Self-contained Underwater Breathing Apparatus Divers Research Articles

Microparticles in Human Perspiration as an Inflammatory Response Index.

A blood component analysis is an early step for evaluating inflammatory disorders, but it can be unfeasible in some settings. This pilot study assessed whether extracellular vesicle (EV) changes in perspiration are parallel to those occurring in blood as an alternative or complementary option to diagnose an inflammatory response. In parallel studies, EVs were analyzed in perspiration and blood obtained before and after five self-contained underwater breathing apparatus (SCUBA) divers at the National Aquarium in Baltimore performed a dive to 3.98 m of sea water for 40 min, and five non-divers performed an exercise routine at ambient atmospheric pressure. The results demonstrated that microparticles (MPs) are present in perspiration, their numbers increase in the blood in response to SCUBA diving, and the interleukin (IL)-1β content increases. In contrast, while blood-borne MPs became elevated in response to terrestrial exercise, no statistically significant increases occurred in perspiration, and there were no changes in IL-1β. There were no statistically significant elevations in the exosomes in perspiration or blood in response to SCUBA diving and few changes following terrestrial exercise. These findings suggest that an MP perspiration analysis could be a non-invasive method for detecting inflammatory responses that can occur due to the oxidative stress associated with SCUBA diving.

Scalloped Hammerhead (Sphyrna lewini) Movement Behavior toward Diver in Banda Waters, Maluku

Shark diving tourism opens opportunities to study shark behavior towards diver. As one of the popular attractions for the marine tourism in Indonesia, shark diving play significant role for the conservation in the eastern part of Indonesia. Banda Sea, as well as Morotai, Derawan, Raja Ampat, Nabire and Teluk Cenderawasih, Bali, Lombok, Komodo, and Gorontalo, is famous for its shark diving attraction. Despite its famous status as a tourism attraction, little is known about the behavior of scalloped hammerhead shark during the interaction with Self-Contained Underwater Breathing Apparatus (SCUBA) diver. The information of scalloped hammerhead shark movement behavior during interaction with SCUBA diver is important for developing ecological assessment, safe diving practice, and shark tourism carrying capacity. This research involves DOV (Diver Operated Video) to record the movement patterns of shark while interacting with SCUBA Diver. Evaluation of approximately 457 photos and 32 videos of the Sphyrna lewini during 14 days of observations has been analyzed during SCUBA diving shows the most common shark agonistic display: pectoral fins depression - apart from other displays such as tail slapping, flank displaying, charging, snout raise, and jaw gapping. It also reveals three (3) new shark agonistic postures which were never been recorded previously: charging, snout raise, and jaw gapping. This study showed that there are consistent behaviors observed while meeting with SCUBA divers and this may be beneficial for development of safety diving management, as well as conservation efforts.

Decompression sickness in SCUBA divers.

There are approximately 2.8 million active self-contained underwater breathing apparatus (SCUBA) divers in the US who are at risk for decompression sickness. This article discusses the pathophysiology, common signs and symptoms, and treatments of this multisystem complication of SCUBA diving.

Decompression sickness in SCUBA divers.

There are approximately 2.8 million active self-contained underwater breathing apparatus (SCUBA) divers in the US who are at risk for decompression sickness. This article discusses the pathophysiology, common signs and symptoms, and treatments of this multisystem complication of SCUBA diving.

Post-mortem computer tomography in ten cases of death while diving: a retrospective evaluation.

Self-contained underwater breathing apparatus (SCUBA) diving deaths have always been a challenge for forensic pathologists. Post-mortem computer tomography (PMCT) allows intracorporeal gas visualization, contributing to identify the cases in which the cause of death is arterial gas embolism (AGE). However, in the literature, it is indicated to perform the radiological examination within 24h after death. In this retrospective study, 32 cases of death who had undergone PMCT 24-48h after death/corpse finding between January 2011 and March 2021 were analyzed, including ten cases of SCUBA divers who died of AGE. All cases' radiological images were reviewed to localize the intracorporeal gas distribution alongside other findings that are usually related to SCUBA diving death. A semi-quantitative evaluation was also performed. Most of the divers showed gas within the left heart and the arteries. In addition, the semi-quantitative evaluation revealed that the divers presented a higher mean amount of intraarterial gas compared to the fresh corpses. On the other hand, the putrefied corpses presented gas within the portal system and generalized subcutaneous emphysema with higher frequency and quantity than the divers and fresh corpses. Our cases suggested that the PMCT, even when performed 24-48h after death, remains a valuable tool to diagnose AGE in cases of SCUBA diving deaths. In addition, with the limit of the small sample size, our data showed that at least a medium quantity of intraarterial gas, when not associated with a high amount of gas within the portal system and subcutaneous emphysema, could be considered a diagnostic criterion of AGE.

Underwater Stereo-Camera Survey Methodology for Estimating Density and Size of Northern Abalone (Haliotis kamtschatkana)

Northern abalone are an important component of the intertidal and subtidal ecosystems of the Pacific Coast. This research was carried out to test the feasibility of utilizing underwater stereo-camera technology to conduct surveys to estimate the abundance and size structure of northern abalone populations. Consistent with other studies, depth and substrate both impacted the density and length of northern abalone, and provided a basis for implementing stratification strategies for density estimation. The average deployment took about 18 min and resulted in 47 useable image quadrats. The estimated time to analyze each frame was about 3 min, translating into ∼2.5 h of processing time per deployment. The precision of the resulting density estimates was high (relative error ∼0.22–0.37 depending on the method used for stratification) and could be improved by increasing the number of study sites to 35 or greater. The pooled density of northern abalone was estimated as 1.07 individuals/ m–2 (SE = 0.21) and the mean length of northern abalone across the study sites was 67.7 mm (SE = 0.08). Future stereo-camera surveys could be used as a cost-effective supplement to self-contained underwater breathing apparatus diver surveys to increase the precision of abundance and size estimates of northern abalone populations.

Inner Ear Disorders in SCUBA Divers: A Review.

Self-Contained Underwater Breathing Apparatus (SCUBA) diving is a popular sport. However, improper diving may injure different organs. The majority of dive-related disorders concern otolaryngology, and may include hearing loss, tinnitus, aural fullness, disequilibrium, and vertigo. Three main inner ear pathological conditions can occur underwater: inner ear barotrauma (IEB), inner ear decompression sickness (IEDS), and alternobaric vertigo (AV). IEB results from inappropriate equalization of middle ear pressure and consequent inner ear injury produced by pressure changes within the middle ear; IEDS is characterized by the formation of gas bubbles within the vessels of the inner ear during rapid ascent; AV typically develops while ascending or performing the Valsalva maneuver and can follow asymmetrical equalization of middle ear pressure transmitted via the oval and round window membranes. The clinical pictures of these pathological conditions are partly superimposable, even if they have specific peculiarities. Before starting SCUBA diving, a fit-to-dive assessment is recommended. It should include an otolaryngologic examination with audiological assessment to evaluate nasal, middle ear, and tubal patency and to minimize the risk of IEB, IEDS, and AV. It is of utmost importance to identify individual risk factors and predisposing pathological conditions that favor inner ear injury before diving, to prevent acute events and preserve auditory and vestibular functions in SCUBA divers. This review aims to provide an overview of the pathological conditions characterized by inner ear injury in SCUBA divers, discussing their pathogenetic mechanisms, diagnostic work-up, and prevention.

A diver\u2019s dilemma \u2013 a case report on bronchopulmonary sequestration

BackgroundAn asymptomatic SCUBA (Self-contained underwater breathing apparatus) diver was discovered to have an intralobar bronchopulmonary sequestration during routine pre-course screening. This is the first reported case of a diver who, having previously completed several recreational and military diving courses, was subsequently diagnosed with a congenital lung condition, possibly contraindicating diving. Presently, there is no available literature providing guidance on the diving fitness of patients with such a condition.Case presentationAn asymptomatic 26-year-old male diver was nominated to attend an overseas naval diving course. Prior to this, he had been medically certified to participate in, and had successfully completed other military and recreational diving courses. He had also completed several hyperbaric dives up to a depth of 50 m and 45 recreational dives up to a depth of 30 m. He did not have a history of diving-related injuries or complications. He had never smoked and did not have any medical or congenital conditions, specifically recurrent respiratory infections. As part of pre-course screening requirements, a lateral Chest X-ray was performed, which revealed a left lower lobe pulmonary nodule. This was subsequently diagnosed as a cavitatory left lower lobe intralobar bronchopulmonary sequestration on Computed Tomography Thorax. The diver remains asymptomatic and well at the time of writing and has been accepted to participate in another overseas course involving only dry diving in a hyperbaric chamber, with no prerequisites for him to undergo surgery.ConclusionAlthough bronchopulmonary sequestrations lack communication with the tracheobronchial tree, they may still contain pockets of air, even if not radiologically visible. This can be attributed to anomalous connections which link them to other bronchi, lung parenchyma and/or pores of Kohn. As such, there is a higher theoretical risk of pulmonary barotrauma during diving, leading to pneumothorax, pneumomediastinum, or cerebral arterial gas embolism. Taking these into consideration, the current clinical consensus is that bronchopulmonary sequestrations and all other air-containing lung parenchymal lesions should be regarded as contraindications to diving. Patients who have undergone definitive and uncomplicated surgical resection may be considered fit to dive.

Blacktip Reefshark (Carcharhinus melanopterus) Movement Displays During Interaction with Self-Contained Underwater Breathing Apparatus Diver in Morotai Waters, Maluku Utara, Indonesia

Shark diving tourism as one of the conservation tools has been growing progressively in the recent decades. Shark diving is among the popular attraction for the marine tourism in Indonesia that plays major role—as rank fourth in the shark tourism world-for the coastal development in the eastern part of Indonesia. Morotai, as well as Derawan, Gorontalo, Biak, Raja Ampat, Nabire and Teluk Cenderawasih, Lombok, Komodo, and Banda Sea, is well known for its shark diving site. Despite its prominent status as a tourism appeal, little is known about the behavior of blacktip reefshark during the interaction with SCUBA diver. The knowledge of shark behavior during interaction with Self- Contained Underwater Breathing Apparatus (SCUBA) diver is important for developing safer diving practice, ecological assessment, and shark tourism carrying capacity. This research involves DOV (Diver Operated Video) to capture the movement patterns of shark while interacting with SCUBA Diver. Analysis of hundreds of movement displays of the Carcharhinus melanopterus during SCUBA diving shows that this shark is having a specific and consistent movement displays while engaging with SCUBA divers.

SCUBA Medicine for Otolaryngologists: Part II. Diagnostic, Treatment, and Dive Fitness Recommendations.

Challenge current practices and misconceptions in treating recreational SCUBA (Self-contained underwater breathing apparatus) divers. Differentiate patients who are fit to dive and those with relative and absolute contraindications. Redefine the standard of care for fitness to dive parameters based on the most up-to-date evidence. We conducted a review of the available medical and diving literature in English, German, Spanish, Italian, Turkish, and French to determine the degree of evidence or lack thereof behind recommendations for treating SCUBA divers. The databases of PubMed, Ovid Medline, and Cochrane library, as well as available textbooks, were queried for relevant data. Current recommendations regarding fitness to dive are overly prohibitive given the available evidence. Insufficient evidence currently exists to justify the level of certainty with which some recommendations have been made previously. This is particularly true with regard to postsurgical patients, including those who have undergone stapedectomy or skull base repairs. Updated treatment guidelines, particularly those regarding the timely differentiation of barotrauma and decompression sickness, as well as clearance for return to diving following surgery or trauma, are presented herein. Current guidelines for otorhinolaryngologists governing the diagnosis and treatment of SCUBA divers are lacking and in some instances founded on insufficient evidence. We present an up-to-date, comprehensive guide for otorhinolaryngologists to utilize going forward. Laryngoscope, 130:59-64, 2020.

SCUBA Medicine for otolaryngologists: Part I. Diving into SCUBA physiology and injury prevention.

Introduce pertinent self-contained underwater breathing apparatus (SCUBA) physiology and corresponding terminology. Appreciate the scope of diving and related otolaryngological injury. Illustrate pathophysiologic mechanisms for diving injuries. Summarize strategies for ear, paranasal sinus, and lung barotrauma prevention, including medical optimization and autoinsufflation techniques. We conducted a review of the available medical and diving literature in English, German, Spanish, Italian Turkish, and French to determine the degree of evidence or lack thereof behind recommendations for treating SCUBA divers. The databases of PubMed, Ovid Medline, and the Cochrane library, as well available textbooks, were queried for relevant data. Divers are subjected to large pressure gradients within the first few meters of descent. This can lead to gas embolism formation as well as barotrauma secondary to gas expansion/compression in potential closed spaces such as the middle ear, paranasal sinuses, and lungs. Physicians can minimize the risk of injury by counseling patients regarding proper equalization and descent/ascent techniques, and optimizing sinonasal and eustachian tube function. The use of decongestants is controversial. Diving is an increasingly popular sport with predominantly otolaryngologic manifestations of injury and disease. Treating SCUBA divers requires a firm understanding of how physiology is altered underwater. This review presents the relevant background information using illustrations to understand the environmental forces acting on divers and how to prevent injury. Laryngoscope, 130:52-58, 2020.

Design and Validation of a Breathing Detection System for Scuba Divers.

Drowning is the major cause of death in self-contained underwater breathing apparatus (SCUBA) diving. This study proposes an embedded system with a live and light-weight algorithm which detects the breathing of divers through the analysis of the intermediate pressure (IP) signal of the SCUBA regulator. A system composed mainly of two pressure sensors and a low-power microcontroller was designed and programmed to record the pressure sensors signals and provide alarms in absence of breathing. An algorithm was developed to analyze the signals and identify inhalation events of the diver. A waterproof case was built to accommodate the system and was tested up to a depth of 25 m in a pressure chamber. To validate the system in the real environment, a series of dives with two different types of workload requiring different ranges of breathing frequencies were planned. Eight professional SCUBA divers volunteered to dive with the system to collect their IP data in order to participate to validation trials. The subjects underwent two dives, each of 52 min on average and a maximum depth of 7 m. The algorithm was optimized for the collected dataset and proved a sensitivity of inhalation detection of 97.5% and a total number of 275 false positives (FP) over a total recording time of 13.9 h. The detection algorithm presents a maximum delay of 5.2 s and requires only 800 bytes of random-access memory (RAM). The results were compared against the analysis of video records of the dives by two blinded observers and proved a sensitivity of 97.6% on the data set. The design includes a buzzer to provide audible alarms to accompanying dive buddies which will be triggered in case of degraded health conditions such as near drowning (absence of breathing), hyperventilation (breathing frequency too high) and skip-breathing (breathing frequency too low) measured by the improper breathing frequency. The system also measures the IP at rest before the dive and indicates with flashing light-emitting diodes and audible alarm the regulator malfunctions due to high or low IP that may cause fatal accidents during the dive by preventing natural breathing. It is also planned to relay the alarm signal to underwater and surface rescue authorities by means of acoustic communication.

Accuracy of a SET of Screening Parameters Developed for the Diagnosis of Arterial Gas Embolism: The SANDHOG Criteria

BackgroundArterial gas embolism (AGE) is a major cause of morbidity and mortality in self-contained underwater breathing apparatus (SCUBA) diving and certain medical procedures. There are currently no well-defined criteria to diagnose AGE. Emergency physicians often find themselves facing a decision whether or not a patient with dive-related symptoms has an AGE and needs to be transferred to a hyperbaric facility. ObjectivesThe objective of this study was to test the accuracy of diagnostic criteria developed by the San Diego Hyperbaric Oxygen Group (SANDHOG) for the diagnosis of AGE. MethodsThis was a retrospective review of consultations completed by the Hyperbaric Medicine Department (HBO) at the University of California San Diego where the diagnosis of AGE was considered. HBO staff blinded to the purpose of the study identified potential cases of AGE. The criterion standard was the final diagnosis by a panel of HBO specialists also blinded to the purpose of this study. Descriptive statistics and comparisons evaluating SANDHOG criteria compared to the criterion standard were performed. ResultsTwenty-six patients were identified for inclusion. Twenty-three of 26 (88%) were SCUBA divers, 2 had intravascular gas injections, and 1 patient had a military training chamber accident. Nineteen of 26 (73%) patients were diagnosed with AGE. A SANDHOG score of 2 had 94.7% sensitivity (95% confidence interval [CI] 71.9–99.7), 85.7% specificity (95% CI 42.0–99.2), positive likelihood ratio of 6.6 (95% CI 1.1–40.8), and negative likelihood ratio of 0.06 (95% CI 0.01–0.43) for AGE. A SANDHOG score <2 had a negative predictive value of 100% for AGE. ConclusionThe SANDHOG criteria appear to be reliable in diagnosing AGE. AGE is unlikely with SANDHOG scores <2, whereas SANDHOG scores ≥2 resulted in high sensitivity and specificity for AGE. Emergency physicians may find this tool useful in evaluating patients for suspected AGE, and it may assist in determining whether to transfer the patient to a hyperbaric facility. Future studies should be performed to further examine and validate the accuracy and inter-rater reliability of this tool.

SCUBA Diving and Asthma: Clinical Recommendations and Safety.

The objective of this article is to review the available studies regarding asthma and SCUBA (self-contained underwater breathing apparatus) diving. A literature search was conducted in MEDLINE to identify peer-reviewed articles related to asthma and SCUBA diving using the following keywords: asthma, allergy, and SCUBA diving. SCUBA diving is a popular sport with more than 9 million divers in the USA. SCUBA diving can be a dangerous sport. Bronchospasm can develop in asthmatic patients and cause airway obstruction. Airway obstruction may be localized to the distal airway which prevents gas elimination. Uncontrolled expansion of the distal airway may result in pulmonary barotrauma. There is also the risk of a gas embolism. Asthmatic divers can also aspirate seawater which may induce bronchospasm. Pollen contamination of their oxygen tank may exacerbate atopic asthma in patients. Diving may be hazardous to the lung function of patients with asthma. Despite the risks of SCUBA diving, many asthmatic individuals can dive without serious diving events. Diving evaluations for asthmatic patients have focused on a thorough patient history, spirometry, allergy testing, and bronchial challenges. For patients that wish to dive, their asthma should be well controlled without current chest symptoms. Patients should have a normal spirometry. Some diving societies recommend that an asthmatic patient should successfully pass a bronchial provocation challenge. Recommendations also state that exercise-, emotion-, and cold-induced asthmatics should not dive. Asthmatic patients requiring rescue medication within 48 h should not dive.

The Forensic Pathology of Drowning and Pulmonary Overexpansion Injury

Drowning deaths are commonly seen in most forensic pathology practices. Experienced forensic pathologists perform autopsies and assign a cause and manner of death in such cases as a matter of routine. Deaths due to pulmonary overexpansion injury and subsequent air embolism are far less common and typically involve individuals who have been breathing compressed gas at depth, generally SCUBA (self-contained underwater breathing apparatus) divers. This review outlines the pathophysiological basis of these two forensic pulmonary issues and recommends an approach to performing and interpreting the results of a forensic autopsy when faced with such cases.

Portal Venous Gas on Computed Tomography Imaging in Patients with Decompression Sickness

BackgroundIt has been reported that portal venous gas is rarely found on computed tomography (CT) imaging in patients with decompression sickness (DCS). However, we propose that this is not true because we have encountered several patients with DCS who presented with portal venous gas on CT before hyperbaric oxygen therapy (HBOT). Here, we review our charts and present these patients’ characteristics. CasesWe treated 37 patients with DCS from April 2007 to September 2011. Nine of these 37 patients underwent CT (thoracic, abdominal, or both) on admission because of dyspnea and other reasons. In four of nine patients, portal venous gas was incidentally found on CT. All patients were male, and three of them were SCUBA (self-contained underwater breathing apparatus) divers. Most of the patients did not have abdominal complaints. Three of four patients presented with gas in other abdominal areas (e.g., mesentery or inferior vena cava). HBOT (United States Navy Treatment Table 6) was performed in all patients, and abdominal CT performed after HBOT in three of four patients revealed the complete disappearance of portal venous gas and other venous gases. One patient died, and the remaining patients survived without any complications. ConclusionsMost patients with DCS do not require CT examination before HBOT. However, if all patients with DCS undergo abdominal CT, the presence of portal venous gas in these patients may no longer be a rare finding. Although routine CT is not required for patients with DCS, it might be helpful for diagnosis.

Derinde Basınçlı Hava Soluyan Serbest Bir Dalgıçta Pulmoner Barotravma

Pulmonary barotrauma (PBT) usually develops in Self Contained Underwater Breathing Apparatus (SCUBA) divers if there is air trapping during ascent caused by uncontrolled decompression, breath holding and emerging of air trapping in the lungs. The air expanded in lungs according to the Boyle's Law should be exhaled enough during ascent to prevent PBT. A 36 years-old-male diver made breath-hold diving to 9 meters. He breathed compressed air from the equipment of a SCUBA diver at the same depth. Afterwards he surfaced leaving the SCUBA diver and did not exhale during ascent. Some air came out of his lung involuntarily before reaching the surface. He had chest pain, dysarthria and sensory changes at surface. Although his neurological complaints disappeared within 30 minutes, substernal pain persisted. The chest computed tomography (CT) scan revealed mediastinal emphysema that disappeared in 3 weeks without treatment. In this case, the diver neglected to exhale the expanded air in the lung during ascent.

SCUBA Medicine

Self-contained underwater breathing apparatus (SCUBA) diving is an ever-growing sport, and despite a myriad of technological advances to improve safety, it remains dangerous. Providers of medical care for SCUBA divers must have an understanding of diving physiology and potential medical problems that can occur. SCUBA diving also can take participants to remote areas, so being properly prepared for potential emergencies can make a significant difference. The following is a review of diving physiology and the medical problems that can occur in SCUBA divers, along with some suggestions as to how to prepare for a SCUBA excursion.

Pulmonary Function in Children After Open Water SCUBA Dives

An increasing number of children and adolescents is diving with Self-Contained Underwater Breathing Apparatus (SCUBA). SCUBA diving is associated with health risks such as pulmonary barotrauma, especially in children and in individuals with airflow limitation. As no data has been published on the effects of open-water diving on pulmonary function in children, the objective of this study was to evaluate the effects of SCUBA dives on airflow in children. 16 healthy children aged 10-13 years underwent spirometry and a cycle-exercise challenge while breathing cold air. They subsequently performed dives to 1-m and 8-m depth in random order. Pulmonary function was measured before and after the exercise challenge and the dives. There were statistically significant decreases in FEV1, FVC, FEV1/FVC, MEF25 and MEF50 after the cold-air exercise challenge and the dives. Changes in lung function following the exercise challenge did not predict the responses to SCUBA diving. In 3 children the post-dive decrements in FEV1 exceeded 10%. These children had a lower body weight and BMI percentile. SCUBA diving in healthy children may be associated with relevant airflow limitation. A low body mass might contribute to diving-associated bronchoconstriction. In the majority of subjects, no clinically relevant airway obstruction could be observed.

Assessment of Extravascular Lung Water and Cardiac Function in Trimix SCUBA Diving

An increasing number of recreational self-contained underwater breathing apparatus (SCUBA) divers use trimix of oxygen, helium, and nitrogen for dives deeper than 60 m of sea water. Although it was seldom linked to the development of pulmonary edema, whether SCUBA diving affects the extravascular lung water (EVLW) accumulation is largely unexplored. Seven divers performed six dives on consecutive days using compressed gas mixture of oxygen, helium, and nitrogen (trimix), with diving depths ranging from 55 to 80 m. The echocardiographic parameters (bubble grade, lung comets, mean pulmonary arterial pressure (PAP), and left ventricular function) and the blood levels of the N-terminal part of pro-brain natriuretic peptide (NT-proBNP) were assessed before and after each dive. Venous gas bubbling was detected after each dive with mean probability of decompression sickness ranging from 1.77% to 3.12%. After each dive, several ultrasonographically detected lung comets rose significantly, which was paralleled by increased pulmonary artery pressure (PAP) and decreased left ventricular contractility (reduced ejection fraction at higher end-systolic and end-diastolic volumes) as well as the elevated NT-proBNP. The number of ultrasound lung comets and mean PAP did not return to baseline values after each dive. This is the first report that asymptomatic SCUBA dives are associated with accumulation of EVLW with concomitant increase in PAP, diminished left ventricular contractility, and increased release of NT-proBNP, suggesting a significant cardiopulmonary strain. EVLW and PAP did not return to baseline during repetitive dives, indicating possible cumulative effect with increasing the risk for pulmonary edema.