Diving and hyperbaric medicine最新文献

Introduction: This report describes the outcomes of sensorineural hearing loss (SNHL) due to cochlear inner ear barotrauma (IEBt) in five divers treated with hyperbaric oxygen (HBOT).

Methods: The case histories of five consecutive divers presenting with SNHL from IEBt due to diving, were reviewed. All divers provided written consent for their data to be included in the study. All had reference pre-injury audiograms. All noted ear problems during or post-dive. Independent audiologists confirmed SNHL in all divers prior to HBOT, then assessed outcomes after HBOT.

Results: Three divers breathed compressed air on low risk dives, and two were breath-hold. None had symptoms or signs other than hearing loss, and none had vestibular symptoms. All could equalise their middle ears. Inner ear decompression sickness was considered unlikely for all cases. All were treated with HBOT 24 hours to 12 days after diving. Two divers received no steroid treatment, one was treated with HBOT after an unsuccessful 10-day course of steroids, and two divers received steroids two days after commencing HBOT. All divers responded positively to HBOT with substantial improvements in hearing across multiple frequencies and PTA4 measurements. Median improvement across all frequencies (for all divers) was 28 dB, and for PTA4 it was 38 dB.

Conclusions: This is the first case series describing use of HBOT for IEBt-induced SNHL. The variable treatment latency and use/timing of steroids affects data quality, but also reflects pragmatic reality, where steroids have minimal evidence of benefit for IEBt. HBOT may benefit diving related SNHL from IEBt with no evidence of perilymph fistula, and provided the divers can clear their ears effectively. A plausible mechanism is via correction of ischaemia within the cochlear apparatus. More study is required including data collection via national or international datasets, due to the rarity of IEBt.

Introduction: Hyperbaric oxygen treatment (HBOT) is considered definitive treatment for decompression illness. Delay to HBOT may be due to dive site remoteness and limited facility availability. Review of cases may help identify factors contributing to clinical outcomes.

Methods: Injured divers treated in Townsville from November 2003 through December 2018 were identified. Information on demographics, initial disease severity, time to symptom onset post-dive, time to pre-HBOT oxygen therapy (in-water recompression or normobaric), time to HBOT, and clinical outcome was reviewed. Data were reported as median (interquartile range [IQR]) with Kruskal-Wallis and chi-square tests used to evaluate group differences. Significance was accepted at P < 0.05.

Results: A total of 306 divers (184 males, 122 females) were included with a median age of 29 (IQR 24, 35) years. Most divers had mild initial disease severity (n = 216, 70%). Time to symptom onset was 60 (10, 360) min, time to pre-HBOT oxygen therapy was 4:00 (00:30, 24:27) h:min, and time to start of HBOT was 38:51 (22:11, 69:15) h:min. Most divers (93%) had a good (no residual or minor residual symptoms) outcome and no treated diver died. Higher initial disease severity was significantly associated with shorter times to symptom onset, oxygen therapy, and HBOT, and with worse outcomes. The paucity of cases receiving HBOT with minimal delay precluded meaningful evaluation of the effect of delay to HBOT.

Conclusions: Most divers had mild initial disease severity and a good outcome. Higher initial disease severity accelerated the speed of care obtained and was the only factor associated with poorer outcome.

Introduction: The aim was to determine the cost-effectiveness and cost-utility of additional hyperbaric oxygen therapy (HBOT) compared to standard care (SC) for ischaemic diabetic foot ulcers (DFUs) regarding limb salvage and health status.

Methods: An economic analysis was conducted, comprising cost-effectiveness and cost-utility analyses, with a 12-month time horizon, using data from the DAMO₂CLES multicentre randomised clinical trial. Cost-effectiveness was defined as cost per limb saved and cost-utility as cost per quality-adjusted life year (QALY). The difference in cost effectiveness between HBOT+SC and SC alone was determined via an incremental cost-effectiveness ratio (ICER).

Results: One-hundred and twenty patients were included, with 60 allocated to HBOT+SC and 60 to SC. No significant cost difference was found in the intention-to-treat analysis: €3,791 (bias corrected and accelerated [BCA] 95% CI, €3,556 - €-11,138). Cost per limb saved showed an ICER of €37,912 (BCA 95% CI €-112,188 - €1,063,561) for HBOT+SC vs. SC. There was no significant difference in mean QALYs: 0.54 for HBOT+SC vs. 0.56 for SC alone (-0.02; BCA 95% CI -0.11-0.08). This resulted in a cost-utility of minus €227,035 (BCA 95% CI €-361,569,550 - €-52,588) per QALY. Subgroup analysis for Wagner stages III/IV showed an ICER of €19,005 (BCA 95%CI, -€18,487 - €264,334) while HBOT did not show any benefit for Wagner stage II.

Conclusions: HBOT as an adjunct to SC showed no significant differences in costs and effectiveness for patients with DFUs regarding limb salvage and health status. However, for patients with Wagner stage III/IV ischaemic DFUs there was a trend towards better effectiveness and cost-effectiveness.

Introduction: Understanding safety issues in competitive freediving is necessary for taking preventive actions and to minimise the risk for the athletes.

Methods: We analysed occurrence of loss of consciousness (LOC) and pulmonary barotrauma (PBt) in various freediving disciplines in 988 competitions over five years (from 2019 to 2023 inclusive), with 38,789 officially registered performances (starts): 26,403 in pool disciplines and 12,386 in depth disciplines.

Results: Average incident rate in competitive freediving (all cases: LOCs plus PBt, 2019-2023) was 3.43% (1,329 incidents / 38,789 starts). The average incident rate of LOC and PBt within five years were 3.31% and 0.38% respectively for all disciplines. Two disciplines present higher risk for LOC: dynamic without fins (DNF) (mean risk ratio (RR) = 1.48, 95% CI, 1.13 to 1.96, P < 0.01) and constant weight without fins (CNF) (mean RR = 2.02, 95% CI, 1.39 to 2.94, P < 0.001). The RR for PBt was not higher in any discipline. The overall risk of all types of incidents (LOC plus PBt) was also higher for DNF (mean RR = 1.55, 95% CI, 1.18 to 2.04, P < 0.01) and CNF (mean RR = 2.80, 95% CI, 1.70 to 5.04, P < 0.001).

Conclusions: The disciplines without fins in the pool (DNF) and at depth (CNF) appear to be the most dangerous in terms of LOC. We may recommend that organisers and safety teams should pay a special attention to no-fin disciplines as most risky for possible LOC.

Introduction: Diving utilising closed circuit pure oxygen rebreather systems has become popular in professional settings. One of the hazards the oxygen diver faces is central nervous system oxygen toxicity (CNS-OT), causing potentially fatal convulsions. At the same time, divers frequently travel by boat, often suffering seasickness. The over-the-counter medication meclizine is an anticholinergic and antihistaminergic agent that has gained popularity in the treatment of seasickness. Reports have shown the inhibitory effect that acetylcholine has on glutamate, a main component in the mechanism leading to CNS-OT seizure. The goal of the present study was to test the effect of meclizine on the latency to CNS-OT seizures under hyperbaric oxygen conditions.

Methods: Twenty male mice were exposed twice to 608 kPa (6 atmospheres) absolute pressure while breathing oxygen after administration of control solution (carboxymethyl cellulose solvent) or drug solution (meclizine) in a randomised crossover design. Latency to tonic-clonic seizures was visually measured.

Results: Mean latency to seizure did not significantly differ between the control group (414 s, standard deviation [SD] 113 s) and meclizine group (434 s, SD 174 s).

Conclusions: Based on results from this animal model, meclizine may be an appropriate option for divers suffering from seasickness, who plan on diving using pure oxygen rebreather systems.

This joint position statement (JPS) on immersion pulmonary oedema (IPO) and diving is the product of a workshop held at the 52nd Annual Scientific Meeting of the South Pacific Underwater Medicine Society (SPUMS) from 12-17 May 2024, and consultation with the United Kingdom Diving Medical Committee (UKDMC), three members of which attended the meeting. The JPS is a consensus of experts with relevant evidence cited where available. The statement reviews the nomenclature, pathophysiology, risk factors, clinical features, prehospital treatment, investigation of and the fitness for future compressed gas diving following an episode of IPO. Immersion pulmonary oedema is a life-threatening illness that requires emergency management as described in this statement. A diver with previous suspected or confirmed IPO should consult a medical practitioner experienced in diving medicine. The SPUMS and the UKDMC strongly advise against further compressed gas diving if an individual has experienced an episode of IPO.

Introduction: Characterisation of the recreational diving community could help to identify scuba divers at risk for accidents.

Methods: We performed a cross-sectional evaluation in a federation for recreational scuba divers in Belgium (Duiken.Vlaanderen). Using binary logistic regression, factors predictive for accidents leading to hospitalisation were identified.

Results: Of the 710 members, 210 (29.6%) participated in the survey, representing 140,133 dives. Age was > 50 years in 55% and the median (interquartile range [IQR]) number of dives was 380 (IQR 140-935). Cardiac (9.5%), orthopaedic (11.0%), ear-nose-throat (ENT, 10.5%) and allergic diseases (30.5%) were the top four morbidities. Twenty percent reported taking cardiovascular medication. Decompression accidents, barotrauma of the ear and musculoskeletal injuries were reported in 11.0, 11.9 and 11.0%. Fifty-five divers (26.2%) reported incidents not necessitating a medical intervention. For 36 divers (17.1%), medical interventions were necessary. Among these, 13 divers (6.2%) were hospitalised at least once and 12 (5.7%) of these needed hyperbaric oxygen therapy (HBOT). The absolute risk for hospitalisation or HBOT was 0.01% per dive. Age, advanced diving qualification, more dives annually, cardiac or ENT pathology and cardiac medication were significantly associated with an increased likelihood of hospitalisation resulting from diving accidents. In a multivariate risk model, ENT comorbidity (odds ratio [OR] 9.3; P = 0.006) and cardiac medication (OR 5.6; P = 0.05) predicted hospitalisation due to a diving accident.

Conclusions: One in six recreational scuba divers required a medical intervention at least once during their career, while 6.2% were hospitalised or received HBOT. Ear nose and throat comorbidity and cardiac medication were strong predictors for accidents. These should be given sufficient weight in dive medical examination.

Introduction: A 54-year-old, previously healthy Caucasian male diver was on a 22-day liveaboard diving holiday. During this time, he performed 75 open-circuit dives, of which 72 were with enriched air nitrox. All dives were within recreational length and depth. After the trip he noticed a worsening of vision and his refraction had changed from the previous -3.75/-5.75 to -5.5/-7.75 dioptres. Hyperoxic myopia is a well-known phenomenon after hyperbaric oxygen treatment (HBOT), but related literature in recreational divers is scarce.

Methods: A systematic literature review on the effect of a hyperoxic environment on the development of myopia was done according to the PRISMA guidelines. Three databases were searched: Ovid MEDLINE, Scopus, and the Cochrane Library. A risk of bias analysis was done on all articles, and the GRADE approach was used to evaluate the quality of evidence. Articles that had sufficient data were used to synthesise a visualisation of oxygen exposure and changes in refraction.

Results: Twenty-two articles were included in this review. These included five case reports, two case series, nine cohort studies, one randomised controlled trial and five reviews, of which one was systematic. Most articles described HBOT patients' ocular complications, although four articles were diver centric. The synthesis of results suggests that divers tend to get a greater myopic shift with a smaller exposure. However, the data were too heterogeneous to perform meaningful statistical analyses. This review is the first to focus on divers instead of HBOT patients.

Conclusions: The case presented led to a systematic literature review on the effects of hyperbaric oxygen on refractive changes in both HBOT patients and divers. The data were too heterogeneous to make meaningful suggestions on a safety limit to prevent myopisation in diving.

This paediatric diving position statement was developed from a targeted workshop at the 51st Annual Scientific Meeting of the South Pacific Underwater Medicine Society (SPUMS) on 8 June 2023. It highlights the factors that SPUMS regards as important when undertaking health risk assessments for diving by children and adolescents (defined as aged 10 to 15 years). Health risk assessments for diving should be performed by doctors who are trained in diving medicine and who are familiar with the specific risks which result from breathing compressed gas in the aquatic environment. Undertaking a diver health risk assessment of children and adolescents requires a detailed history (including medical, mental health, psychological maturity), a comprehensive diver medical physical examination and evaluation of all relevant investigations to exclude unacceptable risks. In addition, assessment of the individual's motivation to dive and reported in-water capability should occur, whilst engaging with their parent /guardian and instructor, where appropriate, to ensure that safety for the child is optimised. The guideline applies to all compressed air diving including scuba and surface supply diving provided in open and contained bodies of water.

Introduction: Breath-hold divers occasionally surface with signs of fluid accumulation and/or bleeding in air-filled spaces. This constellation of symptoms, recently termed 'freediving induced pulmonary syndrome', is thought to come from immersion pulmonary oedema and/or barotrauma of descent and is colloquially termed a 'squeeze'. There is limited understanding of the causes, diagnosis, management, and return to diving recommendations after a squeeze.

Methods: We developed an online survey that queried breath-hold divers on the circumstances and management of individual squeeze events.

Results: A total of 132 (94 M, 38 F) breath-hold divers filled out the survey. Most were recreational or competitive freedivers with mean age of 37 years old and nine years of experience. Of those, 129 (98%) held a certification in freediving from an accredited training agency. A total of 103 individuals reported 140 squeeze events from 2008-2023. The average depth at which a squeeze occurred was 43 m. The top contributors to lung squeezes were described as movement at depth, contractions, and inadequate warm-up. The most common symptoms of a squeeze were cough, sputum production, and fatigue. Divers were instructed to wait an average of two months before returning to diving after a squeeze. On average, divers were able to achieve the same depth of their squeeze event three months after the incident.

Conclusions: Inadequate warm-up, contractions, and abnormal movement at depth are the most reported causes for a squeeze. Most divers do not seek medical treatment after a lung squeeze event and can return to the same depth within three months.