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SCUBA diving poses risks due to pressure changes during descent (compression) and ascent (decompression). Decompression sickness (DCS) occurs due to gas bubble formation as the pressure decreases, causing joint pain, numbness, dizziness, or even paralysis and death. Immediate treatment involves 100% oxygen to help eliminate inert gases and hyperbaric oxygen therapy (HBOT), which is essential to reduce gas emboli formation and inflammation, thus improving symptoms. We evaluated oxy-inflammation biomarkers in the saliva and urine of nine subjects pre- and post-technical dive on the Haven wreck (GE, Italy). A case of DCS occurred during the dive. The injured diver was treated immediately with O2 and transported to the hyperbaric center of "ASST Ospedale Ca Granda" in Milan. He was treated following the U.S. Navy Treatment Table 5 at 2.8 ATA and the day after with Table 15 at 2.4 ATA. Venous blood and urine samples were collected before and after each HBO treatment. Our study shows that dive increased oxy-inflammation biomarkers (ROS +126%; lipid peroxidation +23%; interleukins-6 +81%, -1β +19%, and TNFα +84%) and nitric oxide metabolites levels (+36%). HBOT after a DCS episode reduced oxidative stress, lowering the very high marker of lipid peroxidation (8-iso-PGF2α), and inhibited inflammatory interleukins. Overall, HBOT improved physiological responses in the diver affected by DCS. [ABSTRACT FROM AUTHOR]

Systemic air embolism is a rare but potentially life-threatening complication of computed tomography (CT)-guided lung biopsy. The largest lung biopsy audits report an incidence rate of approximately 0.061% for systemic air embolism, with a mortality rate of 0.07-0.15%. A prompt diagnosis with high index of suspicion is essential, and hyperbaric oxygen treatment (HBOT) is the definitive management. We report the case of a 44-year-old lady who developed a lateral ST elevation myocardial infarction from coronary artery air embolism following CT-guided lung biopsy for evaluation of a left lung lesion. The biopsy was performed in the right lateral decubitus position, and the patient reported chest pain after coughing during the procedure. The clinician decided to proceed, taking four biopsy samples as no pneumothorax was identified in the intraprocedural CT image. The patient was noted to have hypotension with ongoing chest pain post-procedure. Resuscitative measures were taken to stabilise her haemodynamics, and she was successfully treated with HBOT with total resolution of air embolism. She developed a left sided pneumothorax post-treatment and needed intercostal chest drain insertion. The left lung fully re-expanded, and the patient was discharged home after day two of admission. [ABSTRACT FROM AUTHOR]

Diving accidents result from a variety of causes including human error, inadequate health and fitness, environmental hazards and equipment problems. They usually involve a cascade of events resulting in the diver being injured or deceased. The accuracy and usefulness of a diving accident investigation relies on well-targeted interviews, good field investigation, evidence collection and preservation, and appropriate equipment assessment. In the event of a fatality, a thorough and targeted autopsy is indicated. Investigators should have the appropriate knowledge, training, skills and support systems to perform the required tasks. Relevant investigations include the victim's medical and diving history, the dive circumstances and likely accident scenario, management of the accident including rescue and first aid, equipment inspection and testing and a thorough postmortem examination conducted by a forensic pathologist with an awareness of the special requirements of a diving autopsy and the knowledge to correctly interpret the findings. A chain of events analysis can determine the likely accident scenario, identify shortcomings and inform countermeasures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Hyperbaric oxygen treatment (HBOT) is recommended for arterial gas embolism (AGE) with severe symptoms. However, once symptoms subside, there may be a dilemma to treat or not. Case presentation: A 71-year-old man was noted to have a mass shadow in his left lung, and a transbronchial biopsy was performed with sedation. Flumazenil was intravenously administered at the end of the procedure. However, the patient remained comatose and developed bradycardia, hypotension, and ST-segment elevation in lead II. Although the ST changes spontaneously resolved, the patient had prolonged disorientation. Whole-body computed tomography revealed several black rounded lucencies in the left ventricle and brain, confirming AGE. The patient received oxygen and remained supine. His neurological symptoms gradually improved but worsened again, necessitating HBOT. HBOT was performed seven times, after which neurological symptoms resolved almost completely. Conclusions: AGE can secondarily deteriorate after symptoms have subsided. We recommend that HBOT be performed promptly once severe symptoms appear, even if they resolve spontaneously. [ABSTRACT FROM AUTHOR]

Arterial gas embolism following pulmonary barotrauma occurs in 13–24% of cases of diving deaths. The study aimed to evaluate the usefulness of a histomorphometric digital analysis in the detection of air space over-distension due to pulmonary barotrauma. The study was performed on lung parenchyma specimens of 12 divers: six had died due to arterial gas embolism following pulmonary barotrauma (mean age at death of 54 years, range of 41–61 years), and six had drowned in saltwater without a diagnosis of pulmonary barotrauma (mean age at death of 54 years, range of 41–66 years) (positive controls). For negative controls, six cases of non-SCUBA divers (mean age of death of 42 years, range of 23–55 years) who died of intracerebral haemorrhage were evaluated. No significant differences were observed in the characteristics of the air spaces between control groups (positive and negative). However, differences were observed in the area occupied by air spaces and the percentage of air space area when we compared the case group to the controls (p < 0.01); and there was a slight difference in the maximum and minimum diameters of air space (p < 0.05). The mean area occupied by air spaces and the mean percentage of air space were the most useful for discriminating pulmonary barotrauma from other causes of death (100% sensitivity and 91.7% specificity). Based on our study, inclusion of an increased pattern of air spaces as a possible diagnostic criterion for pulmonary barotrauma would be useful in discerning the cause of diving death. [ABSTRACT FROM AUTHOR]

We report the case of a 23-year-old male novice diver who sustained cerebral arterial gas embolism (CAGE) during his open water certification training whilst practising a free ascent as part of the course. He developed immediate but transient neurological symptoms that had resolved on arrival to hospital. Radiological imaging of his chest showed small bilateral pneumothoraces, pneumopericardium and pneumomediastinum. In view of this he was treated with high flow normobaric oxygen rather than recompression, because of the risk of development of tension pneumothorax upon chamber decompression. There was no relapse of his neurological symptoms with this regimen. The utility and safety of free ascent training for recreational divers is discussed, as is whether a pneumothorax should be vented prior to recompression, as well as return to diving following pulmonary barotrauma. [ABSTRACT FROM AUTHOR]

Pulmonary physiology is significantly altered during underwater exposure, as immersion of the body and increased ambient pressure elicit profound effects on both the cardiovascular and respiratory systems. Thoracic blood pooling, increased breathing gas pressures, and variations in gas volumes alongside ambient pressure changes put the heart and lungs under stress. Normal physiologic function and fitness of the cardiovascular and respiratory systems are prerequisites to safely cope with the challenges of the underwater environment when freediving, or diving with underwater breathing apparatus. Few physicians are trained to understand the physiology and medicine of diving and how to recognize or manage diving injuries. This article provides an overview of the physiologic challenges to the respiratory system during diving, with or without breathing apparatus, and outlines possible health risks and hazards unique to the underwater environment. The underlying pathologic mechanisms of dive-related injuries are reviewed, with an emphasis on pulmonary physiology and pathophysiology. [ABSTRACT FROM AUTHOR]

Introduction: Since the U.S. Navy transitioned from the MK10 to the MK11 submarine escape and immersion equipment (SEIE), there has been an increase in the incident rate of pulmonary barotrauma during submarine escape training. This study compares the ascent rate profiles of the MK10 and MK11 SEIE to determine if ascent rate differences between the escape suits are associated with increased pulmonary barotraumas. Methods: Buoyant ascent rates of the MK10 and MK11 SEIE were compared using weighted manikins equivalent to the 1st, 50th, and 99th percentile body weight of a submariner. Human ascents using the MK11 (n=126) were compared to human ascents in the same trainer wearing the MK10 (n=124). Results: Manikin mean ascent times were faster for the MK10 than the MK11 (5.19 seconds vs 5.28 seconds, p < 0.05). Terminal velocity (Vt) was affected by manikin weight (p < 0.001). Human trials confirmed the manikin results. The average mean ascent velocity for the MK10 group was 0.155 meters/ second faster than the MK11 group's mean ascent velocity (p < 0.001). Mean ascent velocity was inversely correlated with all anthropometrics for the MK10 group (p < 0.01). Neither height nor body mass index showed a significant association with mean ascent velocity for the MK11 group. Conclusions: The Vt of buoyant ascents is significantly affected by body weight. As the mean ascent rate of the MK11 is slower than that of the MK10, ascent rate profile differences between the suits do not appear to explain the recent increase in pulmonary barotrauma incident rates during escape training. [ABSTRACT FROM AUTHOR]

Objective: Cerebrovascular autoregulation impairment has been associated with stroke risk in cardiac surgery. We hypothesized that greater arterial emboli exposure in open-chamber surgery might promote dysautoreguation. Methods: Forty patients underwent closed or open-chamber surgery. Transcranial Doppler detected emboli and measured bilateral middle cerebral artery flow velocities. Cerebral autoregulation was assessed by averaging the mean velocity index ("Mx," a continuous moving correlation between cerebral blood flow velocity and mean arterial pressure) over 30 min before and after aortic cross-clamp removal. Results: Median (interquartile range) emboli counts were 775 (415, 1211) and 2664 (793, 3734) in the closed-chamber and open-chamber groups. Most appeared after the removal of the aortic cross-clamp (open-chamber 1631 (606, 2296)), (closed-chamber 229 (142, 384)), with emphasis on the right hemisphere (open-chamber: 826 (371, 1622)), (closed-chamber 181 (66, 276)). Linear mixed model analyses of mean velocity index change showed no significant overall effect of group (0.08, 95% CI: −0.04, 0.21; p = 0.19) or side (0.01, 95% CI: −0.03, 0.05; p = 0.74). There was an interaction between group and side (p = 0.001), manifesting as a greater increase in mean velocity index in the right hemisphere in the open than the closed group (mean difference: 0.15, 95% CI: 0.02, 0.27; p = 0.03). Conclusions: Overall, change in mean velocity index before and after cross-clamp removal did not differ between groups. However, most emboli entered the right cerebral hemisphere where this change was significantly greater in the open-chamber group, suggesting a possible association between embolic exposure and dysautoregulation. [ABSTRACT FROM AUTHOR]

Gas embolism is a potentially fatal occurrence in which bubbles are introduced into the arterial/venous circulation. A multifocal ischemia could be the life-threatening scenario of that and occurring after diving-related activities, or pulmonary barotrauma, or even iatrogenic procedure capable to cause an accidental introduction of gas into the vasculature. The case here reported concerns the good outcome of one of these rare occurrences thanks to a prompt diagnosis and proper management of the ongoing gaseous lesion. Unfortunately, it remains ethically and technically complex to consider feasible Randomized Clinical Trials (RCTs) in hyperbaric medicine in general, and even more so in this type of eventuality. We are happy to share this further favorable result as we believe it is just thanks to growing documented clinical evidence that now anyone, if ever had to be suffering from gas embolism, in presence of a RCT would widely prefer to be included in the arm that can take advantage of oxygen hyperbaric (HBO) therapy.

Introduction: Breath-hold (BH) diving has known risks, for example drowning, pulmonary oedema of immersion and barotrauma. There is also the risk of decompression illness (DCI) from decompression sickness (DCS) and/or arterial gas embolism (AGE). The first report on DCS in repetitive freediving was published in 1958 and from then there have been multiple case reports and a few studies but no prior systematic review or meta-analysis. Methods: We undertook a systematic literature review to identify articles available from PubMed and Google Scholar concerning breath-hold diving and DCI up to August 2021. Results: The present study identified 17 articles (14 case reports, three experimental studies) covering 44 incidences of DCI following BH diving. Conclusions: This review found that the literature supports both DCS and AGE as potential mechanisms for DCI in BH divers; both should be considered a risk for this cohort of divers, just as for those breathing compressed gas while underwater. [ABSTRACT FROM AUTHOR]

Introduction: Minors have been scuba diving for decades, and while the initial concerns about potential long-term complications related to bone development appear to be unfounded, the incidence of scuba diving injuries among them has been poorly studied. Methods: We reviewed 10,159 cases recorded in the DAN Medical Services call center database from 2014 through 2016 and identified 149 cases of injured divers younger than 18 years. Records were analysed for case categorisation on the most common dive injuries. Information about demographics, level of training, risk factors, and relevant behavioural aspects were collected when available. Results: While the most common reason for the call was to rule out decompression sickness, the majority of cases pertained to ear and sinus issues. However, 15% of the dive-related injuries involving minors had a final diagnosis of pulmonary barotrauma (PBt). While no reliable data is available on the incidence of PBt in adult divers, the authors’ impression based on personal experience suggests that the number of cases of PBt in minors trends higher than in the general diving population. The narratives on some relevant records describe unmanageable levels of anxiety leading to panic. Conclusions: Based on the results and narratives on these cases, it is reasonable to infer that psychological immaturity, suboptimal management of adverse situations, and inadequate supervision might have led to severe injuries among these minor divers. [ABSTRACT FROM AUTHOR]

For the purposes of this guideline, a diving accident is defined as an event that is either potentially life-threatening or hazardous to health as a result of a reduction in ambient pressure while diving or in other hyperbaric atmospheres with and without diving equipment. This national consensus-based guideline (development grade S2k) presents the current state of knowledge and recommendations on the diagnosis and treatment of diving accident victims. The treatment of a breath-hold diver as well as children and adolescents does not differ in principle.In this regard only unusual tiredness and itching without visible skin changes are mild symptoms.The key action statements: on-site 100% oxygen first aid treatment, immobilization/no unnecessary movement, fluid administration and telephone consultation with a diving medicine specialist are recommeed.Hyperbaric oxygen therapy (HBOT) remains unchanged as the established treatment in severe cases, as there are no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa.

This case report describes the successful management of an out-of-hospital arrest in a diver following a suspected arterial gas embolism (AGE). It illustrates both the inherent risks of diving and the importance of prompt and effective implementation of the "chain of survival" from bystanders. Rapid on-scene responses from paramedics and helicopter emergency medical services facilitated prompt evacuation to a Category 1 (multiplace) recompression chamber (RCC) where specialists in cardiology and hyperbaric medicine were available. Alternative causes of cardiac arrest were considered, with a presumed AGE successfully treated with multiple rounds of hyperbaric oxygen therapy. The key factors which led to this successful outcome are discussed, including early recognition and call for help, competent cardiopulmonary resuscitation, and direct evacuation to a Category 1 RCC, with additional consideration of the diagnosis leading to cardiac arrest. The case clearly illustrates the need for all those involved in diving regularly to be competent and confident in performing basic life support, as well as the awareness of the emergency services of the need for diving casualties to be treated at appropriate hyperbaric facilities. Were it not for the simple, prompt and effective treatment this diver received, both on scene and in hospital, it is highly unlikely that such a positive outcome would have been achieved. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to determine the characteristics of decompression illness patients and their treatment outcomes, at the Center of Hyperbaric Medicine, Somdech Phra Pinklao Hospital, one of the largest centres in Thailand. Methods: Past medical records of patients with decompression illness from 2015 to 2021 were retrieved and analysed. Results: Ninety-eight records of diving-related illness from 97 divers were reviewed. Most of the divers were male (n = 50), Thai (n = 86), and were certified at least open water or equivalent (n = 88). On-site first aid oxygen inhalation was provided to 17 divers. Decompression sickness (DCS) cases were characterised according to organ systems involved. The most prominent organ system involved was neurological (57%), followed by mixed organs (28%), musculoskeletal (13%), and pulmonary (2%). There were three cases of arterial gas embolism (AGE). Median presentation delay was three days. Ninety patients were treated with US Navy Treatment Table 6. At the end of their hyperbaric oxygen treatment, most divers (65%) recovered completely. Conclusions: Despite oxygen first aid being given infrequently and long delays before definitive treatment, treatment outcome was satisfactory. Basic knowledge and awareness of diving-related illnesses should be promoted among divers and related personnel in Thailand along with further studies. [ABSTRACT FROM AUTHOR]

Respiratory injury during or following hyperbaric oxygen treatment (HBOT) is rare, but associated pressure changes can cause iatrogenic pulmonary barotrauma with potentially severe sequelae such as pneumothoraces. Pulmonary blebs, bullae, and other emphysematous airspace abnormalities increase the risk of respiratory complications and are prevalent in otherwise healthy adults. HBOT providers may elect to use chest X-ray routinely as a pre-treatment screening tool to identify these anomalies, particularly if a history of preceding pulmonary disease is identified, but this approach has a low sensitivity and frequently provides false negative results. Computed tomography scans offer greater sensitivity for airspace lesions, but given the high prevalence of incidental and insignificant pulmonary findings among healthy individuals, would lead to a high false positive rate because most lesions are unlikely to pose a hazard during HBOT. Post-mortem and imaging studies of airspace lesion prevalence show that a significant proportion of patients who undergo HBOT likely have pulmonary abnormalities such as blebs and bullae. Nevertheless, pulmonary barotrauma is rare, and occurs mainly in those with known underlying lung pathology. Consequently, routinely using chest X-ray or computed tomography scans as screening tools prior to HBOT for low-risk patients without a pertinent medical history or lack of clinical symptoms of cardiorespiratory disease is of low value. This review outlines published cases of patients experiencing pulmonary barotrauma while undergoing pressurised treatment/testing in a hyperbaric chamber and analyses the relationship between barotrauma and pulmonary findings on imaging prior to or following exposure. A checklist and clinical decision-making tool based on suggested low-risk and high-risk features are offered to guide the use of targeted baseline thoracic imaging prior to HBOT. [ABSTRACT FROM AUTHOR]

Presence of patent foramen ovale (PFO), particularly if high-grade, increases the risk of decompression illness (DCI) and its severe forms. In unprovoked or recurrent DCI, neurologic, cutaneous, or cardiopulmonary DCI, testing for PFO is indicated with bubble contrast echocardiography or transcranial Doppler using provocative maneuvers. In patients with PFO and history of DCI, evaluation by a cardiologist with expertise in diving medicine is recommended. Consideration should be given to PFO closure if cessation of diving or conservative diving cannot be achieved. Prospective studies evaluating long-term outcomes in patients who continue to dive after PFO closure are required., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Abstract Decompression illness in breath‐hold diving is a rare dysbaric disease mainly characterized by stroke‐like neurological disorders. The early use of DWI‐MRI combined with ADC map in suspected cases can help in the early diagnosis and treatment.

The evaluation and care of an injured scuba diver requires an understanding of the different types of underwater activities that may be deemed scuba diving. Such activities may range from the complex (eg, commercial or technical diving) all the way up to basic recreational scuba or snorkeling. A thorough physical examination should be completed as early as possible with a focus on specific areas at risk for injury and etiology, such as a detailed cardiopulmonary, skin, and neurologic examination. Serial reassessments and supportive care are as equally important as consultation with a dive medicine expert, especially one with hyperbaric capabilities., Competing Interests: Disclosure None declared., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Hydrogen peroxide (H₂O₂) ingestion can lead to severe systemic complications, including neurological sequelae such as acute embolic stroke. We present a case of a 49-year-old male who accidentally ingested approximately 50-60 mL of 50% w/w hydrogen peroxide, resulting in encephalopathy, upper motor neuron quadriparesis, and pulmonary artery thrombosis. The patient's altered sensorium progressed to a stupor, accompanied by acute respiratory distress and abdominal gaseous distension. Imaging revealed multifocal hypodensities in the brain and saddle thrombus in the pulmonary arteries. Hyperbaric oxygen therapy initiated after diagnosis led to a significant improvement in motor power and resolution of abdominal distension during hospitalization. The pathophysiology involves gas embolization and oxidative stress-induced thrombosis. Management includes stabilizing the patient, dilution therapy, and supportive care, with hyperbaric oxygen therapy for severe cases. Prevention strategies focus on education and proper storage. Continuous monitoring and follow-up are essential for managing hydrogen peroxide poisoning. This case underscores the need for awareness and prompt intervention in hydrogen peroxide toxicity., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Padarabinda Tripathy et al.)

Bronchovenous fistula (BVF) is a rare complication and can cause arterial gas embolism in vital organs, including the heart and the brain, resulting in a high mortality rate. A 51-year-old man developed a BVF during pneumonectomy for lung transplantation, which quickly was diagnosed by transesophageal echocardiography (TEE). He required highairway-pressure ventilation due to his severely restrictive ventilatory impairment and had severe left pleural adhesion due to a history of pleurodesis. Intraoperatively, he had a coronary air embolism and required temporary treatment with central venoarterial extracorporeal membrane oxygenation (VA-ECMO), but showed no postoperative cardiac or neurologic complications. BVF may be formed during lung transplantation because lung transplantation recipients often receive high-airway-pressure ventilation and are vulnerable to bronchi and pulmonary vessel injuries during surgery. Intraoperative TEE can contribute to the early detection of air bubbles in the left heart circulation and is helpful for the prevention of arterial gas embolism. [ABSTRACT FROM AUTHOR]

Decompression illness (DCI) describes a syndrome complex caused by inert gas bubbles generated by an inappropriate rate of reduction in ambient environmental pressure or decompression. This “umbrella term” covers both traditional decompression sickness caused by in-situ bubble formation from dissolved inert gas and arterial gas embolism (AGE), in which alveolar gas or venous gas emboli (via shunts or by-passing pulmonary vessels) are introduced into arterial circulation. DCI occurs in divers, compressed air workers, aviators, and astronauts, but AGE could also arise from iatrogenic causes unrelated to decompression. A hundred years ago, serious manifestations and deaths were frequent in divers and caisson workers due to DCI, but they decreased greatly when decompression stops were introduced in diving practice. This review article is of interest to the doctors who face the dilemma of treating the rare syndrome of DCI that could present in the clinical spectrum ranging from itching and minor pain to severe neurological symptoms or other systemic pathology. The first aid lies in the administration of 100% oxygen, and definitive treatment is therapeutic recompression. With appropriate and adequate treatment, recovery is complete, but some severe cases may have lifelong residual deficits, even after extended and multiple recompressions.

Introduction: The Geneva hyperbaric chamber is the main treatment centre for decompression illness (DCI) in Switzerland. The characteristics, symptomatology, treatment and short-term outcome of divers treated at this chamber have not previously been investigated. Methods: This was a retrospective study of patients treated with hyperbaric oxygen (HBO) for DCI from 2010 to 2016. Data were analysed to provide a description of the cases and statistical analysis for possible factors associated with an unfavourable outcome. Results: One hundred and thirty-five patients were treated for DCI. Ninety-two were included in the study. Sixty-four presented with neurological and 28 with mild DCI. One hundred and thirty-five patients were treated for DCI. Ninety-two were included in the study. Sixty-four presented with neurological and 28 with mild DCI. Patients with mild DCI mainly had musculoskeletal symptoms (79%). Patients with neurological DCI mainly had spinal (55%), followed by vestibular (36%) symptoms. Arterial gas embolism was diagnosed in 30% of cases. Diving depths ranged between 15 and 142 metres, and dive times between two and 241 min. Median time to treatment was 6 h. Patients with neurological DCI had a high rate (25%) of persisting deficits after treatment. Older age was associated with an unfavourable outcome in univariate but not in multivariate analysis. No adverse effects of HBO were observed. For spinal DCI, a high Boussuges score was associated with persisting deficits after treatment. Conclusions: Our findings are consistent with other series. Severe DCI was associated with a high rate of persisting deficits. No single factor was associated with a negative outcome. A Boussuges score > 7 had sensitivity of 90% and positive predictive value 53% for predicting an unfavourable outcome in spinal DCI. [ABSTRACT FROM AUTHOR]

A diver practicing controlled emergency ascent training on the island of Guam suffered bilateral pneumothorax, pneumo-mediastinum, coronary arterial gas embolism, and developed multiple organ dysfunction syndrome. Due to limitations of available resources he was medically managed in the intensive care unit until he could be transferred to University of California San Diego for definitive management. We provide an account of our management of the patient, the pathophysiology of injury as well as a review of the safety of recreational diving skills training, current standards of practice and potential pitfalls when considering proper management of a critically injured diver. [ABSTRACT FROM AUTHOR]

Introduction: We aimed to identify the possible chain of events leading to fatal scuba diving incidents in Australia from 2001–2013 to inform appropriate countermeasures. Methods: The National Coronial Information System was searched to identify scuba diving-related deaths from 2001–2013, inclusive. Coronial findings, witness and police reports, medical histories and autopsies, toxicology and equipment reports were scrutinised. These were analysed for predisposing factors, triggers, disabling agents, disabling injuries and causes of death using a validated template. Results: There were 126 known scuba diving fatalities and 189 predisposing factors were identified, the major being health conditions (59; 47%), organisational/training/experience/skills issues (46; 37%), planning shortcomings (29; 23%) and equipment inadequacies (24; 19%). The 138 suspected triggers included environmental (68; 54%), exertion (23; 18%) and gas supply problems (15; 12%) among others. The 121 identified disabling agents included medical-related (48; 38%), ascent-related (21; 17%), poor buoyancy control (18; 14%), gas supply (17; 13%), environmental (13; 10%) and equipment (4; 3%). The main disabling injuries were asphyxia (37%), cardiac (25%) and cerebral arterial gas embolism/pulmonary barotrauma (15%). Conclusions: Chronic medical conditions, predominantly cardiac-related, are a major contributor to diving incidents. Divers with such conditions and/or older divers should undergo thorough fitness-to-dive assessments. Appropriate local knowledge, planning and monitoring are important to minimise the potential for incidents triggered by adverse environmental conditions, most of which involve inexperienced divers. Chain of events analysis should increase understanding of diving incidents and has the potential to reduce morbidity and mortality in divers. [ABSTRACT FROM AUTHOR]

Decompression illness in breath‐hold diving is a rare dysbaric disease mainly characterized by stroke‐like neurological disorders. The early use of DWI‐MRI combined with ADC map in suspected cases can help in the early diagnosis and treatment. [ABSTRACT FROM AUTHOR]

A 30-year-old female with a history of seizure disorder and hypoplastic left heart syndrome treated with a Norwood procedure in 1986 followed by a modified non-fenestrated Fontan (Left SVC to IVC to pulmonary arteries) with a known baffle leak presented to the emergency department. On day of presentation, the patient became unresponsive, with perioral cyanosis, rightward gaze and a left facial droop near the end of a platelet transfusion. An emergent non-contrast head CT revealed intracranial air in the right MCA distribution. She was taken to the hyperbaric chamber and was treated with a U.S. Navy Table 6 in a multiplace chamber with no extensions. Ten minutes into the treatment patient became more alert and spontaneously asked questions. The following day she was treated with a U.S. Navy Table 5. Patient had repeat CT of the head, which showed resolution of intracerebral gas and small areas of ischemia in right frontal lobe and right caudate. On hospital day five neurologic exam was normal, with 5/5 strength and no residual deficits. Treating the patient was a concern because patient has a single ventricle, in which the pulmonary artery is connected directly to the vena cava. There is very little data regarding the effects of hyperbaric oxygen (HBO2)therapy on single-ventricle physiology. Only two case reports of three pediatric patients treated with HBO2 for CAGE in a similar setting are known. In these cases the patients had improvements in their symptoms following HBO2. These cases and ours indicate HBO2 is feasible and indicated for CAGE in patients with cyanotic congenital heart disease. [ABSTRACT FROM AUTHOR]

Introduction Arterial gas embolism (AGE) is a rare but severe complication of scuba diving. While AGE is most commonly encountered in coastal areas with high volumes of recreational divers, at-risk populations exist throughout the United States, making basic knowledge of the disease important for all emergency medicine (EM) physicians. Methods We used a hypothetical simulation case to train EM residents on diagnosis and management of AGE. A 32-year-old male presented with shortness of breath and unilateral neurologic deficits immediately after scuba diving. Residents were challenged to emergently diagnose and treat tension pneumothorax followed by diagnosis and treatment of AGE. A resident, attending, and simulation technician ran the case for four separate simulation teams in the simulation center with the addition of chest tube supplies to the basic resuscitation bay setup. Teams were allowed to use the internet in real time as a reference tool. Results Most teams arrived at the correct diagnosis using real-time internet searches, but none found the Divers Alert Network Emergency Hotline. Learners were debriefed both immediately and in a formal lecture. A follow-up survey showed good retention of knowledge. Discussion This case fills a significant knowledge and training gap for many EM physicians. AGE is a rare but highly morbid complication of diving, and EM residents should have knowledge of the disease and available consultation resources. Most EM residents will not have the opportunity to treat a diver during training, and the simulation environment provides a means to teach and practice this skill set.

Background: Arterial gas embolus (AGE) is a rare complication of esophagoduodenoscopy (EGD) that has been described in only a few case reports in the literature. The exact etiology remains unknown, but many of the cases share some common characteristics.Case Report: We report the case of a 52-year-old otherwise healthy man who underwent outpatient EGD for a sensation of retained food in his esophagus. During the procedure, he suffered a tonic-clonic seizure, bradycardia, and hypoxia. Subsequent emergency department workup showed pneumocephalus on computed tomography brain imaging, and he was diagnosed with a cerebral AGE (CAGE). He was transferred to our facility for treatment of CAGE with hyperbaric oxygen therapy (HBOT). After multiple hyperbaric treatments, he was discharged with a residual left hemiparesis, which represented a significant improvement in his overall neurologic status. We also present a review of similar EGD CAGE cases from the literature and discuss their outcomes and the need for HBOT. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although CAGE from EGD is rare, these patients will often be transferred to the ED from gastrointestinal procedural suites and an emergency physician should understand that an iatrogenic CAGE can result from this procedure and that CAGE is a clinical diagnosis. Definitive care at a critical care-capable hyperbaric chamber will provide the patient with the best chance of meaningful recovery, and transport should be arranged as expeditiously as possible. [ABSTRACT FROM AUTHOR]

Background: Metal phosphides are widely used as a rodenticide and insecticide and poisoning with these substances has a very high mortality. The aim of this study was to evaluate the butyrylcholinesterase (BuCh) level in poisoning with metal phosphides. Methods: In this case series study, 60 poisoned patients with zinc phosphide (ZnP) and aluminum phosphide (ALP) who was admitted to poisoning ward in Hamadan, Iran, enrolled in the study and BuCh level was measured. The sex, age, amount of ingestion, time of consumption, signs and symptoms, ECG and arterial blood gas (ABG) changes and clinical outcomes were evaluated. Results: Most (58.3%) patients were males, the mean age was 32.76±17.65 years. The average amount of ingestion was 7.5±4.6 and 2.5±2.96 gr for ZnP and ALP, respectively. Most signs and symptoms were hypotension (97%), nausea and vomiting (82%) and abdominal pain (32%). The average amount of BuCh level in all patients was 5163.25±2158.31 U/L, that's while in ZnP and ALP poisoned patients was 5608±1577 U/L and 4721.46±2562U/L respectively. The most dysrhythmia (26.7%) was sinus tachycardia. Acidosis was seen in 33.3% of patients. 14 patients died after hospital admission, which caused a 23.3% fatality rate. Conclusion: Our results showed that, there was no significant change in BuCh level in poisoned patients with phosphide compounds. [ABSTRACT FROM AUTHOR]

A 43-year-old female scuba diver was retrieved and treated following a rapid ascent and presumed cerebral arterial gas embolism (CAGE). She subsequently developed respiratory distress and was found to have Takotsubo cardiomyopathy, with transient left ventricular dysfunction, elevated cardiac enzymes, and normal CT coronary angiography. We believe this to be the first report of CAGE associated with Takotsubo cardiomyopathy. [ABSTRACT FROM AUTHOR]

Gas can enter arteries (arterial gas embolism, AGE) due to alveolar-capillary disruption (caused by pulmonary over-pressurization, e.g. breath-hold ascent by divers) or 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 patient 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 then 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. [ABSTRACT FROM AUTHOR]

Iatrogenic arterial gas embolism (AGE) can be life-threatening. The only causal treatment is immediate hyperbaric oxygen therapy (HBOT). This article reports on a case of a 74-year-old male patient who underwent computed tomography (CT)-guided lung biopsy of suspect nodules after squamous cell carcinoma of the tonsils. During puncture, sudden cardiovascular arrest occurred. The CT scan documented severe arterial gas embolism in the aorta, spinal canal, left heart ventricle, and brain. The patient was then transferred to our hospital for HBOT. After the first HBOT, an additional CT scan showed regression of all gas inclusions. In the treatment of gas embolism, HBOT is considered the gold standard and is indispensable. It is primarily used to reduce acute bubble effects and to avoid secondary bubble effects. Unfortunately, the long persisting gas occlusions and perfusion deficits led to severe hypoxic brain damage and a poor prognosis for the patient. In this case report we present the management of (iatrogenic) arterial gas embolism and point out the necessity of immediate HBOT. Furthermore, we discuss the pathophysiology leading to arterial gas embolism on the basis of the gas laws. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 rescued to surface without waiting for clonic seizures to subside. Training organizations for recreational and occupational divers should consider whether this guidance should be applied for civilian divers as well. [ABSTRACT FROM AUTHOR]

Middle ear barotrauma is common in diving. However, facial nerve baroparesis is a relatively rare complication. A dehiscent facial nerve canal may be a predisposing factor to developing this complication. Although there is an increasing number of facial baroparesis cases in the literature, they are likely still under-reported. In order to avoid unnecessary recompression treatments or detrimental effects to a professional diver's career, it is important to consider this in the differential diagnosis while evaluating dive injuries. This case report describes recurrent facial baroparesis in a military diver, which manifested on contralateral sides of his face. His initial presentation was misdiagnosed as an arterial gas embolism, which led to recompression treatment and a cardiac procedure. Upon recurrence about one year later, a complete work-up was done, which included an ENT evaluation and a CT scan. Imaging demonstrated a predisposing anatomic variant bilaterally. His symptoms resolved quickly and spontaneously both times, and he has been able to return to diving. [ABSTRACT FROM AUTHOR]

BACKGROUND: Decompression sickness is a condition th a t results from an abrupt change from a higher to a lower pressure. It is described most commonly in divers; however, it can occur in aviation incidents, which this case report will discuss. CASE REPORT: Following an acute cabin depressurization incident, 36 patients presented to a small outpatient clinic with multiple symptoms, including fatigue, headache, nausea, vomiting, and dizziness. These patients were evaluated, triaged, and some were able to be successfully treated with supplemental oxygen in clinic. Eight of the patients had symptoms that were either persistent or concerning enough that they were referred to the dive medical clinic, where the dive medical team diagnosed six of the patients with Type II decompression sickness and referred them for hyperbaric oxygen chamber therapy. All patients who received hyperbaric therapy experienced at least some relief of symptoms, with most reporting some residual fatigue after the therapy. DISCUSSION: This case provided both lessons in triage and management of multiple patients in a small outpatient clinic, as well as the challenges in making the diagnosis of decompression sickness. [ABSTRACT FROM AUTHOR]

Introduction: Drowning is likely to result from impairment of consciousness when scuba diving. Causes include toxic effects of breathing gas, including nitrogen narcosis and oxygen toxicity, and arterial gas embolism. Methods: Review of the medical records of scuba divers who had impaired consciousness underwater that could not be attributed to toxic effects of breathing gas or arterial gas embolism. Results: Four scuba divers had episodes of impaired consciousness when at shallow depths (8−18 m) underwater. The descriptions of the episodes were very similar. Three had histories of recurrent episodes of vasovagal syncope on land. Conclusions: Absence of other causes for their impaired consciousness underwater leads to the conclusion that the probable cause was vasovagal syncope. [ABSTRACT FROM AUTHOR]

A 75 year-old male developed features of an acute stroke following bubble contrast echocardiography, which was shown on emergent computed tomography scanning to be a result of cerebral arterial gas embolism (CAGE) to the left middle cerebral artery. Ischaemic stroke symptoms have previously been reported as a rare complication of bubble contrast echocardiography. Radiologically proven CAGE from bubble contrast echocardiography had not been reported at the time this case occurred. Immediate provision of 100% oxygen and administration of hyperbaric oxygen are recommended treatments for CAGE and were associated with a substantial recovery for this patient. [ABSTRACT FROM AUTHOR]

Arterial gas embolism (AGE) may result when diving while breathing compressed gas and ascending rapidly or with a closed glottis. Pulmonary over-pressurisation can result in lung stretch injury with entry of bubbles into the pulmonary venous circulation and subsequently the systemic arterial circulation. We present the case of an individual who suffered AGE while breathing compressed air at 1.2 metres’ fresh water (mfw) in a swimming pool and discuss the factors determining the depth at which this form of injury may occur. This case serves to underscore the fact that risk of AGE exists at shallow depths. [ABSTRACT FROM AUTHOR]

Onshore diving operations are often carried out in remote areas with poor or nil medical assistance available at site. Diving crew also tends to be poorly trained and inexperienced. As a result, initially, diving accident cases get treated symptomatically, till proper diagnosis is established and therapeutic recompression carried out after a considerable delay. Pulmonary barotrauma, lung burst, leading to Arterial Gas Embolism ( AGE) and its dreadful effects is a known complication of diving especially amongst novice divers. A case report of embolism in both Anterior Cerebral Artery and Posterior Inferior Cerebellar Artery (ACA and PICA) distribution with successful delayed hyperbaric oxygen treatment ( HBOT)

INTRODUCTION: Because a significant association between training to perform emergency free ascent (EFA) and the occurrence of pulmonary barotrauma (PBT) was demonstrated in 2006, the Belgian Underwater Federation (BUF) decided to discontinue this procedure. An evaluation was needed 10 yr after the implementation of this change. METHODS: All medical records with a diagnosis of PBT that occurred in Belgium from November 2006 to September 2016 were prospectively collected. Data on the proportion of in-water skills training dives were obtained from BUF. RESULTS: A total of 5 cases of PBT were identified, significantly down from 34 cases in the previous 10-yr period. Of those cases, four occurred during training dives (two during ascent training). Analysis of the case files furthermore showed that two should have been medically disqualified from diving. Compared with the retrospective cohort (1995-2005), incidences are significantly reduced from 0.83 to 0.078/10,000 training dives and from 3.33 to 0.11/10,000 ascent-training dives; concomitantly, the incidence of PBT in nontraining dives also was reduced (from 0.0042 to 0.0014X10-4 4/10,000 dives), possibly because less divers undertake the EFA procedure in case of a technical incident and have learned to solve the problem differently. DISCUSSION: Discontinuation of emergency free ascent training was associated with a reduction in the incidence of PBT in the 10-yr follow-up period. We observed a significant decrease of PBT during training dives, confirming the hypothesis that EFA training in its previous form did not contribute significantly to diving safety. [ABSTRACT FROM AUTHOR]

Guidelines for the pre-hospital management of decompression illness (DCI) had not been formally revised since the 2004 Divers Alert Network/Undersea and Hyperbaric Medical Society workshop held in Sydney, entitled "Management of mild or marginal decompression illness in remote locations." A contemporary review was initiated by the Divers Alert Network and undertaken by a multinational committee with members from Australasia, the USA and Europe. The process began with literature reviews by designated committee members on: the diagnosis of DCI; first aid strategies for DCI; remote triage of possible DCI victims by diving medicine experts; evacuation of DCI victims; effect of delay to recompression in DCI; pitfalls in management when DCI victims present at hospitals without diving medicine expertise and in-water recompression. This was followed by presentation of those reviews at a dedicated workshop at the 2017 UHMS Annual Scientific Meeting, discussion by registrants at that workshop and, finally, several committee meetings to formulate statements addressing points considered of prime importance to the management of DCI in the field. The committee placed particular emphasis on resolving controversies around the definition of "mild DCI" arising over 12 years of practical application of the 2004 workshop's findings, and on the controversial issue of in-water recompression. The guideline statements are promulgated in this paper. The full workshop proceedings are in preparation for publication. [ABSTRACT FROM AUTHOR]