Diving and hyperbaric medicine最新文献

Introduction: Extracorporeal membrane oxygenation (ECMO) has not been previously used clinically in the modern hyperbaric chamber. We describe the modifications, validation and clinical performance of the Maquet (Getinge) original series Rotaflow (Rotaflow 1), Quadrox-i adult microporous membrane oxygenator and permanent life support (PLS) circuit under hyperbaric conditions.

Methods: A Rotaflow 1 and Quadrox oxygenator underwent power supply modifications and rigorous safety testing in the hyperbaric environment using a PLS circuit primed with normal saline. Clinical validation was subsequently undertaken during a 'last resort' course of 13 hyperbaric oxygen treatment (HBOT) sessions for a patient suffering a life threatening vaso-invasive fungal infection requiring support with venovenous ECMO.

Results: Preliminary testing and subsequent clinical application in the hyperbaric chamber demonstrated steady flow through the circuit based on pump revolutions per minute, with up to 180 mL (10%) variability demonstrated between the console display compared to the independent flow meter. No significant changes to flow variability were noted during pressurisation and decompression phases. Device temperature remained within safe limits. No bubbles were visually or sonographically detected. There were no performance or integrity issues detected through compression, maintenance and decompression phases. During clinical use, the patient remained stable and hyperoxygenation targets were achieved. Membrane oxygenator oxygen inflow set at up to 8 L·min-1 maintained CO2 clearance.

Conclusions: After safety related modifications to the console's power supply, the Rotaflow 1 console, Quadrox oxygenator and PLS circuit performed satisfactorily up to 243 kPa during repeated clinical use.

Introduction: Idiopathic sudden sensorineural hearing loss (ISSHL) is hearing loss of unknown cause with greater than 30 dB loss over 72 hours or less across three consecutive frequencies. Hyperbaric oxygen therapy (HBOT) is a widely accepted treatment for this condition. HBOT protocols and outcomes measured vary between studies.

Methods: To update a systematic review with meta-analysis of relevant randomised trials to both quantify and estimate the quality of evidence to support or refute the use of HBOT for ISSHL. We followed the Cochrane Handbook for Systematic Reviews of Interventions methodology. We conducted a focussed search of the following databases - AMED, BIOSIS Previews, CENTRAL, CINAHL, Embase, Emcare, Global Health, Medline, Scopus and Web of Science. There were no language or publication status restrictions. The updated search covered 1 April 2012 to 22 February 2023. A total of 148 papers were found with 24 randomised and pseudo-randomised studies identified of which seven contributed to the final analysis. Studies using usual treatment (steroids) plus HBOT or no treatment plus HBOT were included. The ROBB 2 tool for risk of bias and the GRADE tool for certainty of evidence were utilised.

Results: Data pooling was hampered by variation in reporting of changes in pure tone average across these studies. Pooled analysis from five studies suggested the chance of improvement following HBOT and steroids was greater than after steroids alone (RR 1.6, 95% CI 1.3 to 2.0). Pooled data from four trials suggested a greater mean improvement following HBOT (mean difference 15.6 dB, 95% CI 1.5-29.8).

Conclusions: There is moderate evidence that HBOT improves hearing when applied up to 30 days after the onset of ISSHL. HBOT in combination with steroids (oral or intra-tympanic) can be justified as a routine treatment. Future trials should address optimal dose and timing of HBOT and ensure outcomes enable pooling of data in future reviews, as well as addressing some measure of the functional significance of any improvement.

Introduction: There are increasing anecdotal reports of in-water recompression in freedivers who surface with neurological symptoms, likely suffering from decompression illness (DCI). Given the remote locations where many cases occurred, divers often struggled to access medical care, including the gold-standard hyperbaric oxygen treatment (HBOT), thus resorting to in-water recompression (IWR). Currently, IWR guidelines have only been discussed for scuba and surface supplied divers in specific scenarios, with protocols prescribing oxygen breathing at depths ≤ 9 metres maximum for around 1-3 hours.

Methods: We conducted detailed interviews with six competitive freedivers on signs, symptoms, management, and resolution of 13 cases of DCI. We additionally requested records of medical evaluation and treatment, with their consent.

Results: Three cases were suggestive of decompression sickness, six were consistent with arterial gas embolism, and four were ambiguous. Six cases were treated with IWR for 20-90 min at 5-25 metres with partial to complete resolution of symptoms. Four of these cases received HBOT afterwards. One diver reported significant permanent disability. Divers made several regimen changes after these incidents, including staying well-hydrated, reducing lung-packing, slowing their ascent rate, and/or employing prophylactic IWR when diving beyond a specified depth.

Conclusions: Given the remote locations of many incidents, freedivers often faced challenges in accessing HBOT. Self-treatment with IWR was widely used, either as a bridge to HBOT or as a standalone remedy. IWR poses potential risks, especially at the deeper depths reported in this study. This treatment modality is being utilised sometimes without medical oversight and recommended guidelines for IWR for freedivers should be developed.

Introduction: Although defibrillation is the standard treatment for cardiac arrest with shockable rhythms, its safety during hyperbaric oxygen therapy (HBOT) remains uncertain, as the oxygen-enriched atmosphere and increased ambient pressure could, in case of sparking, increase fire and explosion risk. As established guidelines are lacking, this scoping review synthesizes the current knowledge, addressing the unique challenges that arise in this special environment.

Methods: A systematic literature search was conducted in CINAHL, Cochrane Library, EMBASE and PubMed. Two authors independently screened titles and abstracts, with a third author resolving discrepancies. Duplicate records were removed after initial screening. Full-text screening was also performed independently by two authors. Manual data extraction focused on actual defibrillation during HBOT, including outcomes, safety concerns, recommendations and further helpful information.

Results: The search initially identified 10,348 publications, ten of which were included. Screening of reference lists yielded another 23 publications, resulting in 33 finally included publications. Of these, four publications presented five patient cases of actual defibrillation during HBOT, while the remaining publications provided additional information on the topic.

Conclusions: Findings highlight a lack of standardised guidelines and limited empirical data, necessitating cautious consideration of defibrillation during HBOT. Safety protocols, including oxygen level and equipment specifications, vary between monoplace and multiplace hyperbaric chambers, influencing the feasibility of in-chamber defibrillation. There is strong consensus that defibrillation is strictly contraindicated inside monoplace chambers, while in multiplace chambers, risks and benefits must be assessed individually. While defibrillation during HBOT is rare, ensuring its safety remains of paramount importance. Future research should focus on refining safety protocols and establishing guidelines to optimise patient outcomes during HBOT-associated emergencies.

Introduction: Rebreather diving carries a high fatality rate (estimated 1.8-3.8 deaths per 100,000 dives), yet its popularity is growing. Among 54 French military divers who lost consciousness underwater, none died when using a mouthpiece retaining strap (MRS) in a team diving setup. Despite this, MRS use remains limited among recreational divers for whom drowning is a major cause of death. This study assessed knowledge, perceptions, and training regarding MRS use within the rebreather diving community.

Methods: An international online survey targeting certified rebreather divers was disseminated via social media. The survey gathered demographic information, diving experience, MRS usage, and details on related training.

Results: A total of 563 responses were collected. Of these, 133 (23.6%) were instructors, and 210 (37.3%) had received MRS training. On a 0 to 100 scale, divers trained on MRS use rated MRS importance higher (median score: 74 [IQR 33-90]) than divers with no MRS training (median: 49 [IQR 16-67]). Barriers to MRS adoption included negative past experiences, poor training, misuse, and concerns about complications during bailout procedures.

Conclusions: While not widely adopted among recreational divers, the MRS is supported by strong safety data. Formal training significantly improves its perceived value and acceptance. Greater involvement from manufacturers, training agencies, and instructors is essential to promote education and encourage MRS adoption as a key safety measure in rebreather diving.

Introduction: Iatrogenic cerebral air embolism (CAE) is an uncommon, potentially fatal condition characterised by accidental introduction of air into the circulation during invasive procedures. Prompt recognition and treatment with hyperbaric oxygen therapy (HBOT) are required. Data on long-term functional outcome and specifically quality of life (QoL) in patients experiencing CAE are limited.

Methods: This prospective, single-centre, observational cohort study examined patients with iatrogenic CAE who were treated with HBOT. Patient characteristics, clinical severity scores and treatment details were recorded. The primary outcomes of the study were the Glasgow Outcome Scale (GOS) score at discharge and six months, and QoL measured by the World Health Organization quality of life brief version at six months.

Results: A total of 22 patients were included, with 14 patients (64%) having arterial CAE, five (23%) retrograde venous CAE, and the remaining three having either both (n = 1) or unknown (n = 2) forms of CAE. Median time-to-HBOT was seven hours [IQR 5-10]. The overall mortality rate was 23% (n = 5), eight of 22 patients achieving full recovery (GOS 5) at six months, and another six patients having moderate disability (GOS 4) at six months. Nine of 17 survivors (53%) reported a decline in QoL compared to their pre-incident status. Outcome in patients with retrograde venous CAE seemed to be better, and outcome in patients with CAE following neuroangiographic procedures for stroke or subarachnoid haemorrhage seemed to be worse, compared to the remainder of patients.

Conclusions: Iatrogenic CAE is associated with substantial morbidity and mortality, with only a third of patients in our cohort achieving good functional recovery. Over half of survivors in this cohort self-reported reduced QoL as compared to their situation before the CAE incident.

Filamentous soil moulds such as Saksenaea and Fusarium are angioinvasive fungi responsible for severe disseminated infections. Saksenaea causes zygomycosis, with disseminated cases having over ninety percent mortality. Fusarium, a hyphomycetes mould, can also cause disseminated infections in immunocompromised individuals, with high mortality. We describe the case of a normally healthy 20-year-old male who survived major traumatic injuries resulting from an aviation incident. He subsequently developed disseminated cutaneous zygomycetes (Saksenaea) and Fusarium infection with associated immunosuppression, multiorgan dysfunction and sepsis. Treatment strategies included repeated and extensive surgical debridement (inferior orbital region to carotid sheath in the neck, to a depth of buccal mucosa and zygomatic bone in the cheek), antifungal agents including intravenous (IV) liposomal amphotericin B and voriconazole, and IV immunoglobulin and granulocyte colony stimulating factor. Despite maximal medical and surgical treatment, disease control was not achieved. After multi-specialty consensus that current management had failed to control the disease process, hyperbaric oxygen treatment (HBOT) was added to standard therapy on an experimental basis based on several case reports, pathophysiological rationale, and institutional experience with angioinvasive Mucor. The patient was on venovenous extracorporeal membrane oxygenation for all HBOT sessions; details are reported separately. Thirteen treatment sessions (243 kPa [2.4 atmospheres absolute], 95 min) were successfully delivered. Local and systemic disease control was achieved within several days of commencing HBOT, and after a prolonged period of rehabilitation and reconstruction, the patient was discharged home. We conclude that HBOT may have an important role in the management of angioinvasive fungal disease.

Introduction: A multi-trauma patient receiving extracorporeal membrane oxygenation (ECMO) developed severe disseminated vaso-invasive fungal disease. In the absence of any remaining treatment escalation options, hyperbaric oxygen treatment (HBOT) was considered as a last effort at gaining disease control. Previously, the use of modern ECMO devices had not been validated for hyperbaric use at our centre or, to the best of our knowledge, at any other centre around the world. We had, however, identified a potentially hyperbaric compatible ECMO device and had commenced a validation process. The aim of this report is to highlight the practical, operational and governance processes undertaken to safely provide HBOT utilising ECMO at short notice.

Methods: A detailed risk assessment, development of risk reduction strategies and workflows, emergency out-of-session ethics review, clinical innovations committee review, legal advice, executive approvals and informed consent were undertaken over a 32-hour period prior to commencing HBOT.

Results: We present the identified risks, governance approvals, workflow, staffing model, chamber layout and safety checklist utilised to successfully deliver thirteen HBOT sessions to a patient on venovenous (VV) ECMO.

Conclusions: Through an extensive and coordinated effort involving multiple specialties and disciplines at our service, we were able to safely deliver HBOT to a patient supported by VV ECMO.

Introduction: Hypoglycaemic encephalopathy is a potentially life-threatening condition which can present with seizures, altered mental status or focal neurologic deficits. Therapeutic options are limited and the overall prognosis is poor. Among previously reported cases, the maximum time for patients to recover consciousness after hypoglycaemic encephalopathy was 14 days. So far, no studies have reported that hyperbaric oxygen therapy (HBOT) can improve the consciousness disorder of hypoglycaemic encephalopathy.

Case report: We report a case of hypoglycaemic encephalopathy caused by insulinoma who had a refractory consciousness disorder for 90 days and whose recovery was temporally related to institution of HBOT, suggesting that HBOT is a possible treatment for hypoglycaemic encephalopathy.

Conclusions: Hyperbaric oxygen therapy can be considered in hypoglycaemic encephalopathy when the hypoglycaemia has been corrected but patients still have reduced consciousness.

Introduction: Diving necessitates significant physiological adaptations, particularly within the cardiopulmonary system. Resting electrocardiograms (ECGs) are widely used in fitness to dive assessments, but their effectiveness in healthy young divers remains unclear. This study assessed the impact of applying sports medicine ECG criteria compared to traditional clinical standards, aiming to reduce (unnecessary) referrals to a cardiologist without compromising diver safety.

Methods: In this retrospective study covering 10 years, ECGs from Royal Netherlands Navy divers were analysed. Abnormal ECGs identified by clinical criteria between 2010 and 2019 were re-evaluated using international sports medicine ECG criteria. A control group of normal ECGs was matched based on demographic factors. Statistical analyses were performed using Pearson's chi-squared and Fisher's exact test, with significance set at P < 0.05.

Results: Of a total of 3,020 ECGs, 156 were classified as abnormal by clinical criteria. Reassessment using sports medicine standards reduced the number requiring further investigation by 85.9%. In the control group, 1.0% of previously unremarkable ECGs were identified as requiring further investigation upon reassessment. Conduction disorders and rhythm disturbances were the most common findings.

Conclusions: The findings of this study suggest that the application of sports medicine ECG interpretation criteria effectively reduces the number of ECGs requiring further investigation, thereby minimising referrals and associated costs. These results advocate for a re-evaluation of routine ECG screening practices in fitness to dive assessments in military divers, promoting a more tailored approach for this specific group.