A clinical practice guideline for the use of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers

BACKGROUND: The role of hyperbaric oxygen (HBO2) for the treatment of diabetic foot ulcers (DFUs) has been examined in the medical literature for decades. There are more systematic reviews of the HBO2/DFU literature than there have been randomized controlled trials (RCTs), but none of these reviews has resulted in a clinical practice guideline (CPG) that clinicians, patients and policy-makers can use to guide decision-making in everyday practice. METHODS: The Undersea and Hyperbaric Medical Society (UHMS), following the methodology of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group, undertook this systematic review of the HBO2 literature in order to rate the quality of evidence and generate practice recommendations for the treatment of DFUs. We selected four clinical questions for review regarding the role of HBO2 in the treatment of DFUs and analyzed the literature using patient populations based on Wagner wound classification and age of the wound (i.e., acute post-operative wound vs. non-healing wound of 30 or more days). Major amputation and incomplete healing were selected as critical outcomes of interest. RESULTS: This analysis showed that HBO2 is beneficial in preventing amputation and promoting complete healing in patients with Wagner Grade 3 or greater DFUs who have just undergone surgical debridement of the foot as well as in patients with Wagner Grade 3 or greater DFUs that have shown no significant improvement after 30 or more days of treatment. In patients with Wagner Grade 2 or lower DFUs, there was inadequate evidence to justify the use of HBO2 as an adjunctive treatment. CONCLUSIONS: Clinicians, patients, and policy-makers should engage in shared decision-making and consider HBO2 as an adjunctive treatment of DFUs that fit the criteria outlined in this guideline. The current body of evidence provides a moderate level of evidence supporting the use of HBO2 for DFUs. Future research should be directed at improving methods for patient selection, testing various treatment protocols and improving our confidence in the existing estimates.(AU)

Air sparging tracer test to investigate the flow path.

The paper presents a useful method for investigating the flow path of the injected air, estimating the radius of influence, and assisting the design of well spacing of sparging wells. The method applies both tracer and modeling approach. A field test using helium as a tracer was conducted on an air sparging pilot. A 3-dimensional, 3-phase compositional model was utilized to simulate the air sparging process at the pilot. The model was first calibrated with the tracer concentrations observed in the field test at various locations between the air sparging well and the soil vapor extraction well. The calibrated model was then used to predict the flow path of the injected air and to simulate the water saturation distributions in the aquifer. The steady-state water saturation distributions was found useful for estimating the radius of influence of air sparging and for designing the well spacing of sparging well.

Ventriculo-peritoneal shunt performance under hyperbaric conditions.

A novice scuba diver with an implanted ventriculo-peritoneal (VP) shunt inquired about the performance characteristics of his shunt while diving. A literature search revealed no information regarding shunt performance under hyperbaric conditions. The manufacturer could not certify that the shunt would function under pressure. Therefore, four VP shunts were tested according to the manufacturer's testing protocol at 1 and 4 atm abs in a multiplace hyperbaric chamber. The pressure (in mm of H2O) required to establish flow through the shunts was recorded. Trials at 1 atm abs (n = 12) and 4 atm abs (n = 12) show that all shunts performed within the pressure range specified by the manufacturer.

On estimating census undercount in small areas.

"Net undercount rates in the U.S. decennial census have been steadily declining over the last several censuses. Differential undercounts among race groups and geographic areas, however, appear to persist. In the following, we examine and compare several methodologies for providing small area estimates of census coverage by constructing artificial populations. Measures of performance are also introduced to assess the various small area estimates. Synthetic estimation in combination with regression modelling provide the best results over the methods considered. Sampling error effects are also simulated. The results form the basis for determining coverage evaluation survey small area estimates of the 1900 decennial census."