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1.
Int Marit Health ; 75(2): 89-102, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38949219

RESUMO

BACKGROUND: Saturation diving is a standard method of intervention for commercial diving during offshore operations. Current saturation procedures achieve a high level of safety with regards to decompression sickness but still put the divers under multiple stressors: 1) Environmental stress (long confinement, heat/cold, dense gases, high oxygen levels), 2) Work stress (muscular fatigue, psychological pressure, breathing equipment, etc.), 3) venous gas emboli associated with decompression, 4) Inflammation related to oxidative stress and microparticles. We present the results of a saturation divers monitoring campaign performed in the North Sea Danish sector, on the Tyra field, during 2022. The study was supported by TotalEnergies, the field operator, and performed by Boskalis Subsea Services, the diving contractor, onboard the diving support vessel Boka Atlantis. The objective was twofold: document the level of diving stress during saturation operations in the Danish sector, and compare the performances of two saturation procedures, the Boskalis and the NORSOK procedures. MATERIALS AND METHODS: Fourteen divers volunteered for the study. The monitoring package include weight and temperature measurements, psychomotor tests (objective evaluation) and questionnaires (subjective evaluation), Doppler bubble detection and bioimpedance. The results were presented in a radar diagram that provides a general view of the situation. RESULTS: The data were analysed along 3 dimensions: work and environmental, desaturation bubbles, oxidative stress and inflammation. The results showed little or no variations from the reference values. No bubbles were detected after excursion dives and the final decompression, except for two divers with a grade 1 after arriving at surface. No statistical difference could be found between the Boskalis and the NORSOK saturation procedures. CONCLUSIONS: At a depth of 40-50 msw corresponding to the Danish sector, the two saturation procedures monitored induce no or little stress to the divers. The divers know how to manage their diet, equilibrate their hydration and pace their effort. Data available on divers' post saturation period show a recovery over the 24-48 hours following the end of the decompression. Further research should focus on diving deeper than 100 msw where a greater stress can be anticipated.


Assuntos
Doença da Descompressão , Mergulho , Humanos , Mergulho/efeitos adversos , Mergulho/fisiologia , Mar do Norte , Adulto , Masculino , Saturação de Oxigênio/fisiologia , Pessoa de Meia-Idade , Estresse Fisiológico , Dinamarca , Monitorização Fisiológica/métodos
2.
Undersea Hyperb Med ; 51(2): 129-135, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38985149

RESUMO

Inner ear decompression sickness (IEDCS) is an uncommon diving-related injury affecting the vestibulocochlear system, with symptoms typically including vertigo, tinnitus, and hearing loss, either in isolation or combination. Classically associated with deep, mixed-gas diving, more recent case series have shown that IEDCS is indeed possible after seemingly innocuous recreational dives, and there has been one previous report of IEDCS following routine hyperbaric chamber operations. The presence of right-to-left shunt (RLS), dehydration, and increases in intrathoracic pressure have been identified as risk factors for IEDCS, and previous studies have shown a predominance of vestibular rather than cochlear symptoms, with a preference for lateralization to the right side. Most importantly, rapid identification and initiation of recompression treatment are critical to preventing long-term or permanent inner ear deficits. This case of a U.S. Navy (USN) diver with previously unidentified RLS reemphasizes the potential for IEDCS following uncomplicated diving and recompression chamber operations - only the second reported instance of the latter.


Assuntos
Doença da Descompressão , Mergulho , Oxigenoterapia Hiperbárica , Doença da Descompressão/etiologia , Humanos , Mergulho/efeitos adversos , Masculino , Orelha Interna/lesões , Militares , Adulto , Vertigem/etiologia , Zumbido/etiologia , Câmaras de Exposição Atmosférica
3.
Undersea Hyperb Med ; 51(2): 185-187, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38985154

RESUMO

A 60-year-old man with hypertension and dyslipidemia complained of chest pain upon ascending from a maximum depth of 27 meters while diving. After reaching the shore, his chest pain persisted, and he called an ambulance. When a physician checked him on the doctor's helicopter, his electrocardiogram (ECG) was normal, and there were no bubbles in his inferior vena cava or heart on a portable ultrasound examination. The physician still suspected that he had acute coronary syndrome instead of decompression illness; therefore, he was transported to our hospital. After arrival at the hospital, standard cardiac echography showed a flap in the ascending aorta. Immediate enhanced computed tomography revealed Stanford type A aortic dissection. The patient obtained a survival outcome after emergency surgery. To our knowledge, this is the first reported case of aortic dissection potentially associated with scuba diving. It highlights the importance of considering aortic dissection in patients with sudden-onset chest pain during physical activity. In addition, this serves as a reminder that symptoms during scuba diving are not always related to decompression. This report also suggests the usefulness of on-site ultrasound for the differential diagnosis of decompression sickness from endogenous diseases that induce chest pain. Further clinical studies of this management approach are warranted.


Assuntos
Dissecção Aórtica , Dor no Peito , Doença da Descompressão , Mergulho , Humanos , Mergulho/efeitos adversos , Masculino , Pessoa de Meia-Idade , Dissecção Aórtica/etiologia , Dissecção Aórtica/diagnóstico por imagem , Dissecção Aórtica/complicações , Dissecção Aórtica/cirurgia , Dor no Peito/etiologia , Doença da Descompressão/etiologia , Doença da Descompressão/terapia , Doença da Descompressão/complicações , Doença da Descompressão/diagnóstico por imagem , Doença da Descompressão/diagnóstico , Doença Aguda , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/etiologia , Aneurisma Aórtico/complicações , Aneurisma Aórtico/cirurgia , Diagnóstico Diferencial
4.
Undersea Hyperb Med ; 51(2): 107-113, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38985147

RESUMO

A widely accepted belief is that Nathaniel Henshaw was the first practitioner of hyperbaric medicine. He is said to have constructed the first hyperbaric chamber where he treated several disorders and provided opportunities to prevent disease and optimize well-being. While there is little doubt Henshaw was the first to conceptualize this unique medical technology, careful analysis of his treatise has convinced this writer that his was nothing more than a proposal. Henshaw's air chamber was never built. He would have failed to appreciate how its structural integrity could be maintained in the presence of enormous forces generated by envisioned changes in its internal pressure and, likewise, how its door could effectively seal the chamber during hypo-and hyperbaric use. Henshaw would have also failed to appreciate the limitations of his two proposed measuring devices and the toxic nature of one. Neither of these would have provided any quantitative information. The impracticality of his proposed method of compressing and decompressing the chamber is readily apparent. So, too, the likely toxic accumulation of carbon dioxide within the unventilated chamber during lengthy laborious periods required to operate it. Henshaw recommended pressures up to three times atmospheric pressure and durations for acute conditions until their resolution. Such exposures would likely result in fatal decompression sickness upon eventual chamber ascent, a condition of which nothing was known at the time. It would be another 170 years before a functional air chamber would finally become a reality. Henshaw's legacy, then, is limited to the concept of hyperbaric medicine rather than being its first practitioner.


Assuntos
Oxigenoterapia Hiperbárica , Oxigenoterapia Hiperbárica/história , História do Século XIX , História do Século XX , Câmaras de Exposição Atmosférica/história , Doença da Descompressão/terapia , Doença da Descompressão/história
5.
J Cardiothorac Surg ; 19(1): 316, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38824529

RESUMO

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is increasingly being used for critically ill patients with cardiopulmonary failure. Air in the ECMO circuit is an emergency, a rare but fatal complication. CASE PRESENTATION: We introduce a case of a 76-year-old female who suffered from cardiac arrest complicated with severe trauma and was administered veno-arterial extracorporeal membrane oxygenation. In managing the patient with ECMO, air entered the ECMO circuit, which had not come out nor was folded or broken. Although the ECMO flow was quickly re-established, the patient died 6 h after initiating ECMO therapy. CONCLUSIONS: In this case report, the reason for the complication is drainage insufficiency. This phenomenon is similar to decompression sickness. Understanding this complication is very helpful for educating the ECMO team for preventing this rare but devastating complication of fatal decompression sickness in patients on ECMO.


Assuntos
Doença da Descompressão , Oxigenação por Membrana Extracorpórea , Parada Cardíaca , Humanos , Oxigenação por Membrana Extracorpórea/métodos , Feminino , Idoso , Evolução Fatal , Parada Cardíaca/terapia , Parada Cardíaca/etiologia , Doença da Descompressão/terapia
6.
Diving Hyperb Med ; 54(2): 86-91, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38870949

RESUMO

Introduction: Tasmania is a small island state off the southern edge of Australia where a comparatively high proportion of the 558,000 population partake in recreational or occupational diving. While diving is a relatively safe sport and occupation, Tasmania has a significantly higher diving death rate per head of population than other States in Australia (four times the national diving mortality rate). Methods: Three compressed gas diving deaths occurred in seven months between 2021-2022 prompting a review of the statewide approach for the immediate response of personnel to diving-related deaths. The review engaged first responders including the Police Marine and Rescue Service, hospital-based departments including the Department of Hyperbaric and Diving Medicine, and the mortuary and coroner's office. Results: An aide-mémoire for all craft groups, digitalised checklists for first responders (irrespective of diving knowledge), and a single-paged algorithm to highlight inter-agency communication pathways in the event of a diving death were designed to enhance current practices and collaboration. Conclusions: If used, these aids for managing diving related deaths should ensure that time-critical information is appropriately captured and stored to optimise information provided for the coronial investigation.


Assuntos
Mergulho , Mergulho/estatística & dados numéricos , Humanos , Tasmânia/epidemiologia , Masculino , Lista de Checagem , Doença da Descompressão/mortalidade , Doença da Descompressão/terapia , Adulto , Feminino , Algoritmos , Socorristas/estatística & dados numéricos , Pessoa de Meia-Idade
7.
Diving Hyperb Med ; 54(2): 127-132, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38870955

RESUMO

We report a compressed air worker who had diffuse cutaneous decompression sickness with pain in his left shoulder and visual disturbance characteristic of migraine aura after only his third hyperbaric exposure. The maximum pressure was 253 kPa gauge with oxygen decompression using the Swanscombe Oxygen Decompression Table. He was found to have a very large right-to-left shunt across a 9 mm atrial septal defect. He had transcatheter closure of the defect but had some residual shunting with release of a Valsalva manoeuvre. Thirty-two other tunnel workers undertook the same pressure profile and activities in the same working conditions during the maintenance of a tunnel boring machine for a total of 233 similar exposures and were unaffected. As far as we are aware this is the first report of shunt-mediated decompression sickness in a hyperbaric tunnel worker in the United Kingdom and the second case reported worldwide. These cases suggest that shunt-mediated decompression sickness should be considered to be an occupational risk in modern compressed air working. A right-to-left shunt in a compressed air worker should be managed in accordance with established clinical guidance for divers.


Assuntos
Doença da Descompressão , Comunicação Interatrial , Doenças Profissionais , Humanos , Doença da Descompressão/etiologia , Doença da Descompressão/terapia , Masculino , Comunicação Interatrial/cirurgia , Doenças Profissionais/etiologia , Ar Comprimido/efeitos adversos , Adulto , Oxigenoterapia Hiperbárica/métodos , Manobra de Valsalva , Pessoa de Meia-Idade , Mergulho/efeitos adversos
8.
Diving Hyperb Med ; 54(2): 110-119, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38870953

RESUMO

Introduction: Inhalation of high concentrations of carbon dioxide (CO2) at atmospheric pressure can be toxic with dose-dependent effects on the cardiorespiratory system or the central nervous system. Exposure to both hyperbaric and hypobaric environments can result in decompression sickness (DCS). The effects of CO2 on DCS are not well documented with conflicting results. The objective was to review the literature to clarify the effects of CO2 inhalation on DCS in the context of hypobaric or hyperbaric exposure. Methods: The systematic review included experimental animal and human studies in hyper- and hypobaric conditions evaluating the effects of CO2 on bubble formation, denitrogenation or the occurrence of DCS. The search was based on MEDLINE and PubMed articles with no language or date restrictions and also included articles from the underwater and aviation medicine literature. Results: Out of 43 articles, only 11 articles were retained and classified according to the criteria of hypo- or hyperbaric exposure, taking into account the duration of CO2 inhalation in relation to exposure and distinguishing experimental work from studies conducted in humans. Conclusions: Before or during a stay in hypobaric conditions, exposure to high concentrations of CO2 favors bubble formation and the occurrence of DCS. In hyperbaric conditions, high CO2 concentrations increase the occurrence of DCS when exposure occurs during the bottom phase at maximum pressure, whereas beneficial effects are observed when exposure occurs during decompression. These opposite effects depending on the timing of exposure could be related to 1) the physical properties of CO2, a highly diffusible gas that can influence bubble formation, 2) vasomotor effects (vasodilation), and 3) anti-inflammatory effects (kinase-nuclear factor and heme oxygenase-1 pathways). The use of O2-CO2 breathing mixtures on the surface after diving may be an avenue worth exploring to prevent DCS.


Assuntos
Dióxido de Carbono , Doença da Descompressão , Animais , Humanos , Pressão Atmosférica , Mergulho/efeitos adversos , Mergulho/fisiologia
9.
Curr Sports Med Rep ; 23(5): 199-206, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38709946

RESUMO

ABSTRACT: Breath-hold divers, also known as freedivers, are at risk of specific injuries that are unique from those of surface swimmers and compressed air divers. Using peer-reviewed scientific research and expert opinion, we created a guide for medical providers managing breath-hold diving injuries in the field. Hypoxia induced by prolonged apnea and increased oxygen uptake can result in an impaired mental state that can manifest as involuntary movements or full loss of consciousness. Negative pressure barotrauma secondary to airspace collapse can lead to edema and/or hemorrhage. Positive pressure barotrauma secondary to overexpansion of airspaces can result in gas embolism or air entry into tissues and organs. Inert gas loading into tissues from prolonged deep dives or repetitive shallow dives with short surface intervals can lead to decompression sickness. Inert gas narcosis at depth is commonly described as an altered state similar to that experienced by compressed air divers. Asymptomatic cardiac arrhythmias are common during apnea, normally reversing shortly after normal ventilation resumes. The methods of glossopharyngeal breathing (insufflation and exsufflation) can add to the risk of pulmonary overinflation barotrauma or loss of consciousness from decreased cardiac preload. This guide also includes information for medical providers who are tasked with providing medical support at an organized breath-hold diving event with a list of suggested equipment to facilitate diagnosis and treatment outside of the hospital setting.


Assuntos
Barotrauma , Suspensão da Respiração , Doença da Descompressão , Mergulho , Humanos , Mergulho/lesões , Mergulho/efeitos adversos , Barotrauma/etiologia , Barotrauma/diagnóstico , Doença da Descompressão/terapia , Doença da Descompressão/etiologia , Doença da Descompressão/diagnóstico , Hipóxia/etiologia , Narcose por Gás Inerte/etiologia , Narcose por Gás Inerte/diagnóstico
10.
J Appl Physiol (1985) ; 137(1): 63-73, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38660728

RESUMO

We hypothesized that early intra-central nervous system (CNS) responses in a murine model of decompression sickness (DCS) would be reflected by changes in the microparticles (MPs) that exit the brain via the glymphatic system, and due to systemic responses the MPs would cause inflammatory changes lasting for many days leading to functional neurological deficits. Elevations on the order of threefold of blood-borne inflammatory MPs, neutrophil activation, glymphatic flow, and neuroinflammation in cerebral cortex and hippocampus were found in mice at 12 days after exposure to 760 kPa of air for 2 h. Mice also exhibited a significant decline in memory and locomotor activity, as assessed by novel object recognition and rotarod testing. Similar inflammatory changes in blood, neuroinflammation, and functional impairments were initiated in naïve mice by injection of filamentous (F-) actin-positive MPs, but not F-actin-negative MPs, obtained from decompressed mice. We conclude that high pressure/decompression stress establishes a systemic inflammatory process that results in prolonged neuroinflammation and functional impairments in the mouse decompression model.NEW & NOTEWORTHY Elevated glymphatic flow due to astrocyte and microglial activation from high-pressure exposure triggers release of microparticles (MPs) to the circulation where neutrophil activation and production of filamentous (F)-actin expressing MPs result in a persistent feed-forward neuroinflammatory cycle and functional deficits lasting for at least 12 days.


Assuntos
Doença da Descompressão , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Doenças Neuroinflamatórias , Animais , Doença da Descompressão/fisiopatologia , Doença da Descompressão/metabolismo , Camundongos , Masculino , Doenças Neuroinflamatórias/fisiopatologia , Doenças Neuroinflamatórias/metabolismo , Micropartículas Derivadas de Células/metabolismo , Sistema Glinfático/fisiopatologia , Sistema Glinfático/metabolismo , Córtex Cerebral/metabolismo , Córtex Cerebral/fisiopatologia , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Inflamação/fisiopatologia , Inflamação/metabolismo , Ativação de Neutrófilo
11.
Undersea Hyperb Med ; 51(1): 41-46, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38615352

RESUMO

Decompression sickness (DCS) is caused by abrupt changes in extracorporeal pressure with varying severity. Symptoms range from mild musculoskeletal pain to severe organ dysfunction and death, especially among patients with chronic underlying disease. Here, we report an unusual case of a 49-year-old man who experienced DCS after a dive to a depth of 38 meters. The patient's symptoms progressed, starting with mild physical discomfort that progressed to disturbance of consciousness on the second morning. During hospitalization, we identified that in addition to DCS, he had also developed diabetic ketoacidosis, septic shock, and rhabdomyolysis. After carefully balancing the benefits and risks, we decided to provide supportive treatment to sustain vital signs, including ventilation support, sugar-reducing therapy, fluid replacement, and anti-infection medications. We then administered delayed hyperbaric oxygen (HBO2) when his condition was stable. Ultimately, the patient recovered without any sequelae. This is the first case report of a diver suffering from DCS followed by diabetic ketoacidosis and septic shock. We have learned that when DCS and other critical illnesses are highly suspected, it is essential to assess the condition comprehensively and focus on the principal contradiction.


Assuntos
Doença da Descompressão , Diabetes Mellitus , Cetoacidose Diabética , Mergulho , Choque Séptico , Masculino , Humanos , Pessoa de Meia-Idade , Cetoacidose Diabética/complicações , Cetoacidose Diabética/terapia , Doença da Descompressão/complicações , Doença da Descompressão/diagnóstico , Choque Séptico/complicações , Choque Séptico/terapia , Progressão da Doença
12.
Diving Hyperb Med ; 54(1Suppl): 1-53, 2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38537300

RESUMO

Decompression illness is a collective term for two maladies (decompression sickness [DCS] and arterial gas embolism [AGE]) that may arise during or after surfacing from compressed gas diving. Bubbles are the presumed primary vector of injury in both disorders, but the respective sources of bubbles are distinct. In DCS bubbles form primarily from inert gas that becomes dissolved in tissues over the course of a compressed gas dive. During and after ascent ('decompression'), if the pressure of this dissolved gas exceeds ambient pressure small bubbles may form in the extravascular space or in tissue blood vessels, thereafter passing into the venous circulation. In AGE, if compressed gas is trapped in the lungs during ascent, pulmonary barotrauma may introduce bubbles directly into the pulmonary veins and thence to the systemic arterial circulation. In both settings, bubbles may provoke ischaemic, inflammatory, and mechanical injury to tissues and their associated microcirculation. While AGE typically presents with stroke-like manifestations referrable to cerebral involvement, DCS can affect many organs including the brain, spinal cord, inner ear, musculoskeletal tissue, cardiopulmonary system and skin, and potential symptoms are protean in both nature and severity. This comprehensive overview addresses the pathophysiology, manifestations, prevention and treatment of both disorders.


Assuntos
Barotrauma , Doença da Descompressão , Mergulho , Embolia Aérea , Humanos , Doença da Descompressão/etiologia , Doença da Descompressão/terapia , Doença da Descompressão/diagnóstico , Mergulho/efeitos adversos , Mergulho/fisiologia , Barotrauma/etiologia , Embolia Aérea/etiologia , Embolia Aérea/terapia , Embolia Aérea/diagnóstico , Descompressão
13.
Diving Hyperb Med ; 54(1): 39-46, 2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38507908

RESUMO

Introduction: Diving injuries are influenced by a multitude of factors. Literature analysing the full chain of events in diving accidents influencing the occurrence of diving injuries is limited. A previously published 'chain of events analysis' (CEA) framework consists of five steps that may sequentially lead to a diving fatality. This study applied four of these steps to predominately non-lethal diving injuries and aims to determine the causes of diving injuries sustained by divers treated by the Diving Medical Centre of the Royal Netherlands Navy. Methods: This retrospective cohort study was performed on diving injuries treated by the Diving Medical Centre between 1966 and 2023. Baseline characteristics and information pertinent to all four steps of the reduced CEA model were extracted and recorded in a database. Results: A total of 288 cases met the inclusion criteria. In 111 cases, all four steps of the CEA model could be applied. Predisposing factors were identified in 261 (90%) cases, triggers in 142 (49%), disabling agents in 195 (68%), and 228 (79%) contained a (possible-) disabling condition. The sustained diving injury led to a fatality in seven cases (2%). The most frequent predisposing factor was health conditions (58%). Exertion (19%), primary diver errors (18%), and faulty equipment (17%) were the most frequently identified triggers. The ascent was the most frequent disabling agent (52%). Conclusions: The CEA framework was found to be a valuable tool in this analysis. Health factors present before diving were identified as the most frequent predisposing factors. Arterial gas emboli were the most lethal injury mechanism.


Assuntos
Doença da Descompressão , Mergulho , Embolia Aérea , Humanos , Mergulho/efeitos adversos , Mergulho/lesões , Países Baixos/epidemiologia , Estudos Retrospectivos , Acidentes , Doença da Descompressão/epidemiologia , Doença da Descompressão/etiologia , Doença da Descompressão/terapia
14.
Diving Hyperb Med ; 54(1): 23-38, 2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38507907

RESUMO

Introduction: This is a review of commercial heliox saturation decompression procedures. The scope does not include compression, storage depth or bell excursion dive procedures. The objectives are to: identify the sources of the procedures; trace their evolution; describe the current practice; and detect relevant trends. Methods: Eleven international commercial diving companies provided their diving manuals for review under a confidentiality agreement. Results: Modern commercial diving saturation procedures are derived from a small number of original procedures (United States Navy, Comex, and NORSOK). In the absence of relevant scientific studies since the late 80's, the companies have empirically adapted these procedures according to their needs and experience. Such adaptation has caused differences in decompression rates shallower than 60 msw, decompression rest stops and the decision to decompress linearly or stepwise. Nevertheless, the decompression procedures present a remarkable homogeneity in chamber PO2 and daily decompression rates when deeper than 60 msw. The companies have also developed common rules of good practice; no final decompression should start with an initial ascending excursion; a minimum hold is required before starting a final decompression after an excursion dive. Recommendation is made for the divers to exercise during decompression. Conclusions: We observed a trend towards harmonisation within the companies that enforce international procedures, and, between companies through cooperation inside the committees of the industry associations.


Assuntos
Doença da Descompressão , Mergulho , Humanos , Descompressão/efeitos adversos , Oxigênio , Hélio , Doença da Descompressão/etiologia
15.
J Appl Physiol (1985) ; 136(4): 949-953, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38420678

RESUMO

Decompression sickness (DCS) is caused by gaseous nitrogen dissolved in tissues forming bubbles during decompression. To date, no method exists to identify nitrogen within tissues, but with advances in positron-emission tomography (PET) technology, it may be possible to track gaseous radionuclides into tissues. We aimed to develop a method to track nitrogen movement in vivo and under hyperbaric pressure that could then be used to further our understanding of DCS using nitrogen-13 (13N2). A single anesthetized female Sprague-Dawley rat was exposed to 625 kPa, composed of air, isoflurane, and 13N2 for 10 min. The PET scanner recorded 13N2 during the hyperbaric exposure with energy windows of 250-750 keV. The PET showed an increase in 13N2 concentration in the lung, heart, and abdominal regions, which all reached a plateau after ∼4 min. This showed that it is possible to gain noninvasive in vivo measurements of nitrogen kinetics through the body while at hyperbaric pressures. Tissue samples showed radioactivity above background levels in the blood, brain, liver, femur, and thigh muscle when assessed using a γ counter. The method can be used to evaluate an array of challenges to our understanding of decompression physiology by quantifying nitrogen load through γ counts of 13N2, and signal intensity of the PET. Further development of the method will improve the specificity of the measured outcomes, and enable it to be used with larger mammals, including humans.NEW & NOTEWORTHY This article describes a method for the in vivo quantification and tracking of nitrogen through the mammalian body whilst exposed to hyperbaric pressure. The method has the potential to further our understanding of decompression sickness, and quantitatively evaluate the effectiveness of both the treatment and prevention of decompression sickness.


Assuntos
Doença da Descompressão , Mergulho , Oxigenoterapia Hiperbárica , Radioisótopos de Nitrogênio , Humanos , Ratos , Animais , Feminino , Nitrogênio , Doença da Descompressão/diagnóstico por imagem , Mergulho/fisiologia , Ratos Sprague-Dawley , Descompressão/efeitos adversos , Gases , Oxigenoterapia Hiperbárica/métodos , Tomografia por Emissão de Pósitrons , Mamíferos
16.
Laryngoscope ; 134(7): 3044-3048, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38284795

RESUMO

OBJECTIVE: To understand the role of a single laryngologist, Andrew Heermance Smith, in elucidating the mechanisms of Caisson Disease and controlling it effects on bridge workers. DATA SOURCES: Scientific and lay publications, letters and records of the Roebling family, obituaries and internet sources. REVIEW METHODS: Historical review. RESULTS: AH Smith combined physiological observations and experiments in the Brooklyn Bridge caissons with a review of the existing engineering and medical literature to describe the Caisson Disease and to devise strategies to ameliorate its effects. CONCLUSION: Despite an incorrect conclusion about the pathophysiology of decompression sickness, Smith's stringent standards and timely interventions allow completion of the masonry towers of the Brooklyn Bridge. LEVEL OF EVIDENCE: NA Laryngoscope, 134:3044-3048, 2024.


Assuntos
Otolaringologia , Humanos , História do Século XIX , História do Século XX , Otolaringologia/história , Doença da Descompressão/etiologia , Doença da Descompressão/prevenção & controle
17.
Mil Med ; 189(1-2): e401-e404, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-37436921

RESUMO

3d Reconnaissance Battalion, a forward-deployed Marine Corps unit in Okinawa, Japan, frequently performs diving operations. Often throughout the year, several reconnaissance teams are diving simultaneously in different locations for training. We present a case of an otherwise healthy 30-year-old-male Reconnaissance Marine who surfaced from a dive with abnormal symptoms and received prompt care from exercise participants who were nonmedical personnel. Studies have demonstrated improved morbidity outcomes in decompression illness patients with shorter times to hyperbaric treatment following the onset of symptoms. High-risk military exercises with diving components have a mandatory safety structure that includes recompression chamber support. All United States Marine Corps Reconnaissance, Marine Corps Special Operations Command, and U.S. Navy dive operations are required to have at least one diving supervisor. To expand the diving capabilities of the unit, Marines are encouraged to attend training and qualify as diving supervisors. This case study demonstrates the efficacy and importance of training Recon Marines to recognize decompression illness as diving supervisors.


Assuntos
Doença da Descompressão , Mergulho , Embolia Aérea , Oxigenoterapia Hiperbárica , Militares , Humanos , Masculino , Estados Unidos , Adulto , Embolia Aérea/etiologia , Embolia Aérea/terapia , Doença da Descompressão/complicações , Doença da Descompressão/terapia , Mergulho/efeitos adversos
18.
Diving Hyperb Med ; 53(4): 299-305, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38091588

RESUMO

Introduction: To develop the diving capacity in the Swedish armed forces the current air decompression tables are under revision. A new decompression table named SWEN21 has been created to have a projected risk level of 1% for decompression sickness (DCS) at the no stop limits. The aim of this study was to evaluate the safety of SWEN21 through the measurement of venous gas emboli (VGE) in a dive series. Methods: A total 154 dives were conducted by 47 divers in a hyperbaric wet chamber. As a proxy for DCS risk serial VGE measurements by echocardiography were conducted and graded according to the Eftedal-Brubakk scale. Measurements were done every 15 minutes for approximately 2 hours after each dive. Peak VGE grades for the different dive profiles were used in a Bayesian approach correlating VGE grade and risk of DCS. Symptoms of DCS were continually monitored. Results: The median (interquartile range) peak VGE grade after limb flexion for a majority of the time-depth combinations, and of SWEN21 as a whole, was 3 (3-4) with the exception of two decompression profiles which resulted in a grade of 3.5 (3-4) and 4 (4-4) respectively. The estimated risk of DCS in the Bayesian model varied between 4.7-11.1%. Three dives (2%) resulted in DCS. All symptoms resolved with hyperbaric oxygen treatment. Conclusions: This evaluation of the SWEN21 decompression table, using bubble formation measured with echocardiography, suggests that the risk of DCS may be higher than the projected 1%.


Assuntos
Doença da Descompressão , Mergulho , Embolia Aérea , Humanos , Mergulho/efeitos adversos , Doença da Descompressão/diagnóstico por imagem , Suécia , Teorema de Bayes , Embolia Aérea/diagnóstico por imagem , Ultrassonografia , Medição de Risco , Descompressão
19.
Diving Hyperb Med ; 53(4): 321-326, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38091591

RESUMO

Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects. Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen. Inert gas volume was extrapolated from these inputs using the ideal gas law. The device's ability to detect volume differences while connected to a breathing machine was analysed by injecting a given gas volume eight times. One hundred and seventy-two coupled before-and-after measurements were then compared with a paired t-test. Drift in measured inert gas volume during unlabored breathing was evaluated in three subjects at rest using multilevel linear regression. A quasi-experimental cross-over study with the same subjects was conducted to evaluate the device's ability to detect inert gas changes in relation to diving interventions and simulate power. Results: The difference between the injected volume (1,996 ml) and the device's measured volume (1,986 ml) was -10 ml. The 95% confidence interval (CI) for the measured volume was 1,969 to 2,003 ml. Mean drift during a 43 min period of unlaboured breathing was -19 ml, (95% CI, -37 to -1). Our power simulation, based on a cross-over study design, determined a sample size of two subjects to detect a true mean difference of total inert gas wash-out volume of 100 ml. Conclusions: We present a portable device with acceptable precision and accuracy to measure inert gas wash-out differences that may be physiologically relevant in the pathophysiology of decompression sickness.


Assuntos
Doença da Descompressão , Mergulho , Humanos , Nitrogênio , Estudos Cross-Over , Mergulho/fisiologia , Oxigênio
20.
Diving Hyperb Med ; 53(4): 333-339, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38091593

RESUMO

Introduction: Venous gas emboli (VGE) are widely used as a surrogate endpoint instead of decompression sickness (DCS) in studies of decompression procedures. Peak post-dive VGE grades vary widely following repeated identical dives but little is known about how much of the variability in VGE grades is proportioned between-diver and within-diver. Methods: A retrospective analysis of 834 man-dives on six dive profiles with post-dive VGE measurements was conducted under controlled laboratory conditions. Among these data, 151 divers did repeated dives on the same profile on two to nine occasions separated by at least one week (total of 693 man-dives). Data were analysed for between- and within-diver variability in peak post-dive VGE grades using mixed-effect models with diver as the random variable and associated intraclass correlation coefficients. Results: Most divers produced a wide range of VGE grades after repeated dives on the same profile. The intraclass correlation coefficient (repeatability) was 0.33 indicating that 33% of the variability in VGE grades is between-diver variability; correspondingly, 67% of variability in VGE grades is within-diver variability. DCS cases were associated with an individual diver's highest VGE grades and not with their lower VGE grades. Conclusions: These data demonstrate large within-diver variability in VGE grades following repeated dives on the same dive profile and suggest there is substantial within-diver variability in susceptibility to DCS. Post-dive VGE grades are not useful for evaluating decompression practice for individual divers.


Assuntos
Doença da Descompressão , Mergulho , Embolia Aérea , Masculino , Humanos , Estudos Retrospectivos , Embolia Aérea/diagnóstico por imagem , Embolia Aérea/etiologia , Mergulho/efeitos adversos , Veias
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