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Diving as a method of fishing is used worldwide in small-scale fisheries. However, one of the main causes of morbidity and mortality among fishermen is decompression sickness (DCS). We report the case of a 46-year-old male fisherman diver who presented with chronic inguinal pain that radiated to the lower left limb. Living and working in a fishing port in Yucatan, he had a prior history of DCS. A diagnosis of avascular necrosis in the left femoral head secondary to DCS was made via analysis of clinical and radiological findings. The necrosis was surgically resolved by a total hip arthroplasty. Dysbaric osteonecrosis is a more probable diagnosis. In this region fishermen undergo significant decompression stress in their daily fishing efforts. Further studies regarding prevalence of dysbaric osteonecrosis among small-scale fisheries divers are needed. In a community where DCS is endemic and has become an epidemic, as of late, the perception of this health risk remains low. Furthermore, training and decompression technique are lacking among the fishing communities. DOI: 10.22462/04.06.2019.17

The complete pathophysiology of decompression illness is not yet fully understood. What is known is that the longer a diver breathes pressurized air at depth, the more likely nitrogen bubbles are to form once the diver returns to surface [1]. These bubbles have varying mechanical, embolic and biochemical effects on the body. The symptoms produced can be as mild as joint pain or as significant as severe neurologic dysfunction, cardiopulmonary collapse or death. Once clinically diagnosed, decompression illness must be treated rapidly with recompression therapy in a hyperbaric chamber. This case report involves a middle-aged male foreign national who completed three dives, all of which incurred significant bottom time (defined as: “the total elapsed time from the time the diver leaves the surface to the time he/she leaves the bottom)” [2]. The patient began to develop severe abdominal and back pain within 15 minutes of surfacing from his final dive. This case is unique, as his presentation was very concerning for other medical catastrophes that had to be quickly ruled out, prior to establishing the diagnosis of severe decompression illness. After emergency department resuscitation, labs and imaging were obtained; abdominal decompression illness was confirmed by CT, revealing a significant ..

Dermal injection of fillers is a popular and relatively safe aesthetic procedure. Severe complications are rare, but they do occur. One of the most threatening complications after dermal filler injection is skin necrosis due to vascular occlusion. Different treatment options are available, including the use of hyperbaric oxygen (HBO2) therapy. A 46-year-old female received facial dermal filler injections with calcium hydroxylapatite at an aesthetic clinic. A few days after injection she developed a burning pain, numbness of the skin and white discoloration in the injected area. Two days after injection treatment was started with hyaluronidase and warm compresses. In addition, the patient received prednisolone, sildenafil and nifedipine. After the start of these treatments, the pain, numbness and discoloration of the skin persisted. Because of dermal ischemia and to improve healing she was referred for HBO2. Treatment consisted of 10 sessions of 100% oxygen for 90 minutes in a multiplace chamber at 2.5 atmospheres absolute pressure. During HBO2 the discoloration resolved, pain and numbness disappeared, and the tissue healed completely. After a six-month follow-up she had an excellent cosmetic outcome. Given the pathophysiologic mechanisms of vascular complications after dermal filler injection, HBO2 should be considered when treating these complications. DOI: 10.22462/04.06.2019.15

Carbon monoxide intoxication occurs usually via inhalation of carbon monoxide that is emitted as a result of a fire, furnace, space heater, generator, motor vehicle. A 37-year-old male patient was admitted to the emergency department at about 5:00 a.m., with complaints of nausea, vomiting and headache. He was accompanied by his wife and children. His venous blood gas measures were: pH was 7.29, partial pressure of carbon dioxide (pCO2) was 42 mmHg, partial pressure of oxygen (pO2) was 28 mmHg, carboxyhemoglobin (COHb) was 12.7% (reference interval: 0.5%-2.5%) and oxygen saturation was 52.4%. Electrocardiogram (ECG) examination showed that the patient was not in sinus rhythm but had atrial fibrillation. After three hours the laboratory examination was repeated: Troponin was 1.2 pg/ml and in the arterial blood gas COHb was 3%. The examination of the findings on the monitor showed that the sinus rhythm was re-established. The repeated ECG examination confirmed the conversion to the sinus rhythm. He was monitored with the normobaric oxygen administration. DOI: 10.22462/04.06.2019.14

We present the case of a 42-year-old female who was critically ill due to an arterial gas embolism (AGE) she experienced while diving in Maui, Hawaii. She presented with shortness of breath and dizziness shortly after surfacing from a scuba dive and then rapidly lost consciousness. The diver then had a complicated hospital course: persistent hypoxemia (likely secondary to aspiration) requiring intubation; markedly elevated creatine kinase; atrial fibrillation requiring cardioversion; and slow neurologic improvement. She had encountered significant delay in treatment due to lack of availability of local hyperbaric oxygen (HBO2) therapy. Our case illustrates many of the complications that can occur when a patient suffers a severe AGE. These cases may occur even without a history of rapid ascent or risk factors for pulmonary barotrauma, and it is imperative that they be recognized and treated as quickly as possible with HBO2. Unfortunately, our case also highlights the challenges in treating critically ill divers, particularly with the growing shortage of 24/7 hyperbaric chambers able to treat these ICU-level patients. DOI: 10.22462/04.06.2019.13

Decompression illness (DCI) is an uncommon problem but can be significant in terms of morbidity and, very rarely, mortality. The mechanisms of DCI are pulmonary barotrauma and decompression sickness due to inert gas supersaturation. After the initial management phase, identification of predisposing factors is important to help advise divers regarding future risk and avoidance. Here we present four cases of DCI where pulmonary barotrauma was the likely causative mechanism. We highlight the important features in assessment for pulmonary barotrauma and advising divers on the risk of a recurrence. DOI: 10.22462/04.06.2019.12

Objective: An analysis of factors that may indicate both the type and degree of dehydration of a diver’s body following a dry chamber hyperbaric exposure. Methods: The study was participated by 63 men – professional divers, with extensive diving experience, aged 24-51 years (average age 32.6). The subjects underwent two hyperbaric exposures, one to a pressure of 0.3 MPa and one to a pressure of 0.6 MPa, with oxygen decompression. The exposures were carried out in a hyperbaric chamber pursuant to the decompression tables of the Polish Navy, with the observance of a 24-hour interval between exposures. Blood samples were collected from the participants in order to perform a blood morphology test. Body weight was measured with the bioelectrical impedance method using the Maltron BioScan 920 device. The results were subjected to statistical analysis. The following blood morphology parameters were analyzed: hematocrit (Ht), erythrocyte size (MCV), color index (MCHC) and body weight composition: total water (TBW), extracellular water (ECW), intracellular water (ICW). Results: The studies have shown that during a hyperbaric exposure in the chamber the diver’s body becomes dehydrated, with observable loss of both intracellular water as evidenced by the reduction of hematocrit content and erythrocyte size, as well as ..

Divers Alert Network Europe has created a database with a large amount of dive-related data that has been collected since 1993 within the scope of the Diving Safety Laboratory citizen science project. The main objectives of this study are the grouping divers by their health information and revealing significant differences in diving parameters using data mining techniques. Due to the methodology of the project, data cleaning was performed before applying clustering methods in order to eliminate potential mistakes resulting from inaccuracies and missing information. Despite the fact that 63% of the data were lost during the cleaning phase, the remaining 1,169 “clean” diver data enabled meaningful clustering using the “two-step” method. Experienced male divers without any health problems are in Cluster 1. Male and female divers with health problems and high rates of cigarette smoking are in Cluster 2; healthy, overweight divers are in Cluster 3. There are significant differences in terms of dive parameters including pre- and post-dive conditions with respect to each group, such as: exercise level, alcohol consumption, thermal comfort, equipment malfunctions, and maximum depth. The study proves the usefulness of citizen science projects, while data collection methodologies can be improved to decrease potential mistakes resulting ..

Purpose: Nitric oxide (NO) has been shown to protect against bubble formation and the risk of decompression sickness. We hypothesize that oxidation of tetrahydrobiopterin (BH4) leads to a decreased production of NO during simulated diving. Methods: Human umbilical vein endothelial cells (HUVEC) were exposed to hyperoxia or simulated diving for 24 hours. The levels of biopterins (BH4, BH2 and B) were determined by LC-MS/MS, and the production of NO by monitoring the conversion of L-arginine to L-citrulline. Results: Exposure to hyperoxia decreased BH4 in a dose-dependent manner; by 48 ± 15% following exposure to 40 kPa O2 (P < 0.001 vs. control at 20 kPa O2), and 70 ± 16% following exposure to 60 kPa O2. Exposure to 40 kPa O2 decreased NO production by 25 ± 9%, but there was no further decrease when increasing oxygen exposure to 60 kPa (25 ± 10%). No additional effects of simulated diving were observed, indicating no additive or synergistic effects of hyperbaria and hyperoxia on the BH4 level or NO generation. Conclusion: NO generation in intact human endothelial cells was decreased by simulated diving, as well as by hyperoxic exposure, while BH4 levels seem to be affected only by hyperoxia. Hence, the results suggest ..

In 2018, the Medical Panel of the NATO Underwater Diving Working Group (UDWG) discussed the question of the rescue and management of a submerged unresponsive compressed-gas diver. The Panel reviewed the 2012 recommendation by the UHMS Diving Committee with respect to the specific recommendation in a convulsing diver using a half-face mask and separate mouthpiece, to delay surfacing until the clonic phase had subsided if the mouthpiece was in place. There is a paucity of scientific, epidemiological, experimental and observational human studies to substantiate this guidance. Experimental animal studies suggest that the likelihood of a complete airway obstruction during an ongoing seizure is low and that there is a high likelihood of surviving pulmonary barotrauma caused by complete airway closure. Airway management and control is an essential step in the management of the unresponsive diver and would be challenging to achieve in the underwater environment. Even in the military setting, it will be difficult to provide sufficient training to enable divers to handle such a situation. In this very rare scenario it is considered that emergency guidelines should be clear, concise and easy to follow. The UDWG therefore recommends that all unconscious military divers in this situation should be ..

Background: Hyperbaric oxygen (HBO2) therapy improves myocardial function and reduces clinical restenosis in coronary arteries. This study aims to evaluate whether the HBO2 therapy can improve vascular endothelial dysfunction in patients undergoing coronary stent implantation. Methods: The retrospective study included 115 patients undergoing coronary stent implantation. Patients receiving HBO2 therapy were included in the HBO2 group (n=55) and those without HBO2 therapy were included as controls (n=60). The levels of brachial artery endothelial-dependent flow-mediated dilation (FMD), endothelial-independent nitrate-mediated dilatation (NMD), nitric oxide (NO), endothelin-1(ET-1), calcitonin gene-related peptide (CGRP) and high-sensitivity C-reactive protein (hs-CRP) were used to evaluate vascular endothelial function. Results: There were no significant differences with regard to the above parameters at baseline in either group (p>0.05). In both the HBO2 and control groups the levels of FMD, NO and CGRP after treatment were significantly higher than those before treatment (p<0.05). The levels of hs-CRP and ET-1 after treatment were significantly lower than those before treatment (p<0.05). After treatment, the levels of FMD, NO and CGRP in the HBO2 group were significantly higher than those of the control group (p<0.05), whereas the hs-CRP and ET-1 levels were significantly lower than those of the control group (p<0.05). Conclusion: Using HBO2 therapy as ..

Purpose: Hyperbaric medicine is nascent in Korea when compared to other developed countries, such as the United States and Japan. Our facility has been managed by physicians with certifications from the Undersea and Hyperbaric Medical Society (UHMS) and National Oceanic and Atmospheric Administration in diving and clinical diseases since October 2016. This study was conducted to share similar issues that are encountered during the establishment of a program in a new area through our experiences in the operation of a hyperbaric oxygen (HBO2) therapy center.  Methods: In this retrospective observational study we collected data on HBO2 patients treated at our center between October 2016 and June 2018 after HBO2 was conducted by HBO2-certified physicians. We then compared demographic data of patients with data from January 2011 to September 2015 – before HBO2 operations were conducted by HBO2-certified physicians. Result: A total of 692 patients received 5,130 treatments. Twelve indicated diseases were treated using HBO2 therapy. Fifty-six critically ill patients with intubation received HBO2. Although two patients experienced seizure due to oxygen toxicity during the study period, certified physicians and inside attendant took immediate corrective action. Conclusion: After the establishment of the HBO2 center operated by physicians with certification, more patients, including critically ..

In recent years, hyperbaric oxygen (HBO2) therapy has been considered as an effective method for the treatment of gentamicin (GM)-induced renal toxicity. However, the findings related to the use of HBO2 for GM toxicity are limited and contradictory. The aim of this study is to investigate the protective role of HBO2 on GM-induced nephrotoxicity. For this purpose, Wistar albino rats (n=28) were randomly divided into four equal groups: C, HBO2, GM and GM+HBO2. GM (100 mg/kg, ip) and HBO2 were applied over seven days. On the eighth day blood and kidney tissue samples were harvested. The albumin, creatinine, and urea levels were determined from serum samples. Superoxide dismutase (SOD), glutathion peroxidase (GSH-Px) activities, malondialdehyde (MDA), total antioxidant status (TAS) and total oxidant status (TOS) values were analyzed spectrophotometrically. The relative expression level of TNF-α, IL-1β and Kim-1 gene were determined by qRT-PCR assays; histopathologic investigation was completed in kidney tissue samples. Serum urea, albumin and creatinine levels significantly increased in the GM group compared to the GM+HBO2 group. For antioxidant parameters the GM+HBO2 group was not statistically different from the C group but was significantly different compared with the GM group. TNF-α, IL-1β and Kim-1 gene expression levels in ..

Objectives: Hyperbaric oxygen (HBO2) exposure may enhance cardiorespiratory fitness. Exercise training and HBO2 exposure stimulate mitochondrial biogenesis, increase capillary density, and induce adaptive antioxidant mechanisms. We hypothesized that an exercise regimen of sprint interval training (SIT) while breathing HBO2 would lead to a greater improvement in exercise performance compared to the same training breathing ambient air. Methods: Healthy long-term intermediate-altitude residents, ages 20-39 years, with normal spirometry and cardiorespiratory fitness were randomized to two groups: one performing six sessions of an SIT regimen over two weeks in a hyperbaric chamber (1.4 ATA [141.9 kPa], FiO2=1.0); the other performing under ambient pressure conditions (0.85 ATA [86.1 kPa], FiO2=0.21). Training effect was evaluated by comparing incremental cycle ergometry cardiopulmonary exercise testing before and after the training regimen. The primary outcome measure was peak oxygen consumption (V̇O2), while secondary outcomes included additional exercise parameters. The effect of study group on exercise parameters was assessed using two-factor repeated measures ANOVA.  Results: Of 58 participants randomized, 49 completed the training program and all cardiopulmonary exercise tests (n=23 HBO2, n=26 ambient). Both groups experienced an increase in peak V̇O2: 8.1% HBO2 and 7.1% ambient; the differences were not significant (p=0.50). Secondary parameters of peak work rate and ..

Middle ear barotrauma (MEB), one of the side effects of hyperbaric oxygen (HBO2) therapy, sometimes cannot be directly diagnosed during the therapy itself. Instead, its incidence and degree are judged based on subjective statements made by patients when in conversation with medical staff regarding how they feel. To prevent MEB in practice it is proposed that the tympanic membrane evaluation system and automatic control chamber developed in a previous study be applied as part of a prevention algorithm [16]. The proposed algorithm, which determines and equalizes the unbalanced pressure of a subject based on their tympanic admittance, was evaluated in conjunction with conventional HBO2 therapy in an experiment involving 100 subjects. Among the 50 subjects in the control group who received HBO2 therapy 16 subjects experienced MEB. In contrast, the experimental group of 50 subjects were treated with a hyperbaric chamber protocol incorporating the automatic control system and proposed algorithm. At the conclusion of the treatment, no subjects exhibited middle ear barotrauma. In the case of the control group, while the target pressure was achieved, middle ear barotrauma still occurred. However, in the case of the experimental group, the pressure inside the chamber was adjusted as per the algorithm, ..

Hyperbaric-associated middle ear barotrauma (MEB) is one of the most common side effects of the exposure to hyperbaric oxygen (HBO2) therapy. This retrospective observational study of 5,962 patients undergoing long-termtherapy for chronic conditions took place at the local Diving & Hyperbaric Medicine Unit (DHMU) in Villafranca- Verona (Italy), a DHMU that administers, in multiplace chambers, more than 20,000 HBO2 treatments per year. The study was designed to weight and analyze both the incidence and severity of MEBs at the facility. Thanks to a systematic recording method over eight years, 2003-2010, we observed 549 MEBs (9.2% of all HBO2 treatments). The majority of them were female patients older than 50. MEBs observed were usually of minor complexity, with minimal otoscopic changes (69.03% of our occurrences were registered as Wallace-Teed Grade 1). MEBs were registered in 20.3% of those patients already suffering from difficulties in equalizing ear pressure, and/or presenting ear pain during the initial compression phase (descent) of the hyperbaric treatment. Inflammatory diseases of the upper respiratory tract, with special attention to rhinitis, appear to be a condition capable of predisposing patients in developing MEB. MEB did lead to the suspension of therapy for 89 patients in our case series. ..

Introduction: Symptomatic Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common reported complications during hyperbaric oxygen (HBO2) treatment. There is no standardized rate of compression (ROC) reported to decrease the incidence rates of ETD and MEB during hyperbaric treatments. Few studies actually demonstrate that the ROC decreases the incidence of ETD or MEB.Methods: Our study was designed to determine an optimal hyperbaric chamber compression rate that might reduce the incidence of symptomatic ETD leading to MEB during the compression phase of treatment in a multiplace hyperbaric chamber. Data was collected prospectively over 2,807 elective patient treatments compressed using a U.S. Navy Treatment Table 9 (USN TT9) with a modified ROC. ROC was assigned using two variables, time (10 vs.15 minutes) and slope (linear vs. non-linear compression). Patients were exposed to all four compression schedules in a consecutive daily fashion. We recorded any patient requiring a stop during initial compression due to ear discomfort. Anyone requiring a stop was evaluated post treatment for MEB. Findings were compared to our standard 10-minute linear ROC. Evaluation of the tympanic membrane was accomplished using video otoscopy. Barotrauma when present was classified using both the Teed and O’Neill grading systems. ..