Underwater Breathing Apparatus Research Articles

Oxy-Inflammation in Humans during Underwater Activities.

Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O2 availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The "diving response", including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported.

Traumatic Events Preceding the Development of Superior Canal Dehiscence Syndrome.

To describe the features of antecedent head trauma in patients with superior canal dehiscence syndrome (SCDS). Cross-sectional survey. Tertiary referral center. An online survey was sent to 450 adult patients who underwent surgical repair for SCDS patients asking questions about the nature of internal or external traumatic events preceding symptoms. One-hundred and thirty-six patients (avg. age, 51.9 years, 62.8% female) completed the survey, of which 61 (44.9%) described either preceding external head trauma (n = 35, 26%), preceding internal pressure event (n = 33, 25%), or both (8, 6%). Of those endorsing external trauma, 22 (63%) described a singular event (head hit by object (n = 8); head hit ground (n = 5); motor vehicle accident (n = 4); assault (n = 2); other (n = 3). One-third experienced loss of consciousness because of the trauma. For those describing internal pressure events (n = 33), the most common events were heavy physical exertion (9, 27%); pressure changes while flying (6, 18%); coughing, nose blowing with illness (5, 15%); childbirth (5, 15%); and self contained underwater breathing apparatus diving events (3, 9%). The interval between trauma and onset of symptoms averaged 5.6 years (SD, 10.7 years). One-third (n = 19) described onset of symptoms immediately after the external trauma or internal pressure event. Symptoms began on the side ipsilateral to the trauma in 91%. Sound- and pressure-induced vertigo/oscillopsia developed more commonly after external trauma versus internal pressure events (68% and 61% vs 44% and 32%, respectively). Trauma or internal pressure-related events precede SCDS symptoms in nearly half of cases, with roughly half of preceding events being external.

The past, present, and future of underwater spaces: From tourist experiences to the possibility of habitation

AbstractThis paper reviews contemporary geography literature pertaining to the development and experience of underwater spaces. Examining the underwater world as a space of practices, experiences, and visions that are both phenomenologically and geopolitically rich, the review covers research studies from human geography and cognate fields concentrating on the tourism and travel literature. After a brief overview of the many activities taking place underwater worldwide—from the evolution of the mythical Atlantis to the development of modern‐day Atlantis such as underwater hotels—the paper focuses studies in three areas: the consumption of cultural and natural heritage, Self‐contained underwater breathing apparatus diving and divers' experiences, and the possibility of human inhabitation of underwater realms in habitats such as underwater hotels and submarine research sites. It is argued that by becoming more familiar with underwater spaces, geographers who concentrate on tourism and marine environments can gain new perspectives that are likely to challenge the terrestrial imagination.

Dynamics of pH at Santa Catalina Island

The local expression of ocean acidification may depend on local oceanographic features in addition to global forcings. Our objective is to provide a baseline of pH behavior at Santa Catalina Island, situated within the unique oceanographic characteristics of the Southern California Bight, and to gain insight into ocean acidification at the island. Measurements of the upper water column (to 30-m depth) of pH, temperature, conductivity, chlorophyll and dissolved oxygen at Santa Catalina were made from a fixed mooring and by profiling the water column from a boat and on Self-Contained Underwater Breathing Apparatus (SCUBA). The average pH (8.095 at 18-m depth) was found to be higher than that reported off the nearby mainland and the Northern Channel Islands. The higher value is thought to result from both downwelling produced by internal waves as well as less upwelling at the island compared to other locations. Large modulations in pH at depth corresponded to advection of gradients by internal waves. Within the accuracy of the sensors there was no seasonal dependence detected at near-surface, nor a pH signal associated with the sub-surface chlorophyll and oxygen maxima. We conclude that marine life living at depths affected by internal waves experience significant variation in pH.

Polymer Characterization of Submerged Plastic Litter from Lake Tahoe, United States.

Monitoring plastic litter in the environment is critical to understanding the amount, sources, transport, fate, and environmental impact of this pollutant. However, few studies have monitored plastic litter on lakebeds which are potentially important environments for determining the fate and transport of plastic litter in freshwater basins. In this study, a self-contained underwater breathing apparatus was used for litter collection at the lakebed along five transects in Lake Tahoe, United States. Litter was brought to the surface and characterized by litter type. Plastic litter was subsampled, and polymer composition was determined using attenuated total reflection Fourier transform infrared spectroscopy. The average plastic litter from the lakebed for the five dive transects was 83 ± 49 items per kilometer. The top plastic litter categories were other plastic litter (plastic litter that did not fall in another category), followed by food containers, bottles <2 L, plastic bags, and toys. These results are in line with prior studies on submerged litter, and intervention approaches or ongoing education are needed. The six polymers most frequently detected in the subsamples were polyvinyl chloride, polystyrene/expanded polystyrene, polyethylene terephthalate/polyester, polyethylene, polypropylene, and polyamide. These observations reflect global plastic production and microplastic studies from lake surface water and sediments. We found that some litter subcategories were primarily comprised of a single polymer type, therefore, in studies where the polymer type cannot be measured but litter is categorized, these results could provide an estimate of the total polymer composition for select litter categories.

The use of dive computers in forensic investigations of fatal breath-hold diving accidents: a case study.

Freediving is a type of diving in which divers rely solely on how long they can hold their breath underwater during their dive, which is why it can also be referred to as 'breath-hold diving'. Unlike scuba (self-contained underwater breathing apparatus) diving, individuals do not require training or licencing to perform freediving and may not be aware of the risks of this activity. This paper presents a case in which coastguards retrieved a free diver's lifeless body from the seafloor. In most cases such as this, the deceased individual's cause of death would be ruled as drowning. With the deceased diver's dive computer, we concluded that a shallow water blackout caused him to drown. Data from the dive computer were extracted, graphed, and analysed to explain how a skilled swimmer and diver drowned on one of his seemingly ordinary diving trips. The dive computer can be the sole witness to a fatal dive event and provide invaluable information to forensic scientists since the diver is almost always alone. To our knowledge of the available literature, dive computers have been used in scuba diving fatality investigations; however, we believe that they have not been used in death investigations of breath-hold divers. Deficient or hasty conclusions are often based solely on autopsy findings without data collected by diving technicians and investigators. It is crucial to wait to draw conclusions until all possible dive information has been gathered and studied. This study discusses the deficiency in presenting a reasonable idea to the grieving family and friends of how their beloved relative could have drowned even though he was known to be a fit and skilled diver and avid swimmer.

Pulmonary Physiology and Medicine of Diving.

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

Efficacy of closed cell wet-suit at various depths and gas mixtures for thermoprotection during military training dives.

Purpose: To evaluate a closed-cell wet-suit for thermal protective capability during extreme cold water exposure at various depths. Methods: Thirteen (n = 13) elite military divers who were tasked with cold-water training, participated in this study. To mimic various depths, the Ocean Simulation Facility (OSF) at the Navy Experimental Diving Unit (NEDU) was pressurized to simulate dive depths of 30, 50, and 75fsw. Water temperature remained at 1.8-2.0°C for all dives. Four divers dove each day and used the MK16 underwater breathing apparatus with gas mixes of either N202 (79:21) or HeO2 (88:12). Mean skin temperature (TSK) (Ramanathan, 1964), core temperature (Tc), hand and foot readings were obtained every 30min for 30 and 50fsw and every 15min during the 75fsw dive. Results: TC was significantly reduced across all dives (p = 0.004); however, was preserved above the threshold for hypothermia (post dive Tc = 36.5 ± 0.4). There was no effect of gas mix on TC. TSK significantly decreased (p < 0.001) across all dives independent of depth and gas. Hand and foot temperatures resulted in the termination of three of the dives. There were no significant main effects for depth or gas, but there were significant main effects for time on hand temperature (p < 0.001) and foot temperature (p < 0.001). Conclusion: Core temperature is maintained above threshold for hypothermia. Variatioins in TC and TSK are a function of dive duration independent of depth or gas for a closed-cell wet-suit in cold water at various depths. However, both hand and foot temperatures reached values at which dexterity is compromised.

Lethal event in diving with self-contained underwater breathing apparatus: A forensic study

Introduction: In fatal accidents during scuba diving, it is necessary to differentiate a death from primary drowning from a secondary drowning death that is primarily due to other etiopathogenetic factors. The inhalation of water can only be the end point of a series of events capable of causing the diver’s exitus. This study aims to demonstrate that even low-risk heart disease in daily life become potentially fatal during scuba diving. Methods: In this case series, we describe all cases of deaths in the course of diving that came to the observation of the Forensic Institute of the University Bari over 20 years (2000-2020). A judicial autopsy was performed on all subjects, with ancillary execution of histological and toxicological investigations. Results: The results of the medicolegal investigations carried out in the complex identified heart failure with acute myocardial infarction as the cause of death in four cases characterized by severe myocardiocoronarosclerosis, a primary drowning in a subject without previous pathological substrate in one case, and a terminal atrial fibrillation induced by acute dynamic heart failure due to functional overload of the right ventricle in one case Conclusion: Our study demonstrates that lethal events during diving are often related to the presence of unrecognized or subclinical cardiovascular diseases. Such deaths could be prevented and avoided if a greater regulatory sensitivity to preventing and controlling diving was encouraged, considering both the inherent risks of this activity and the possible unrecognized or underestimated pathologies.

Advancing Diversity and Inclusivity in Ocean Sciences by Re-Envisioning Overlooked Barriers in Scientific Diving Training

Self-contained underwater breathing apparatus (scuba) is an essential tool in some marine science fields. However, financial costs and racial disparities in swimming participation can be a barrier to entry for many aspiring marine scientists of color. Scientific diving programs could improve access to scientific diving training by offering training as part of their standard undergraduate curriculum and by maintaining a stock of scuba gear for use during courses. Similarly, the American Academy of Underwater Scientists (AAUS) could make training more accessible by re-envisioning components of the swim test and by building water safety skills into AAUS training—​all without compromising safety. Combined, these two actions would expand pathways for students of color to careers in marine science, adding much needed diversity to the field.

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.

Design features of underwater breathing apparatus

The problem of finding and disposing of explosive objects in the water areas of seas and rivers that remain as a result of hostilities on the territory of our country is urgent and requires appropriate technical equipment. The technical support (equipment) for performing underwater work, which is in service with the Armed Forces of Ukraine, is outdated and can pose a threat to the life and health of sapper divers during the performance of complex combat tasks on a regular basis. One of the pressing issues today is the transition of the Armed Forces of Ukraine to NATO standards. Taking this into account, the issue of not only transitioning to international standards that regulate the processes of development, planning, testing, operation, repair or modernization of weapons and equipment, but also the preservation of the lives of personnel during combat missions is an urgent issue. Accordingly, the search for ways to increase the safety of military personnel during diving descents with explosive work is relevant. The purpose of the study is to analyze the possibility of making structural changes in underwater breathing apparatus (UBA) with an open breathing circuit of the ABA type and to evaluate the effectiveness of the changes made using a composite efficiency index. The types of UBAs with an open breathing circuit of the ABA type are analyzed, the main advantages and disadvantages of UBAs with open, semi-closed and closed circuits of gas supply for breathing are indicated. The principlescheme of the UBA type ABA was considered and constructive solutions were proposed to increase the safety of diving descents and works. Introducing a fundamentally different design of the reducer and the reserve air supply valve into the design scheme will provide an opportunity to control the air supply in the UBA, increase the safety of diving descents and work. The proposed changes in the design will improve the safety of diving descents and underwater work. The obtained results can be used in further scientific research in the direction of modernization and development of promising means of diving equipment.

Multi-resonance flextensional hydrophone for open-circuit scuba diver detection

A multi-resonance Cymbal hydrophone for detection of the open-circuit self-contained underwater breathing apparatus (scuba) diver was designed and fabricated in this work, which has the advantages of multi-resonant frequency, high sensitivity, and narrow bandwidth. By using standard hydrophones, the underwater acoustic signal of the open-circuit scuba diver in the pool was collected and the characteristics of the signal were analyzed: the signal was mainly distributed in high frequency and low frequency. According to this characteristic, a Cymbal hydrophone with multi-resonance frequencies was designed in the finite element method, and the resonant frequency, receiving sensitivity, and bandwidth of the hydrophone were calculated. The accuracy of the calculation was verified with the performance test of the prototypes fabricated in this work. Finally, the underwater acoustic signal of an open-circuit scuba diver in the pool was tested by the prototype to demonstrate that the multi-resonance Cymbal hydrophone developed in this paper can be used for open-circuit scuba diver detection.

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.

Orofacial problems in scuba diving: prevalence and prevention-a large-scale survey among civilian divers in France.

Self-contained underwater breathing apparatus (SCUBA) diving is becoming widely democratized among hobbyist practitioners. It can cause orofacial problems, mostly linked to pressure changes. The aim of this study was to assess the prevalence of these problems and to analyze civilian divers' behavior about their dental prevention in France, via a cross-sectional study. Data from 1015 French civilian divers were collected via a nationwide online questionnaire in which participants indicated information concerning orofacial experienced problems during their diving activity, and their medical preventive habits. As results, oral manifestations were experienced by 25.2% of the divers, including barodontalgia (10.8%), mouth syndrome (13.4%), gum pain (2.8%) and dental fractures caused by barotrauma (3.7%) or shocks (1.9%). Mouth syndrome was more frequent among women (18.6%) and divers aged between 18 and 34years (18.9%). The prevalence of dental fractures increased significantly with age. High diving level was associated with more frequent barodontalgia (17.5%), gum pain (7%) and barotrauma (7.6%). Among respondents, 43.5% completed a dental examination before a diving season and showed fewer oral problems during their scuba diving practice than those who did not. In conclusion, oral problems in scuba diving represent frequent events that can compromise the safety of divers. Despite awareness rising, there is a lack of recourse to the dentist. This leads to incomplete information, especially concerning the preventive means available to divers.

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.

Notes on the fecundity of the caridean shrimp Cuapetes americanus (Kingsley, 1878) in two preserved areas in São Paulo State: Laje de Santos and Vitória Island

In the Atlantic Ocean, the shrimp Cuapetes americanus (Kingsley, 1878) is well distributed. This species has been studied regarding its taxonomic status, distribution records, and some biological and reproductive traits. However, its fecundity and reproductive aspects have never been evaluated in Brazilian waters before. SCUBA (Self Contained Underwater Breathing Apparatus) diving and Artificial Refuge Substrate were used to sample C. americanus specimens quarterly in a sheltered location in the Marine State Parks of Laje de Santos and Vitória Island for a year (2015-2016). A total of 45 animals (carapace length 1.35-4.54 mm) were sampled: 6 females; 18 ovigerous females; 3 juveniles; and 17 males. The major axis references were employed to analyze the relationship between the second pleura (SPL) and the carapace length (CL). The fecundity was 87.05 ± 80.50 eggs and it was similar to other populations connected to it, and it was exclusively associated favorably with CL. Despite being a small and inconspicuous species, C. americanus is a caridean shrimp species that has evolved to thrive and breed on continental islands. The importance of the creation and revision of management plans for no-take marine areas on the Brazilian coast is supported when many kinds of information about the ecology and biology of the species are available, such as caridean shrimps, which can be present as a link between trophic levels of the aquatic food web.

Changes in the expression level of the genes involved in the innate and adaptive immunity of divers

From time immemorial, humans had engaged in breath-hold diving. Developing the scuba (self-contained underwater breathing apparatus) in the last century has made humans increase the capabilities and efficiency of diving. Shallow diving is usually without side effects, but there may be a series of side effects called Decompression Sickness (DCS), which can even lead to severe neurological damages and death in deep and long dives. Scuba diving and its complications alter the pattern of many genes expression involved in innate and adaptive immunity. Researchers have reported various types of these changes in both the genomes of healthy and sick divers. This study surveyed the ten gene expression levels imported into immune responses like apoptosis and inflammation by real-time PCR in Iranian professional fit divers in steady-state. These genes were: Interleukins (IL-6, IL-8, IL-10), Tumor Necrosis Factor (TNFα), complement C3 (C3α), Tumor Necrosis Factor Receptor Type 1 - Associated Death Domain (TRADD), bradykinin receptor B2 (BDKRB2), rennin (REN), arachidonate 5-lipoxygenase (ALOX5), and prostaglandin-endoperoxide synthase 2 (PTGS2). The results showed that the expression levels of TNFα, ALOX5, TRADD, and interleukin genes increased, but PTGS2, REN, and C3α genes' expression levels did not change much. BDKRB2 gene expression level also decreased.

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.