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. 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. 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. 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.

A patent foramen ovale (PFO) is present in approximately 25% of the general population. Its clinical significance is primarily in patients with cryptogenic stroke. Randomized trials have evaluated whether transcatheter PFO closure reduces recurrent stroke compared to medical therapy. Evidence outside stroke, including migraine, decompression illness, and platypneaorthodeoxia syndrome, is limited. We reviewed major randomized controlled trials and extended follow-up studies evaluating transcatheter PFO closure in patients with cryptogenic stroke. Key trials included RESPECT, REDUCE, CLOSE, DEFENSEPFO, and RESPECTLate. Study populations, procedural outcomes, and post-procedural management were summarized. Non-stroke indications were evaluated using available randomized and observational data. In the RESPECT trial (n=980; mean age 46±11 years; 38% female; median follow-up 5.9 years), recurrent ischemic stroke occurred in 3.6% of patients undergoing PFO closure vs 5.8% with medical therapy (HR 0.55; 95% CI, 0.31–0.999; p=0.046). The REDUCE trial (n=664; mean age 45±10 years; 42% female) demonstrated a 77% relative risk reduction in recurrent stroke with closure vs antiplatelet therapy alone (1.4% vs 5.4%; p=0.002). The CLOSE trial (n=663; mean age 45±11 years; 40% female) reported no recurrent strokes in the closure group vs 14 events (6%) in the anti-platelet group over 5.3 years (p<0.001). DEFENSEPFO (n=120; mean age 52±12 years; 45% female) showed stroke in 0% vs 12.9% with medical therapy at 2 years (p=0.013). RESPECTLate demonstrated sustained benefit over 10 years (HR 0.54; 95% CI, 0.29–0.999; p=0.046). Pooled analysis across trials indicated a 59% lower risk of recurrent stroke with closure (HR 0.41; 95% CI, 0.200.83). The benefit was most pronounced in patients with large shunts or atrial septal aneurysms. Post-procedural atrial fibrillation occurred in 35% of patients; serious procedural complications were <2%. Dual antiplatelet therapy was administered for 3–6 months, and successful shunt elimination exceeded 90%. Evidence for PFO closure in migraine with aura or decompression illness remains limited; closure in platypneaorthodeoxia syndrome shows symptomatic improvement based on small case series. Transcatheter PFO closure significantly reduces recurrent stroke in adults aged 1860 years with cryptogenic stroke and highrisk anatomical features. The procedure is generally safe, with low rates of serious complications. Nonstroke indications remain investigational, and patient selection with multidisciplinary evaluation is essential to maximize benefit and minimize risk.

ABSTRACT Doğan M, Atan Y, Dağ MA, Üzün İ. Multifactorial Determinants of Diving-Associated Deaths in Turkey: Autopsy-Based Insights and the Imperative of Integrated Forensic Assessment. Undersea Hyperb Med. 2026 First Quarter; 53(1):1-14. Introduction: This autopsy-based study aims to investigate the underlying causes and forensic characteristics of fatal diving incidents in Turkey, emphasizing the autopsy-based strategies employed to distinguish drowning from other diving-related pathologies such as decompression illness and arterial gas embolism. Methods: A retrospective analysis was conducted on 11 fatal diving cases evaluated by the First Forensic Medicine Specialization Board between 2002 and 2023. Data were retrieved from judicial records, including detailed autopsy reports, histopathological findings, toxicological analyses, and scene investigations. Results: The decedents consisted of ten males and one female (median age: 45), reflecting the male- dominant profile of diving activity. Diving modalities included SCUBA (n=7), breath-hold (n=2), and surface-supplied compressor diving (n=2). The leading cause of death was drowning (n=5), followed by arterial gas embolism (AGE; n=2), sudden cardiac death (n=2), subarachnoid hemorrhage (n=1), and asphyxia due to mechanical entrapment (n=1). AGE cases demonstrated intravascular gas via specialized autopsy techniques. Cardiovascular comorbidities were identified in four cases, while medications— primarily prescribed—were detected in five. Alcohol and illicit drugs were absent in all cases. Discussion: Diving fatalities pose complex medicolegal challenges that require a multidisciplinary approach. Drowning and AGE were the most frequent causes, often accompanied by cardiovascular pathology. Proper autopsy techniques, scene correlation, and pre-dive medical screening remain critical for accurate diagnosis and prevention. The findings underscore the need for standardized forensic protocols, especially in regions with limited access to postmortem imaging. Keywords: arterial gas embolism; autopsy; cardiovascular disease; compressor diving; decompression illness; diving fatalities; drowning; forensic pathology; postmortem diagnosis; SCUBA

The lung surfactant dipalmitoylphosphatidylcholine (DPPC) settles on the luminal aspect of blood vessels to form active hydrophobic spots (AHS). The nanobubbles that develop at these spots are gas micronuclei from which decompression bubbles expand upon decompression. Variability between "bubblers" and "non-bubblers" is derived from the variability in the AHS. We expected that the level of DPPC in the heart would correlate with the severity of decompression illness (DCI). Thirty-six rats were exposed to 8 bar for 32 minutes. After decompression, they were examined for DCI and defined as non-DCI rats (ND, n=18), DCI-inflicted rats (DCI, n=13), and dead rats (DEATH, n=5). The DPPC concentration in the hearts (mg/g) was 2.97 ± 0.56 SD for ND, 2.87 ± 0.62 SD for DCI, and 2.81 ± 0.46 SD for DEATH. There was no significant difference between the three groups. The results are discussed, and a further study to explore the correlation between bubbling and heart DPPC is suggested.

This is the first published study examining decompression illness (DCI) among divers in Algeria. DCI is a complex syndrome caused by bubbles of inert gas that form in the body due to an improper decompression process, following exposure to increased pressure underwater. Algerian diving conditions pose significant challenges to divers. The study focuses on red coral diving, a popular and long-standing practice in eastern Algeria. We present three case reports describing dysbaric osteonecrosis of the humeral head with varying degrees of severity and presentation. Dysbaric osteonecrosis (DON), a rare complication in professional divers and compressed-air workers, presents a controversial link to previous decompression sickness (DCS) with musculoskeletal pain (type 1 DCS). The potential for these ischemic lesions to progress to osteonecrosis after DCS remains unclear. This report describes a professional diver declared permanently unfit for diving due to advanced dysbaric osteonecrosis of the shoulder, following type 1 DCS in the same region treated with hyperbaric oxygen therapy. This case highlights the potential association between these events and emphasizes the importance of close monitoring after acute type 1 DCS. Early magnetic resonance imaging (MRI) evaluation of all DCS cases with musculoskeletal pain is recommended to detect potential osteo-medullary damage. Such damage could worsen with continued diving and potentially transition into bone necrosis.

Sleep and Scuba Diving: Prevalence of Sleep Disorders and Their Potential Links with Decompression Illness in Recreational Divers

This autopsy-based study aims to investigate the underlying causes and forensic characteristics of fatal diving incidents in Turkey, emphasizing the autopsy-based strategies employed to distinguish drowning from other diving-related pathologies such as decompression illness and arterial gas embolism. A retrospective analysis was conducted on 11 fatal diving cases evaluated by the First Forensic Medicine Specialization Board between 2002 and 2023. Data were retrieved from judicial records, including detailed autopsy reports, histopathological findings, toxicological analyses, and scene investigations. The decedents consisted of ten males and one female (median age: 45), reflecting the male-dominant profile of diving activity. Diving modalities included SCUBA (n=7), breath-hold (n=2), and surface-supplied compressor diving (n=2). The leading cause of death was drowning (n=5), followed by arterial gas embolism (AGE; n=2), sudden cardiac death (n=2), subarachnoid hemorrhage (n=1), and asphyxia due to mechanical entrapment (n=1). AGE cases demonstrated intravascular gas via specialized autopsy techniques. Cardiovascular comorbidities were identified in four cases, while medications- primarily prescribed-were detected in five. Alcohol and illicit drugs were absent in all cases. Diving fatalities pose complex medicolegal challenges that require a multidisciplinary approach. Drowning and AGE were the most frequent causes, often accompanied by cardiovascular pathology. Proper autopsy techniques, scene correlation, and pre-dive medical screening remain critical for accurate diagnosis and prevention. The findings underscore the need for standardized forensic protocols, especially in regions with limited access to postmortem imaging.

Thailand is situated between two abundant bodies of water, the Andaman Sea and the Gulf of Thailand. Therefore, multiple industries are based around these waters. One of the largest economic incomes is from tourism, where recreational diving is a popular activity with multiple dive sites scattered across multiple provinces in Thailand. Moreover, there are types of diving such as military diving, occupational diving, and traditional (fishermen) diving. A retrospective descriptive study reviewing medical records of 178 decompression illness (DCI) patients from various hyperbaric chamber centers in Thailand, between January 2020 to December 2023. Out of all the patients, 73.6% achieved complete resolution of symptoms, while 26.4% had residual symptoms. Traditional divers were at a higher risk of having residual symptoms after treatment (42%). Missing safety stops showed significant association with incomplete treatment outcomes (p = 0.008), univariate logistic regression confirmed significance (OR = 2.495, 95% CI: 1.263-4.926, p = 0.008); after multivariate logistic regression this factor lost its significance, but remained a strong predictor (adjusted OR = = 2.208, 95% CI: 0.962-5.069, p = 0.062). As for affected organs, spinal cord involvement was strongly related to incomplete outcomes (p = 0.001). First-aid high flow oxygen was given to only 18.5% of patients but had no significant associations with treatment outcomes. This study was one of the first multi-center studies in Thailand, it raises multiple concerns for the diving industry in both the traditional and recreational sector. Both sectors can benefit from targeted education for divers, creating safety standards, and providing proper first-aid and treatment.

Breath-hold divers can surface with neurological symptoms consistent with nitrogen buildup in tissues or gas entry into the arterial circulation, collectively termed decompression illness (DCI). While DCI has historically been attributed to diving with compressed air, breath-hold divers have reported similar syndromes. The causes, diagnosis, and management of DCI in breath-hold divers is poorly understood. We developed an online survey that queried breath-hold divers on the symptoms they experienced during decompression illness events and the medical management of each event. A total of 36 (31 M, 5 F) breath-hold divers filled out the survey. A majority identified as recreational freedivers, competitive freedivers, and/or spearfishers with an average age of 45 years and 18 years of breath-hold diving experience. Of those surveyed, 33 (92%) held a certification from an accredited training agency. A total of 18 (50%) reported experiencing DCI, with 21 DCI incidents reported by 13 individuals from 1999-2024. Sixteen (76%) of DCI incidents occurred during training, with an average depth of 83.4 m and average speed of 1.0 m∙s-1. Thirteen (62%) percent of DCI incidents occurred while diving to depths shallower than a previous personal best. The most common symptoms were weakness, numbness, slurred speech, and fatigue. The most common treatment modalities were surface oxygen, in-water recompression, and hyperbaric oxygen therapy. Sixteen divers (76%) had partial or complete resolution of their symptoms. The top cited contributors to the DCI incidents were depth, short surface interval between dives, and pulmonary barotrauma. Breath-hold divers can experience DCI even when diving within their limits. The most cited contributors to DCI were depth, short surface interval between dives, and pulmonary barotrauma. Most divers' symptoms resolved after treatment with surface oxygen, in-water recompression, and/or hyperbaric oxygen therapy.

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. 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. 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. 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.

Decompression illness (DCI) encompasses two major diving-related disorders: decompression sickness (DCS) and arterial gas embolism (AGE). Both conditions are characterized by the formation of gas bubbles that act as the primary mechanism of tissue injury, resulting in overlapping clinical manifestations and similar therapeutic approaches. This study aims to review the pathophysiology, clinical presentation, diagnosis, and management of DCI that presents with stroke-like neurological symptoms. The method used was a literature review approach based on current evidence from recent scientific publications. Findings show that DCS occurs when dissolved inert gases, such as nitrogen, become supersaturated during ascent and form bubbles within tissues and the venous circulation. AGE typically arises from pulmonary barotrauma, allowing trapped gas to enter the pulmonary veins and reach the arterial circulation, with the brain as the most vulnerable target organ. DCI is considered a medical emergency requiring definitive management with hyperbaric oxygen therapy (HBOT). Neurological manifestations of DCI often resemble conventional ischemic stroke but demonstrate distinct clinical and temporal patterns related to pressure changes. Therefore, in addition to recompression therapy, patients may require standard acute stroke management. Prognosis depends heavily on the promptness of diagnosis and treatment, as early intervention is critical to preventing permanent neurological injury.

Neutrophil extravasation and NETosis in decompression illness lung injury: A P-selectin/PSGL-1/NOX2/PAD4 axis governed pathway validated by multi-model interrogation.

Background: Hyperbaric oxygen treatment (HBOT) is a systemic medical procedure in which a patient is placed within a specially designed hyperbaric chamber and given a high proportion of oxygen at pressures greater than one atmosphere. These days, it is being increasingly utilised to treat medical diseases including decompression illness and to help patients with chronic conditions like osteonecrosis, hypoxic wounds, air or gas embolism, carbon monoxide poisoning; cyanide poisoning; smoke inhalation. Objectives: This study aims to assess the awareness, knowledge and practice of Hyperbaric Oxygen Therapy (HBOT) as a treatment modality among Nigeria trained doctors. Methodology: This study was carried out using a 24-question anonymous questionnaire to gauge participants’ awareness, knowledge, and use of hyperbaric oxygen therapy. The study’s participants were qualified Nigerian physicians, and descriptive statistics were used to examine the data. Results: The study observed that most of these doctors demonstrated limited awareness and knowledge of HBOT. Sadly, about 86% reported never visited a hyperbaric unit or chamber which is a critical facility for HBOT delivery. Similarly, only 23% and 15% knew HBOT is indicated for carbon monoxide poisoning and gas embolism. Conclusion: The findings of the study simply reflect the huge awareness and knowledge gap as well as practice of Hyperbaric Oxygen Therapy among Nigeria trained doctors. Therefore, there is need for all concerned authorities to urgently set up awareness campaigns, training programs and set up centres for hyperbaric oxygen therapy to bridge this knowledge and practice gap.

Decompression illness (DCI) occurs due to absorbed extracorporal gas resulting from a decrease in environmental pressure during decompression. This term includes both arterial gas embolism (AGE), where alveolar or venous gas emboli enter the arterial circulation, and decompression sickness (DCS), which may result from in-situ bubble formation due to dissolved inert gas. AGE commonly presents with stroke-like symptoms affecting the brain, while DCS can impact various organs including the brain, spinal cord, inner ear, musculoskeletal tissue, cardiopulmonary system, and skin. DCI symptoms vary widely in nature and severity, ranging from itching and minor pain to severe neurological symptoms, cardiac collapse, and death. Symptoms are mostly non-specific; therefore, the diagnosis of DCI is based on careful evaluation of the circumstances of the dive, known risk factors, and the post-dive latency and nature of the manifestations. Treatment of choice is the on-site administration of 100% oxygen as soon as possible after onset of symptoms. First aid also includes supportive general care, immobilizing the injured patient, and giving isotonic fluids. Adjunct pharmacotherapy is usually not recommended; NSAIDs (Non steroidal anti-inflammatory drugs) can be used if there are no contraindications. Hyperbaric oxygen therapy is the primary treatment for decompression illness due to its ability to reduce bubble volume, enhance tissue oxygenation, and ameliorate inflammatory responses that contribute to tissue injury. Most DCS cases respond well to a single hyperbaric session, but repetitive treatments may be needed based on initial response. Delayed intervention is associated with increased morbidity and residual sequelae. Adhering to conservative dive profiles and screening for medical risk factors can reduce risk of decompression illness. This clinical review summarizes current knowledge on the pathophysiology, clinical presentation, diagnostic approach, treatment, and prevention of dive-related DCI. Key Words: Arterial Gas Embolism, AGE, DCS, Diving, Treatment, Pathophysiology, Diagnostic, Prevention

Patent foramen ovale (PFO) is a normal fetal communication between the right and left atrium that persists after birth. It is a common finding, occurring in 20-25% of the population, although its prevalence decreases with age. In most cases, PFO remains asymptomatic throughout life. However, it has been linked to conditions such as cryptogenic stroke, migraine with aura, decompression illness, and systemic arterial embolism. The evidence supporting PFO closure for these conditions primarily comes from non-randomized cohort studies, which often yielded conflicting results. This focused review aims to address the most common questions regarding the diagnosis, management, and treatment of PFO based on the latest available guidelines.

Since 1971, the U.S. Naval Base Guam recompression chamber (NBGRC) has provided hyperbaric oxygen therapy (HBO2) to primarily treat diving decompression sickness (DCS) but also to treat other indicated medical conditions. In 2017, Rendina etal. last reviewed the NBGRC's utilization. The current paper is an update of the chamber's activity from January 2017 through October 2024 including pre- and post-COVID-19 data. The goal of the current study is to report the diagnoses, treatments, demographic data, and estimated costs when providing HBO2 at NBGRC. This information will potentially assist the Defense Policy Review Initiative plan for future staff and resources. All cases of HBO2 performed at NBGRC from January 1, 2017, to November 1, 2024 were retrospectively reviewed. Paper and electronic medical records including consents, transport summaries, consult notes, insurance records, and hospital records were abstracted for diagnoses, treatments, and eligibility data. In addition, using the eligibility data and Medicare/Medicaid billing codes, charges for HBO2 services for non-Tricare beneficiaries were determined. From 2017 to 2024, 66 patients underwent 176 HBO2 treatments: 31 civilians (47%); 29 active duty (AD) personnel (44%); and 6 retirees (9%).During the study period, there were 180 HBO2 indications. There were 106 (59%) indications for non-dive diagnoses such as diabetic ulcers and wound therapy; 63 (35%) for DCS; 6 (3%) for arterial gas embolism (AGE); 4 (2%) for carbon monoxide (CO) poisoning; and 1 (1%) for cabin decompression. There were 70 HBO2 indications for decompression illness (DCI) (which includes DCS, cabin decompression, and AGE) from January 2017 to October 2024. Pre-COVID, 2017-2019, there were 42 DCI indications; during COVID, 2020-2021, there were 19 DCI indications; and post-COVID, 2022-2024, there were 9 DCI indications. There was a significant difference in DCI indications pre-COVID (M = 14 ± 4.97) compared to post-COVID (M = 3 ± 0.82); t(2) = 3.13, P = .044. Total Reimbursement for non-Tricare beneficiaries from 2017 to 2024 was $102,274.94. Pre-COVID charges were $56,377.18; during COVID, $29,587.52; and post-COVID, $16,310.24. The primary purpose of NBGRC is to support AD operations. However, the current study demonstrates that the treatment of civilian dive injuries is actually the major utilizer of the recompression chamber. Meticulous billing and collecting of facility fees and physician fees from non-Tricare patients for HBO2 services should be emphasized. The COVID decline in treatments has not rebounded to pre-COVID levels, in large part, because of the decline in the Guam tourism industry. Hyperbaric oxygen therapy treatments are expected to increase as Guam tourism improves. In addition, the upcoming relocation of Marines from Okinawa to Guam will also increase HBO2 treatment numbers. The Defense Policy Review initiative needs to factor in the increase in HBO2 treatments because of both these factors. Although the intent of this article is not necessarily to discuss the impact, it should be emphasized that the Navy undersea community and the utilization of recompression chambers and hyperbaric medicine is a life-saving service. Policy changes and resource allotment should always remember this most important mission.

Abstract Introduction: Decompression illness can caused by the release of dissolved gas from blood following underwater diving causing clinical manifestations. It is a function of Henry's Law in which a pressure reduction while ascending after a dive can cause dissolved nitrogen to be released into the tissues and blood, causing intravascular and extravascular bubble formation. It could present with mild pain to complete vascular obstruction and lead to the compromise of hemodynamics and respiration. Case report: 38-year-old female with a past medical history of anxiety and ADHD initially presented to the emergency department for unconsciousness. Code stroke was activated. Initial workup includes CT brain without contrast, CTA head and neck does not show any acute hemorrhage or demonstrate vascular occlusion or infarct. Patient gain consciousness and, start complaining about pain in the elbows shoulders, back and knees and she was requiring oxygen. she stated around morning 6 AM she went for the dive she descended about 85 feet down and was there for about 25 minutes at that time she got separated from her diving party and panicked so she ascended rapidly and reach to the surface in 1 to 2 minutes during that event she missed her safety top. She was feeling weird and short of breath, she took some rest and later on decided to go for second dive at this time she descended down to 65 feet and was there for about 12 minutes. Later on, she does not remember what happened how she came back. Upon examination she was not in acute distress, her skin was warm, non-tender no lesions were seen extremities does not show any cyanosis or edema. Patient started on hyperbaric treatment with a concern of decompression sickness. She improved and discharged home with pain medications. Conclusion: Decompression illness is rare with the rate of occurrence estimated to be around 0.03% in recreational divers. Decompression illness can presents as variety of manifestations and divided into two types. Type I usually include rash and musculoskeletal pain however, type II includes neurological and cardiopulmonary symptoms. The initial resuscitative step in a person with decompression illness should be the administration of oxygen, ideally at FiO2 of 100%. The mainstay of treatment of decompression illness remains hyperbaric therapy. And should be initiated as soon as possible.

ABSTRACTDiving can affect neuropsychiatric functions. Previous studies of Taravana syndrome in Polynesian pearl divers, which have similarities to decompression illness following breath‐hold diving, and of Chiyamai in Japanese breath‐hold divers, which have symptoms like panic disorder, show what modern medicine can learn from the wisdom of tradition. Among Japanese traditional breath‐hold divers, known as Ama, in the Shima region, there is frightening folklore about something called Tomokazuki, a phantom‐like figure that appears to an Ama in life‐threatening situations. Although Tomokazuki may be a medically explainable phenomenon, to date it has not been analyzed scientifically. We review neuropsychiatric manifestations in traditional breath‐hold divers, with a particular focus on Iwata Junichi's Ama of Shima, published in 1939, which records the traditional fishing practices of the Ama and includes 12 orally passed down episodes concerning Tomokazuki. Seven of the 12 Tomokazuki episodes were self‐like visions, four were visions of others, and the remaining one was an auditory experience of a voice. Three episodes described feelings of being separated by a netlike membrane (similar to mosquito netting). Hypothermia, loss of consciousness due to hypoxia, sensory deprivation, isolation, and exhaustion were presumed to relate to the hallucinatory events both individually and in combination. The contents of hallucinations in similar occupational, sport, and clinical situations have not been well researched. Tomokazuki deserves attention from sociological and medical perspectives.

Measurements of forced vital capacity (FVC) have shown that divers have larger lungs than members of the general population. Bullae or decompression illness (DCI) secondary to pulmonary barotrauma is more likely to occur in large lungs (LLs) than in normal lungs (NLs). This study retrospectively compared lung function, high-resolution CT (HRCT) scan anomalies, the unfit-to-dive rate, and the prevalence of DCI in groups of divers with LLs and NLs. The results of fitness examinations of divers with LLs (FVC z-score > 1.96) and NLs (FVC z-score ≤ 1.96) from 2011 to 2020 were retrospectively evaluated. Data were obtained from lung function tests, HRCT results, fitness examination outcomes, and whether the diver did or did not have DCI. The study included 1,069 divers, with 65 subjects, all male, fulfilling the requirements for LLs. Subjects with LLs had a significantly higher z-scores for FVC and FEV1 but a significantly lower FEV1/FVC ratio, than subjects with NLs. The rates of bullae, DCI, and unfit-to-dive did not differ significantly in the two groups. Although FEV1/FVC ratio was significantly lower in the LL than in the NL group, there were no between-group differences in the rates of bullae and DCI. These findings suggest that subjects with LLs are not at a higher risk of bullae and DCI than are subjects with NLs.

Hyperbaric oxygen therapy (HBOT) administers 100% oxygen in a pressurised chamber at pressures above 1 atmosphere absolute. Inside hyperbaric personnel accompany patients during sessions and breathe compressed air, exposing them to risks like decompression illness and respiratory changes. This study investigated whether hyperbaric exposure affects the long-term lung function of inside hyperbaric personnel. An analysis was conducted on spirometry data from 14 personnel working between 2012 and 2023. Lung function tests measured forced vital capacity (FVC), forced expiratory volume in one second (FEV1), mid breath forced expiratory flow (FEF25-75), and peak expiratory flow (PEF) before and after hyperbaric exposure. Participants were categorised based on age, body mass index, number of HBOT sessions, and duration of employment. No clinically or statistically significant differences were found in FVC, FEV1, or PEF measurements before and after hyperbaric exposures (P > 0.05). However, FEF25-75, an indicator of small airway function, showed a (mean) 16% reduction in personnel with more than 150 HBOT sessions (P = 0.038). A post-hoc analysis confirmed a significant difference in FEF25-75 between personnel with fewer than 74 sessions and those with 150 or more sessions (P = 0.015). No clinically significant symptoms such as dyspnoea were reported during the study period. The FEF25-75 reduction, without changes in FEV1, FVC, or PEF, could be due to improper performance of the FVC manoeuvre. Maintaining pulmonary health in inside hyperbaric personnel is essential, emphasising the importance of accurate FVC execution in assessments. Further studies are recommended to explore the long-term implications of these findings and the effects of repeated hyperbaric exposure on respiratory health.