Undersea and Hyperbaric Medicine最新文献

Medication has become an integral part of modern life, as well as in people working in hyperbaric conditions. However, our understanding of how drugs interact with pressure variations, gas compositions, physical exertion, and physiological changes in a hyperbaric environment is very limited. Firstly, the medical condition for which a medication is being taken must be evaluated in the context of fitness for occupational diving. Secondly, the desired or adverse effect of the medication needs to be evaluated in the context of occupational diving. Some potential adverse effects include changes in alertness and cardiovascular or pulmonary functions. These can affect the fitness to dive, increase the risk of decompression illness, or mimic its symptoms. Hence, special concern must be paid to medications affecting the cardiovascular, respiratory, and central nervous systems. The purpose of this work was to evaluate what is known about commonly used drugs in the setting of occupational diving. We found that most of the data available is either anecdotal or based on recreational diving and, therefore, needs to be cautiously adapted to the working environment.

Gas can enter arteries (arterial gas embolism) due to alveolar-capillary disruption (caused by pulmonary overpressurization, e.g. breath-hold ascent by divers), veins (venous gas embolism, VGE) as a result of tissue bubble formation due to decompression (diving, altitude exposure), or during certain surgical procedures where capillary hydrostatic pressure at the incision site is subatmospheric. Both AGE and VGE can be caused by iatrogenic gas injection. AGE usually produces stroke-like manifestations, such as impaired consciousness, confusion, seizures, and focal neurological deficits. Small amounts of VGE are often tolerated due to filtration by pulmonary capillaries; however, VGE can cause pulmonary edema, cardiac "vapor lock," and AGE due to transpulmonary passage or right-to-left shunt through a patent foramen ovale. Intravascular gas can cause arterial obstruction or endothelial damage and secondary vasospasm and capillary leak. Vascular gas is frequently not visible with radiographic imaging, which should not be used to exclude the diagnosis of AGE. Isolated VGE usually requires no treatment. AGE treatment is similar to decompression sickness (DCS), with first aid oxygen followed by hyperbaric oxygen. Although cerebral AGE (CAGE) often causes intracranial hypertension, animal studies have failed to demonstrate a benefit of induced hypocapnia. An evidence-based review of adjunctive therapies is presented.

Diving diseases originating from lung-related pathology are not the most prominent but are considered the most severe. To minimize this risk, a good respiratory tract assessment is important. Organizations like the British Thoracic Society (2003) and the European Diving Technology Committee (EDTC) (2004) have provided guidelines regarding this assessment. However, most of the guidelines are 20 years old. The EDTC has revised its guidelines based on the present literature and published it last year. This review discusses a few topics that have changed or are newly introduced in the new EDTC guidelines. Importantly, additional tests might be necessary when assessing the respiratory tract based on history taking and spirometry, leading to a case-by-case decision regarding the fitness to dive. Particular attention should be paid to individuals with large lungs or cysts, those who have undergone thoracic surgery, and those with a history of asthma, immersion pulmonary edema, COVID-19 infection, or sleep apnea.

Musculoskeletal decompression sickness (MS DCS) is a clinical condition characterized by joint pain following scuba diving. Recent studies have shown a potential link between MS DCS and bone lesions, including dysbaric osteonecrosis. This article highlights the importance of early detection and management of bone damage in MS DCS patients. It is recommended that a specialist diving doctor be consulted for a comprehensive assessment to ensure an accurate diagnosis and treatment plan. Ordering a joint MRI two months after the accident is the best way to detect the presence of intraosseous edema, the main risk of which is osteonecrosis, especially if the humeral or femoral head is involved. This clinical communication highlights the need for caution when resuming diving activities after MS DCS involving the shoulder or hip, as bone involvement may complicate recovery. Hyperbaric oxygen therapy sessions have been shown to have an anti-edematous effect, which can be beneficial in accelerating intraosseous healing and limiting the risk of progression to osteonecrosis. Overall, this article underscores the critical role of the diving physician in ensuring the safe return to diving for individuals recovering from MS DCS.

Most medical examinations performed on divers and compressed air workers to assess their fitness to work focus on the risks associated with exposure to increased and changing environmental pressure. However, these employees are also exposed to numerous other hazards in their workplace that may have long- and short-term health impacts. The potential adverse impact must be assessed and risk managed by companies working with a Contract Medical Advisor (CMA) assigned to the works via a Hazard Identification and Risk Assessment (HIRA) process. The appointed CMA should visit the work site to be in a position to provide adequate input into a workplace health and safety plan by directly participating in that HIRA process. A detailed analysis follows to determine whether medical surveillance would be required for hazards that are considered potential health risks. This process is reviewed with practical examples from the literature. This review does not intend to comprehensively cover all workplace hazards and risks to health associated with diving and hyperbaric operations. It aims to introduce aspects of occupational medicine and HIRA processes to Diving Medical Examiners who have not yet considered occupational hazards beyond those related to pressure. We strongly urge those doctors to work closer with the employers of divers and compressed air workers and to consider further formal study in occupational medicine. In many countries, diving medicine doctors involved with occupational divers must also have a formal occupational medicine qualification.

Objective: Risk assessment is worked out for diving after surgery on middle ears with differentiation on different interventions such as Myringoplasty, Tympanoplasty, Mastoidectomy, Stapes surgery, and implantable hearing systems.

Methods: Data research was carried out via the National Library of Medicine (pubmed.ncbi.nlm.gov) and ResearchGate (researchgate.net). In the literature, no evidence-based studies were found on barotraumatic injuries after ear surgery nor on non-operated ears. Therefore, Risk assessments are based on interpreting anatomical, physiological, and physical facts, the results of pressure-exposed cadaver tests, and the studies concerning follow-up observations on post-op ears after pressure exposition.

Results: Critical conditions after tympanoplasty type I, temporal fascia, cartilage, perichondrium, transposition of auto-ossicles, titanium TORP and PORP, omega connector, stapes surgery, malleovestibulopexy, canal wall down (CWD) and canal wall up (CWU) after cholesteatoma, obliteration of CWD, active hearing implants CI and soundbridge are presented. Immersion depth values are represented by the pressure difference between the auditory canal and the middle ear.

Discussion: Tympanoplasty type I: after the complete healing process and regular tympanometry type A, the risk is not higher than in non-operated ears. Minimal burst pressure is 35 kPa (11,71 ft or 3,57 msw) when diving without Valsalva and regular tympanic membrane (TM), 30 kPa (9,84 ft or 3,0 msw) in TM with atrophic scars. PORP: same risk as type I. TORP: risk is higher than type I: burst pressure 25 kPa (8,2 ft (2,5 msw). When the stapes footplate has contact with the matrix of the cholesteatoma, diving is contraindicated. CWU: same risk as type I. CWD: contraindication for diving. Stapes surgery: same risk as for non-operated ears with regular vestibular function (verified by tympanometry).

Middle ear barotrauma (MEBT) is the most common complication in providing hyperbaric oxygen therapy (HBO₂). This study explored the impact of altering the shape of the time-pressure curve with the aim of reducing the occurrence of MEBT and optimizing the HBO₂ experience during the pressurization process. Four distinct mathematically derived protocols-Constant Pressure Difference (CPD), Constant Volume Difference (CVD), Constant Ratio (CR), and Inverted Constant Ratio (ICR)-were investigated using computer simulations on a simple ear model. Results indicated varying levels of ear strain during pressurization. The CR pressurization demonstrated balanced ear strain levels and outperformed other modalities in several measures, including the impact on the simulated ear cavity volume. The potential for enhanced patient comfort through the application of sophisticated pressurization protocols warrants further research to validate and extend the findings of this study in real-world HBO₂ settings.

Introduction: When administering HBO₂ , pressures can range from 1.4 atmospheres absolute (ATA) to 3 ATA. While different treatment profiles have been proposed, there is a paucity of literature comparing the effectiveness and risk profile associated with different pressures treating the same condition. Considering the therapeutic divergence, this study aims to survey Undersea and Hyperbaric Medical Society (UHMS) members on pressure modalities and their use in different clinical conditions.

Methods: The study was a voluntary cross-sectional survey administered online and open to healthcare providers who were Undersea and Hyperbaric Medical Society members. UHMS itself distributed the survey link. The survey period lasted from November 2022 until January 2023. Data were collected utilizing the Qualtrics platform and analyzed through Microsoft Excel.

Results: A total of 265 responses were recorded. The majority responded with utilizing 2.4 ATA (35.2%) as the pressure of choice, followed by 2.0 ATA only (27.1%), and those who utilized differing therapeutic pressures (26.4%). The overwhelming choice for treatment of osteoradionecrosis (ORN) of the jaw, radiation proctitis/cystitis, diabetic foot ulcer, and chronic osteomyelitis was 2.0 ATA (68.0- 74.9%). Among listed adverse effects, myopia was the most commonly reported complication at 24.4%, followed by barotrauma (14.9%) and confinement anxiety (11.5%).

Conclusions: There is currently little consensus regarding the best treatment modalities for conditions treated with HBO₂. As adverse effects appear non-negligible, future prospective studies must be conducted weighing the risks and benefits of higher-pressure therapies compared to safer lower-pressure options.

Background: Hyperbaric Oxygen Therapy (HBO₂) is a treatment modality that exposes patients to 100% oxygen at higher atmospheric pressures. Recently, HBO₂ has emerged as a potential therapeutic option for various liver diseases, offering advantages such as improved tissue oxygenation, anti-inflammatory effects, enhanced wound healing, and potential hepatoprotective properties. Understanding the benefits of HBO₂ in liver diseases can pave the way for novel therapeutic strategies and improved patient outcomes. This study aimed to investigate the hepatoprotective effect of HBO₂ in arthritic rats treated with leflunomide (LEF) through anti-inflammatory and antioxidant pathways.

Material and methods: 24 male Sprague-Dawley rats were divided into three groups (8 animals in each group (n = 8)). 1^st group was the control group, which received no treatment. 2^nd group was RA + LEF 5 mg/kg, 3^rd group was RA + LEF 5 mg/kg + HBO₂. Rheumatoid arthritis was induced using Complete Freund's Adjuvant (CFA). The treatment was initiated on the 10^th day following induction and lasted for a total of 18 days. The impact on disease progression was assessed through histological changes, which were evaluated using hematoxylin-eosin staining, while the Anti-TNF-α antibody levels were determined.

Results: TCompared with the RL group, the RLH group significantly decreases necrotic cells, Lymphocyte- rich mononuclear cells, and active anti-TNF-α .

Conclusion: HBO₂ showed a beneficial effect and decreased hepatotoxicity on Leflunomide-induced liver injury.

Decompression after diving may inevitably cause the production of bubbles in the body, even without protocol violation. Bubbles produced in the circulation may damage the vascular cells, leading to vascular dysfunction. In this study, five subjects were recruited and subjected to hyperbaric exposure (15 meters; 100 minutes). The function of the brachial artery was assessed by measuring diameter, systolic peak velocity (SPV), resistance index (RI), and flow-mediated dilation (FMD) of the brachial artery before and after hyperbaric exposure. Our results showed that hyperbaric air exposure slightly increased the diameter of the brachial artery and significantly increased its RI but reduced the FMD and markedly decreased the SPV. This study indicates that hyperbaric air exposure at low pressure may also alter the function of the brachial artery.