement from 12 to 15 would represent an important clinical benefit, but an improvement from three to six would leave the patient with severe and highly dependent impairment). The routine application of HBOT to these patients cannot be justified from this review. Given the modest number of patients, methodological shortcomings of included trials and poor reporting, the results should be interpreted cautiously. An appropriately powered trial of high methodological rigour is required to define which patients, if any, can be expected to benefit most from HBOT.

The Undersea and Hyperbaric Medical Society. A report on the annual scientific meeting 2012, Phoenix, AZ, USA June 21-23

This is a report on the content of the 45th annual scientific meeting of the Undersea and Hyperbaric Medical Society (UHMS) in Phoenix AZ, USA last June 21-23, 2012. The UHMS is the major representative body for both physicians and scientists in diving and hyperbaric physiology and medicine.

Hyperbaric oxygen therapy for promoting fracture healing and treating fracture non-union

BACKGROUND

Hyperbaric oxygen therapy (HBOT) consists of intermittently administering 100% oxygen at pressures greater than one atmosphere absolute (ATA) in a pressure vessel. This technology has been used to treat a variety of diseases and has been described as helping patients who have delayed healing or established non-union of bony fractures. This is an update of a Cochrane Review first published in 2005, and previously updated in 2008.

OBJECTIVES

The aim of this review is to assess the evidence for the benefit of hyperbaric oxygen treatment (HBOT) for the treatment of delayed bony healing and established non-union of bony fractures.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (July 2012), the Cochrane Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 7), MEDLINE (1946 to July Week 1 2012), EMBASE (1974 to 2012 July 16), CINAHL (1937 to 17 July 2012), the Database of Randomised Controlled Trials in Hyperbaric Medicine (accessed July 2012), the WHO International Clinical Trials Registry Platform (17 July 2012) and reference lists of articles.

SELECTION CRITERIA

We aimed to include all randomised controlled trials comparing the clinical effects of HBOT with no HBOT (no treatment or sham) for healing of bony fractures and fracture non-unions.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened electronic search results, and all three authors independently performed study selection. We planned independent data collection and risk of bias assessment by two authors using standardised forms.

MAIN RESULTS

No trials met the inclusion criteria. In this update, we identified three ongoing randomised controlled trials. Among the eight excluded studies were three randomised trials comparing HBOT with no treatment that included patients with fractures. One of these trials had been abandoned and the other two did not report on fracture healing outcomes.

AUTHORS' CONCLUSIONS

This systematic review failed to locate any relevant clinical evidence to support or refute the effectiveness of HBOT for the management of delayed union or established non-union of bony fractures. Good quality clinical trials are needed to define the role, if any, of HBOT in the treatment of these injuries. There are three randomised controlled trials underway and we anticipate these will help provide some relevant clinical evidence to address this issue in the future.

Recommendations for rescue of a submerged unresponsive compressed-gas diver

The Diving Committee of the Undersea and Hyperbaric Medical Society has reviewed available evidence in relation to the medical aspects of rescuing a submerged unresponsive compressed-gas diver. The rescue process has been subdivided into three phases, and relevant questions have been addressed as follows. Phase 1, preparation for ascent: If the regulator is out of the mouth, should it be replaced? If the diver is in the tonic or clonic phase of a seizure, should the ascent be delayed until the clonic phase has subsided? Are there any special considerations for rescuing rebreather divers? Phase 2, retrieval to the surface: What is a "safe" ascent rate? If the rescuer has a decompression obligation, should they take the victim to the surface? If the regulator is in the mouth and the victim is breathing, does this change the ascent procedures? If the regulator is in the mouth, the victim is breathing, and the victim has a decompression obligation, does this change the ascent procedures? Is it necessary to hold the victim's head in a particular position? Is it necessary to press on the victim's chest to ensure exhalation? Are there any special considerations for rescuing rebreather divers? Phase 3, procedure at the surface: Is it possible to make an assessment of breathing in the water? Can effective rescue breaths be delivered in the water? What is the likelihood of persistent circulation after respiratory arrest? Does the recent advocacy for "compression-only resuscitation" suggest that rescue breaths should not be administered to a non-breathing diver? What rules should guide the relative priority of in-water rescue breaths over accessing surface support where definitive CPR can be started? A "best practice" decision tree for submerged diver rescue has been proposed.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

This is an update of a Cochrane Review first published in The Cochrane Library in Issue 1, 2005 and previously updated in 2007 and 2009.Idiopathic sudden sensorineural hearing loss (ISSHL) is common and has a significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and result in an improvement in hearing.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; Database of Randomised Trials in Hyperbaric Medicine (DORCTHIM); CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 2 May 2012, following previous searches in 2009, 2007 and 2004.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and tinnitus of HBOT and alternative therapies.

DATA COLLECTION AND ANALYSIS

Three authors evaluated the quality of trials using the 'Risk of bias' tool and extracted data from the included trials.

MAIN RESULTS

Seven trials contributed to this review (392 participants). The studies were small and of generally poor quality. Pooled data from two trials did not show any significant improvement in the chance of a 50% increase in hearing threshold on pure-tone average with HBOT (risk ratio (RR) with HBOT 1.53, 95% confidence interval (CI) 0.85 to 2.78, P = 0.16), but did show a significantly increased chance of a 25% increase in pure-tone average (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was 5 (95% CI 3 to 20). There was also an absolute improvement in average pure-tone audiometric threshold following HBOT (mean difference (MD) 15.6 dB greater with HBOT, 95% CI 1.5 to 29.8, P = 0.03). The significance of any improvement in tinnitus could not be assessed.There were no significant improvements in hearing or tinnitus reported for chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with acute ISSHL, the application of HBOT significantly improved hearing, but the clinical significance remains unclear. We could not assess the effect of HBOT on tinnitus by pooled analysis. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously. An appropriately powered trial is justified to define those patients (if any) who can be expected to derive most benefit from HBOT.There is no evidence of a beneficial effect of HBOT on chronic ISSHL or tinnitus and we do not recommend the use of HBOT for this purpose.

The use of deep tables in the treatment of decompression illness: the Hyperbaric Technicians and Nurses Association 2011 Workshop

In August 2011, a one-day workshop was convened by the South Pacific Underwater Medicine Society and the Hyperbaric Technicians and Nurses Association to examine the use of deep recompression treatment tables for the treatment of decompression illness in Australia and New Zealand. The aim of the workshop was to develop a series of consensus statements to guide practice around the region. The workshop chose to focus the discussion on the use of 405 kPa (30 msw) maximum depth tables using helium-oxygen breathing periods, and covered indications, staffing and technical requirements. This report outlines the evidence basis for these discussions and summarises the series of consensus statements generated. These statements should assist hyperbaric facilities to develop and maintain appropriate policies and procedures for the use of such tables. We anticipate this work will lead to the formulation of a standard schedule for deep recompression to be developed at a future workshop.

Recompression and adjunctive therapy for decompression illness

BACKGROUND

Decompression illness (DCI) is due to bubble formation in the blood or tissues following the breathing of compressed gas. Clinically, DCI may range from a trivial illness to loss of consciousness, death or paralysis. Recompression is the universally accepted standard treatment of DCI. When recompression is delayed, a number of strategies have been suggested in order to improve the outcome.

OBJECTIVES

To examine the effectiveness and safety of both recompression and adjunctive therapies in the treatment of DCI.

SEARCH METHODS

In our previous update we searched until October 2009. In this version we searched CENTRAL (The Cochrane Library, October 2011); MEDLINE (1966 to October 2011); CINAHL (1982 to October 2011); EMBASE (1980 to October 2011); the Database of Randomised Controlled Trials in Hyperbaric Medicine (October 2011); and handsearched journals and texts.

SELECTION CRITERIA

We included randomized controlled trials that compared the effect of any recompression schedule or adjunctive therapy with a standard recompression schedule. We did not apply language restrictions.

DATA COLLECTION AND ANALYSIS

Three authors extracted the data independently. We assessed each trial for internal validity and resolved differences by discussion. Data were entered into RevMan 5.1.

MAIN RESULTS

Two randomized controlled trials enrolling a total of 268 patients satisfied the inclusion criteria. The risk of bias for Drewry 1994 was unclear as this study was presented as an abstract, while Bennett 2003 was rated as at low risk. Pooling of data was not possible. In one study there was no evidence of improved effectiveness with the addition of a non-steroidal anti-inflammatory drug (tenoxicam) to routine recompression therapy (at six weeks: relative risk (RR) 1.04, 95% confidence interval (CI) 0.90 to 1.20, P = 0.58) but there was a reduction in the number of compressions required when tenoxicam was added from three to two (P = 0.01, 95% CI 0 to 1). In the other study, the odds of multiple recompressions were lower with a helium and oxygen (heliox) table compared to an oxygen treatment table (RR 0.56, 95% CI 0.31 to 1.00, P = 0.05).

AUTHORS' CONCLUSIONS

Recompression therapy is standard for the treatment of DCI, but there is no randomized controlled trial evidence for its use. Both the addition of a non-steroidal anti-inflammatory drug (NSAID) and the use of heliox may reduce the number of recompressions required, but neither improve the odds of recovery. The application of either of these strategies may be justified. The modest number of patients studied demands a cautious interpretation. Benefits may be largely economic and an economic analysis should be undertaken. There is a case for large randomized trials of high methodological rigour in order to define any benefit from the use of different breathing gases and pressure profiles during recompression therapy.

Hyperbaric oxygen therapy for late radiation tissue injury

BACKGROUND

Cancer is a significant global health problem. Radiotherapy is a treatment for many cancers and about 50% of patients having radiotherapy with be long-term survivors. Some will experience late radiation tissue injury (LRTI) developing months or years later. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based upon the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of problems following surgery.

OBJECTIVES

To assess the benefits and harms of HBOT for treating or preventing LRTI.

SEARCH METHODS

In March 2011 we updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 1), MEDLINE, EMBASE, DORCTIHM and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of the relevant trials using the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and extracted the data from the included trials.

MAIN RESULTS

Eleven trials contributed to this review (669 participants). For pooled analyses, investigation of heterogeneity suggested important variability between trials but there was some evidence that HBOT is more likely to achieve mucosal coverage with osteoradionecrosis (ORN) (risk ratio (RR) 1.3; 95% confidence interval (CI) 1.1 to 1.6, P = 0.003, number needed to treat for an additional beneficial outcome (NNTB) 5). From single studies there was a significantly increased chance of improvement or cure following HBOT for radiation proctitis (RR 1.72; 95% CI 1.0 to 2.9, P = 0.04, NNTB 5), and following both surgical flaps (RR 8.7; 95% CI 2.7 to 27.5, P = 0.0002, NNTB = 4) and hemimandibulectomy (RR 1.4; 95% CI 1.1 to 1.8, P = 0.001, NNTB 5). There was also a significantly improved probability of healing irradiated tooth sockets following dental extraction (RR 1.4; 95% CI 1.1 to 1.7, P = 0.009, NNTB 4).There was no evidence of benefit in clinical outcomes with established radiation injury to neural tissue, and no data reported on the use of HBOT to treat other manifestations of LRTI. These trials did not report adverse effects.

AUTHORS' CONCLUSIONS

These small trials suggest that for people with LRTI affecting tissues of the head, neck, anus and rectum, HBOT is associated with improved outcome. HBOT also appears to reduce the chance of ORN following tooth extraction in an irradiated field. There was no such evidence of any important clinical effect on neurological tissues. The application of HBOT to selected patients and tissues may be justified. Further research is required to establish the optimum patient selection and timing of any therapy. An economic evaluation should be undertaken.

Hyperbaric oxygen therapy for chronic wounds

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 first update we searched the Cochrane Wounds Group Specialised Register (searched 12 January 2012); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4); Ovid MEDLINE (1950 to January Week 1 2012); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, 11 July 2012); Ovid EMBASE (1980 to 2012 Week 01); and EBSCO CINAHL (1982 to 6 January 2012).

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 nine trials (471 participants). Eight trials (455 participants) enrolled people with a diabetic foot ulcer: pooled data of three trials with 140 participants showed an increase in the rate of ulcer healing (risk ratio (RR) 5.20, 95% confidence interval (CI) 1.25 to 21.66; P = 0.02) 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 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.

Hyperbaric oxygenation for tumour sensitisation to radiotherapy

BACKGROUND

Cancer is a common disease and radiotherapy is one well-established treatment for some solid tumours. Hyperbaric oxygenation therapy (HBOT) may improve the ability of radiotherapy to kill hypoxic cancer cells, so the administration of radiotherapy while breathing hyperbaric oxygen may result in a reduction in mortality and recurrence.

OBJECTIVES

To assess the benefits and harms of radiotherapy while breathing HBO.

SEARCH METHODS

In March 2011 we searched The Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 3), MEDLINE, EMBASE, DORCTHIM and reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing the outcome of malignant tumours following radiation therapy while breathing HBO versus air.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of the relevant trials and extracted the data from the included trials.

MAIN RESULTS

Nineteen trials contributed to this review (2286 patients: 1103 allocated to HBOT and 1153 to control). With HBOT, there was a reduction in mortality for head and neck cancers at both one year and five years after therapy (risk ratio (RR) 0.83, P = 0.03, number needed to treat (NNT) = 11; and RR 0.82, P = 0.03, NNT = 5 respectively), as well as improved local tumour control at three months (RR with HBOT 0.58, P = 0.006, NNT = 7). The effect of HBOT varied with different fractionation schemes. Local tumour recurrence was less likely with HBOT at one year (head and neck: RR 0.66, P < 0.0001, NNT = 5), two years (uterine cervix: RR 0.60, P = 0.04, NNT = 5) and five years (head and neck: (RR 0.77, P = 0.01, NNT = 6). Any advantage is achieved at the cost of some adverse effects. There was a significant increase in the rate of both severe radiation tissue injury (RR 2.35, P < 0.0001, (number needed to harm (NNH) = 8) and the chance of seizures during therapy (RR 6.76, P = 0.03, NNH = 22) with HBOT.

AUTHORS' CONCLUSIONS

There is some evidence that HBOT improves local tumour control and mortality for cancers of the head and neck, and local tumour recurrence in cancers of the head and neck, and uterine cervix. These benefits may only occur with unusual fractionation schemes. HBOT is associated with significant adverse effects including oxygen toxic seizures and severe tissue radiation injury. The methodological and reporting inadequacies of the studies included demand a cautious interpretation. More research is needed for head and neck cancer, but is probably not justified for bladder cancer. There is little evidence available concerning malignancies at other anatomical sites on which to base a recommendation.

WITHDRAWN: Hyperbaric oxygen therapy for promoting fracture healing and treating fracture non-union

BACKGROUND

Hyperbaric oxygen therapy (HBOT) consists of intermittently administering 100% oxygen at pressures greater than one atmosphere absolute (ATA) in a pressure vessel. This technology has been used to treat a variety of diseases and has been described as helping patients who have delayed healing or established non-union of bony fractures.

OBJECTIVES

The aim of this review was to assess the evidence for the benefit of hyperbaric oxygen treatment (HBOT) for the treatment of delayed bony healing and established non-union of bony fractures.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (April 2008), the Cochrane Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2008), MEDLINE (OVID 1966 to April week 3, 2008), CINAHL (OVID 1982 to April week 3, 2008), EMBASE (OVID 1980 to week 17 2008), the locally developed Database of Randomised Controlled Trials in Hyperbaric Medicine (available at www.hboevidence.com) from inception to May 2008, and reference lists of articles.

SELECTION CRITERIA

We aimed to include all randomised controlled trials that compared the effect of HBOT with no HBOT (no treatment or sham).

DATA COLLECTION AND ANALYSIS

We planned independent data collection by two authors using standardised forms.

MAIN RESULTS

No trials met the inclusion criteria. We excluded one trial that compared HBOT with no treatment because no clinical outcomes were reported.

AUTHORS' CONCLUSIONS

This systematic review failed to locate any relevant clinical evidence to support or refute the effectiveness of HBOT for the management of delayed union or established non-union of bony fractures. Good quality clinical trials are needed to define the role, if any, of HBOT in the treatment of these injuries.

Hyperbaric oxygen therapy for acute coronary syndrome

BACKGROUND

Acute coronary syndrome (ACS), includes acute myocardial infarction and unstable angina, is common and may prove fatal. Hyperbaric oxygen therapy (HBOT) will improve oxygen supply to the threatened heart and may reduce the volume of heart muscle that perishes. The addition of HBOT to standard treatment may reduce death rate and other major adverse outcomes.

OBJECTIVES

To assess the benefits and harms of adjunctive HBOT for treating ACS.

SEARCH STRATEGY

We updated the search of the following sources in June 2010, finding one further trial: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, DORCTHIM, LILACS and checked the references from selected articles. Relevant journals were handsearched and researchers in the field contacted. No language restrictions were applied.

SELECTION CRITERIA

Randomised studies comparing the effect on ACS of regimens that include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three reviewers independently evaluated the quality of trials using the guidelines of the Cochrane Handbook and extracted data from included trials.

MAIN RESULTS

Six trials with 665 participants contributed to this review. There was a significant decrease in the risk of death with HBOT (risk ratio (RR) 0.58, 95% CI 0.36 to 0.92, P = 0.02). The extent of heart muscle damage was lower following HBOT, as shown by a lesser rise in muscle enzyme in the blood (mean difference (MD) 493 IU, P = 0.005) and a better LVEF (MD 5.5%, P = 0.001). There was evidence from individual trials of reductions in the risk of major adverse coronary events (MACE) (RR 0.12, P = 0.03); re-infarction (RR 0.28, P = 0.04) and dysrhythmias following HBOT (RR 0.59, P = 0.01, and the time to relief of pain was reduced with HBOT (MD 353 minutes shorter, P < 0.00001). One trial suggested a significant incidence of claustrophobia in single occupancy chambers of 15% (RR of claustrophobia with HBOT 31.6, P = 0.02).

AUTHORS' CONCLUSIONS

For people with ACS, there is some evidence from small trials to suggest that HBOT is associated with a reduction in the risk of death, the volume of damaged muscle, the risk of MACE and time to relief from ischaemic pain. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. The routine application of HBOT to these patients cannot be justified from this review.

Hyperbaric oxygen for carbon monoxide poisoning

BACKGROUND

Poisoning with carbon monoxide (CO) remains an important cause of accidental and intentional injury worldwide. Several unblinded non-randomized trials have suggested that the use of hyperbaric oxygen (HBO) prevents the development of neurological sequelae. This has led to the widespread use of HBO in the management of patients with carbon monoxide poisoning.

OBJECTIVES

To examine randomised trials of the efficacy of hyperbaric oxygen (HBO) compared to normobaric oxygen (NBO) for the prevention of neurologic sequelae in patients with acute carbon monoxide poisoning.

SEARCH STRATEGY

We searched the following electronic databases; Cochrane Injuries Group Specialised Register (searched June 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 2), MEDLINE (Ovid SP) 1950 to June 2010, EMBASE (Ovid SP) 1980 to June 2010, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) 1970 to June 2010, ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) 1990 to June 2010.

SELECTION CRITERIA

All randomised controlled trials of HBO compared to NBO, involving non-pregnant adults who are acutely poisoned with carbon monoxide (regardless of severity).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted from each trial information on: the number of randomised patients, types of participants, the dose and duration of the intervention, and the prevalence of neurologic symptoms at follow-up.

MAIN RESULTS

Seven randomised controlled trials of varying quality were identified; one was excluded because it did not evaluate clinical outcomes. Of the six remaining trials involving 1361 participants, two found a beneficial effect of HBO for the reduction of neurologic sequelae at one month, while four others did not. One of these is an incomplete publication (an abstract of an interim analysis). Although pooled random effects meta-analysis does not suggest a significant benefit from HBOT (OR for neurological deficits 0.78, 95%CI 0.54 to 1.12), significant methodologic and statistical heterogeneity was apparent among the trials, and this result should be interpreted cautiously. Moreover, design or analysis flaws were evident in all trials. Importantly, the conclusions of one positive trial may have been influenced by failure to adjust for multiple hypothesis testing, while interpretation of the other positive trial is hampered by a high risk of bias introduced during the analysis including an apparent change in the primary outcome. Both were also stopped early 'for benefit', which is likely to have inflated the observed effect. In contrast three negative trials had low power to detect a benefit of HBO due to exclusion of severely poisoned patients in two and very poor follow-up in the other. One trial that was said to be finished around eight years ago has not reported the final analysis in any forum.

AUTHORS' CONCLUSIONS

Existing randomised trials do not establish whether the administration of HBO to patients with carbon monoxide poisoning reduces the incidence of adverse neurologic outcomes. Additional research is needed to better define the role, if any, of HBO in the treatment of patients with carbon monoxide poisoning. This research question is ideally suited to a multi-center randomised controlled trial.

Outcomes of appendicectomy in an acute care surgery model

OBJECTIVE

To assess the outcomes of appendicectomy in an acute care surgery (ACS) model compared with a traditional on-call (Trad) model.

DESIGN

Retrospective historical control study comparing appendicectomy outcomes in the Trad period (April 2004 to March 2005) with outcomes in the ACS period (April 2006 to March 2007).

SETTING

The Prince of Wales Public Hospital, a metropolitan tertiary referral centre in Sydney.

PATIENTS

All adult patients undergoing appendicectomy during 1-year periods before and after the introduction of the ACS model.

INTERVENTION

The introduction of an ACS model for managing all emergency general surgical presentations.

MAIN OUTCOME MEASURE

Complication rate.

RESULTS

A total of 402 appendicectomies were performed, 176 during the Trad period and 226 during the ACS period. There was no perioperative mortality. The complication rate was lower in the ACS period than the Trad period (9.3% v 17.0%; P = 0.02). After the intervention, there was no significant change in the time from presentation to arrival in theatre or in length of stay, but the proportion of operations performed at night (24:00-08:00) was reduced from 26.1% to 15.0% (P = 0.006). The proportion of negative appendicectomies was reduced from 22.7% to 17.3%, but the change was not statistically significant (P = 0.08). There was no difference in perforation rate before and after the intervention (13.6% v 13.3%; P = 0.86).

CONCLUSION

The ACS model provides a safe surgical environment for patients and is associated with a reduced complication rate. Under the ACS model, there was an increase in the number of patients treated conservatively overnight, but this did not lead to an overall increase in perforation rate or length of stay.

Referral patterns and outcomes of dive medical examinations in a tertiary hyperbaric facility

INTRODUCTION

Scuba diving involves risks, and candidates in Australia usually have a medical evaluation prior to undertaking a diving course. Hyperbaric physicians act as secondary referral practitioners for these assessments. This study aimed to identify reasons for these secondary referrals, and document the assessment process and outcome for potential dive candidates.

METHODS

This was a retrospective case-note analysis of candidates for dive medicals presenting to the Department of Diving and Hyperbaric Medicine (DDHM) at the Prince of Wales Hospital, Sydney, over 10 years.

RESULTS

We identified a total of 191 candidates aged 12 to 67 years. Most were candidates for recreational diving (n = 148, 77.5%) and 119 (62.3%) were male. Commercial dive candidates had higher median total number of dives (P = 0.005), median maximum depth (P < 0.001) and median years, diving (P = 0.018) than recreational dive candidates. Respiratory problems were the most common referral reason for presentation (35%), followed by CNS (14%), ENT (13%) and cardiovascular conditions (9%). Most candidates were assessed as 'fit to dive' (136 or 71%), 49 (26%) were 'unfit', while six (3%) were subject to restrictions. Forty-three candidates (22%) presented with a diagnosis of asthma, of whom 25 (13%) were considered 'fit to dive'.

CONCLUSION

The most common presentation for evaluation was for respiratory conditions, particularly asthma, but a wide range of medical conditions were assessed, and subjects were evaluated on an individual basis. Although current standards in Australia discourage asthmatic subjects from diving, over half of the candidates presenting with a possible diagnosis of asthma were assessed as 'fit to dive'.

A retrospective audit of three different regional anaesthetic techniques for circumcision in children

Postoperative analgesia for male circumcision surgery has been traditionally provided by a landmark-based dorsal penile nerve block (DPNB-LM) or by caudal epidural analgesia (CEA). In this study we report on a retrospective analysis of the effectiveness and safety of CEA, DPNB-LM and ultrasound-guided dorsal penile nerve block (DPNB-US) in our institution over a six-year period. Information was gathered from each patient's medical record. A total of 216 circumcisions were performed on patients aged from five months to 15 years. One hundred and fifteen patients received CEA, 46 DPNB-LM and 55 DPNB-US. Patients in the DPNB-LM group required rescue morphine administration in the recovery unit more frequently (30.4%) than either the DPNB-US (3.5%) or CEA groups (3.6%). Similarly, the DPNB-LM group required a larger total dose of morphine, and had longer recovery ward stays than CEA or DPNB-US groups. Time to first analgesia was greatest for the CEA group while there was no significant difference between time to first analgesia for DPNB-LM and DPNB-US. Sixty-three percent of patients in the DPNB-LM group, 1.7% of CEA and 5.5% of the DPNB-US required intraoperative opiates (P < 0.0001). There was no difference in time to hospital discharge.