Diving emergencies

Injuries and medical emergencies among international travellers

BACKGROUND

Tropical infectious diseases and vaccine-preventable emergencies are the mainstay of pre-travel consultations. However, non-communicable diseases, injuries and accidents that occur during travel are not emphasized enough in these settings.

METHODS

We performed a narrative review based on a literature search of PubMed, Google Scholar, UpToDate, DynaMed and LiSSa and on reference textbooks and medical journals dedicated to travel, emergency and wilderness medicine. Relevant secondary references were extracted. We also aimed to discuss newer or neglected issues, such as medical tourism, Coronavirus Disease 2019, exacerbations of co-morbidities associated with international travel, insurance coverage, health care seeking abroad, medical evacuation or repatriation and tips for different types of travellers' emergency medical kits (personal, group, physician handled).

RESULTS

All sources reviewed led to the selection of >170 references. Among epidemiological data on morbidity and deaths while abroad, only retrospective data are available. Deaths are estimated to occur in 1 in 100 000 travellers, with 40% caused by trauma and 60% by diseases, and <3% linked to infectious diseases. Trauma and other injuries acquired during travel, such as traffic accidents and drowning, can be reduced by up to 85% with simple preventive recommendations such as avoiding simultaneous alcohol intake. In-flight emergencies occur on 1 in 604 flights on average. Thrombosis risk is two to three times greater for travellers than for non-travellers. Fever during or after travel can occur in 2-4% of travellers, but in up to 25-30% in tertiary centres. Traveller's diarrhoea, although rarely severe, is the most common disease associated with travel. Autochthonous emergencies (acute appendicitis, ectopic pregnancy, dental abscess) can also occur.

CONCLUSIONS

Pre-travel medicine encounters must include the topic of injuries and medical emergencies, such as the risk-taking behaviours and foster better planning in a comprehensive approach along with vaccines and infectious diseases advices.

Case report: tracheobronchial diverticulum, a potential risk for diving?

Tracheobronchial diverticulum (TBD) is an asymptomatic, benign cystic lesion outside the lumen of the trachea and bronchus. This is the first report case of a SCUBA (self contained underwater breathing apparatus) diver diagnosed with TBD, which is a potential risk to diving. No literature or guideline is available so far on the diving fitness for patients with congenital or acquired TBD condition. A healthy 26-year-old male professional diver has records of SCUBA diving up to a depth of 40 meters sea water. He did not have any diving-related injuries or symptoms during his career and had no history of smoking, drinking, or other special illnesses except for a COVID-19 infection. A tracheal diverticulum was found accidentally by computed tomography (CT), but its communication with the trachea was not clear initially. Therefore, high-resolution CT and electronic bronchoscopy were done to clarify the situation of the diverticulum and identify the diving risk. High-resolution CT showed a possible opening in the diverticulum, but this was not seen under electronic bronchoscopy. Although a potential opening was shown in high-resolution CT, the lack of visual bronchoscopic evidence made it likely to be a dead cavity. As there is a higher theoretical risk of barotrauma during decompression, leading to pneumomediastinum, hemorrhage, or arterial gas embolism, the current clinical consensus is that air-containing tissue should be regarded as a relative contraindication for diving. Overall, it is recommended that the diver should dive carefully and avoid ascending too rapidly.

Bilateral pneumatic blowout fractures in a patient with silent sinus syndrome while diving

A 37-year-old scuba diver developed sudden severe headache, mid-facial pressure/pain and diplopia while diving. Upon examination, he had signs and symptoms consistent with silent sinus syndrome (SSS), including bilateral enophthalmos, hypoglobus, and diplopia/strabismus in conjunction with CT findings of occluded maxillary sinus ostia, atrophic/collapsed maxillary sinuses, and bilateral orbital floor fractures with fat herniation. As there was no history of trauma or chronic sinusitis, this rare case of bilateral SSS was deemed the cause of the spontaneous fractures (i.e. barotrauma secondary to a lack of equalization to ambient surrounding pressure). Transconjunctival repair of the fractures was successful and maxillary sinus antrostomies re-established aeration of the sinuses. We present this case and its management, as well as review the literature concerning sinus barotrauma as a result of diving and SSS. There have been no reports of orbital fractures primarily caused by scuba diving, nor secondarily from diving with the rare entity, SSS.

The management of patent foramen ovale in divers: where do we stand?

Diving is a fascinating activity, but it does not come without any cost; decompression illness (DCI) is one of the most frequent diseases occurring in divers. Rapid surfacing after diving causes alveolar rupture and bubbles release, which enter in the systemic circulation and could embolize numerous organs and tissues. The presence of patent foramen ovale (PFO) contributes to the passage of venous gas bubbles into the arterial circulation, increasing the risk of complications related to DCI. The diagnosis is established with a detailed medical history, a comprehensive clinical evaluation, and a multimodal imaging approach. Although the percutaneous closure of PFO is ambiguous for divers, as a primary prevention strategy, transcatheter management is considered as beneficial for DCI recurrence prevention. The aim of this study is to introduce the basic principles of DCI, to review the pathophysiological connection between DCI and PFO, to highlight the risk factors and the optimal treatment, and, last but not least, to shed light on the role of closure as primary and secondary prevention.

Latent Class Analysis of Decompression Sickness Symptoms of Women Divers

This study aimed to investigate the types of clinical manifestations of decompression sickness among women divers (haenyeos) in Jeju using latent class analysis and to identify factors related to the condition. A total of 527 haenyeos who received their certification in diving fishery from Jeju and were working from 15 March to 31 May 2021 were included in this study. According to the results of the study, the latent classes were classified into type 1, type 2, and mixed symptoms groups (Akaike information criterion (AIC) = 6587.29, Bayesian information criterion (BIC) = 6698.23, sample size-adjusted BIC (saBIC) = 6615.70). For personal characteristics, age (χ2 = 40.31, p < 0.001) and education level (χ2 = 28.15, p < 0.001) showed a significant difference by latent class type. For work-related characteristics, diving experience (χ2 = 29.99, p < 0.001) and break time (χ2 = 9.32, p = 0.011) showed a significant difference by latent class type. The health-related characteristics, menopausal period (χ2 = 40.10, p < 0.001), body mass index (χ2 = 14.80, p = 0.013), and fatigue level (χ2 = 58.23, p < 0.001), showed a significant difference by latent class type. Rather than approaching the management of work-related diseases simply from the work environment perspective, it is important to increase the availability of health professionals who are capable of continuous health monitoring and management of women divers in their workplace.

SCUBA Diver's Knee: A Case Report

ABSTRACT

With more than 9 million recreational certified self-contained underwater breathing apparatus divers in the United States, clinicians should be aware of the unique diving-related injuries. One of the most common diving-related injuries is type 1 decompression sickness, or "the bends." The bends commonly manifest as localized joint pain, most often occurring within 24 h of surfacing and resolving over the following 1 to 2 d. We report a unique case of a patient who experienced an exacerbation of musculoskeletal joint pain following initial recovery. This 35-year-old man had nearly complete resolution of his joint pain following the bends, then developed severe right knee pain with swelling after a high-volume lower body workout. Following unremarkable imaging and unsuccessful conservative treatment, ultrasound-guided aspiration of his right knee was performed, which resolved the patient's symptoms. This case highlights a unique presentation of the bends and demonstrates a potentially beneficial treatment if recurrence of the bends is suspected.

Into the deep blue sea: A review of the safety of recreational diving in people with diabetes mellitus

People with diabetes, particularly those being insulin treated, have been for many years considered ineligible for diving, because of the high risk of adverse events. Blood glucose levels tend to decline during diving, probably because of changes in insulin requirements and resistance, due to increased physical activity and effects of hyperbaric environment on glucose tolerance. Strict adherence to safety protocols, in conjunction with optimal physical status, lack of diabetic complications (especially impaired awareness of hypoglycaemia) and satisfactory baseline glycaemic control, seem to minimise the risk of complications during diving. The integration of modern technology into diabetes management, providing potential for underwater continuous glucose monitoring, can be useful in optimising metabolic control before, during and after diving. Despite the significant progress been made on safety issues, there is still a need to implement the relevant recommendations into divers' everyday practice. Existing evidence is mainly derived from small studies and there is a wide heterogeneity in terms of study designs and explored outcomes, rendering the extraction of definitive conclusions challenging. The aim of this review is to present and critically evaluate available evidence, use of technology, and gaps in existing knowledge that deserve further evaluation by future studies.

Development of Rope Connected Life-Saving Equipment for Transferring Numerous People

BACKGROUND

This study is focused on a rapid and safe transfer when there are many people who need rescuing in unapproachable location. Generally, a stretcher, a basket or a mesh drawing is used to transfer injured people or survivors in the emergency rescue, however, it turned out that it takes long time to transfer a number of people with a stretcher and it is difficult to transfer injured people safely with a basket or a mesh drawing. It would expect to transfer many people who need rescuing promptly and harmlessly.

METHODS

In this article, Targeted Acceptable Responses to Generated Events of Tasks (TARGETS), an event-based team performance measurement methodology was used to investigate the effects of Mission Oriented Protective Posture (MOPP) on the behavioral processes underlying team performance during simulated rescue tasks while wearing chemical protective equipment. In addition, this study determined which team processes were related to team performance outcomes. Results of six primary analyses indicated that team process performance was not degraded by MOPP 4 on any rescue task and that the team processes critical for successful task performance are task-dependent.

RESULTS

As a result, authors have developed a new life-saving equipment. Numerous people who need rescuing can be quickly and safely rescued and transferred to the hospital with it. From a medical point of view, it reduces the risk of secondary damage from transport and helps avoid missing the golden time for first aid caused by delay in transferring emergency patients as numerous people can be transferred safely and quickly.

CONCLUSION

The article is due to introduce the equipment which can transfer people who need rescuing promptly and effectively in a situation such as when numerous people need rescuing in the mountain. In a rescue situation such as mountain rescue, rope connected life-saving equipment is dropped to the rescue site with a rope from a rescue helicopter and laying down the injured on the life-saving equipment body and equip life-saving equipment to the rope consecutively. In this way, it is expected to transfer the injured rapidly and safely.

Highs and lows of hyperoxia: physiological, performance, and clinical aspects

Molecular oxygen (O₂) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O₂ delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the "bench to bedside." The first section will focus on the basic physiological principles of partial pressure of arterial O₂, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O₂ delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O₂ toxicity and future research directions are also considered.

Severe Decompression Illness: Case Report, Prehospital Recognition, and Regional Transport Considerations

A 46-year-old male presented to our tertiary care emergency department (ED) with shortness of breath and chest pain following an uneventful four-hour SCUBA dive at 100 feet. His prehospital emergency medical services (EMS) assessment revealed transient hypotension and hypoxia. He later developed progressive skin mottling. Serology was significant for acute kidney injury, transaminitis, hemoconcentration, and hypoxia on an arterial blood gas. Computed tomography (CT) angiography demonstrated intravascular gas throughout the mesenteric and pulmonary arteries as well as the portal venous system. No abnormality was seen on head CT and the patient had normal mental status. Prehospital nonrebreather oxygen therapy was changed to continuous positive airway pressure (CPAP) upon ED arrival, and the patient was intubated prior to transfer to a hyperbaric facility. However, within 24 hours the patient was found to have multiorgan failure, diffuse cerebral edema, and brain death despite no further episodes of hypotension or hypoxia. No intracranial gas was seen on repeat head CT. Our case demonstrates the importance of early recognition of decompression illness by EMS personnel, consideration of ground versus flight transportation of these patients to the nearest hyperbaric center, and the possible use of prehospital CPAP as an alternative to enhance oxygenation.

Scary gas: intravascular, intracranial, and intraspinal ectopic gas (part III)

While ectopic gas can be a sign of dangerous disease requiring immediate medical or surgical intervention, it can also be an incidental and benign finding. Intravenous gas and spinal vacuum gas are common and almost always benign. Intravascular gas is most often related to instrumentation and, if intraarticular, can cause end-organ ischemia; however, treatment is usually supportive. Pneumocephalus arises from a communication with paranasal sinuses or mastoids more often than from meningeal infection and can usually be managed nonoperatively. In part 3 of this series, the different causes of ectopic gas in the vessels, skull, and spine are reviewed, as are the imaging features that can help to narrow the differential diagnosis.

Neurologic Deep Dive: A Simulation Case of Diagnosing and Treating Decompression Sickness for Emergency Medicine Residents

INTRODUCTION

Decompression sickness (DCS) is a rare and dangerous complication from a rapid decrease in environmental pressure, commonly seen in patients leaving a compressed-air environment, such as scuba divers, aviators, and deep tunnel workers. Failure to clinically diagnose and adequately treat DCS with hydration and supplemental oxygen before bridging to hyperbaric oxygen (HBO) therapy can result in permanent residual symptoms or, in rare cases, death. Despite the increasing incidence of DCS, there are limited published simulation case studies discussing this perilous environmental exposure.

METHODS

This fictional simulation case is written for emergency medicine residents to diagnose and manage DCS from a live-actor patient presenting with unilateral neurologic symptoms and concealed cyanotic mottling (cutis marmorata). This case ran for four separate iterations at a simulation center, with a resident, fellow, and attending acting as specific confederates for their respective roles. Following each case, the learners were debriefed at bedside, discussed a PowerPoint presentation, and underwent a question-and-answer session.

RESULTS

Based on postsimulation qualitative assessments, junior and senior residents correctly identified DCS, but junior residents alone were less likely to elicit pertinent social history or to fully physically examine the patient without the presence of senior residents. Both resident groups were able to verbally explain the fundamental DCS pathophysiology to the patient, but junior residents were unable to specifically direct oxygenation, hydration, and HBO protocols for DCS. After case completion and debriefing, all learners demonstrated achievement of primary learning objectives.

DISCUSSION

Overall, we noted this case worked well for junior EM residents with senior-resident backup. Both learner groups appreciated the concealed elements of case, including scuba diving history and exposed dermatologic findings, and reported that these were invaluable learning moments for all future patient encounters, not just those limited to DCS.

Lesson of the month 1: A review of a diving emergency

Physicians should consider barotrauma and decompression illness (DCI) in any patient presenting after a recent scuba dive, even apparently shallow dives. If and when DCI is suspected, clinicians should act without delay to transfer the patient to a recompression facility, even if diagnostic certainty has not been attained. We present a case of hyperbaric injury in an asthmatic woman who had an atypical presentation in view of the depth of dive.

Neurologic emergencies in sports

PURPOSE OF REVIEW

Sports neurology is an emerging area of subspecialty. Neurologists and non-neurologists evaluating and managing individuals participating in sports will encounter emergencies that directly or indirectly involve the nervous system. Since the primary specialty of sports medicine physicians and other practitioners involved in the delivery of medical care to athletes in emergency situations varies significantly, experience in recognition and management of neurologic emergencies in sports will vary as well. This article provides a review of information and elements essential to neurologic emergencies in sports for the practicing neurologist, although content may be of benefit to readers of varying background and expertise.

RECENT FINDINGS

Both common neurologic emergencies and less common but noteworthy neurologic emergencies are reviewed in this article. Issues that are fairly unique to sports participation are highlighted in this review. General concepts and principles related to treatment of neurologic emergencies that are often encountered unrelated to sports (eg, recognition and treatment of status epilepticus, increased intracranial pressure) are discussed but are not the focus of this article. Neurologic emergencies can involve any region of the nervous system (eg, brain, spine/spinal cord, peripheral nerves, muscles). In addition to neurologic emergencies that represent direct sports-related neurologic complications, indirect (systemic and generalized) sports-related emergencies with significant neurologic consequences can occur and are also discussed in this article.

SUMMARY

Neurologists and others involved in the care of athletes should consider neurologic emergencies in sports when planning and providing medical care.

Memory and metacognition in dangerous situations: investigating cognitive impairment from gas narcosis in undersea divers

OBJECTIVE

The current study tested whether undersea divers are able to accurately judge their level of memory impairment from inert gas narcosis.

BACKGROUND

Inert gas narcosis causes a number of cognitive impairments, including a decrement in memory ability. Undersea divers may be unable to accurately judge their level of impairment, affecting safety and work performance.

METHOD

In two underwater field experiments, performance decrements on tests of memory at 33 to 42 m were compared with self-ratings of impairment and resolution. The effect of depth (shallow [I-II m] vs. deep [33-42 m]) was measured on free-recall (Experiment I; n = 41) and cued-recall (Experiment 2; n = 39) performance, a visual-analogue self-assessment rating of narcotic impairment, and the accuracy of judgements-of-learning JOLs).

RESULTS

Both free- and cued-recall were significantly reduced in deep, compared to shallow, conditions. This decrement was accompanied by an increase in self-assessed impairment. In contrast, resolution (based on JOLs) remained unaffected by depth. The dissociation of memory accuracy and resolution, coupled with a shift in a self-assessment of impairment, indicated that divers were able to accurately judge their decrease in memory performance at depth.

CONCLUSION

These findings suggest that impaired self-assessment and resolution may not actually be a symptom of narcosis in the depth range of 33 to 42 m underwater and that the divers in this study were better equipped to manage narcosis than prior literature suggested. The results are discussed in relation to implications for diver safety and work performance.

Effect of pre-breathing oxygen at different depth on oxidative status and calcium concentration in lymphocytes of scuba divers

AIM

In-water pre-breathing oxygen at various depths reduces decompression-induced bubble formation and platelet activation, but it could induce side effects such as oxidative stress. The aim of this study was to investigate the effect of in-water pre-breathing oxygen, at different depths, on the oxidative status and intracellular calcium ([Ca(2+) ]i) of peripheral blood lymphocytes isolated from six divers. They participated in a 4-diving protocol. Two week recovery time was allowed between successive dives. Before diving, all divers, for 20 min, breathed normally at sea level (dive 1), 100% oxygen at sea level (dive 2), 100% oxygen at 6 msw (dive 3), 100% oxygen at 12 msw (dive 4). Then they dived to 30 msw for 20 min with air tank.

METHODS

Blood samples were collected before and after each dive. Hydrogen peroxide (H(2) O(2) ) levels, catalase (CAT) activity, mRNA expression of CAT, glutathione peroxidase (GPx) and superoxide dismutase (SOD), and the [Ca(2+) ]i in lymphocytes were measured.

RESULTS

The dives slightly decreased lymphocyte number and significantly reduced lymphocyte H(2) O(2) levels. CAT activity was higher after scuba diving and, dive 3 enhanced mRNA gene expression of CAT, GPx and SOD. The [Ca(2+) ]i was higher after dive 1 and 2 than pre-diving, while was maintained at pre-diving value after dive 3 and 4.

CONCLUSION

Our results suggest that pre-breathing oxygen, in particular at 12 msw, may enhance lymphocyte antioxidant activity and reduce reactive oxygen species levels. Pre-breathing oxygen in water may also preserve calcium homeostasis, suggesting a protective role in the physiological lymphocyte cell functions.

Acute ischemic colitis secondary to air embolism after diving

Ischemic colitis (IC) secondary to air embolism from decompression sickness or barotrauma during diving is an extremely rare condition. After extensive review of the available literature, we found that there has been only one reported case of IC secondary to air embolism from diving. Although air embolization from diving and the various medical complications that follow have been well documented, the clinical manifestation of IC from an air embolism during diving is very rare and thus far unstudied. Common symptoms of IC include abdominal pain, bloody or non-bloody diarrhea or nausea or vomiting or any combination. Emergency physicians and Critical Care specialists should consider IC as a potential diagnosis for a patient with the above-mentioned symptoms and a history of recent diving. We report a case of IC from air embolism after a routine dive to 75 feet below sea level in a 53-year-old White female who presented to a community Emergency Department complaining of a 2-day history of diffuse abdominal pain and nausea. She was diagnosed by colonoscopy with biopsies and treated conservatively with antibiotics, bowel rest, and a slow advancement in diet.

First aid kits for recreational dive boats, what should they contain?

BACKGROUND

Well-equipped first-aid kits are necessary but not always provided on recreational dive boats. We aimed to review the types of illness and injury likely to be encountered on such boats and inform a content list for such kits.

METHOD

We conducted a 3-round Delphi study by email using a volunteer panel of 18 experts drawn from diving, dive medicine and nursing. In round 1, panellists shared examples of illnesses and injuries they had come across personally. These scenarios were circulated along with findings from a literature review, including existing recommendations. In rounds 2 and 3, the list of kit for dive boats in different settings was iteratively refined through online discussion and feedback.

MAIN FINDINGS

Passengers and crew on recreational dive boats may encounter a range of medical problems from minor injuries to serious accidents and non-dive-related illnesses. Recommended kit varied depending on context and setting (e.g. distance from land, qualifications and experience of crew). Consensus was quickly reached on key first-aid items but experts' views on emergency medicines differed.

CONCLUSIONS

The study highlights the diversity of medical problems encountered on recreational dive boats. We offer preliminary guidance on the content of suitable first-aid kits and suggest areas for further research.

The psychological impact of accidents on recreational divers: a prospective study

OBJECTIVE

The present study aimed to examine the medium and long term psychological impact of diving accidents on the victims (n=52), compared with the impact on two control groups: the victim's diving "buddy" (n=40) who simply witnessed the accident, and a second control from the same boat who did not dive with the victim (n=38).

METHODS

This was a prospective cohort study of the impact of an accident on the victims who attended the Hyperbaric Unit, in comparison with the two control groups. Pre-accident psychological morbidity was assessed using the General Health Questionnaire. Trauma symptoms were assessed using the Revised Impact of Events Scale at 3, 6 and 12 months post accident.

RESULTS

The accident victims endorsed more trauma symptoms and experienced them more intensely and for longer, compared with the two control groups.

CONCLUSION

A significant minority of diving accident victims (between 25% and 50%) continued to suffer from the psychological impact of the accident, some for over a year. This has important implications for their future health care, for their safety on subsequent dives, and for dive training.

Effect of in-water oxygen prebreathing at different depths on decompression-induced bubble formation and platelet activation

Effect of in-water oxygen prebreathing at different depths on decompression-induced bubble formation and platelet activation in scuba divers was evaluated. Six volunteers participated in four diving protocols, with 2 wk of recovery between dives. On dive 1, before diving, all divers breathed normally for 20 min at the surface of the sea (Air). On dive 2, before diving, all divers breathed 100% oxygen for 20 min at the surface of the sea [normobaric oxygenation (NBO)]. On dive 3, before diving, all divers breathed 100% O2 for 20 min at 6 m of seawater [msw; hyperbaric oxygenation (HBO) 1.6 atmospheres absolute (ATA)]. On dive 4, before diving, all divers breathed 100% O2 for 20 min at 12 msw (HBO 2.2 ATA). Then they dove to 30 msw (4 ATA) for 20 min breathing air from scuba. After each dive, blood samples were collected as soon as the divers surfaced. Bubbles were measured at 20 and 50 min after decompression and converted to bubble count estimate (BCE) and numeric bubble grade (NBG). BCE and NBG were significantly lower in NBO than in Air [0.142+/-0.034 vs. 0.191+/-0.066 (P<0.05) and 1.61+/-0.25 vs. 1.89+/-0.31 (P<0.05), respectively] at 20 min, but not at 50 min. HBO at 1.6 ATA and 2.2 ATA has a similar significant effect of reducing BCE and NBG. BCE was 0.067+/-0.026 and 0.040+/-0.018 at 20 min and 0.030+/-0.022 and 0.020+/-0.020 at 50 min. NBG was 1.11+/-0.17 and 0.92+/-0.16 at 20 min and 0.83+/-0.18 and 0.75+/-0.16 at 50 min. Prebreathing NBO and HBO significantly alleviated decompression-induced platelet activation. Activation of CD62p was 3.0+/-0.4, 13.5+/-1.3, 10.7+/-0.9, 4.5+/-0.7, and 7.6+/-0.8% for baseline, Air, NBO, HBO at 1.6 ATA, and HBO at 2.2 ATA, respectively. The data show that prebreathing oxygen, more effective with HBO than NBO, decreases air bubbles and platelet activation and, therefore, may be beneficial in reducing the development of decompression sickness.

Release of VCAM-1 associated endothelial microparticles following simulated SCUBA dives

Microparticles (MP) are shed into the circulation from endothelium following activation or apoptosis. Vascular cell adhesion molecule-1 (VCAM-1) is expressed on endothelial cells following activation and here we report quantification of VCAM-1 positive microparticles (VCAM + MP) following simulated SCUBA dives, breathing either air or oxygen. VCAM + MP were quantified pre-dive (09:00 and 13:00) and post-dive (+1, +3 and +15 h) on both air and oxygen dives and compared with control samples taken from the same subjects. VCAM + MP followed a similar trend in all experiments, however both dives caused a change in endothelial state, as measured by VCAM + MP. A significant increase in VCAM + MP was observed 1 h post-air dive relative to the control (p = 0.013), which was not observed after the oxygen dive (p = 0.095). Oxidative stress (TBARS) was correlated with VCAM + MP. Data presented highlights the potential of MP as a biological marker of both endothelial state and decompression illness.

Forensic Lung Pathology

Sudden and unexpected natural deaths and nonnatural deaths may result from various pulmonary conditions. Additionally, several nonpulmonary conditions of forensic significance may be complicated by the development of respiratory lesions. Certain situations with pulmonary pathology are particularly likely to be critically scrutinized and may form the basis of allegations of medical negligence, other personal injury liability, or wrongful death.1

Epilepsy and Recreational Scuba Diving: An Absolute Contraindication or Can There Be Exceptions? A Call for Discussion

Recreational scuba diving is a popular sport, and people with epilepsy often ask physicians whether they may engage in diving. Scuba diving is not, however, without risk for anyone; apart from the risk of drowning, the main physiological problems, caused by exposure to gases at depth, are decompression illness, oxygen toxicity, and nitrogen narcosis. In the United Kingdom, the Sport Diving Medical Committee advises that, to dive, someone with epilepsy must be seizure free and off medication for at least 5 years. The reasons for this are largely theoretical. We review the available evidence in the medical literature and diving websites. The risk of seizures recurring decreases with increasing time in remission, but the risk is never completely abolished. We suggest that people with epilepsy who wish to engage in diving, and the physicians who certify fitness to dive, should be provided with all the available evidence. Those who have been entirely seizure-free on stable antiepileptic drug therapy for at least 4 years, who are not taking sedative antiepileptic drugs and who are able to understand the risks, should then be able to consider diving to shallow depths, provided both they and their diving buddy have fully understood the risks.

Orbital subperiosteal hemorrhage while scuba diving

PURPOSE

To report an uncommon case of unilateral subperiosteal hemorrhage while scuba diving involving the orbit, a condition characterized by proptosis and associated severe ocular motility disturbances with displacement of the eyeball.

MATERIAL AND METHODS

Observational case report.

RESULTS

Unilateral subperiosteal hemorrhage in a 31-year-old woman while scuba diving at a depth of 20 meters. This was documented by clinical and radiographic examination. Computed tomography (CT) scan demonstrated a subperiosteal hemorrhage as a self-limited mass protruding into the left orbit. The process resolved without treatment and without visual or motility sequelae. A CT-scan, nuclear magnetic resonance, and conventional angiography did not show any venous abnormalities in the brain.

CONCLUSION

During scuba diving at a depth of 20 meters, the pressure is three atmospheres, whereas within the diving mask the pressure is one atmosphere if it is not equilibrated; thus, a negative pressure is created within the mask. Small vessels can be broken in the conjunctiva or subperiosteal space by this force. It is important to exclude vascular abnormalities, especially if there is a positive family history.

An adolescent scuba diver with 2 episodes of diving-related injuries requiring hyperbaric oxygen recompression therapy: a case report with medical considerations for child and adolescent scuba divers

Worldwide, more than 1000 scuba (self-contained underwater breathing apparatus) diving injuries per year requiring hyperbaric recompression are documented. Approximately 80 to 90 fatalities per year are reported in North America. On average, there were 16 diving injuries requiring hyperbaric recompression therapy in scuba divers aged 19 years and younger in North America between 1988 and 2002. The youngest injured diver was 11 years old, and the youngest fatality was 14 years old during this time period. In the year 2000, certifying recreational scuba diving organizations lowered the minimum age to 8 from age 12 years for participation in the sport. We report a case of a highly trained adolescent scuba diver who, despite having advanced diving certifications, had 2 separate episodes of diving-related injuries requiring hyperbaric recompression therapy. A discussion of medical considerations in the care of the child and adolescent scuba diver is included.

Microbubbles

Gas embolism is a known complication of various invasive procedures, and its management is well established. The consequence of gas microemboli, microbubbles, is underrecognized and usually overlooked in daily practice. We present the current data regarding the pathophysiology of microemboli and their clinical consequences. Microbubbles originate mainly in extracorporeal lines and devices, such as cardiopulmonary bypass and dialysis machines, but may be endogenous in cases of decompression sickness or mechanical heart valves. Circulating in the blood stream, microbubbles lodge in the capillary bed of various organs, mainly the lungs. The microbubble obstructs blood flow in the capillary, thus causing tissue ischemia, followed by inflammatory response and complement activation. Aggregation of platelets and clot formation occurs as well, leading to further obstruction of microcirculation and tissue damage. In this review, we present evidence of the biological and clinical detrimental effects of microbubbles as demonstrated by studies in animal models and humans, and discuss management of the microbubble problem with regard to detection, prevention, and treatment.

SCUBA diving for individuals with disabilities

Self-contained underwater breathing apparatus (SCUBA) diving has become an increasingly popular recreational activity, enjoyed by millions of individuals. There has also been a growing interest in SCUBA diving in the disabled population for rehabilitation and recreation. This review discusses medical issues relevant to individuals with disabilities who wish to participate in SCUBA diving. In addition, specialized equipment, adaptations in techniques, and additional precautions will be presented. SCUBA diving can be an enriching experience, potentially helping to improve self-image and quality of life. Knowledgeable healthcare professionals can help to guide their patients who are interested in SCUBA diving.