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Jishan D, Quan S, Hao Z, Yongmei T, Shasha W, Weiwei W, Yu L, Jianguo W. Saturation Diving Decompression Treatment for Severe Type II Decompression Sickness Following Emergency Ascent. Undersea Hyperb Med. 2026 Third Quarter; 53(3):417-422. Introduction: Decompression sickness (DCS) is a critical concern in diving operations. Severe type II DCS, characterized by neurological involvement, is particularly disabling and life - threatening. Traditional decompression treatments often show limitations in severe cases. This case report highlights the effectiveness of saturation diving decompression in the treatment of such severe DCS. Case Report: A 33-year-old male diver experienced severe type II decompression sickness (DCS) following an emergency ascent from a depth of 56 meters of seawater (msw) due to an underwater explosion. The condition was characterized by coma, as well as bleeding from the nose and ears. Initial treatment utilizing a 60 msw recompression protocol demonstrated limited efficacy, with symptom recurrence observed during the decompression process. Subsequently, a 15 msw air saturation diving decompression treatment was implemented, which extended the stay time at each station to facilitate the desaturation of gas bubbles. The patient's symptoms improved significantly. Repeat MRI 4 days later showed a ≥50 % reduction in lesion volume. The patient was discharged neurologically intact on day 11 and, at 3-month follow-up, had resumed land-based duties without sequelae. Discussion: This ..

Körpinar Ş, Esen E, Siddikoğlu D, Aylanç N. Prevalence of Dysbaric Osteonecrosis in Professional Divers and Analysis of Influencing Factors. Undersea Hyperb Med. 2026 Third Quarter; 53(3):423- 432. Introduction: Dysbaric osteonecrosis (DON) is an occupational hazard that can lead to joint deformity in professional divers who represent the young workforce. This study aimed to determine the prevalence of DON in professional divers and to investigate the factors that would justify requests for magnetic resonance imaging (MRI) as part of periodic fitness-to-dive examinations, particularly in asymptomatic cases. Methods: In this retrospective study, medical records and imaging data of 120 professional divers who underwent routine fitness-to-dive evaluations between June 2018 and March 2024 were reviewed. Both X-rays and MRI scans were assessed for signs of osteonecrosis. Demographic data, diving profiles, clinical history, and biochemical parameters were analyzed to identify potential risk factors associated with DON. Results: Dysbaric osteonecrosis was identified in 10 out of 120 divers (8.3%). The most affected anatomical region was the right humerus. MRI detected 9 of 10 DON cases, while X-rays identified only one. Statistically significant risk factors for DON included a cumulative diving duration exceeding 900 hours, weekly diving time over 15 hours, diving depths beyond 35 meters, and diving experience greater than 9.5 years. A previous history of decompression sickness (DCS) and a prior ..

Yifan L, Wenwu L, Haoze Z, Chenglong L, Jia H, Shifeng W. Assessment of Lung Injury Based on the Decompression Scheme of Lung Toxicity Dose Unit and K Value. Undersea Hyperb Med. 2026 Third Quarter; 53(3):433-442. Introduction: This study aimed to assess hyperoxic lung injury (HLI) during a heliox dive based on the unit pulmonary toxic dose (UPTD), K index, and equivalent surface oxygen time (ESOT). Methods: The UPTD, K index, and ESOT values of each schedule in the Helium-Oxygen Decompression Table of China were calculated. Based on the recommended thresholds, the risk of lung injury was analyzed, and suggestions were proposed to modify certain schedules. Results: The K index and ESOT were more conservative than UPTD in predicting HLI. After a deeper dive, the UPTD, K index, and ESOT values were generally higher than the recommended thresholds. For schedules in which the UPTD, K index, and ESOT values do not exceed the thresholds, we recommend prolonging time on oxygen with or without reducing time on air, or recommending oxygen inhalation after surfacing, which may improve safety without increasing the risk of lung injury. For most schedules, the lung injury may resolve within 12 hours after surfacing, according to the K index. Discussion: Decompression schedules can be adjusted in real time according to K or ESOT values, ..

Del Cima OM, de Carvalho Teixeira AVN, Rocha CM, Wienke BR. Ostwald Ripening for Gas Bubbles and Decompression in Diving. Undersea Hyperb Med. 2026 Third Quarter; 53(3):443-454. Introduction: The Ostwald ripening phenomenon for gas bubbles in a liquid consists mainly in gas transfer from smaller to larger bubbles. While the phenomenon itself is well known, the consequence of the temporal evolution of bubbles in the bloodstream in human physiology lacks deeper investigation. Methods: In this work, a series of direct experiments was carried out in which the Ostwald ripening for air bubbles in a viscous fluid was reproduced. There, the time evolution of the bubbles' mean radius, number of bubbles, and radius size distribution was measured, where the initial bubble distribution behaves like a Tsallis (q-Weibull) distribution. Results: The results show the usual behavior of wet foam, where smaller bubbles disappear, whereas the larger bubbles, potentially dangerous for the diver, grow, and the number of bubbles decreases in time. On the other hand, a long-time power-law regime was found with an exponent smaller than that of the LSW (Lifshitz-Slyozov-Wagner) model, and the radius size distribution showed positive asymmetry throughout the experiment. Discussion: From the results obtained, it is presumed that such a bubble broadening effect could contribute, even minimally, to decompression illness: decompression sickness and arterial gas embolism. This ..

Arieli R. Bubbles or microparticles: which are the main initial cause of decompression illness? Undersea Hyperb Med. 2026 Third Quarter; 53(3):535-540. Introduction: There are two leading schools of thought on the mechanism that causes decompression illness (DCI). The old school attributes DCI to decompression bubbles, while the new school, mostly led by S. Thom, attributes DCI mainly to microparticles (MP). Microparticles: Microparticles were found to be elevated at high pressures before decompression and, more so, after decompression. Decompression MP activate neutrophils and platelets, enhance inflammation, stimulate proinflammatory cytokines, and proto-coagulant activity. The predominant presence of endothelial MP is obvious. It was suggested that large MP contain a gas phase of nitric oxide (NO) and its derivatives and serve as gas micronuclei for decompression bubbles. Formation of a gas phase from very soluble NO is unlikely. Bubbles: Bubbling is crucial in the decompression from depth, and one cannot simply shoot up from the depth to the surface. The inconsistency between the relations of venous bubbles and DCI can be related to DCI unrelated to shunted/non-shunted venous bubbles, like distal arterial bubbles and local bubble formation. It was suggested that a detached bubble tears off the underlying endothelial cells, and when the bubble becomes lodged in the lung, it diminishes to a gas-containing microparticle enveloped by an endothelial membrane. Discussion: The main ..

Wu Z, Yang X, Li C, Lai H, Liu Y, Zhang C, Cao D, Liu F. Evaluation of the Effect of Hyperbaric Oxygen Preconditioning in Spinal Cord Injury Rats Using Diffusion Tensor Imaging. Undersea Hyperb Med. 2026 Third Quarter; 53(3):455-466. Introduction: To investigate the potential value of diffusion tensor imaging (DTI) in spinal cord injury (SCI) rats undergoing hyperbaric oxygen preconditioning (HBO-PC) at different time points. Methods: Seventy-two rats were randomly allocated into three groups: sham-operated group (laminectomy only); SCI group (the spinal cord weight dropping model); HBO-PC group (HBO-PC for five consecutive days before SCI). Each group was further randomized into four time-point subgroups (6 hours, 24 hours, three days, seven days). Basso, Beattie, Bresnahan (BBB) scores and DTI parameters, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD), were collected and analyzed. Spinal cord tissues were processed for hematoxylin, eosin, and Nissl staining. Results: HBO-PC groups exhibited higher FA values than SCI groups at different time points (all p < 0.05). RD and MD values were higher in SCI groups than in HBO-PC groups from 24 hours to 7 days (all p < 0.05). The SCI group showed more pronounced inflammatory cell infiltration and neuronal atrophy than the HBO-PC group. The number of surviving neurons in the injured spinal cord ..

Asserson DB, Becker DB, Alleman TL, Kruchevsky D. Hyperbaric Oxygen as a Treatment Modality for Radiation-Induced Breast Calcinosis. Undersea Hyperb Med. 2026 Third Quarter; 53(3):467-470. Introduction: Breast calcinosis is a rare late complication of radiation therapy that can present years after treatment and pose significant reconstructive challenges. Management of radiation-induced breast calcinosis requires an approach to address both tissue damage and impaired wound healing. Case Report: We present a case of a 59-year-old female who developed breast calcinosis more than a decade following radiation. Our multistep treatment plan, which has not been previously published, involved hyperbaric oxygen (HBO2) treatment, surgical excision, negative pressure wound therapy, and additional HBO2 treatment. As a result, the patient’s wound decreased to 95% of its size in less than two months. Discussion: This case highlights the potential utility of a staged multidisciplinary approach for managing radiation-induced breast calcinosis and supports further investigation of HBO2 treatment as an adjunct to optimize wound healing in these complex patients. Keywords: breast cancer; dystrophic calcifications; hyperbaric oxygen; radiation therapy

Çevik SG, Ozbek M, Simsek M, Taşkın G, Orak MS, Artunay O. Time-Dependent Efficacy of Hyperbaric Oxygen Therapy in Central Retinal Artery Occlusion. Undersea Hyperb Med. 2026 Third Quarter; 53(3):471-480. Introduction: To determine the effect of the timing of hyperbaric oxygen (HBO2) treatment on functional and structural outcomes in central retinal artery occlusion (CRAO). Methods: This single‑center retrospective cohort study analyzed 101 eyes with CRAO treated with HBO2. Eyes were stratified by symptom‑to‑treatment interval: ≤12 hours (Group 1), 12–24 hours (Group 2), 24– 36 hours (Group 3), and >36 hours (Group 4). Best‑corrected visual acuity (BCVA-logMAR), central macular thickness (CMT), and inner retinal hyperreflective band thickness (IRHBT) were recorded at presentation, week 1, and month 6. Results: Presentation BCVA was 2.16 ± 1.04, improving to 1.77 ± 1.02 at month 6 (p = 0.03). The mean BCVA gain was greatest in Group 1: −0.85 ± 0.96, and declined markedly with delayed treatment initiation (Group 2: −0.48 ± 1.38; Group 3: −0.10 ± 1.50; Group 4: −0.08 ± 1.77). In Group 1, the mean BCVA improved significantly from 2.04 ± 0.78 logMAR at presentation to 1.19 ± 0.56 logMAR at the 6-month follow-up (p = 0.02). Early treatment was also associated with more pronounced reductions in CMT and IRHBT, whereas anatomical changes were negligible when therapy was initiated beyond 24 ..

Murray RA. A Critical Look at Soft-Sided and Hard-Sided “Mild” Hyperbaric Chambers – Risks, Regulations, and Ethical Oversights. Undersea Hyperb Med. 2026 Third Quarter; 53(3):523-534. Soft-sided hyperbaric chambers, as well as some hard-sided (mild) hyperbaric chambers, which are low-pressure, hyperbaric chambers that are typically designed for operational pressures of 3-5psi, have gained popularity in recent years. They are marketed as safe and effective for various conditions but lack compliance with critical regulatory and safety standards and codes. This raises concerns regarding patient safety, the validity of manufacturers’ claims, and the ethical obligations of medical professionals and regulators. This manuscript examines the risks, regulatory gaps, and ethical implications of using soft-sided fabric chambers, as well as hard-sided (mild) hyperbaric chambers, focusing on their failure to meet FDA clearance, NFPA 99 & NFPA 101 codes, and ASME-PVHO standards. A comprehensive review of regulatory guidelines, safety reports, and marketing practices was conducted, supplemented by illustrations of adverse events linked to the use of these devices. Ethical principles, including beneficence, non-maleficence, and informed consent, were applied to analyze the responsibilities of manufacturers, healthcare providers, patients, and regulators. These chambers are often marketed with misleading claims about their efficacy and safety. Their non- compliance with FDA clearance, as well as not following industry standards and safety codes increases the risk of ..

Evanger K, Vaagbø G, Haugen OH, Müller B. Myopic Shift in Patients During Hyperbaric Oxygen Treatment: A Systematic Review. Undersea Hyperb Med. 2026 Third Quarter; 53(3):481-494. Introduction: Reversible myopic shift (MS) is a common side effect of hyperbaric oxygen treatment (HBO2) resulting from refractive changes in the lens. Single studies indicate that the myopic shift increases with longer duration of HBO2 and may differ between hyperbaric chamber types and oxygen breathing systems. This review aims to improve knowledge on the frequency and magnitude of myopic shift after standard-length HBO2. Methods: A systematic search for original studies of myopic shift after HBO2 was conducted in medical databases. Included were published full-text articles in English with specified details on oxygen administration, pressure, number of treatments, and use of conventional techniques to measure refraction. Studies with exposure other than HBO2, patients with artificial lenses, and single-case reports were excluded. Results: Of 153 reports identified, eight studies with 263 patients were included. Treatment durations covered 18-21, 30, and 40 treatments in either monoplace or multiplace chambers using hoods or masks. For the mean values of myopic shift and the incidence of a myopic shift ≥ 0.5 D, a range was seen from the lowest values after 20 treatments in multiplace chambers using a mask (0.4 D and 53%, respectively), to the highest values after ..

Aguiar ARR, Noversa R, Queiroz I, Gaio-Lima C, Barata P, Camacho Ó. Hyperbaric Oxygen Therapy for Medication-Related Osteonecrosis of the Jaw: Retrospective Study. Undersea Hyperb Med. 2026 Third Quarter; 53(3):495-504. Introduction: Medication-related osteonecrosis of the jaw (MRONJ) is a complication associated with the use of different drugs, including bisphosphonates. Hyperbaric oxygen (HBO2) treatment might be effective in this condition through multiple mechanisms, although evidence in the literature remains limited. Methods: A single-institutional retrospective study included patients who underwent HBO2 treatment for MRONJ in our Unit. Data were collected at baseline and after treatment . The primary outcome was clinical response to HBO2 treatment . Descriptive analysis was followed by paired samples tests comparing variables before and after treatment . Univariate analyses were made to investigate possible predictors of clinical response and relapse rate. Statistical analysis was performed using SPSS® (p < 0.05). Results: Eighteen patients were included, mostly female, with a mean age of 60.6 ± 13.5 years. Clinical response was observed in most patients (61.1%), with a significant decrease in MRONJ stage severity. There was a significant decrease in pain intensity, number of oral lesions, area of bone exposure, and orofacial inflammatory signs. Five patients relapsed after treatment , with a median time until relapse of 2.0 months. No significant predictors of clinical improvement or relapse rate were found ..

Aydin G, Zaman T. Hyperbaric Oxygen Treatment in the Management of Post-surgical Pyoderma Gangrenosum Following Reduction Mammoplasty: A Case Report. Undersea Hyperb Med. 2026 Third Quarter; 53(3):505-510. Introduction: Postoperative pyoderma gangrenosum (PSPG) is a rare but potentially destructive complication following surgery, often misdiagnosed as infection or necrosis. Mismanagement with antibiotics or debridement can exacerbate lesions due to the pathergy phenomenon. Hyperbaric oxygen treatment (HBO2) has been proposed as an adjunctive treatment through its effects on tissue oxygenation, angiogenesis, and immunomodulation. Case Report: A 52-year-old woman developed a painful ulcer at the surgical site following bilateral reduction mammoplasty. Initially treated as a wound infection with antibiotics and repeated debridements, the lesion rapidly progressed. Histopathology and clinical features supported the diagnosis of PSPG. Despite systemic corticosteroids, cyclosporine, and infliximab, wound healing stagnated after three months. The patient was then referred for HBO2(2.4 ATA, 120 minutes, once daily). After 17 sessions of HBO2 combined with atraumatic wound care, marked improvement was observed with progressive contraction and granulation. Complete epithelialization was achieved by postoperative week 38, and no recurrence occurred during six months of follow-up. Discussion: This case highlights the diagnostic challenges of PSPG and the hazards of inappropriate interventions. HBO2, when combined with immunosuppressive treatment, may provide an effective and safe adjunctive option, accelerating wound healing by improving oxygenation and modulating the inflammatory response. Controlled ..

Sun L, Mohr NM, Rajwani H, Fietsam AC, Wagner B, Bates ML, Vasilyev M, Doerschug KC, Sharma A. Hyperbaric Oxygen Therapy in Septic Shock: A First-in-Human Pilot Trial. Undersea Hyperb Med. 2026 Third Quarter; 53(3):511-522. Introduction: Septic shock, a severe, life-threatening infection resulting in organ failure, has seen no successful, novel therapies emerge in the past two decades. In addition to hypoperfusion and inflammation, organ dysfunction in septic shock is caused by microvascular, mitochondrial, and immune dysfunction. Animal studies support the use of hyperbaric oxygen treatment to improve mitochondrial function and reduce the inflammatory cascade, suggesting a potential role for hyperbaric oxygen in treating septic shock. Methods: A phase I open-label matched clinical trial was conducted to measure the effect of hyperbaric oxygen on microvascular function, mitochondrial function, and inflammatory cytokines. Four experimental subjects who received 60 minutes of hyperbaric oxygen (2.5 ATA, 25-min descent and ascent) plus standard sepsis management, then four age-matched (ages 29–75) and vasopressor dose- matched (norepinephrine equivalents of 0.05-0.35 ug/kg/min at enrollment) controls were enrolled. The primary outcome was microvascular function, measured using the rate of reoxygenation after upper-limb ischemia by real-time near-infrared spectroscopy. Secondary outcomes included mitochondrial function (ex vivo neutrophils and monocytes) and serum inflammatory cytokine levels (IL-6, IL-10, TNF-alpha). The data were analyzed graphically to identify trends in matched subjects. Results: Hyperbaric ..