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.

Evaluation of the Abbot FreeStyle Optium Neo H blood glucose meter in the hyperbaric oxygen environment.

INTRODUCTION: This study investigated the effects of hyperbaric oxygen treatment (HBOT) on the accuracy and reliability of point-of-care fingertip capillary blood glucose values in euglycaemic non-diabetic participants compared against venous serum blood glucose samples processed in an accredited pathology laboratory. METHOD: Ten non-diabetic hyperbaric staff members (age 35-55 years) underwent a standard 243 kPa HBOT exposure for 95 minutes. Blood glucose levels were measured via (i) finger-prick capillary test using the FreeStyle Optium™ Neo H glucometer and (ii) venous serum test using the Cobas 6000 laboratory analyser. Samples were taken at (T1) 0 minutes (pre-HBOT), (T2) 25 minutes, and (T3) 55 minutes into HBOT. RESULTS: All participants were euglycaemic at T1 (BGL 3.8-5.4 mmol·L⁻¹). The highest venous serum value was 5.90 mmol·L⁻¹ at T3 and the highest capillary value was 6.30 mmol·L⁻¹ at T1. Post hoc tests showed a statistically significant difference between the mean capillary result pre-dive (T1) and readings at T2 (P = 0.001) and T3 (P < 0.001) while differences between T2 and T3 capillary results were not statistically significant, illustrating the effect of HBOT on capillary beds. Differences in venous values across the time points were not significant. CONCLUSION: Venous serum glucose samples processed in an accredited laboratory may be more consistently accurate, but capillary point-of-care testing avoids delays in sample processing and provides glucose data that are of clinical relevance. The FreeStyle Optium™ Neo H glucometer is safe to use and provides a reliable measurement of blood glucose in the HBOT environment.

Identifying and acting on potentially inappropriate care? Inadequacy of current hospital coding for this task.

INTRODUCTION: Recent Australian attempts to facilitate disinvestment in healthcare, by identifying instances of 'inappropriate' care from large Government datasets, are subject to significant methodological flaws. Amongst other criticisms has been the fact that the Government datasets utilized for this purpose correlate poorly with datasets collected by relevant professional bodies. Government data derive from official hospital coding, collected retrospectively by clerical personnel, whilst professional body data derive from unit-specific databases, collected contemporaneously with care by clinical personnel. AIM: Assessment of accuracy of official hospital coding data for hyperbaric services in a tertiary referral hospital. METHODS: All official hyperbaric-relevant coding data submitted to the relevant Australian Government agencies by the Royal Hobart Hospital, Tasmania, Australia for financial year 2010-2011 were reviewed and compared against actual hyperbaric unit activity as determined by reference to original source documents. RESULTS: Hospital coding data contained one or more errors in diagnoses and/or procedures in 70% of patients treated with hyperbaric oxygen that year. Multiple discrete error types were identified, including (but not limited to): missing patients; missing treatments; 'additional' treatments; 'additional' patients; incorrect procedure codes and incorrect diagnostic codes. Incidental observations of errors in surgical, anaesthetic and intensive care coding within this cohort suggest that the problems are not restricted to the specialty of hyperbaric medicine alone. Publications from other centres indicate that these problems are not unique to this institution or State. CONCLUSIONS: Current Government datasets are irretrievably compromised and not fit for purpose. Attempting to inform the healthcare policy debate by reference to these datasets is inappropriate. Urgent clinical engagement with hospital coding departments is warranted.

Identifying and acting on inappropriate metadata: a critique of the Grattan Institute Report on questionable care in Australian hospitals.

INTRODUCTION: In an era of ever-increasing medical costs, the identification and prohibition of ineffective medical therapies is of considerable economic interest to healthcare funding bodies. Likewise, the avoidance of interventions with an unduly elevated clinical risk/benefit ratio would be similarly advantageous for patients. Regrettably, the identification of such therapies has proven problematic. A recent paper from the Grattan Institute in Australia (identifying five hospital procedures as having the potential for disinvestment on these grounds) serves as a timely illustration of the difficulties inherent in non-clinicians attempting to accurately recognize such interventions using non-clinical, indirect or poorly validated datasets. AIM: To evaluate the Grattan Institute report and associated publications, and determine the validity of their assertions regarding hyperbaric oxygen treatment (HBOT) utilisation in Australia. METHODS: Critical analysis of the HBOT metadata included in the Grattan Institute study was undertaken and compared against other publicly available Australian Government and independent data sources. The consistency, accuracy and reproducibility of data definitions and terminology across the various publications were appraised and the authors' methodology was reviewed. Reference sources were examined for relevance and temporal eligibility. RESULTS: Review of the Grattan publications demonstrated multiple problems, including (but not limited to): confusing patient-treatments with total patient numbers; incorrect identification of 'appropriate' vs. 'inappropriate' indications for HBOT; reliance upon a compromised primary dataset; lack of appropriate clinical input, muddled methodology and use of inapplicable references. These errors resulted in a more than seventy-fold over-estimation of the number of patients potentially treated inappropriately with HBOT in Australia that year. CONCLUSION: Numerous methodological flaws and factual errors have been identified in this Grattan Institute study. Its conclusions are not valid and a formal retraction is required.

Erratum.

In the paper: Smart DR, Van den Broek C, Nishi R, Cooper PD, Eastman D. Field validation of Tasmania's aquaculture industry bounce-diving schedules using Doppler analysis of decompression stress. Diving Hyperb Med. 2014 September:44(3):124-136. Numbering in the reference list starts at 3, whereas it should start from number 1. The numbering sequence in the text is correct.

Field validation of Tasmania's aquaculture industry bounce-diving schedules using Doppler analysis of decompression stress.

INTRODUCTION: Tasmania's aquaculture industry produces over 40,000 tonnes of fish annually, valued at over AUD500M. Aquaculture divers perform repetitive, short-duration bounce dives in fish pens to depths up to 21 metres' sea water (msw). Past high levels of decompression illness (DCI) may have resulted from these 'yo-yo' dives. This study aimed to assess working divers, using Doppler ultrasonic bubble detection, to determine if yo-yo diving was a risk factor for DCI, determine dive profiles with acceptable risk and investigate productivity improvement. METHODS: Field data were collected from working divers during bounce diving at marine farms near Hobart, Australia. Ascent rates were less than 18 m·min⁻¹, with routine safety stops (3 min at 3 msw) during the final ascent. The Kisman-Masurel method was used to grade bubbling post dive as a means of assessing decompression stress. In accordance with Defence Research and Development Canada Toronto practice, dives were rejected as excessive risk if more than 50% of scores were over Grade 2. RESULTS: From 2002 to 2008, Doppler data were collected from 150 bounce-dive series (55 divers, 1,110 bounces). Three series of bounce profiles, characterized by in-water times, were validated: 13-15 msw, 10 bounces inside 75 min; 16-18 msw, six bounces inside 50 min; and 19-21 msw, four bounces inside 35 min. All had median bubble grades of 0. Further evaluation validated two successive series of bounces. Bubble grades were consistent with low-stress dive profiles. Bubble grades did not correlate with the number of bounces, but did correlate with ascent rate and in-water time. CONCLUSIONS: These data suggest bounce diving was not a major factor causing DCI in Tasmanian aquaculture divers. Analysis of field data has improved industry productivity by increasing the permissible number of bounces, compared to earlier empirically-derived tables, without compromising safety. The recommended Tasmanian Bounce Diving Tables provide guidance for bounce diving to a depth of 21 msw, and two successive bounce dive series in a day's diving.

The death of buddy diving?

Dear Editor, By focussing on the details of the Watson case, I believe Bryan Walpole has missed the thrust of my earlier letter. I agree this was a complex case, which is why I deliberately avoided the murky specifics in order to consider the 'big-picture' ramifications of the judgement. My concerns relate to the potential consequences of the unintended interplay between unrelated developments in the medical and legal arenas. Taken together, I believe these developments threaten the very institution of buddy diving. I have been unable to verify Dr Walpole's claim that the statute under which Mr Watson was convicted has not been used previously in a criminal trial. I must, however, refute his assertion that this legislation is some sort of idiosyncratic historical hangover or legal curiosity unique to Queensland. Although the original legislation pre-dates Australian federation, this statute has survived intact through 110 years of reviews and amendments to the Queensland Criminal Code. The application of this 19th century law to the Watson case now provides a direct, post-federation, 21st century relevance. Nor is Queensland alone in having such a statute on its books. Section 151 of the Criminal Code Act in Dr Walpole's home state of Tasmania states "When a person undertakes to do any act, the omission to do which is or may be dangerous to human life or health, it is his duty to do that act." Similar statutes can also be found in the legislation of other Australian states and as far afield as New Zealand and Canada. The phrasing of the relevant sections is, in many cases, almost identical to Queensland's, reflecting the common judicial heritage of these places. Even if this ruling's reach extended no further than the Queensland border its ramifications would be immense. Tourism statistics reveal that over 1.2 million visitors perform nearly 3.5 million dives/snorkels in Queensland each year. An estimated 93% of international divers visiting Australia stopover in Queensland and 40% of domestic recreational diving holidays occur there. This ruling, however, has implications potentially far beyond this single State. In the absence of local precedents, courts may examine precedents arising in other jurisdictions with which they share a common legal heritage. Rare cases may indeed make bad law but precedent is one of the cornerstones of our legal system. The medical profession, through the revised SPUMS guidelines on recreational diving medical examinations, has now made explicit the level of support expected from dive buddies (e.g., to diabetic divers). The legal profession, through the Watson judgement, has demonstrated the potential consequences of failure to perform an act that a diver has undertaken to perform towards their buddy. The halcyon days of casually agreeing to act as someone's buddy are now gone. Serious consideration should be given to the personal consequences of undertaking this role. The potential to face a custodial sentence for criminally negligent manslaughter if a diver fails in his/her duty-of-care increases the pressure to save their buddy at all costs - or die in the attempt.

Hyperbaric chamber attendant safety II: 14-year health review of multiplace chamber attendants.

INTRODUCTION: The multiplace hyperbaric chamber provides a unique working environment for health-care personnel. The major foci of concern regarding staff health under these conditions have tended to be decompression sickness (DCS) and barotrauma. Incidences of DCS as high as 1.3% have been reported in hyperbaric attendants exposed to routine treatment tables. Occupational health risks of this magnitude are not acceptable in routine clinical practice. Significant variations in procedures exist between institutions in an attempt to enhance staff safety. In extreme cases the use of multiplace chambers has been abandoned. AIM: To determine the actual incidence of work-related health issues amongst attendants at a full-time clinical hyperbaric unit. DESIGN: retrospective staff health survey. Facility: university teaching hospital. SUBJECTS: 155 medical, nursing and technical staff routinely exposed to hyperbaric conditions. RESULTS: There were no cases of DCS encountered in 6,062 attendant exposures, across all hyperbaric profiles, during this 14-year period (95% CI 0, 0.06%). Twenty-eight work-related injuries occurred during this time (0.46%), of which 25 (0.41%) were hyperbaric-specific. CONCLUSION: A multiplace hyperbaric chamber can be viewed as a relatively safe working environment.

Hyperbaric chamber attendant safety I: Doppler analysis of decompression stress in multiplace chamber attendants.

INTRODUCTION: Incidences of decompression sickness of 0.76% have been reported in hyperbaric attendants exposed to routine 243 kPa treatment tables. Occupational health risks of this magnitude are not acceptable in routine clinical practice. Significant variations in procedures are therefore found between institutions in an attempt to enhance staff safety. In extreme cases, the use of multiplace chambers has been abandoned. Doppler ultrasound provides an objective tool to assess the sub-clinical decompression stress associated with any particular exposure. AIMS: To assess the decompression stress imposed upon staff exposed to our routine 243 kPa table and to elucidate demographic details within the attendant population that impact upon that stress. DESIGN: prospective observational cohort study. Profile: 243 kPa for 90 min with a 20 min decompression on oxygen. SUBJECTS: 28 nursing and medical personnel routinely undertaking patient care under hyperbaric conditions. PROCEDURE: Doppler assessment at 20 min intervals for up to 120 min post-exposure. Scoring: aural grading of intravascular bubbles using the Kisman-Masurel (K-M) scoring system; 163 exposures were scrutinized in this manner. RESULTS: 68% of exposures resulted in 'low' (K-M Grades 0-I), 22% in 'intermediate' (Grade II) and 10% in 'high' sub-clinical decompression stress (Grades III-IV). Female gender and increasing age, weight and exposure frequency showed trends towards higher bubble grades. There were no cases of clinical decompression sickness. CONCLUSIONS: Our standard 243 kPa table conforms to DCIEM definitions of 'acceptable' decompression stress (Grade II or fewer bubbles in ≥50% of the subjects). Significant inter- and intra-individual variability was evident even within this one, tightly controlled dive profile.