Introduction:This study's aim was to determine the number of scuba tank fills done in Victoria, Australia from 1 July 2024 to 30 June 2025 to provide an estimate of the number of scuba dives conducted during that period and, from that, estimates of the fatality and decompression illness rates. Methods:Suppliers of compressed gas for scuba diving in Victoria were identified through internet searches, industry liaison and the Australasian Diving Safety Foundation records. Those identified were emailed an invitation to participate in the tank fill survey and provided with dedicated spreadsheets. Email reminders were sent to collect monthly data on air, nitrox and 'other' fills. Data were compiled and, at the end of the survey period, non-regular participants were approached to provide actual numbers or estimates of the year's fills. Results:Overall, 38/40 (95%) identified current suppliers participated in the survey, with 27 submitting regular monthly data and the remainder providing actual or estimated annual fills. There were 46,720 reported fills, including 39,386 air, 6,758 nitrox, and 576 others, with proportions of 84%, 15% and 1%, respectively. During that period, 11 scuba divers were treated for decompression illness (DCI) (eight of whom had dived locally) and there were two fatalities. Conclusions:It is estimated that around 50,000 scuba tank fills were provided, equating to approximately 50,000 dives conducted in Victorian waters during from 1 July 2024 to 30 June 2025. During that period, there were eight open circuit divers who had dived in Victoria treated for DCI and two scuba diving fatalities, yielding estimates of 16 DCI cases and four deaths per 100,000 dives.
Introduction:The primary objective of this review was to evaluate the effectiveness of hyperbaric oxygen therapy (HBOT) in the treatment of inner ear decompression sickness (IEDCS). Secondary objectives were to summarise the diver characteristics, HBOT parameters and outcome measures. Methods:All descriptive observational study designs including case series and individual case reports involving divers suffering IEDCS treated with HBOT were included. PubMed, Scopus, CINAHL and EMBASE were used to search for texts reporting the outcome for divers treated with HBOT. Eligible studies were appraised by two independent reviewers and any disagreements resolved via the third reviewer. Data were extracted using standardised tools and narrative synthesis was undertaken. Results:3,683 records were identified with 24 included in the final review representing 539 cases of IEDCS. Mean age was 44, average (in-water) dive depth 29 metres of seawater and dive duration 38 minutes. Mean onset of symptoms was 32 minutes and 74% had a right sided lesion. Only 37% had residual symptoms on discharge despite 68% showing dysfunction on laboratory testing. Follow-up duration and assessment methods were variable. Vestibular rehabilitation was underutilised and only 46% of divers went on to have patent foramen ovale (PFO) screening despite the well-established link to IEDCS. Conclusions:A standardised method of examination and assessment of symptoms should be considered along with vestibular rehabilitation (or referral to this service). All divers should be counselled on PFO screening. A standard 3-month follow-up is recommended to allow for assessment of residual dysfunction / symptoms and discussion regarding returning to diving. Further research should focus on assessment of vestibular deficit / symptoms over time to assess efficacy of HBOT including the effects of delay to recompression and number of treatments. Laboratory testing should be utilised to determine the mechanism of injury and recovery.
The gender identity of transgender people is not fully aligned with their sex assigned at birth. It has been estimated that approximately 355 of 100,000 people in the general population consider themselves transgender. Transgender people are increasingly choosing to transition through gender-affirming hormone therapy, including treatment with testosterone or oestrogens and gender-affirming surgeries. Occupational diving is performed in a unique, highly hostile physiological environment. An occupational diver should be free of pulmonary, cardiovascular, neurological, and psychological risk factors that could increase the risk of diving-associated adverse events. Dive medical assessments can identify these risk factors. The increasing number of people openly identifying as transgender raises the likelihood that more will want to participate in occupational diving. To date, however, no guidelines have been specifically designed for safe occupational diving by transgender individuals. This review, involving 43 systematic reviews and/or meta-analyses, was therefore designed to assess the long-term health effects in transgender individuals and how these influence occupational diving. Although transgender people face some additional health risks that could affect occupational diving, these risks can be managed by adhering to regular occupational fitness-to-dive guidelines.
Introduction:During clinical use of extracorporeal membrane oxygenation (ECMO) in hyperbaric conditions at our centre, upward titration of indicated sweep gas flow rates is required to maintain adequate CO₂ clearance. This project measured the impact of hyperbaric pressure on oxygen flow rates delivered by the Comweld Ezi-Flow flowmeters used in our centre. Methods:Oxygen flow rates through Comweld Ezi-flow standard and low oxygen gas flowmeters were set at 101.3 kPa (1 atmosphere absolute [atm abs]) and then measured at intervals up to 284 kPa (2.8 atm abs) using a calibrated gas flow analyser, with cross verification against a small Douglas bag test type apparatus. During testing, the chamber was compressed and decompressed at a rate of 10 kPa·min⁻¹. Flow rates during chamber compression and decompression were compared. Results:The indicated rate of oxygen gas flow through the unadjusted flowmeters changed minimally - typically rising by a maximum of half of the diameter of the indicator ball. The actual (volumetric) flow, tested across indicated flow rates from 3 to 12 L·min⁻¹, was consistently reduced by approximately 50% as the chamber pressure increased from 101.3 to 284 kPa (1 to 2.8 atm abs). A slightly smaller reduction was observed when assessing the low flowmeter across the same pressure range; reductions of 40.0 and 43.3% were demonstrated at 0.3 to 0.6 L·min⁻¹ respectively. Differences in flow rates between compression and decompression were minor except at the very lowest flows. Conclusions:At 284 kPa (2.8 atm abs), actual volumetric flow of oxygen through Comweld Ezi-Flow flowmeters is dramatically reduced and this needs appropriate compensation to ensure therapeutic aims are achieved.
Introduction:Transoesophageal echocardiography (TOE) is claimed to be the investigation of choice for detecting a persistent foramen ovale (PFO) with almost 100% diagnostic accuracy. If true, TOE would detect all large/clinically significant PFOs. Methods:Retrospective analysis to determine the sensitivity of TOE for detection of clinically significant PFOs. Patients were from a consecutive series of 150 patients who had transcatheter closure of a PFO following events attributed to paradoxical embolism (decompression sickness or stroke). In each patient, transthoracic echocardiogram with bubble contrast showed a clinically significant atrial right-to-left shunt. The data reported are from the sub-group of the 150 patients with a clinically significant PFO who also had a TOE performed in other hospitals. Results:Twenty seven of 150 consecutive patients had a total of 31 TOEs performed at 22 United Kingdom regional cardiac centres. TOE failed to detect a PFO in 17 of the 27 patients. Four patients had a TOE on two separate occasions and in each case both of the TOEs failed to show a PFO. TOE gave a false negative test in 21 of 31 investigations (sensitivity 32%). The mean PFO diameter was 9.4 mm (median 9 mm, range 5-16 mm) in the 21 patients in whom balloon sizing was performed and 9.8 mm (median 10 mm, range 5-16 mm) in the 13 patients in whom balloon sizing was performed and a TOE failed to show a PFO. Conclusions:These finding demonstrate that the precision of TOE for detecting a PFO in real world clinical practice is considerably lower than generally believed.
