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Purpose This study explores the role of scuba diving therapy in growth experiences of ex-servicemen. Previous research has focused on difficulties arising from re-entering civilian life after deployment. Known mental health challenges occurring after severe combat related trauma exposure include depression, anxiety, and posttraumatic stress disorder (PTSD). However, less is known about the potential positive transformation which can occur when individuals navigate these challenges. Known facilitators of this positive transformation, often referred to as posttraumatic growth (PTG), are still sparse in this participant pool. Methods This study utilized an in-depth qualitative approach of interpretative phenomenological analysis utilizing semi-structured interviews. A homogeneous sample of five male British ex-service personnel with a diagnosis of PTSD who identified with PTG was recruited. Results All participants reported positive mental health benefits from diving with four themes emerging: human connection; meaningful leisure; embodiment; and the calm. Conclusions Scuba diving appeared to afford instant access to lasting relief of anxiety, stress, and symptoms of PTSD and reduction of physical symptoms of their trauma connected to underwater weightlessness. The reduction of PTSD symptoms carved space for PTG, facilitated through a meaningful leisure environment with opportunities for human connection with individuals who had gone through similar experiences.Implications for rehabilitationVeterans with posttraumatic stress disorder (PTSD) respond less well to conventional treatments for PTSD than civilian populations.Scuba diving has the potential to benefit veterans by giving access to relief from anxiety and symptoms of PTSD, such as hypervigilance and invasive thoughts.Scuba diving not only reduces symptoms of physical and psychological ill health but can facilitate wellbeing and growth.Scuba diving, as a meaningful leisure activity, could potentially enhance medical and psychological therapy.

As the popularity of scuba diving increases internationally, physicians interacting with divers in the clinical setting must be familiar with the cardiovascular stresses and risks inherent to this activity. Scuba presents a formidable cardiovascular challenge by combining unique environmental conditions with the physiologic demands of underwater exercise. Haemodynamic stresses encountered at depth include increased hydrostatic pressure leading to central shifts in plasma volume coupled with cold water stimuli leading to simultaneous parasympathetic and sympathetic autonomic responses. Among older divers and those with underlying cardiovascular risk factors, these physiologic changes increase acute cardiac risks while diving. Additional scuba risks, as a consequence of physical gas laws, include arterial gas emboli and decompression sickness. These pathologies are particularly dangerous with altered sensorium in hostile dive conditions. When present, the appropriate management of patent foramen ovale (PFO) is uncertain, but closure of PFO may reduce the risk of paradoxical gas embolism in divers with a prior history of decompression sickness. Finally, similar to other Masters-level athletes, divers with underlying traditional cardiovascular risk should undergo complete cardiac risk stratification to determine ‘fitness-to-dive’. The presence of undertreated coronary artery disease, occult cardiomyopathy, channelopathy and arrhythmias must all be investigated and appropriately treated in order to ensure diver safety. A patient-centred approach facilitating shared decision-making between divers and experienced practitioners should be utilised in the management of prospective scuba divers.

Introduction: The aim of this study was to describe the nature of regular medications taken by active comorbid scuba divers (having a declared medical comorbidity) and scuba divers and snorkellers who died following a diving incident. Methods: We undertook a retrospective, observational study from July to October, 2020. Data on 268 active comorbid divers were obtained through a 2013 survey of Divers Alert Network Asia-Pacific members. Data on 126 deceased scuba divers and 175 deceased snorkellers were obtained predominantly from 2001–2013 reports to Australian State Coronial Services. Results: The active comorbid divers were significantly older, less likely to be male, and more likely to be taking one or more medications than the two deceased subject groups (P < 0.001). Cardiovascular, endocrine and psychotropic medications accounted for 53.4%, 9.9% and 6.4% of all medications taken, respectively. Almost one tenth of the deceased divers took at least one psychotropic medication, a proportion significantly greater than the other groups (P = 0.01). Conclusions: Medication use among active comorbid divers is common which likely reflects their declared medical condition. Nevertheless, they appear to be diving relatively safely, often with conditions once thought to be absolute contradictions to scuba diving. The deceased divers took significantly more psychotropic medications. It is possible that their underlying psychological/psychiatric conditions rendered them more at risk of a diving incident. Increased vigilance for psychological conditions may need to be considered during diving medical examinations.

Observing modern decompression protocols alone cannot fully prevent diving injuries especially in repetitive diving. Professional audio Doppler bubble measurements are not available to sports scuba divers. If those non-professionals were able to learn audio Doppler self-assessment for bubble grading, such skill could provide significant information on individual decisions with respect to diving safety. We taught audio Doppler self-assessment of subclavian and precordial probe position to 41 divers in a 45-min standardized, didactically optimized training. Assessment before and after air dives within sports diving limits was made through 684 audio Doppler measurements in dive-site conditions by both trained divers and a medical professional, plus additional 2D-echocardiography reference. In all dives (average maximum depth 22 m; dive time 44 min), 33% of all echocardiography measurements revealed bubbles. The specificity of audio bubble detection in combination of both detection sites was 95%, and sensitivity over all grades was 40%, increasing with higher bubble grades. Dive-site audio-Doppler-grading underestimated echo-derived bubble grades. Bubble detection sensitivity of audio Doppler self-assessments, compared to an experienced examiner, was 62% at subclavian and 73% at precordial position. 6 months after the training and 4.5 months after the last measurement, the achieved Doppler skill level remained stable. Audio Doppler self-assessment can be learned by non-professionals in a single teaching intervention. Despite accurate bubble grading is impossible in dive-site conditions, relevant high bubble grades can be detected by non-professionals. This qualitative information can be important in self-evaluating decompression stress and assessing measures for increased diving safety.

Objective: This study aimed to evaluate the frequency of episodic primary headaches (EPH) and temporomandibular dysfunction’s (TMD) effect in experienced scuba divers.Methods: A form consisting of ...

Objective: The aim of this study was to investigate scuba diving induced exercise response in novice divers as required in open water scuba diving certification. Methods: Maximal cardiopulmonary exercise test (CPET) was performed in 30 novice divers before and within 24 hours after a standard scuba diving open water certification diving protocol of four open water dives. Results: A significant increase in maximal oxygen consumption (VO2max) in mL·kg-1·min-1 after scuba diving training [25.84 (6.0) vs. 27.04 (7.0)] (p

Scuba diving can be practiced recreationally or professionally. In both modalities the diver can be exposed to risks such as decompression syndrome and thus, the use of a hyperbaric chamber, hyper-oxygenation of the gas cylinder, barotrauma, and immersion in closed circuits. These situations have some phenomena in common, such as the great pressure differences, which can cause a wide range of alterations, including ophthalmological ones. The development of index myopia and nuclear cataract are ocular findings frequently associated with increased oxygen pressure. In this context, an imbalance is established between oxidative species and antioxidant defences, such as glutathione, which has a key role in maintaining the transparency of the lens. The cases are presented of 2 young coral fisher patients, who had recently developed a progressive myopisation associated with nuclear cataracts.

Made available in DSpace on 2021-06-25T12:38:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-12 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundacao RENOVA Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) FAPES Instituto Linha D'Agua Understanding habitat-level variation in community structure provides an informed basis for natural resources' management. Reef fishes are a major component of tropical marine biodiversity, but their abundance and distribution are poorly assessed beyond conventional SCUBA diving depths. Based on a baited-video survey of fish assemblages in Southwestern Atlantic's most biodiverse region we show that species composition responded mainly to the two major hard-bottom megahabitats (reefs and rhodolith beds) and to the amount of light reaching the bottom. Both megahabitats encompassed typical reef fish assemblages but, unexpectedly, richness in rhodolith beds and reefs was equivalent. The dissimilar fish biomass and trophic structure in reefs and rhodolith beds indicates that these systems function based on contrasting energy pathways, such as the much lower herbivory recorded in the latter. Rhodolith beds, the dominant benthic megahabitat in the tropical Southwestern Atlantic shelf, play an underrated role as fish habitats, and it is critical that they are considered in conservation planning. Univ Fed Rio de Janeiro, Inst Biol, Rio De Janeiro, RJ, Brazil Univ Fed Rio de Janeiro, SAGE COPPE, Rio De Janeiro, RJ, Brazil Univ Fed Rural Rio de Janeiro, Lab Ecol Aquat & Educ Ambiental, Tres Rios, RJ, Brazil Univ Fed Sul Bahia, Lab Ecol & Conservacao Marinha, Porto Seguro, BA, Brazil Univ Estadual Paulista, Inst Biociencias, Lab Pesquisa Elasmobranquios, Sao Vicente, SP, Brazil Univ Fed Sao Paulo, Inst Mar, Lab Ecol & Conservacao Marinha, Santos, SP, Brazil Univ Fed Espirito Santo, Vitoria, ES, Brazil Univ Estadual Paulista, Inst Biociencias, Lab Pesquisa Elasmobranquios, Sao Vicente, SP, Brazil

Scuba diving could increase free radicals production which acts as signaling molecules to induce adaptation against oxidative attack. The aim of the new research was to study the impact of scuba diving effects on multiple gas composition responses from the exhaled breath of professional divers. Ethylene, ammonia, and carbon dioxide concentrations from diver s respiration were measured before and after the immersion to 8 m depth in the Black Sea. The ethylene gas (for oxidative stress condition), the ammonia gas (for proteins degradation) and the carbon dioxide gas from the respiration of the six divers were evaluated by mean of the breath test using infrared laser absorption spectroscopy. The experimental results for each breath test of scuba divers will be presented and discussed.

It is widely accepted that bubbles are a necessary but insufficient condition for the development of decompression sickness. However, open questions remain regarding the precise formation and behavior of these bubbles after an ambient pressure reduction (decompression), primarily due to the inherent difficulty of directly observing this phenomenon in vivo. In decompression research, information about these bubbles after a decompression is gathered via means of ultrasound acquisitions. The ability to draw conclusions regarding decompression research using ultrasound is highly influenced by the variability of the methodologies and equipment utilized by different research groups. These differences play a significant role in the quality of the data and thus the interpretation of the results. The purpose of this review is to provide a technical overview of the use of ultrasound in decompression research, particularly Doppler and brightness (B)-mode ultrasound. Further, we will discuss the strengths and limitations of these technologies and how new advancements are improving our ability to understand bubble behavior post-decompression

This study investigated the death anxiety (DA) scores of participants in outdoor-adventure recreational (OAR) activities, and the relationship of the DA scores to several demographic features and experience of DA. The study included 589 individuals with various leisure-time OAR experience levels (131 women, 458 men; Mage=29.79±9.64). Their sports included climbing (n=200), scuba diving (n=142), and paragliding (n=247). DA was measured by the Thorson-Powell Death Anxiety Scale. Overall, the DA scores were low, with no significant differences between OAR activities. However, the DA scores were affected by age and gender, and length of OAR experience. More specifically, the DA scores were highest for 18-28-year-old participants, women, and participants with 4-6 years of middle-level OAR experience. Previous negative DA experiences did not increase the DA scores. Key words: adventure recreation, death, death anxiety, experience, outdoor sports

(Buwalda M, Querido AL, van Hulst RA. Children and diving, a guideline. Diving and Hyperbaric Medicine. 2020 December 20;50(4):399–404. doi: 10.28920/dhm50.4.399-404. PMID: 33325022.) Scuba diving is an increasingly popular recreational activity in children and adolescents. During the dive medical examination aspects of human physiology, anatomy, and psychology, that differ between adults and children, deserve our special attention. For example, lack of mental maturity, diminished Eustachian tube function and heat loss can pose problems during diving. It is important that children who wish to take up scuba diving are seen by a dive physician, with extra attention to Eustachian tube function. In children, asthma, bronchial hyperreactivity, pulmonary hypertension, and right-to-left shunts are contra-indications for scuba diving. Attention deficit hyperactivity disorder is a relative contra-indication. This article provides a review of the current literature and presents recommendations for recreational diving in children and adolescents. These recommendations are based solely on ‘expert’ opinion and were accepted by the Dutch Society of Diving and Hyperbaric Medicine in 2020.

(Elia A, Gennser M. Considerations for scuba and breath-hold divers during the COVID-19 pandemic: A call for awareness. Diving and Hyperbaric Medicine. 2020 December 20;50(4):413–416. doi: 10.28920/dhm50.4.413-416. PMID: 33325024.) In late 2019, a highly pathogenic novel coronavirus (CoV), severe acute respiratory syndrome (SARS)-CoV-2 emerged from Wuhan, China and led to a global pandemic. SARS-CoV-2 has a predilection for the pulmonary system and can result in serious pneumonia necessitating hospitalisation. Computed tomography (CT) chest scans of patients with severe symptoms, show signs of multifocal bilateral ground or ground-glass opacities (GGO) associated with consolidation areas with patchy distribution. However, it is less well known that both asymptomatic and mild symptomatic patients may exhibit similar lung changes. Presumably, the various pathological changes in the lungs may increase the risk of adverse events during diving (e.g., lung barotrauma, pulmonary oedema, etc.), thus these lung manifestations need to be considered prior to allowing resumption of diving. Presently, it is not known how the structural changes in the lungs develop and to what extent they resolve, in particular in asymptomatic carriers and patients with mild disease. However, current evidence indicates that a month of recovery may be too short an interval to guarantee complete pulmonary restitution even after COVID-19 infections not demanding hospital care.

Hyperpneumatization of the temporal bone (HPTB) is a rare finding, and its clinical impact is poorly described in literature. We report the case of a 34-year-old woman with no previous otologic condition, complaining of paroxysmal vertigo and right pulsatile tinnitus shortly after a first scuba diving session. Clinical neurotologic assessment found a right vestibular impairment. Cranial tomodensitometry showed a bilateral hyperpneumatization of the petrosal air cell system. Brain magnetic resonance imaging to rule out any retrocochlear pathology was normal, although the cochleo-vestibular nerve (CVN) appeared to be over lengthened in a narrowed internal auditory canal (IAC), especially on the right-hand side. Pain was alleviated by administration of a low-dose anti-epileptic drug. The clinical, neurological, and radiological findings evoked a right vestibulopathy generated by a limited compression of the CVN; HPTB appeared to contribute to the narrowing of the IAC, especially on the right-hand side.

Introduction: Pulmonary fluid shifts can occur while scuba diving. Such shifts, generally thought to be rare, may result in a life-threatening phenomenon known as immersion pulmonary edema (IPE). This study aims to better classify the normal physiology of diving using ultrasound (US) to determine if these fluid shifts occur routinely during commercial diving work at the NASA Neutral Buoyancy Laboratory (NBL). Methods: Chest US was performed on commercial divers prospectively pre- and post-dive to evaluate the presence of B-lines in a total of 12 intercostal points on the anterior, posterior, and lateral chest wall. The number of B-lines at each anatomic site was recorded and scored by two independent reviewers. An increase in the number of B-lines postdive was considered a positive result. Results: There were 67 exposures; 39 (58%) had an increase of one or more B-lines post dive; 64% of the female exposures and 57% of the male exposures were positive for B-lines post-dive, suggesting no difference across gender (Fisher’s exact; p = 0.763). After the dive, all divers remained asymptomatic. Conclusions: From our results, fluid shifts can be viewed as a normal, transient, and physiologic process in commercial divers. This correlation can be compared to the formation of low-grade venous gas emboli (VGE) from decompression that does not result in decompression sickness. Further study of US B-lines in symptomatic divers may define the utility of field US in the diagnosis and management of IPE, and help identify associated risk factors.

ZUSAMMENFASSUNGDer Trend zum Gerätetauchen besteht auch bei Kreuzfahrtgästen, die häufig spontan in ihrem Urlaub einen Tauchschein erwerben wollen. Es handelt sich nicht nur um junge, gesunde Gäste, sondern auch um Gäste mit Vorerkrankungen und um Kinder und Erwachsene über 40 Jahre. Wir beleuchten Möglichkeiten und Grenzen der Durchführung von leitliniengerechten Tauchtauglichkeitsuntersuchungen an Bord von Kreuzfahrtschiffen. Wenn an Bord eine Lungenfunktion und ein Ruhe-EKG durchgeführt werden können, ist von tauchmedizinisch qualifizierten Schiffsärzten die Beurteilung und Attestierung der Tauchtauglichkeit von Gästen bis 39 Jahren möglich. Bei Gästen über 40 Jahren sollte keine Tauchtauglichkeit attestiert werden, wenn die vorgeschriebene Belastungsergometrie an Bord nicht durchgeführt werden kann. Daher empfehlen wir aus für den Arzt rechtlichen Gründen und für den Gast zur gesundheitlichen Sicherheit auf die Ausstellung einer Tauchtauglichkeit für Gäste ab 40 Jahren zu verzichten, wenn die Voraussetzung der Durchführung einer Belastungsergometrie nicht vorliegt.

With the increasing popularity of recreational scuba diving, rare complications are becoming more commonly encountered. Although diving is generally safe, novice divers may be unfamiliar with the potential hazards of scuba diving and the resulting sequelae. Dive-related injuries are commonly due to barotrauma or from breathing gas at increased pressures, resulting in decompression illness (DCI), a term that includes both decompression sickness (DCS) and arterial gas embolism (AGE). Symptoms can range from minor aches and pains to neurologic or cardiopulmonary complications resulting in death. Clinical symptoms and diagnosis may initially go unrecognized and can present in a delayed manner, often remote to the diving location. When DCI is suspected standard treatment with hyperbaric oxygen (HBO2) therapy should be considered immediately. Current literature questions the efficacy of delayed HBO2 therapy longer than 24-48 hours after symptom onset. Here we present a case of two divers who simultaneously experienced DCS and were both successfully treated after receiving delayed HBO2 therapy nearly eight days after initiation of symptoms.

Introduction: Hydration status is considered a parameter likely to influence the risk of decompression sickness (DCS), but scientific evidence is scarce and conflicting. This experiment aimed to analyse the influence of pre-hydration on DCS occurrence in a rat model. Methods: Intra-peritoneal injections of saline solution were administered to rats (NaCl 0.9% 0 ml (Control), 0.1 ml (Group 1), or 1 ml·100g-1 body mass (Group 2) at each of 24 h, 12 h, and 30 min prior to simulated air dives (45 min at 1,010 kPa; compression and decompression rates 101 kPa·min-1; stops 5 min at 202 kPa, 5 min at 160 kPa, 10 min at 130 kPa). Evaluation of DCS occurrence and severity was made after decompression. Results: Pre-dive hydration reduced severe DCS from 47% (Control) to 29% (Group 1) and 0% (Group 2), and increased the proportion of animals without any signs of DCS from 40 (Control) to 57% (Group 1) and 93% (Group 2); Chi2 P = 0.041. Conclusions: This experiment demonstrated that pre-hydration can drastically reduce the DCS occurrence in an animal model. In the context of scuba diving, this result highlights the importance of elucidating the mechanisms linking hydration status and DCS risk.

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.

Background Decompression illness often presents with a wide variety of vague neurologic symptoms. Animal models have suggested that intracranial hemorrhages may result from nitrogen bubble ischemic insults. However, there is a paucity of cases and no known case reported to date of non-aneurysmal subarachnoid hemorrhage after rapid ascension from diving. Case Description A 60-year-old man presented with headache, nausea, emesis, and confusion 2 days after ascending rapidly from scuba diving. Given the severity and his symptoms unremitting despite oxygen at home, a computed tomography scan of the head was obtained revealing a prepontine and right sylvian fissure subarachnoid hemorrhage with ventriculomegaly. No underlying vascular abnormality was discovered. The patient was discharged from the hospital posthemorrhage day 7, neurologically intact. Conclusions In patients presenting with persistent headache, nausea, emesis and/or other neurologic symptoms after diving, health care providers should consider intracranial hemorrhage in their work up.

Swimming-induced pulmonary edema (SIPE), also called immersion pulmonary edema (IPE), is a medical condition seen in various water-based activities such as scuba diving, swimming, aqua jogging, triathlete competition and snorkeling. It occurs when transcapillary filtration of low protein fluid collects in the lungs, in the absence of water aspiration during an aquatic activity, causing acute dyspnea, cough and/or hemoptysis. The hallmark of this entity is the complete resolution of symptoms within 48 hours. SIPE in snorkeling is an under-reported and understudied subject. The true prevalence of SIPE is unknown with an estimated range from 1.8–60% among combat swimmers trainee and 1.4% in triathletes. Recent developments have been done in elucidating the pathophysiology of SIPE with regards to pulmonary capillary pressure so that the predisposing factors and potential causes can be targeted. SIPE can be a potentially life-threatening condition, which needs to be recognized by the swimmers, divers, supervising physicians in order to diagnose and manage it promptly. We report a rare case of SIPE in snorkeling which presented with acute respiratory symptoms and managed with supportive measures in the hospital.

BACKGROUND: Scuba diving-related otological injuries comprise the majority of diving-related incidents that present to general practitioners (GPs). Correct diagnosis and management are key to prevent permanent hearing loss and vertigo. OBJECTIVE: The aim of this article is to increase awareness of the pathophysiology of otological diving injuries and provide an approach to initial assessment and treatment, as well as to highlight particular circumstances in which onward referral is required. DISCUSSION: Accurate diagnosis and treatment of diving-related otological injuries by GPs can have profound positive effects on a patient's long-term outcomes. Complete otolaryngological assessment in those who have previously had a dive-related injury is critical to ensure patient safety prior to recommencing scuba diving.

New findings What is the central question of this study? What are the characteristics of cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. What is the main finding and its importance? Acute alterations in CBF regulation at rest, including extra-cranial vasodilatation, reductions in shear patterns and elevations in intra-cranial blood velocity were observed at rest following a single SCUBA dive. These subtle changes in CBF regulation did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or neurovascular coupling following a single SCUBA dive. Abstract Reductions in vascular function during a SCUBA dive - due to hyperoxia-induced oxidative stress, arterial and venous gas emboli and altered endothelial integrity - may also extend to the cerebrovasculature following return to the surface. This study aimed to characterize cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. Prior to and following the dive, participants (n = 11) completed (1) resting CBF in the internal carotid (ICA) and vertebral (VA) arteries (duplex ultrasound) and intra-cranial blood velocity (v) of the middle and posterior cerebral arteries (MCAv and PCAv, respectively) (transcranial Doppler ultrasound); (2) cerebrovascular reactivity to acute poikilocapnic hypoxia (i.e. F I O 2 , 0.10) and hyperoxia (i.e. F I O 2 , 1.0); and (3) neurovascular coupling (NVC; regional CBF response to local increases in cerebral metabolism). Global CBF, cerebrovascular reactivity to hypoxia and hyperoxia, and NVC were unaltered following a SCUBA dive (all P > 0.05); however, there were subtle changes in other cerebrovascular metrics post-dive, including reductions in ICA (-13 ± 8%, P = 0.003) and VA (-11 ± 14%, P = 0.021) shear rate, lower ICAv (-10 ± 9%, P = 0.008) and VAv (-9 ± 14%, P = 0.028), increases in ICA diameter (+4 ± 5%, P = 0.017) and elevations in PCAv (+10 ± 19%, P = 0.047). Although we observed subtle alterations in CBF regulation at rest, these changes did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or NVC. Whether prolonged exposure to hyperoxia and hyperbaria during longer, deeper, colder and/or repetitive SCUBA dives would provoke changes to the cerebrovasculature requires further investigation.

INTRODUCTION: Anxiety is a substantial consideration in scuba diving and may influence a diver’s performance and cognitive activities. This study aimed to simultaneously observe the effect of anxiety trait on actual diving performance and underwater cognitive processing ability. METHODS: Twenty-seven scuba divers completed the STAI-T component of the State-Trait Anxiety Inventory, and were subdivided into two groups on the basis of trait anxiety scores ≥ 39 and < 39. Scuba diving performance was measured in a pool. The completion time of four standardised scuba skills was recorded by a diving instructor. The correct completion rate and response time for a cognitive function assessment (number-Stroop test) were measured both on land (‘dry’) and underwater at 5 metres’ fresh water. RESULTS: Anxiety trait was associated with prolonged mask clearing: mean completion time 7.1 (SD 3.2) s vs. 10.8 (5.4) s in low and high anxiety trait divers respectively (P = 0.04). Low (vs high) anxiety trait divers had reduced response times for the number-Stroop test: 49.8 (3.0) s vs. 53.3 (5.4) s (P = 0.04) dry, and 64.4 (5.0) s vs. 72.5 (5.5) s (P < 0.01) underwater. Performance of other skills was not significantly affected by trait anxiety nor correlated with the number-Stroop test results. CONCLUSIONS: Personal anxiety trait prolongs mask clearing and underwater cognitive processing ability but the latter did not affect execution of other underwater scuba diving skills.

Introduction Scuba diving likely has an impact on the autonomic nervous system (ANS). In the course of conducting trials of underwater ECG recording for measurement of heart rate variability, there was an unexpected stressful event; one participant's regulator iced and began to free-flow. Methods A custom-made, water- and pressure-tight aluminum housing was used to protect a portable Holter monitor. ECGs were recorded in three experienced divers who witnessed an unplanned moderately stressful incident during diving. The ECG signals were analysed for measures of heart rate variability (HRV). Results Analysis for different short-term HRV measures provided consistent results if periods of interest were appropriately time-aligned. There was improvement in sympatho-vagal balance. One diver unexpectedly exhibited an increase in both sympathetic and vagal activity shortly after the incident. Conclusions A conventional open-water dive affected the ANS of experienced recreational divers as measured by HRV which provides a global evaluation of the ANS and alterations in its two branches. The heart rate variability data gathered from several participating divers around the time of this event illustrate the potential utility of this variable in quantifying stress during diving. HRV data may be useful in addressing relevant diving related questions such as effects of cold, exercise or different breathing gases on ANS function.

Introduction This study identified characteristics of victims of fatal scuba diving incidents to determine contributing factors and inform appropriate countermeasures. Methods The National Coronial Information System (NCIS) was searched to identify scuba diving deaths for 2001-2013, inclusive. Data were extracted from witness and police reports, medical histories and autopsies. Descriptive statistics were used to analyse these data. Results There were 126 scuba diving-related fatalities identified during the study period. The mean age was 44 years, 99 (79%) victims were male and 83 (77%) were either overweight or obese. Most deaths occurred in New South Wales and Queensland, often in a commercial setting. Twenty-three (79%) Queensland victims were overseas tourists. At least 52 (41%) were novices and 17 (13%) died during training or an introductory scuba experience. Only 35 (28%) were with a buddy when the incident occurred and at least 81 (64%) were still wearing weights when recovered. Conclusions The age of these victims may reflect an older cohort of participants and the associated higher prevalence of chronic medical conditions. The high prevalence of obesity suggests that this may be a risk factor. The high proportion of deaths in overseas tourists highlights an on-going need for appropriate screening and monitoring in what may be a higher risk cohort. The number of deaths that occurred under instruction highlights the importance of careful assessment of the site, prevailing conditions, an appropriate instructor-student ratio and close supervision.

Purpose: Previous studies have shown an increase in erythrocyte lipid peroxidation and a decrease in red blood cell (RBC) count, hemoglobin, and hematocrit after only one recreational scuba diving session. The aim of this study was to examine the effect of repetitive scuba diving on RBC parameters and erythropoiesis. Methods: Divers (N = 14) conducted one dive per week over 5 weeks at a depth of 20-30 m for 30 min. For measuring RBC parameters, erythropoietin, iron, and ferritin, blood samples were collected before and after the first, third, and fifth dive. Results: Between pre- and post-dive results, a statistically significant increase in RBC count, hemoglobin, hematocrit, mean corpuscular volume (MCV), RBC distribution width (RDW), iron, and ferritin was observed. Analysis of the results between the first, third, and fifth dive showed that the erythropoietin increase at the third (pre-dive p = 0.009 ; post-dive p = 0.004) and fifth dive (pre-dive p < 0.001 ; post-dive p = 0.003) was not accompanied by changes in RBC count, hemoglobin, iron, and ferritin. In parallel, a continuous increase in hematocrit, MCV, and RDW was observed, whereas mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) decreased. Conclusions: Changes in RBC indices and EPO elevation indicate that the occasional switch from hyperoxia to normoxia or mechanisms for plasma volume regulation may be a step in the maintenance of erythropoiesis.

Objectives The present study revealed the presence of bioactive constituents in Hyrtios aff. erectus sponge (HES) extract collected from the Red Sea using skin and scuba diving. Materials and methods Cytotoxicity was tested against hepatocellular carcinoma cell lines as a prescreening test. Results The HES extract had high contents of total phenolic compounds (0.061 mg/g), flavonoids (0.2839 mg/g), and carotenoids (1.976 mg/g). Moreover, the HES extract showed high antioxidant capacity with 93.0% and 99% at 1 mg using 2.2'-Diphenyl-α-picrylhydrazyl and 2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), respectively. Cytotoxic activity against cancerous cell lines showed that the HES extract could inhibit cell growth effectively with IC50=47.5 μg/mL. Furthermore, anticancer activity using protein tyrosine kinase and sphingosine kinase 1 inhibitor screening assays resulted in 71.66% and 85.21% inhibition activity, respectively. The anti-inflammatory assays showed that the inhibition activity against cyclooxygenase (COX1), COX2, interleukin-6, and tumor necrosis factor-α was 71.82%, 81.13%, 80.89%, and 59.74%, respectively. At the same time, the anti-Alzheimer results using acetylcholine inhibition assay showed high activity at 1 mg with 83.51%. Additionally, the antiviral activity using the reverse transcriptase inhibition assay was 91.70%. Conclusion This marine sponge isolated from the Red Sea showed tremendous activity against many diseases and it is considered an excellent source for bioactive pharmaceutical compounds.

Immersion pulmonary edema (IPE) is a rare condition observed in divers. We report a case of a 66-year-old man on maintenance dialysis who developed acute dyspnea and blood-tinged sputum after scuba diving. Vital signs on admission were significant for elevated blood pressure at 209/63 mmHg and hypoxia with an oxygen requirement of 6 L/min. Physical examination was remarkable for bilateral coarse crackles and systolic ejection murmur. Chest radiography revealed bilateral pulmonary edema. Echocardiography showed aortic stenosis and diffuse hypokinesis of left ventricular wall motion. We started bilevel positive airway pressure and administered nitroglycerin and nicardipine to maintain adequate oxygenation and reduce blood pressure. We started hemodialysis and extracorporeal ultrafiltration to remove excess fluid. His dyspnea subsided and oxygen was no longer required on Day 3. His long-standing hypertension, increased afterload due to vasoconstriction induced by cold water, increased capillary pressure due to impaired left ventricular motion and increased preload caused by exertion, and aortic stenosis probably contributed to pulmonary congestion. We propose maintenance dialysis as a novel risk factor for IPE due to its tendency to induce volume overload, increase pulmonary capillary pressure, and increase aortic stenosis risk. Patients on hemodialysis should refrain from diving to prevent this life-threatening condition.

Background There are no reports of immersion pulmonary edema induced by excessive alcohol intake. We describe the case of a novice scuba diver who developed apnea due to immersion pulmonary edema during scuba diving after heavy alcohol intake. Case Presentation A 71‐year‐old hypertensive man, without regular antihypertensive therapy, performed diving after excessive alcohol intake (total amount, approximately 253 g) until the night before. When swimming at a depth of 12 m, the patient experienced chest discomfort and ascended immediately but became unconscious. Respiratory arrest was confirmed, and he spat pink foamy sputum. On hospital admission, hypoxemia was confirmed, and chest radiography revealed butterfly‐shaped shadows. Therefore, mechanical ventilation was initiated. The next day, his blood oxygenation level improved, and the radiographic shadows disappeared. He was discharged on day 7 of hospitalization without sequelae. Conclusion A scuba diver with untreated hypertension might develop immersion pulmonary edema during diving after heavy alcohol intake., We present the case of a novice scuba diver who developed apnea due to immersion pulmonary edema (IPE) during diving after heavy alcohol intake. It is believed that IPE developed when the patient was exposed to a high‐pressure environment with strongly edematous lungs due to heavy drinking.

(Wilmshurst P, Clamp M. Impaired consciousness when scuba diving associated with vasovagal syncope. Diving and Hyperbaric Medicine. 2020 December 20;50(4):421–423. doi: 10.28920/dhm50.4.421-423. PMID: 33325026.) 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.

We report a case of anterior choroidal artery territory infarction due to internal carotid artery dissection presumably caused by scuba diving. A 44-year-old man presented with left facial palsy and hemiparesis. He had a history of scuba diving for 18 months. His last dive was 7 days ago, and he skipped decompression practice at that dive. We assumed that repetitive traumas and microbubbles during scuba diving, which made endothelium vulnerable to damage may have caused a carotid dissection.

Occult diaphragmatic injury was uncovered in a patient who returned to scuba diving after a traumatic injury. Diaphragmatic injury can be a difficult diagnosis in the setting of trauma and a significant number of injuries are missed on the initial presentation. This has potential implications to those wishing to return to diving after trauma, and diving doctors must maintain a high degree of suspicion for such injuries.

The purpose of this study was to investigate the effects of a single bout of heliox non-saturation diving on the cardiovascular system and cognitive function. Ten recreational scuba divers (10 males, ~35 years old) participated in this study. These subjects made two pool dives within a one-week interval, alternating gases with compressed air (21% O2, 79% N2) and with heliox (21% O2 and 79% He). The depth was to 26 meters over a 20-minute duration. The results showed that heliox diving significantly increased blood O2 saturation by 1.15% and significantly decreased blood lactate levels by ~57% when compared with air diving (P

Aim: The aim of this study was to examine first aid measures applied in a large series of Australian dive-related fatalities to better determine where improvements can be made. Methods: The National Coronial Information System was searched to identify scuba diving and snorkeling-related cases reported to various Australian Coroners for the years 2001-2013 inclusive. Coronial documents examined included witness statements, police reports and ambulance and medical reports where available. Information relating to the recovery, rescue and/or resuscitation of the victims was extracted, compiled and analyzed. Results: 126 scuba diving and 175 snorkeling-related fatalities were identified during the study period, with airway management complications reported in one-third. Cardiopulmonary resuscitation was performed in three-quarters of the incidents. An automated external defibrillator was attached to 40 victims as a first aid measure, and shocks were indicated and delivered in five cases. Although three-quarters of the reports included no information about whether supplemental oxygen was provided, it was confirmed in 19% of both the scuba diving and snorkeling incidents. Conclusion: There were often considerable delays in the recognition, rescue and/or recovery of an unconscious snorkeler or diver and, consequently, the time to commencement of basic life support. Such delays can affect chances of survival and need to be minimized. Delivery of supplemental oxygen during resuscitation appears to be relatively infrequent and sometimes suboptimal; improvement appears necessary. Some measures that would have improved availability and/or better use in these cases include the selection of appropriate equipment compatible with likely circumstances and operator skills; improved training and ongoing skills practice; and regular checking and maintenance of equipment Improved data collection and recording by official on-site investigators, preferably with knowledge of diving, would better inform potential or necessary improvements.

Human diving is known to induce endothelial dysfunction. The aim of this study was to decipher the mechanism of ROS production during diving through the measure of mitochondrial calcium concentration, peroxynitrite, NO°, and superoxide towards better understanding of dive-induced endothelial dysfunction. Air diving simulation using bovine arterial endothelial cells (compression rate 101 kPa/min to 808 kPa, time at depth 45 min) was performed in a system allowing real-time fluorescent measurement. During compression, the cells showed increased mitochondrial superoxide, peroxynitrite, and mitochondrial calcium, and decreased NO° concentration. MnTBAP (peroxynitrite scavenger) suppressed superoxide, recovered NO° production and promoted stronger calcium influx. Superoxide and peroxynitrite were inhibited by L-NIO (eNOS inhibitor), but were further increased by spermine-NONOate (NO° donor). L-NIO induced stronger calcium influx than spermine-NONOate or simple diving. The superoxide and peroxynitrite were also inhibited by ruthenium red (blocker of mitochondrial Ca2+ uniporter), but were increased by CGP (an inhibitor of mitochondrial Na+-Ca2+ exchange). Reactive oxygen and nitrogen species changes are associated, together with calcium mitochondrial storage, with endothelial cell dysfunction during simulated diving. Peroxynitrite is involved in NO° loss, possibly through the attenuation of eNOS and by increasing superoxide which combines with NO° and forms more peroxynitrite. In the field of diving physiology, this study is the first to unveil a part of the cellular mechanisms of ROS production during diving and confirms that diving-induced loss of NO° is linked to superoxide and peroxynitrite.

The aim of the research was to evaluate the occurrence of arrhythmias and heart rate variability during diving in recreational divers. Continuous electrocardiographic (ECG) Holter monitoring was conducted in a group of 50 divers (age 36,8 ± 8,7). The recorded data included the duration of the dive, including a period of 60 minutes before the dive and 60 minutes after the dive. Moreover, divers filled in a questionnaire that had been prepared for the purpose of the study and the psychological tests State-Trait Anxiety Inventory (STAI). The ECG recordings were synchronised with dive computers to correlate the ECG changes with diving events and analysed for the heart rate, arrhythmias and conduction disorders. The average heart rate was the highest (M=107.34 beats/minute) before diving, and the lowest after diving (M = 102.00 beats/minute). Supraventricular arrhythmias were recorded in nineteen (38%) of the participants of the study. The number of arrhythmias during diving (M = 14,45) is significantly higher than before (M = 9,93, p < 0,01) and after dive (M = 6,02, p < 0,05). All results were obtained from the continuous ECG Holter monitoring. It seems that using continuous ECG monitoring in conditions similar to diving (physical and psychological stress), brings more benefits than traditional, resting electrocardiogram.

Objective: Scuba diving and freediving are popular activities around the world, and their growth has increased the frequency of related pathology. A good ability to equalize is of paramount importance for diving. This is especially true for freediving, during which dive time is limited to just one breath. Even though equalization disorders are quite common in divers, a scoring system does not exist to date. In this paper we propose a new scoring system for equalization problems of freedivers: the EP score – shorthand for “equalization problems.” Methods: We administered the EP score assessment to 40 Italian freediving spearfishermen who were divided in two groups: Group A comprised 20 freedivers complaining of equalization problems and multiple barotraumas but totally asymptomatic in their everyday lives. These individuals had already received medical treatment and nasal surgery without improvement and then had undergone Eustachian tube balloon dilation. Group B comprised 20 healthy freedivers without any history of equalization disorders. We performed a statistical analysis to evaluate the reliability of this scoring system and to evaluate its usefulness in diagnosis and follow-up. Results: Our data show substantial statistical differences between healthy freedivers and freedivers complaining of equalization disorders (Z-Score = -5.396 at p < 0.05); data do not show any statistical difference between healthy freedivers and patients successfully treated by Eustachian tube balloon dilation (U-value = 152.5 and Z-Score= -1.271 at p < 0.05). Conclusion: The EP score assessment seems to be a reliable tool to quantify equalization disorders during freediving and to evaluate how the difficulty varies over time and after treatment. Since equalization disorders could be present in different populations, the EP score assessment could be applicable to a wider group.

Background: Immersion can cause immersion pulmonary edema (IPE) in previously healthy subjects. We performed a case-control study to better identify IPE risk factors. Methods: We prospectively included recreational scuba divers who had presented signs of IPE and control divers who were randomly chosen among diving members of the French Underwater Federation. We sent an anonymous questionnaire to each diver, with questions on individual characteristics, as well as the conditions of the most recent dive (controls) or the dive during which IPE occurred. Univariate logistic regressions were performed for each relevant factor. Then, multivariate logistic regression was performed. Results: Of the 882 questionnaires sent, 480 (54%) were returned from 88 cases (90%) and 392 control divers (50%). Multivariate analysis identified the following independent risk factors associated with IPE: • being aged over 50 years ((OR) 3.30, (95%CI) 1.76-6.19); • female sex (OR 2.20, 95%CI 1.19-4.08); • non-steroidal anti-inflammatory drug (NSAID) intake before diving (OR 24.32, 95%CI 2.86-206.91); • depth of dive over 20 m (OR 2.00, 95%CI 1.07-3.74); • physical exertion prior to or during the dive (OR 5.51, 95%CI 2.69-11.28); • training dive type (OR 5.34, 95%CI 2.62-10.86); and • daily medication intake (OR 2.79, 95%CI 1.50-5.21); this latter factor appeared to be associated with hypertension in the univariate analysis. Conclusions: To reduce the risk of experiencing IPE, divers over 50 years of age or with hypertension, especially women, should avoid extensive physical effort, psychological stress, deep dives and NSAID intake before diving.

INTRODUCTION: This research reports the epidemiology of diving injuries managed in the Hyperbaric Medicine Unit of the Canary Islands University Hospital. METHODS: Data were extracted from the clinical records of all divers injured and admitted to the unit for treatment of dysbaric diving injuries between 2008 and 2017, inclusive. RESULTS: One-hundred and thirty diving injuries were recorded. Most (71%) occurred in men and 43% were foreigners. Eighteen per cent either had no diving certification or that information was not recorded in the clinical chart. Only a third of the 40% of divers who had some form of on-site first aid treatment received oxygen and oral rehydration. Type 1 decompression sickness (DCS) was diagnosed in 56 divers (43%) and Type 2 in 67 (52%), whilst seven were treated for omitted decompression. At discharge, 122 (94%) were asymptomatic, whilst 5% experienced some residual sensory or other changes. One diver who presented late remained quadriparetic and one, admitted in a state of coma, died. Only 76% of the injured divers had specific diving accident insurance and, of those, 58% were foreign divers. CONCLUSIONS: Over half of the injured divers did not receive any on-site first aid. The majority (94%) of treated injured divers were discharged without sequelae. Based on these data, several public health recommendations for the Canary Islands are made.

Airplane ear or ear discomfort during flight is common irrespective of ticket price we pay for our flights according to class. Whether we get extra leg space or extra facilities during flying in business class, air travelers often face this problem of airplane ear (Figure 1). Airplane ear is also known as ear barotrauma, barotitis media or aerotitis media [1]–[5]. Severe earache affects individuals of varying levels of social determinants of health as it is entirely a physiological phenomenon [3]. Airplane ear is commonly experienced when the airplane is ascending or descending, which makes it one of the commonest health problems for people travelling in air routes. Open in a separate window Figure 1. Airplane ear. 2. Etiology Generally, airplane ear occurs due to quick changes in altitude and quick changes in air pressure [4]. In normal physiological conditions, the air pressure in our middle ear cavity is nearly equivalent to that of the external ear canal. This equalization of air pressure is maintained physiologically and contributes to regular auditory function and maintenance of normal balance among individuals. However, the eustachian tube dysfunction may occur with any changes in pressure and failure to ventilate through the middle ear space. This may result in outward bulging of the tympanic membrane causing moderate to severe earache. This phenomenon can be compared with a bread expanding while baking [3],[5]. Conversely, due to the vacuum effect, if the air pressure inside the middle ear space reduces rapidly compared to the external ear pressure, the tympanic membrane may be pulled inside due to the pressure gradient. The eustachian tube becomes flattened during the pressure changes and it necessitates bringing air into the middle ear (Figure 2). During sudden ascend or descend of an aeroplane, ear cavity pressure is often decreased complemented by an increase in the cabin compared to the outside air pressure. In such a scenario, the unusual stretching of the eardrum or tympanic membrane may precipitate pain in the ear. At the same time, individuals may also experience decreased hearing abilities and muffled sounds as the eardrum as it becomes unable to vibrate normally [2]–[4]. Open in a separate window Figure 2. Imbalance of air pressure in the middle ear. The pathophysiology remains the same in cases of scuba diving, in hyperbaric oxygen chambers, and during explosions happening nearby [2].