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Risberg J. Acclimatization to diving: a systematic review. Undersea Hyperb Med 2021; 48:127-147. [PMID: 33975403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Multiday hyperbaric exposure has been shown to reduce the incidence of decompression sickness (DCS) of compressed-air workers. This effect, termed acclimatization, has been addressed in a number of studies, but no comprehensive review has been published. This systematic review reports the findings of a literature search. PubMed, Ovid Embase, The Cochrane Library and Rubicon Research Repository were searched for studies reporting DCS incidence, venous gas embolism (VGE) or subjective health reports after multiday hyperbaric exposure in man and experimental animals. Twenty-nine studies fulfilled inclusion criteria. Three epidemiological studies reported statistically significant acclimatization to DCS in compressed-air workers after multiday hyperbaric exposure. One experimental study observed less itching after standardized simulated dives. Two human experimental studies reported lower DCS incidence after multiday immersed diving. Acclimatization to DCS has been observed in six animal species. Multiday diving had less consistent effect on VGE after hyperbaric exposure in man. Four studies observed acclimatization while no statistically significant acclimatization was reported in the remaining eight studies. A questionnaire study did not report any change in self-perceived health after multiday diving. This systematic review has not identified any study suggesting a sensitizing effect of multiday diving, and there is a lack of data supporting benefit of a day off diving after a certain number of consecutive diving days. The results suggest that multiday hyperbaric exposure probably will have an acclimatizing effect and protects from DCS. The mechanisms causing acclimatization, extent of protection and optimal procedure for acclimatization has been insufficiently investigated.
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Affiliation(s)
- Jan Risberg
- Office of Submarine and Diving Medicine, Norwegian Armed Forces Joint Medical Services
- NUI AS, Bergen, Norway
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Papadopoulou V, Lindholm P. An echo from the past: Building a Doppler repository for big data in diving research. Undersea Hyperb Med 2021; 48:57-58. [PMID: 33648034 DOI: 10.22462/01.03.2021.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Decompression sickness (DCS) remains a major operational concern for diving operations, submarine escape and high-altitude jumps. Aside from DCS symptoms, venous gas emboli (VGE) detected with ultrasound post-dive are often used as a marker of decompression stress in humans, with a specificity of 100% even though the sensitivity is poor [1]. Being non-invasive, portable and non-ionizing, ultrasound is particularly suited to regular and repeated monitoring. It could help elucidate inter- and intra-subject variability in VGE and DCS susceptibility, but analyzing these recordings remains a cumbersome task [2].
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Affiliation(s)
- Virginie Papadopoulou
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, North Carolina U.S
| | - Peter Lindholm
- Department of Emergency Medicine, School of Medicine, University of California, San Diego, La Jolla, California, U.S.S
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Abstract
Multiday hyperbaric exposure has been shown to reduce the incidence of decompression sickness (DCS) of compressed-air workers. This effect, termed acclimatization, has been addressed in a number of studies, but no comprehensive review has been published. This systematic review reports the findings of a literature search. PubMed, Ovid Embase, The Cochrane Library and Rubicon Research Repository were searched for studies reporting DCS incidence, venous gas embolism (VGE) or subjective health reports after multiday hyperbaric exposure in man and experimental animals. Twenty-nine studies fulfilled inclusion criteria. Three epidemiological studies reported statistically significant acclimatization to DCS in compressed-air workers after multiday hyperbaric exposure. One experimental study observed less itching after standardized simulated dives. Two human experimental studies reported lower DCS incidence after multiday immersed diving. Acclimatization to DCS has been observed in six animal species. Multiday diving had less consistent effect on VGE after hyperbaric exposure in man. Four studies observed acclimatization while no statistically significant acclimatization was reported in the remaining eight studies. A questionnaire study did not report any change in self-perceived health after multiday diving. This systematic review has not identified any study suggesting a sensitizing effect of multiday diving, and there is a lack of data supporting benefit of a day off diving after a certain number of consecutive diving days. The results suggest that multiday hyperbaric exposure probably will have an acclimatizing effect and protects from DCS. The mechanisms causing acclimatization, extent of protection and optimal procedure for acclimatization has been insufficiently investigated.
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Affiliation(s)
- Jan Risberg
- Office of Submarine and Diving Medicine, Norwegian Armed Forces Joint Medical Services
- NUI AS, Bergen, Norway
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Dunford RG, Denoble PD, Forbes R, Pieper CF, Howle LE, Vann RD. A study of decompression sickness using recorded depth-time profiles. Undersea Hyperb Med 2020; 47:75-91. [PMID: 32176949 DOI: 10.22462/01.03.2020.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
INTRODUCTION 122,129 dives by 10,358 recreational divers were recorded by dive computers from 11 manufacturers in an exploratory study of how dive profile, breathing gas (air or nitrox [N2/O2] mixes), repetitive diving, gender, age, and dive site conditions influenced observed decompression sickness (DCSobs). Thirty-eight reports were judged as DCS. Overall DCSobs was 3.1 cases/10⁴ dives. METHODS Three dive groups were studied: Basic (live-aboard and shore/dayboat), Cozumel Dive Guides, and Scapa Flow wreck divers. A probabilistic decompression model, BVM(3), controlled dive profile variability. Chi-squared test, t-test, logistic regression, and log-rank tests evaluated statistical associations. RESULTS (a) DCSobs was 0.7/10⁴ (Basic), 7.6/10⁴ (Guides), and 17.3/104 (Scapa) and differed after control for dive variability (p ≺ 0.001). (b) DCSobs was greater for 22%-29% nitrox (12.6/10⁴) than for 30%-50% nitrox (2.04/10⁴) (p ≤ 0.0064) which did not differ from air (2.97/1010⁴). (c) For daily repetitive dives (≺12-hour surface intervals (SI)), DCS occurred only following one or two dives (4.3/1010⁴ DCSobs; p ≺ 0.001) where SIs were shorter than after three or more dives. (d) For multiday repetitive dives (SIs ≺ 48 hours), DCS was associated with high multiday repetitive dive counts only for Guides (p = 0.0018). (e) DCSobs decreased with age at 3%/year (p ≤ 0.0144). (f) Males dived deeper (p ≺ 0.001) but for less time than females (p ≺ 0.001). CONCLUSION Collecting dive profiles with dive computers and controlling for profile variability by probabilistic modeling was feasible, but analytical results require independent confirmation due to limited observed DCS. Future studies appear promising if more DCS cases are gathered, stakeholders cooperate, and identified data collection problems are corrected.
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Affiliation(s)
| | | | | | - Carl F Pieper
- Department of Orthopaedic Surgery, Juntendo University School of Medicine
| | - Laurens E Howle
- Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina U.S
| | - Richard D Vann
- AN America, Durham, North Carolina U.S
- Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina U.S
- Hyperbaric Center and Anesthesia Department, Duke Medical Center, Durham, North Carolina U.S
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Lippmann J. Rescue and resuscitation factors in scuba diving and snorkeling fatalities in Australia, 2001-2013. Undersea Hyperb Med 2020; 47:101-109. [PMID: 32176951 DOI: 10.22462/01.03.2020.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- John Lippmann
- DAN Asia-Pacific Foundation / Australasian Diving Safety Foundation (ADSF), Canterbury, Victoria, Australia
- Department of Public Health and Preventive Medicine, Monash University, Victoria
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Edmonds C, Lippmann J, Bove A. Immersion pulmonary edema: an analysis of 31 cases from Oceania. Undersea Hyperb Med 2019; 46:603-610. [PMID: 31683357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
AIM To review incidents of immersion pulmonary edema (IPE) from Oceania, to determine the demographics, diving parameters, and comorbidities that may be related to this disorder. METHOD Incidents of IPE, most of which were documented by Divers Alert Network Asia-Pacific (DAN AP) or reported in our medical literature, were analyzed. They included interviews with the survivors and a review of available medical records. Only incidents diagnosed as IPE by specialist diving physicians or pathologists with experience in the investigation of diving accidents were included. RESULTS Thirty-one IPE incidents in divers from Oceania were documented. There were two surface snorkelers, 22 scuba air divers and seven nitrox divers, which included three closed-circuit rebreathers (CCR). The mean (SD) age was 53 (12) years, 58% of victims were females, and the average dive profile was to a maximum depth of 19 msw for 25 minutes. Six victims (19%) had previous episodes of IPE. There were nine recorded fatalities in this cohort. Medical comorbidities were recorded in 68%, with 42% being cardiac. The latter included valvular disease in 29%, transient cardiomyopathies in 26% and dysrhythmias in 16%. CONCLUSION IPE was more likely in middle-aged females, in experienced divers, and during ascent or after surfacing. Commonly reported associations such as exertion, stress, cold exposure, negative inspiratory pressure, hypertension, overhydration, tight wetsuit, aspiration and certain medications were identified. This series supports the hypothesis that the elderly IPE subjects are likely to have comorbidities and be susceptible to IPE recurrences and fatalities unless the contributing factors can be identified and addressed.
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Affiliation(s)
| | - John Lippmann
- DAN Asia-Pacific Foundation/Australasian Diving Safety Foundation, Victoria, Australia
- Department of Public Health and Preventative Medicine, Monash University, Victoria, Australia
| | - Alfred Bove
- Department of Public Health and Preventative Medicine, Monash University, Victoria, Australia
- Lewis Katz School of Medicine, Temple University, PA, U.S
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Ozyigit T, Yavuz C, Egi SM, Pieri M, Balestra C, Marroni A. Clustering of recreational divers by their health conditions in a database of a citizen science project. Undersea Hyperb Med 2019; 46:171-183. [PMID: 31051062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Divers Alert Network Europe has created a database with a large amount of dive-related data that has been collected since 1993 within the scope of the Diving Safety Laboratory citizen science project. The main objectives of this study are the grouping divers by their health information and revealing significant differences in diving parameters using data mining techniques. Due to the methodology of the project, data cleaning was performed before applying clustering methods in order to eliminate potential mistakes resulting from inaccuracies and missing information. Despite the fact that 63% of the data were lost during the cleaning phase, the remaining 1,169 "clean" diver data enabled meaningful clustering using the "two-step" method. Experienced male divers without any health problems are in Cluster 1. Male and female divers with health problems and high rates of cigarette smoking are in Cluster 2; healthy, overweight divers are in Cluster 3. There are significant differences in terms of dive parameters including pre- and post-dive conditions with respect to each group, such as: exercise level, alcohol consumption, thermal comfort, equipment malfunctions, and maximum depth. The study proves the usefulness of citizen science projects, while data collection methodologies can be improved to decrease potential mistakes resulting from inconsistencies, inaccuracies and missing information. It is hypothesized that if naturally occurring clusters of divers were identified it might be possible to identify risk factors arising from different clusters while merging the database with other dive accident databases in the future.
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Affiliation(s)
- Tamer Ozyigit
- Galatasaray University Computer Engineering Department, Besiktas, Istanbul, Turkey
| | - Cuneyt Yavuz
- Galatasaray University Computer Engineering Department, Besiktas, Istanbul, Turkey
| | - Salih Murat Egi
- Galatasaray University Computer Engineering Department, Besiktas, Istanbul, Turkey
- DAN Europe Research Division, Roseto, Italy
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Koca E, Sam B, Arican N, Toklu A. Evaluation of fatal diving accidents in Turkey. Undersea Hyperb Med 2019; 45:633-638. [PMID: 31166684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In any kind of diving there is a risk of accidents, as the move from the topside environment to underwater can affect a diver’s physiological and psychological condition. It is important to investigate dive accidents to clarify the causative factors and determine preventive measures. In this study, autopsy files of fatal dive accident cases were reviewed to evaluate demographic data, type of diving, purpose of dive, seasonal distribution, autopsy findings, and causes of death. We reviewed 56 fatal dive accident files from autopsy units in cities where dive activities are concentrated and from the archive of the Turkish Underwater Federation. Four cases were excluded from the study since we were unable to obtain autopsy reports. Of 52 cases there were 20 scuba divers, two surface-supplied divers and 30 breath-hold divers. The majority of cases involved males (94%). The average age of 50 cases was 38.6; age estimation for two cases could not be determined due to advanced putrefaction. Of these fatal dive accidents 75% took place over a period of six months between May and October. Drowning was recorded as the primary cause of death in these cases. X-ray imaging was used in four (8%) cases. A special autopsy technique was used for nine (17%) cases, to detect possible pulmonary barotrauma and arterial gas embolism. The forensic specialist who is planning to conduct the autopsy for a dive fatality should have knowledge and experience about dive physics and physiology as well as physiopathology of dysbaric injuries.
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Affiliation(s)
- Eylem Koca
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Bulent Sam
- Council of Forensic Medicine, Istanbul, Turkey
| | - Nadir Arican
- Department of Forensic Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Akin Toklu
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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Abstract
INTRODUCTION Scuba diving has long been contraindicated for asthmatics. Recommendations are evolving towards authorisation under certain conditions. Our objective was to review the literature on the risks associated with scuba diving among asthmatics and about recommendations on this subject. MATERIALS AND METHODS We used the MEDLINE and LiSSa databases, until June 2018, in French, English or Spanish language, with the keywords "asthma AND diving" and "asthme plongée" respectively. References to the first degree were analyzed. RESULTS We have included 65 articles. Risk of bronchospasm is well documented, particularly in cold and/or deep water, or in the event of exposure to allergens (compressor without filter). Nonasthmatic atopic divers may be at greater risk of developing bronchial hyper-reactivity. Although the theoretical risk exists, epidemiological studies do not seem to show an over-risk of barotrauma, decompression sickness or arterial gas embolism in asthmatics. French, British, American, Spanish and Australian societies agreed on the exclusion of patients with moderate to severe persistent asthma, FEV1<80%, active asthma in the last 48hours, exercise/cold asthma and poor physical fitness. CONCLUSION A diver's examination should include a triple assessment: asthma control, number of exacerbations and treatment compliance. Homogenizing the recommendations would improve the framework for the practice of diving among asthmatics and allow larger studies in this population. Communicating the current recommendations remains important to divers, dive instructors and doctors in the context of the development of scuba diving.
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Affiliation(s)
- A Muller
- Université de Lille, 59000 Lille, France
| | - M Rochoy
- Université de Lille, 59000 Lille, France.
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Chin W, Huchim-Lara O, Ramachandran M, Endo B, Sprau S. Understanding dive behavior of artisanal fishermen divers of the Yucatán Peninsula. Undersea Hyperb Med 2018; 45:623-638. [PMID: 31158929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
INTRODUCTION/BACKGROUND Artisanal fishermen dive for sustenance. The lifetime prevalence of decompression sickness (DCS) in this population is alarmingly high. We wanted to understand the level of decompression stress fishermen in this region of the Yucatán experience in their daily fishing effort. We used a mathematical model to quantify nitrogen-loading in a nine-tissue compartment model. MATERIALS AND METHODS Approved by the UCLA IRB 2 #13-000532, this study was conducted during fishing seasons 2012 through 2017. Diving fishermen were instructed to attach dive recorders to their waists every fishing day during the study period. Sensus Ultra dive recorders (ReefNet Inc.), with an accuracy of ±1 foot of seawater (fsw), 0.304 meters, and an activation depth of 10 fsw, 3.04 meters, were used to record dive parameters. Sampling interval was set to 10 seconds. A program in RStudio was created to extract the dive profiles of each fishing day and curtail into single-line outputs: pressure, time, date, start of dive and end of dive. An exponential decay formula was used to calculate the nitrogen-loading pressures for nine theoretical tissue compartments. Final nitrogen pressure, controlling compartments, decompression stop and time at stop were calculated. RESULTS Fishermen completed 4,961 dives over 1,758 diving days during the study period. The 40-minute compartment controlled most of the dives. The 80-minute compartment controlled 5%-20% of dives two through five. Decompression stop times for the last dive ranged from one minute to 190 minutes. Most of the required stop time observed was seen at depths of 1-15 fsw.
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Affiliation(s)
- Walter Chin
- UCLA Radiation Oncology, Los Angeles, California U.S
| | | | | | - Brandon Endo
- UCLA Emergency Medicine, Los Angeles, California U.S
| | - Susan Sprau
- UCLA Hyperbaric Medicine, Los Angeles, California U.S
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Lafère P, Germonpré P, Guerrero F, Marroni A, Balestra C. Decreased Incidence of Pulmonary Barotrauma After Discontinuation of Emergency Free Ascent Training. Aerosp Med Hum Perform 2018; 89:816-821. [PMID: 30126514 DOI: 10.3357/amhp.5003.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Because a significant association between training to perform emergency free ascent (EFA) and the occurrence of pulmonary barotrauma (PBT) was demonstrated in 2006, the Belgian Underwater Federation (BUF) decided to discontinue this procedure. An evaluation was needed 10 yr after the implementation of this change. METHODS All medical records with a diagnosis of PBT that occurred in Belgium from November 2006 to September 2016 were prospectively collected. Data on the proportion of in-water skills training dives were obtained from BUF. RESULTS A total of 5 cases of PBT were identified, significantly down from 34 cases in the previous 10-yr period. Of those cases, four occurred during training dives (two during ascent training). Analysis of the case files furthermore showed that two should have been medically disqualified from diving. Compared with the retrospective cohort (1995-2005), incidences are significantly reduced from 0.83 to 0.078/10,000 training dives and from 3.33 to 0.11/10,000 ascent-training dives; concomitantly, the incidence of PBT in nontraining dives also was reduced (from 0.0042 to 0.0014×10-4/10,000 dives), possibly because less divers undertake the EFA procedure in case of a technical incident and have learned to solve the problem differently. DISCUSSION Discontinuation of emergency free ascent training was associated with a reduction in the incidence of PBT in the 10-yr follow-up period. We observed a significant decrease of PBT during training dives, confirming the hypothesis that EFA training in its previous form did not contribute significantly to diving safety.Lafère P, Germonpré P, Guerrero F, Marroni A, Balestra C. Decreased incidence of pulmonary barotrauma after discontinuation of emergency free ascent training. Aerosp Med Hum Perform. 2018; 89(9):816-821.
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Mendez-Dominguez N, Huchim-Lara O, Chin W, Carrillo-Arceo L, Camara-Koyoc I, Cárdenas-Dajdaj R, Dogre-Sansores O. Body mass index in association with decompression sickness events: cross-sectional study among small-scale fishermen-divers in southeast Mexico. Undersea Hyperb Med 2018; 45:445-451. [PMID: 30241124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
INTRODUCTION Decompression sickness is endemic to small-scale fishermen-divers from coastal communities in southeast Mexico; overweight and obesity are also highly prevalent in the region. Existing literature suggests it is possible that fat tissue could play a role in decompression sickness pathophysiology. Our aim in this study is to describe the association between the number and severity of DCS events treated at the hyperbaric program and fishermen-diver body mass index. METHODS In this cross-sectional study, we obtained anthropometric measurements of 105 fishermen-divers and reviewed clinical records of each participant at a hyperbaric program. RESULTS Average BMI among participants was 34.5 ± 4.7, while 9.5% (n=10) were healthy-weighted, 28.6% (n=30) were overweight and 42.8% (n=65) were obese. Number of DCS events per diver was associated with BMI and severity of DCS in linear regression models. CONCLUSIONS Overweight and obesity are highly preventable health problems; our results suggest that an association between these conditions and the frequency and the severity of DCS are an important topic to be further considered in longitudinal prospective studies.
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Affiliation(s)
| | | | - Walter Chin
- UNEXMAR, Universidad Marista de Mérida, Mérida, Yucatán
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13
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Huchim-Lara O, Seijo JC. Risk perception in small-scale fishers and hyperbaric personnel: A risk assessment of hookah diving. Undersea Hyperb Med 2018; 45:313-322. [PMID: 30028918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hookah diving is a fishing method used in many small-scale fisheries in the Gulf of Mexico and the Caribbean Sea, as well as in many coastal fisheries around the world. Many high-value species like sea cucumber and spiny lobster, among others, are harvested via hookah diving. However, the fishing method presents a risk for both decompression illness and carbon monoxide poisoning, both causes of disabilities and death among small-scale fishers, and with significant negative impacts on the social and economic status of households and coastal communities. Currently, there is a misunderstanding among fishers concerning diving risks. Using a mixed-method analysis, this study reports the risk perceptions of small-scale fishers and hyperbaric personnel about hookah diving, and the actual diving accidents which occur in the spiny lobster and sea cucumber fisheries in the Yucatán northeastern ports. The study highlights the need for appropriate fishing technologies and increased awareness among fishers about the consequences of hookah diving. Fishery managers and health services can make priority decisions based on the information generated.
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Brett KD, Meintjes W. Incidence of otic barotrauma in Canadian Armed Forces shallow-water diver candidate students 2011-2015. Undersea Hyperb Med 2018; 45:249-255. [PMID: 30028912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
INTRODUCTION While otic barotrauma (OBT) is a common condition experienced by divers, data related to military divers is limited. This study aimed to determine the incidence of OBT in Canadian armed forces (CAF) shallow-water diver (SWD) students trained through the Fleet Dive Unit (Atlantic) (FDU[A]) between 2011-2015. METHODS A retrospective cohort evaluation was performed. The study group consisted of all SWD candidates who embarked on an SWD course through FDU(A) between 2011-2015. A total of 241 subjects comprised the final data analysis. RESULTS A total of 56 individuals (23.2%) suffered 60 instances of OBT, yielding an incidence density rate of 8.68 per 1,000 person-days on course. A total of 73 diving days (10.44 per 1,000 planned person-course days, or 4.87 diving days per course) were lost due to OBT. Of the reported OBT cases, 18% resulted in cessation of training, 72% in temporary removal from diving. There was no statistically significant association between sex, history of environmental allergies, previous dive qualification, age or rank and the development of OBT. CONCLUSIONS This study reveals that OBT is prevalent among CAF SWD candidates, with operational impact due to missed diving days. This study is limited, and further prospective study is recommended.
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Affiliation(s)
- K D Brett
- Canadian Forces Health Services, Canadian Armed Forces
- Division of Health Systems and Public Health, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Waj Meintjes
- Division of Health Systems and Public Health, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
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15
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Bárbara-Bataller E, Méndez-Suárez JL, Alemán-Sánchez C, Sánchez-Enríquez J, Sosa-Henríquez M. Change in the profile of traumatic spinal cord injury over 15 years in Spain. Scand J Trauma Resusc Emerg Med 2018; 26:27. [PMID: 29622032 PMCID: PMC5887209 DOI: 10.1186/s13049-018-0491-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/21/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Traumatic spinal cord injury remains a serious public health and social problem. Although incidence rates are decreasing in our environment, it is a high cost condition that is associated with great disability. The objective of this study was to describe the epidemiological and demographic characteristics of traumatic spinal cord injury and to analyse its epidemiological changes. METHODS This study was an observational study with prospective monitoring of all traumatic spinal cord injury patients in the Canary Islands, Spain (2.1 million inhabitants) between 2001 and 2015. RESULTS Over the specified period of the study, 282 patients suffered a traumatic spinal cord injury. The crude incidence rate was 9.3 cases per million people/year. The patients' mean age increased from 38 years (2001-2005) to 48 years (2011-2015) (p < 0.05). Overall, 80.1% of patients were males. The trauma mechanisms of spinal cord injury were falls in 44%, traffic accidents in 36.5%, diving accidents in 8.9% and others in 10.7%. While traffic accidents decreased, falls increased, particularly in the elderly (p < 0.05). The most frequently affected level was the cervical spine (50.9%), and incomplete tetraplegia was the most prevalent group (29.8%). A total of 76.6% of all patients suffered a vertebral fracture, and 91.6% of these required surgery. Among 282 patients, 12.5% were transferred to residences. The patients transferred increased from 8.5% in the first period to 20.0% (p < 0.05) in the last period. Such cases were related to age, cervical level injuries and injuries associated with poor functionality (p < 0.05). CONCLUSIONS The rise in the number of falls among the older population, as well as the reduction in traffic accidents, decreased the incidence of traumatic spinal cord injury in our environment. This change in the profile of new traumatic spinal cord injuries led us to reformulate the functional objectives planned for these patients upon admission to specialized units, to plan destination-upon-discharge in advance and to promote campaigns to prevent spinal cord injury in older adults.
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Affiliation(s)
- Enrique Bárbara-Bataller
- Unit of Spinal Cord Injury, Rehabilitation Service of the University Insular Hospital of Gran Canaria, Avenida Maritima S/N, 350016 Las Palmas de Gran Canaria, Spain
| | - José Luis Méndez-Suárez
- Unit of Spinal Cord Injury, Rehabilitation Service of the University Insular Hospital of Gran Canaria, Avenida Maritima S/N, 350016 Las Palmas de Gran Canaria, Spain
| | - Carolina Alemán-Sánchez
- Unit of Spinal Cord Injury, Rehabilitation Service of the University Insular Hospital of Gran Canaria, Avenida Maritima S/N, 350016 Las Palmas de Gran Canaria, Spain
| | - Jesús Sánchez-Enríquez
- Unit of Spinal Cord Injury, Rehabilitation Service of the University Insular Hospital of Gran Canaria, Avenida Maritima S/N, 350016 Las Palmas de Gran Canaria, Spain
| | - Manuel Sosa-Henríquez
- University Institute for Biomedical and Health Research, Osteoporosis and Mineral Metabolism Research Group, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
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16
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Rendina C. A historical review of the U.S. Navy's busiest recompression chamber in the Pacific theater with a current perspective on caring for civilian divers within its area of responsibility: short communication. Undersea Hyperb Med 2018; 45:183-189. [PMID: 29734570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
On the island Nation of Guam, the United States Department of Defense has stationed military personnel from every service branch. Guam is utilized as a strategic waypoint for the U.S. military in the Pacific theater. As the largest service branch in the region, the Navy has placed a few Diving Medical Officers in Guam to collectively manage and treat patients with recompression therapy. Guam is also a popular tourist destination, with multiple recreational diving companies certifying individuals who are looking to take advantage of the beautiful warm water and exotic marine life. Unfortunately, with an increase in training and certifying inexperienced divers, came an increase in the operational tempo of the U.S. Navy's recompression chamber on Guam. The recompression chamber on Naval Base Guam (NBG) has been treating patients since 1971. With the only multiplace chamber in the Mariana Islands, Diving Medical Officers, with the accompanying chamber staff, treat military personnel, active-duty sponsored patients and civilian patients. Treating civilian patients by military providers through military treatment facilities presents multiple issues that must be addressed in an effort to provide efficient quality medical care. This article reviews the records, documents, and activity of the NBG chamber over the last four decades. Through the obtained data the information provides projected financial reimbursement from civilian patients. The article also sheds light on areas of needed improvement with regard to data collection, third-party financial collection efforts and the necessity of an inclusive electronic health record (EHR) for military and civilian patients.
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Affiliation(s)
- Christopher Rendina
- USNH Guam Occupational Medicine, U.S. Naval Hospital Guam, BLDG 50 Farenholt Ave, Agana Heights, GU 96910
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Meyer MF, Boor M, Jansen S, Pracht ED, Felsch M, Klünter HD, Hüttenbrink KB, Beutner D, Grosheva M. Influence of repetitive diving in saltwater on pressure equalization and Eustachian tube function in recreational scuba divers. Diving Hyperb Med 2017; 47:214-215. [PMID: 29241230 PMCID: PMC6706334 DOI: 10.28920/dhm47.4.216-222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 09/11/2017] [Indexed: 11/05/2022]
Abstract
INTRODUCTION We investigated in a prospective, observational trial the feasibility of using the Eustachian tube function test (ETFT) to measure the effect of repetitive pressure exposure during open seawater dives on Eustachian tube function. METHODS The study included 28 adult divers during six consecutive days of diving in the Red Sea. Participants underwent otoscopy and ETFT before the first dive, between each dive and after the last dive. ETFT included regular tympanometry (R-tymp), tympanometry after Valsalva (V-tymp) and after swallowing (S-tymp). The R-tymp was obtained as 'baseline' peak pressure. After a Valsalva, the peak pressure should shift (positively), revealing a positive shift of the tympanic membrane. This pressure shift is defined here as R-VdP. The changes in compliance and peak pressure were recorded and correlated with otoscopic findings and diving experience. Middle ear barotrauma was scored using the Edmonds modified TEED scale. RESULTS The 28 participants performed 437 dives. Positive shift of pressure in the middle ear was evident with significant changes from day one to day three (P < 0.0001). Divers with barotrauma showed significantly lower values of R-tymp peak pressure and significantly higher negative R-VdP, compared to divers with normal otoscopic findings (P < 0.05). Diving experience significantly correlated with R-tymp peak pressure and prevalence of middle ear barotrauma. CONCLUSION Significant changes in middle ear pressure and pressure equalization from repeated pressure exposure in saltwater were seen using ETFT. Repetitive, multi-day diving led to significantly decreased compliance and increased R-tymp peak pressure (overpressure) in the middle ear. Most profound changes were observed in less and intermediate experienced divers.
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Affiliation(s)
- Moritz F Meyer
- Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Cologne, Kerpener Straβe 62, 50937 Cologne, Germany,
| | - Manuela Boor
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
| | - Stefanie Jansen
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
| | | | - Moritz Felsch
- Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Germany
| | - Heinz D Klünter
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
| | - Karl-Bernd Hüttenbrink
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
| | - Dirk Beutner
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
| | - Maria Grosheva
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
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Abstract
The venous bubble load in the body after diving may be used to infer risk of decompression sickness (DCS). Retrospective analysis of post-dive bubbling and DCS was made on seven studies. Each of these investigated interventions, using an 18 meters of sea water (msw) air dive profile from Royal Navy Table 11 (Mod Air Table), equivalent to the Norwegian Air tables. A recent neurological DCS case suggested this table was not safe as thought. Two-hundred and twenty (220) man-dives were completed on this profile. Bubble measurements were made following 219 man-dives, using Doppler or 2D ultrasound measurements made on the Kisman-Masurel and Eftedal-Brubakk scales, respectively. The overall median grade was KM/EB 0.5 and the overall median maximum grade was KM/EB 2. Two cases of transient shoulder discomfort ("niggles") were observed (0.9% (95% CL 0.1% - 3.3%)) and were treated with surface oxygen. One dive, for which no bubble measurements were made, resulted in a neurological DCS treated with hyperbaric oxygen. The DCS risk of this profile is below that predicted by models, and comparison of the cumulative incidence of DCS of these data to the large dataset compiled by DCIEM [1, 2] show that the incidence is lower than might be expected.
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Affiliation(s)
- S Lesley Blogg
- SLB Consulting, c/o The Barn, Winton, Kirkby Stephen, Cumbria, CA17 4HL, United Kingdom
| | - Andreas Møllerløkken
- Barophysiology Group, Department of Circulation and Medical Imaging, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Mikael Gennser
- Section for Environmental Physiology, School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Sweden
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Huchim-Lara O, Chin W, Salas S, Rivera-Canul N, Cordero-Romero S, Tec J, Joo E, Mendez-Dominguez N. Decompression sickness among diving fishermen in Mexico: observational retrospective analysis of DCS in three sea cucumber fishing seasons. Undersea Hyperb Med 2017; 44:149-156. [PMID: 28777905 DOI: 10.22462/3.4.2017.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The probabilities of decompression sickness (DCS) among diving fishermen are higher than in any other group of divers. Diving behavior of artisanal fishermen has been directed mainly to target high-value species. The aim of this study was to learn about the occurrence of DCS derived from sea cucumber harvesting in the Yucatán Peninsula, Mexico. We conducted a retrospective chart review of diving fishermen treated at a multiplace hyperbaric chamber in Tizimín, Mexico. In total, 233 recompression therapies were rendered to 166 diving fishermen from 2014 to 2016. The average age was 36.7 ± 9.2 years (range: 20-59 years); 84.3% had experienced at least one DCS event previously. There was a correlation between age and DCS incidents (F: 8.3; R2: 0.07) and differences in the fishing depth between seasons (H: 9.99; p⟨0.05). Musculoskeletal pain was the most frequently reported symptom. Three divers, respectively, suffered permanent hearing loss, spinal cord injury and fatal outcome. Diving fishermen experience DCS at an alarmingly high rate, probably due to the type of species targeted, given the requirements in each case. Understanding divers' behaviors and their incentives while in pursuit of high-value species such as sea cucumber could help to find ways to mitigate health risks and help enforce regulation.
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Affiliation(s)
| | - Walter Chin
- University of California, Los Angeles, Los Angeles, California U.S
| | - Silvia Salas
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Mérida, Mérida, Yucatán, México
| | | | | | - Juan Tec
- Instituto Mexicano del Seguro Social, HGSMF 5, Tizimín, Yucatán, México
| | - Ellie Joo
- University of California, Los Angeles, Los Angeles, California U.S
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20
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Wingelaar TT, van Ooij PJA, van Hulst RA. Otitis externa in military divers: more frequent and less harmful than reported. Diving Hyperb Med 2017; 47:4-8. [PMID: 28357818 PMCID: PMC6147244 DOI: 10.28920/dhm47.1.4-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 01/25/2017] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Although otitis externa (OE) is a common disease, data related to (military) divers are limited. This study aimed to determine the incidence of OE in military divers during their initial training. We also wished to consider seasonal influences on incidence and whether early detection increases completion of the diving course. METHODS From January 2011 to October 2016 the Royal Netherlands Navy Diving School trained 189 divers. Up to December 2015 we used the training records for the analyses. From January 2016 onward all divers were prospectively screened. Pearson's chi-squared 2 and Fisher's exact tests were used to analyse the data. RESULTS In the 162 included divers, 30 cases of OE were identified. The incidence in 2016 was significantly higher than in 2011-2015 (17/35 (49%) versus 13/127 (10%), P < 0.001). Almost all cases developed after three weeks of diving. No influence of season was found (P = 0.354). Early diagnosis and treatment of OE does not seem to affect completion of diving courses (P = 0.28). Only in three cases did a diver have to discontinue the course due to OE. DISCUSSION This study suggests that OE is more frequent among military divers than earlier reported, most likely caused by prolonged water exposure. Diving activities can often be continued with standard topical treatment.
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Affiliation(s)
- Thijs T Wingelaar
- Royal Netherlands Navy Diving Medical Center, Rijkszee en marinehaven, 1780 CA Den Helder, The Netherlands
- Department of Anesthesiology, Academic Medical Center, University of Amsterdam
| | | | - Rob A van Hulst
- Department of Anesthesiology, Academic Medical Center, University of Amsterdam
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Lippmann J, McD Taylor D, Stevenson C, Mitchell S. The demographics and diving behaviour of DAN Asia-Pacific members with and without pre-existing medical conditions. Diving Hyperb Med 2016; 46:200-206. [PMID: 27966201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/05/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION This report examines Diver Alert Network Asia-Pacific (DAN AP) members with and without cardiac or respiratory conditions, diabetes or hypertension and compares their demographics, health and diving activities. METHODOLOGY Two online cross-sectional surveys of DAN AP members were conducted. The first sought information from 833 divers who applied for membership between July 2009 and August 2013 and who had declared the targeted medical conditions. The second, conducted between December 2014 and April 2015, was sent to 9,927 current members with known email addresses. The groups were compared for age, gender, body mass index, fitness, smoking and diving qualifications, history, currency and practices. RESULTS Of 343 (41%) respondents to the first survey, 267 (32%) provided sufficient information for inclusion. Of 1,786 (18%) respondents to the second survey, 1,437 (15%) had no targeted medical condition and were included in the analysis. Those with medical conditions were on average 4.7 years older (P 〈 0.001); more overweight or obese (68% versus 57%, P = 0.001); took more medications (57% vs. 29%, P 〈 0.001), smoked less (4% vs. 7%, P = 0.02) and did less repetitive diving (median 75 vs 90, P 〈 0.001). Other diving demographics were similar. CONCLUSIONS A substantial number of people are diving with medical conditions and there is a need to better understand the associated risks. Divers need to be well-educated about the potential impact such conditions may have on diving safety and should monitor their health status, especially as they age.
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Affiliation(s)
- John Lippmann
- Divers Alert Network Asia-Pacific, Ashburton, Victoria, Australia
- Health and Social Development, Deakin University, Melbourne, Victoria, Australia
- PO Box 384, Ashburton VIC 3147, Australia.
| | - David McD Taylor
- Emergency Medicine Research, Austin Hospital, Melbourne
- Department of Medicine, University of Melbourne, Melbourne
| | | | - Simon Mitchell
- Department of Anaesthesiology, School of Medicine, University of Auckland, New Zealand
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Lippmann J, Stevenson C, McD Taylor D, Williams J. Estimating the risk of a scuba diving fatality in Australia. Diving Hyperb Med 2016; 46:241-246. [PMID: 27966203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION There are few data available on which to estimate the risk of death for Australian divers. This report estimates the risk of a scuba diving fatality for Australian residents, international tourists diving in Queensland, and clients of a large Victorian dive operator. METHODOLOGY Numerators for the estimates were obtained from the Divers Alert Network Asia-Pacific dive fatality database. Denominators were derived from three sources: Participation in Exercise, Recreation and Sport Surveys, 2001-2010 (Australian resident diving activity data); Tourism Research Australia surveys of international visitors to Queensland 2006-2014 and a dive operator in Victoria 2007-2014. Annual fatality rates (AFR) and 95% confidence intervals (95% CI) were calculated using an exact binomial test. RESULTS Estimated AFRs were: 0.48 (0.37-0.59) deaths per 100,000 dives, or 8.73 (6.85-10.96) deaths per 100,000 divers for Australian residents; 0.12 (0.05-0.25) deaths per 100,000 dives, or 0.46 (0.20-0.91) deaths per 100,000 divers for international visitors to Queensland; and 1.64 (0.20-5.93) deaths per 100,000 dives for the dive operator in Victoria. On a per diver basis, Australian residents are estimated to be almost twenty times more likely to die whilst scuba diving than are international visitors to Queensland, or to lower than fourfold on a per dive basis. On a per dive basis, divers in Victoria are fourteen times more likely to die than are Queensland international tourists. CONCLUSIONS Although some of the estimates are based on potentially unreliable denominator data extrapolated from surveys, the diving fatality rates in Australia appear to vary by State, being considerably lower in Queensland than in Victoria. These estimates are similar to or lower than comparable overseas estimates, although reliability of all such measurements varies with study size and accuracy of the data available.
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Affiliation(s)
- John Lippmann
- Divers Alert Network (DAN) Asia-Pacific, Ashburton, Victoria, Australia
- School of Health and Social Development, Deakin University, Victoria, Australia
- PO Box 384, Ashburton VIC 3147, Australia.
| | | | - David McD Taylor
- Emergency Department, Austin Hospital, Victoria, Australia
- Department of Medicine, University of Melbourne, Victoria, Australia
| | - Jo Williams
- School of Health and Social Development, Deakin University, Victoria, Australia
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23
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Haynes P. Increasing the probability of surviving loss of consciousness underwater when using a rebreather. Diving Hyperb Med 2016; 46:253-259. [PMID: 27966205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/14/2016] [Indexed: 06/06/2023]
Abstract
Re-circulating underwater breathing apparatus (rebreathers) have become increasingly popular amongst sport divers. In comparison to open-circuit scuba, rebreathers are complex life support equipment that incorporates many inherent failure modes and potential for human error. This individually or in combination can lead to an inappropriate breathing gas. Analysis of rebreather diving incidents suggests that inappropriate breathing gas is the most prevalent disabling agent. This can result in spontaneous loss of consciousness (LoC), water aspiration and drowning. Protecting the airway by maintaining the diver/rebreather oral interface may delay water aspiration following LoC underwater; the possibility of a successful rescue is, thus, increased. One means of protecting the airway following LoC underwater is the use of a full-face mask (FFM). However, such masks are complex and expensive; therefore, they have not been widely adopted by the sport diving community. An alternative to the FFM used extensively throughout the global military diving community is the mouthpiece retaining strap (MRS). A recent study documented 54 LoC events in military rebreather diving with only three consequent drownings; all divers were reported to be using a MRS. Even allowing for the concomitant use of a tethered diving partner system in most cases, the low number of fatalities in this large series is circumstantially supportive of the efficacy of the MRS. Despite drowning featuring as a final common pathway in the vast majority of rebreather fatalities, the MRS has not been widely adopted by the sport rebreather diving community.
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Affiliation(s)
- Paul Haynes
- Director, Haynes Marine Ltd, 12 Polbare Close Stonehaven, Aberdeenshire AB39 3LG, Scotland, UK.
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Lippmann J, Lawrence C, Fock A, Jamieson S, Harris R. Provisional report on diving-related fatalities in Australian waters in 2011. Diving Hyperb Med 2016; 46:207-240. [PMID: 27966202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION An individual case review of diving-related deaths reported as occurring in Australia in 2011 was conducted as part of the DAN Asia-Pacific dive fatality reporting project. METHOD The case studies were compiled using reports from witnesses, the police and coroners. In each case, the particular circumstances of the accident and, where available, details from the post-mortem examination are provided. A chain of events analysis was conducted for each case. RESULTS In total, there were 30 reported fatalities (10 more than in 2010). These included 15 snorkel/breath-hold divers, 14 scuba divers and one diver using surface-supplied breathing apparatus. Twenty-four victims were males. The mean age of snorkelling victims was 49.6 (range 23-75) years and compressed gas divers 42.2 (range 23-55) years. Cardiac-related issues were thought to have been the disabling injury in the deaths of at least seven snorkel divers and five scuba divers. Immersion pulmonary oedema was implicated in at least one death; and three fatalities resulted from attacks by marine animals. Two novices died while under instruction/supervision after separation from their instructor in poor visibility. CONCLUSIONS Pre-existing medical conditions, separation and inadequate supervision and seafood collection in areas frequented by marine predators were once again features in several deaths in this series.
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Affiliation(s)
- John Lippmann
- Divers Alert Network (DAN) Asia-Pacific, Ashburton, Victoria, Australia
- Deakin University, Victoria, Australia
- PO Box 384, Ashburton VIC 3147, Australia.
| | | | - Andrew Fock
- Departments of Hyperbaric Medicine and Intensive Care Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Scott Jamieson
- Divers Alert Network (DAN) Asia-Pacific, Ashburton, Victoria, Australia
| | - Richard Harris
- Department of Diving and Hyperbaric Medicine, Royal Adelaide Hospital, South Australia. Australia
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Ranapurwala SI, Poole C, Marshall SW, Kucera KL, Denoble PJ, Wing S. Factors influencing adherence to pre-dive checklists among recreational scuba divers. Undersea Hyperb Med 2016; 43:827-832. [PMID: 28777520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pre-dive checklists can prevent mishaps, injuries, and deaths in recreational scuba diving. However, the prevalence of checklist use remains low. Understanding the environmental and individual factors influencing a diver's checklist use may help in promoting checklists. In the summer of 2012, 617 divers were enrolled in the intervention group of a cluster randomized trial. The divers received an intervention pre-dive checklist to use before they made dives. Logistic regression analyses were used to model adherence to pre-dive checklist with generalized estimating equations. About 70% divers (n=430) adhered to the intervention pre-dive checklist. Factors associated with greater adherence were the use of a diver's own written self-checklist - odds ratio (OR) = 2.48 (95% confidence interval: 0.95, 6.44), older age (⟩ 35 years) - OR = 1.67 (1.15, 2.42), and higher average annual dives (6-10 dives vs. 0-5 dives) - OR = 1.87 (1.09, 3.21). Factors associated with lower adherence were diving in North Carolina as compared to the Caribbean - OR = 0.42 (0.20, 0.85), non-white race - OR = 0.54 (0.27, 1.09), and female gender - OR = 0.77 (0.54, 1.12). Checklist adherence is also a function of risk perception, facilitators, and barriers. Future studies should try to understand diver risk perceptions, promote facilitators, and reduce barriers to foster the use of pre-dive checklists.
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Affiliation(s)
- Shabbar I Ranapurwala
- Injury Prevention Research Center, Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa U.S
- Divers Alert Network, Durham, North Carolina U.S
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina U.S
| | - Charles Poole
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina U.S
| | - Stephen W Marshall
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina U.S
| | - Kristen L Kucera
- Department of Exercise and Sports Science, University of North Carolina, Chapel Hill, North Carolina U.S
| | | | - Steve Wing
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina U.S
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Vinkel J, Bak P, Hyldegaard O. Danish diving-related fatalities 1999-2012. Diving Hyperb Med 2016; 46:142-149. [PMID: 27723014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 06/30/2016] [Indexed: 06/06/2023]
Abstract
AIM The purpose was to explore causative tendencies among diving fatalities to prevent similar injuries in the future. METHODS We report 33 fatal diving injuries that occurred among Danish divers during the period 1999-2012 in Scandinavian waters. The study was performed as a retrospective overview. The empiric data consists of police reports, forensic autopsy reports and examination of the diving equipment. Data were assembled and analyzed using Pivot and Excel. Frequencies and means (± SD) were used to describe categorical and continuous variables respectively. RESULTS The mean age was 38.9 years and drowning was considered the cause of death in 24 of 28 divers for whom a diagnosis was possible. Elevated body mass index (18 of 22 divers had a BMI 〉 25) was overrepresented in our group compared to the background population. A drysuit was worn by 17 divers. Diving independently of a dive centre and mishandling of buoyancy aids were common risk factors. Only two divers released their weights. Three-quarters of those who did not would have increased their chance of survival by doing so; nevertheless, in a quarter of cases the weights were not readily releasable or not releasable at all. CONCLUSION Unfamiliarity with drysuit diving, lack of a diving buddy and mismanagement of weights were important contributors to diving injuries.
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Affiliation(s)
- Julie Vinkel
- Hyperbaric Medicine Centre, Department of Anesthesiology and Surgery, Head and Orthopedic Centre, Rigshospitalet 2100 Copenhagen, Denmark.
| | - Peter Bak
- Hyperbaric Medicine Centre, Department of Anesthesiology and Surgery, Head and Orthopedic Centre, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Ole Hyldegaard
- Hyperbaric Medicine Centre, Department of Anesthesiology and Surgery, Head and Orthopedic Centre, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
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Potts L, Buzzacott P, Denoble P. Thirty years of American cave diving fatalities. Diving Hyperb Med 2016; 46:150-154. [PMID: 27723015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Cave divers enter an inherently dangerous environment that often includes little visibility, maze-like passageways and a ceiling of rock that prevents a direct ascent to the surface in the event of a problem. METHODS Reports of cave diving fatality cases occurring between 01 July 1985 and 30 June 2015 collected by Divers Alert Network were reviewed. Training status, safety rules violated, relevancy of the violations, and root causes leading to death were determined. RESULTS A total of 161 divers who died were identified, 67 trained cave divers and 87 untrained. While the annual number of cave diving fatalities has steadily fallen over the last three decades, from eight to less than three, the proportion of trained divers among those fatalities has doubled. Data regarding trained cave divers were divided into two equal 15-year time periods. Trained cave divers who died in the most recent time period were older but little else differed. The most common cause of death was asphyxia due to drowning, preceded by running out of breathing gas, usually after getting lost owing to a loss of visibility caused by suspended silt. An overwhelming majority of the fatalities occurred in the state of Florida where many flooded caves are located. CONCLUSION Even with improvements in technology, the greatest hazards faced by cave divers remain unchanged. Efforts to develop preventative interventions to address these hazards should continue.
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Affiliation(s)
- Leah Potts
- Divers Alert Network, Durham, North Carolina, Department of Agricultural and Biological Engineering, University of Florida, Gainesville, Florida, USA
| | - Peter Buzzacott
- School of Sports Science, Exercise and Health, University of Western Australia, Crawley, Australia, Divers Alert Network 6 West Colony Place, Durham, 27705, USA,
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Cialoni D, Pieri M, Giunchi G, Sponsiello N, Lanzone AM, Torcello L, Boaretto G, Marroni A. Detection of venous gas emboli after repetitive breath-hold dives: case report. Undersea Hyperb Med 2016; 43:449-455. [PMID: 28763174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Neurological symptoms after breathhold (BH) diving are often referred to as "Taravana" and considered a form of decompression sickness. However, the presence of "high" gas embolism after BH diving has never been clearly shown. This study showed high bubble formation after BH diving. MATERIALS AND METHODS We performed transthoracic echocardiography on a 53-year-old male spearfishing diver (180 cm; 80 kg; BMI 24.7) 15 minutes before diving and at 15-minute intervals for 90 minutes after diving in a 42-meter-deep pool. Number of dives, bottom time and surface intervals were freely determined by the diver. Dive profiles were digitally recorded for depth, time and surface interval, using a freediving computer. Relative surface interval (surface interval/diving time) and gradient factor were calculated. REULTS High bubble grades were found in all the recorded echocardiograms. From the first to third recording (45 minutes), Grade 4 Eftedal-Brubakk (EB) bubbles were observed. The 60-, 75- and 90-minute recordings showed a reduction to Grades 3, 2 and 1 EB. Mean calculated GF for every BH dive was 0.22; maximum GF after the last dive was 0.33. CONCLUSIONS High bubble grades can occur in BH diving, as confirmed by echocardiographic investigation. Ordinary methods to predict inert gas supersaturation may not able to predict Taravana cases.
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Affiliation(s)
- D Cialoni
- DAN Europe Research Division, Roseto degli Abruzzi, Italy
- Apnea Academy Research, Padua, Italy
| | - M Pieri
- DAN Europe Research Division, Roseto degli Abruzzi, Italy
| | - G Giunchi
- DAN Europe Research Division, Roseto degli Abruzzi, Italy
| | - N Sponsiello
- DAN Europe Research Division, Roseto degli Abruzzi, Italy
- Apnea Academy Research, Padua, Italy
| | - A M Lanzone
- UU.OO. di Cardiologia e Cardiochirurgia; Istituto Clinico San Rocco, Ome (Bs), Lombardy, Italy
| | - L Torcello
- Habilita, Hyperbaric Department; Zingonia (BG), Lombardy, Italy
| | - G Boaretto
- Swimming pool Y-40 research coordinator, Padua, Italy
| | - A Marroni
- DAN Europe Research Division, Roseto degli Abruzzi, Italy
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Guenzani S, Mereu D, Messersmith M, Olivari D, Arena M, Spanò A. Inner-ear decompression sickness in nine trimix recreational divers. Diving Hyperb Med 2016; 46:111-116. [PMID: 27334999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/12/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Recreational technical diving, including the use of helium-based mixes (trimix) and the experimentation of new decompression algorithms, has become increasingly popular. Inner-ear decompression sickness (DCS) can occur as an isolated clinical entity or as part of a multi-organ presentation in this population. Physiological characteristics of the inner ear make it selectively vulnerable to DCS. The inner ear has a slower gas washout than the brain thus potentially making it more vulnerable to deleterious effects of any bubbles that cross a persistent foramen ovale (PFO) and enter the basilar artery, whilst the inner ear remains supersaturated but the brain does not. METHODS A questionnaire was made widely available to divers to analyse the incidence of inner-ear DCS after technical dives. One-hundred-and-twenty-six divers submitted completed questionnaires, and we studied each incident in detail. RESULTS Nine (7.1%) of the 126 responders reported to have had at least one episode of inner-ear DCS, of which seven occurred without having omitted planned decompression stops. Of these seven, four suffered from DCS affecting just the inner ear, while three also had skin, joint and bladder involvement. Five of the nine divers affected were found to have a PFO. All affected divers suffered from vestibular symptoms, while two also reported cochlear symptoms. Three divers reported to have balance problems long after the accident. CONCLUSIONS This small study is consistent with a high prevalence of PFO among divers suffering inner-ear DCS after trimix dives, and the pathophysiological characteristics of the inner ear could contribute to this pathology, as described previously. After an episode of DCS, vestibular and cochlear injury should always be examined for.
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Affiliation(s)
- Silvia Guenzani
- Hyperbaric Center, Niguarda Hospital, Reparto di anestesia e rianimazione Bozza Blocco DEA primo piano, Niguarda Hospital, Piazza dell'ospedale maggiore, Milano, Italy, Phone: +39-(0)34-9868-3498, E-mail:
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Svendsen Juhl C, Hedetoft M, Bidstrup D, Jansen EC, Hyldegaard O. Decompression illness treated in Denmark 1999-2013. Diving Hyperb Med 2016; 46:87-91. [PMID: 27334996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/13/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION The incidence, diver characteristics and symptomatology of decompression illness (DCI) in Denmark has not been assessed since 1982, and the presence of long-term residual symptoms among divers receiving hyperbaric oxygen therapy in Denmark has never been estimated to our knowledge. METHODS We undertook a retrospective study of the incidence and characteristics of DCI cases in Denmark for the period of 1999 to 2013. Medical records and voluntary questionnaires were reviewed, extracting data on age, gender, weight, height, diver certification level, diving experience, number of previous dives, type of diving, initial type of hyperbaric treatment and DCI symptoms. Trend in annual case numbers was evaluated using run chart analysis and Spearman's correlation. Age, height, weight, and BMI were evaluated using linear regression. The presence of long-term residual symptoms was investigated by phone interviewing the subgroup of divers treated in 2009 and 2010. RESULTS Two-hundred-and-five DCI cases were identified. The average annual case load was 14 with no significant trend during the study period (P = 0.081). Nor did we find any trend in age, weight, height or BMI. The most frequent symptoms were paraesthesia (50%), pain (42%) and vertigo (40%). Thirteen out of the subgroup of 30 divers had residual symptoms at discharge from hospital, and six out of 24 of these divers had residual symptoms at the time of follow-up. CONCLUSIONS We observed a more than ten-fold increase in DCI-cases since the period 1966-1980. In the subgroup of divers treated in 2009/2010, a quarter had long-term residual symptoms as assessed by telephone interview, which is in keeping with the international literature, but still a reminder that DCI can have life-long consequences.
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Affiliation(s)
- Christian Svendsen Juhl
- Hyperbaric Medicine Centre, Department of Anaesthesiology, Centre of Head and Orthopaedics, University Hospital of Copenhagen, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark,
| | - Morten Hedetoft
- Hyperbaric Medicine Centre, Department of Anaesthesiology, Centre of Head and Orthopaedics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Daniel Bidstrup
- Hyperbaric Medicine Centre, Department of Anaesthesiology, Centre of Head and Orthopaedics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Erik Christian Jansen
- Hyperbaric Medicine Centre, Department of Anaesthesiology, Centre of Head and Orthopaedics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Ole Hyldegaard
- Hyperbaric Medicine Centre, Department of Anaesthesiology, Centre of Head and Orthopaedics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
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Cummings B. The world as it is. British Sub-Aqua Club (BSAC) diving incidents report 2014. Diving Hyperb Med 2015; 45:259-260. [PMID: 26821389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Shykoff BE. Residual oxygen time model for oxygen partial pressure near 130 kPa (1.3 atm). Undersea Hyperb Med 2015; 42:547-564. [PMID: 26742255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A two-part residual oxygen time model predicts the probability of detectible pulmonary oxygen toxicity P(P[O2tox]) after dives with oxygen partial pressure (PO2) approximately 130 kPa, and provides a tool to plan dive series with selected risk of P[O2tox]. Data suggest that pulmonary oxygen injury at this PO2 is additive between dives. Recovery begins after a delay and continues during any following dive. A logistic relation expresses P(P[O2tox]) as a function of dive duration (T(dur)) [hours]: P(P[O2tox]) = 100/[1+exp (3.586-0.49 x T(dur))] This expression maps T(dur) to P(P[O2tox]) or, in the linear mid-portion of the curve, P(P[O2tox]) usefully to T(dur). For multiple dives or during recovery, it maps to an equivalent dive duration, T(eq). T(eq) was found after second dives of duration T(dur 2). Residual time from the first dive t(r) = T(eq) - T(dur2). With known t(r), t and T(dur) a recovery model was fitted. t(r) = T(dur) x exp [-k x((t-5)/T(dur)2], where t = t - 5 hours, k = 0.149 for resting, and 0.047 for exercising divers, and t represents time after surfacing. The fits were assessed for 1,352 man-dives. Standard deviations of the residuals were 8.5% and 18.3% probability for resting or exercise dives, respectively.
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Blake DF, Gibbs CR, Commons KH, Brown LH. Middle ear barotrauma in a tourist-oriented, condensed open-water diver certification course: incidence and effect of language of instruction. Diving Hyperb Med 2015; 45:176-180. [PMID: 26415068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 08/09/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION In Professional Association of Diving Instructors (PADI) Open Water Diver certification courses that cater to tourists, instruction is often condensed and potentially delivered in a language that is not the candidate's native language. OBJECTIVE To assess the incidence of middle ear barotrauma (MEBt) in open-water diver candidates during a condensed four-day certification course, and to determine if language of instruction affects the incidence of MEBt in these divers. METHOD The ears of participating diving candidates were assessed prior to commencing any in-water compression. Tympanic membranes (TM) were assessed and graded for MEBt after the confined and open-water training sessions. Tympanometry was performed if the candidate had no movement of their TM during Valsalva. Photographs were taken with a digital otoscope. RESULTS Sixty-seven candidates participated in the study. Forty-eight had MEBt at some time during their course. MEBt was not associated with instruction in non-native language (adjusted odds ratio = 0.82; 95% confidence intervals 0.21-3.91). There was also no significant association between the severity of MEBt and language of instruction. CONCLUSION Open-water diver candidates have a high incidence of MEBt. Education in non-native language does not affect the overall incidence of MEBt.
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Affiliation(s)
- Denise F Blake
- School of Marine and Tropical Biology, James Cook University, Townsville, IMB 23, Emergency Department 100 Angus Smith Drive, The Townsville Hospital, Douglas, Queensland, Australia, 4814, Phone: +61-(0)7-4433-1111, E-mail:
| | - Clinton R Gibbs
- Emergency Department, The Townsville Hospital, Townsville, School of Medicine, James Cook University, Townsville, Queensland, Australia
| | - Katherine H Commons
- Emergency Department, The Townsville Hospital, Townsville, Queensland, Australia
| | - Lawrence H Brown
- Mount Isa Centre for Rural and Remote Health, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Townsville, Australia
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St Leger Dowse M, Waterman MK, Penny CE, Smerdon GR. Does self-certification reflect the cardiac health of UK sport divers? Diving Hyperb Med 2015; 45:184-189. [PMID: 26415070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/27/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Since 2009, the United Kingdom diving incident data show an increasing number of fatalities in the over-50s age group. Previous studies also suggest some divers take cardiac medications. Since 2001, diving medicals have not been mandatory for UK sport divers. Instead, an annual medical self-certification form, submitted to their club/school or training establishment, is required. We documented in a survey of UK sport divers the prevalence of cardiac events and medications and the frequency of medical certifications. METHODS An anonymous on-line questionnaire was publicised. Measures included diver and diving demographics, prescribed medications, diagnosed hypertension, cardiac issues, events and procedures, other health issues, year of last diving medical, diagnosed persistent foramen ovale (PFO), smoking and alcohol habits, exercise and body mass index. RESULTS Of 672 completed surveys, hypertension was reported by 119 (18%) with 25 of these (21%) having not had a diving medical. Myocardial infarction 6 (1%), coronary artery bypass grafting 3 (< 1%), atrial fibrillation 19 (3%) and angina 12 (2%) were also reported. PFOs were reported by 28 (4%), with 20 of these opting for a closure procedure. From 83 treated incidences of decompression illness (DCI), 19 divers reported that a PFO was diagnosed. CONCLUSIONS Divers inevitably develop health problems. Some continue to dive with cardiac issues, failing to seek specialised diving advice or fully understand the role of the diving medical. Physicians without appropriate training in diving medicine may inform a diver they are safe to continue diving with their condition without appreciating the potential risks. The current procedure for medical screening for fitness to dive may not be adequate for all divers.
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Affiliation(s)
- Marguerite St Leger Dowse
- DDRC Healthcare, Hyperbaric Medical Centre, Plymouth Science Park, Research Way, Plymouth PL6 8BU, Devon, United Kingdom Phone: +44 (0) 1752 209999, E-mail:
| | | | | | - Gary R Smerdon
- Diving Diseases Reasearch Centre Healthcare, Plymouth, United Kingdom
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Harris RJ, Frawley G, Devaney BC, Fock A, Jones AB. A 10-year estimate of the incidence of decompression illness in a discrete group of recreational cave divers in Australia. Diving Hyperb Med 2015; 45:147-153. [PMID: 26415066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 07/07/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION The vast majority of freshwater cave diving in Australia occurs within the limestone caves of the Gambier karst in the south-east of South Australia. The incidence of decompression illness (DCI) in cave divers is presumed to be higher than open-water recreational divers because of the greater depths involved, but has not previously been reported. Our aim was to determine the incidence of DCI in cave divers, the patterns of diving and the outcome of hyperbaric treatment. METHODS This was a retrospective cohort study of cave divers with DCI presenting to the Royal Adelaide Hospital or The Alfred Hospital over a 10-year period between 2002 and 2012. We reviewed case notes of cave divers who were treated for DCI after diving in the Mt Gambier karst. As there are no records of the number of dives performed during the study period we generated a denominator for the incidence of DCI by extrapolating available data and making a number of assumptions about the number of dives per dive permit issued. RESULTS Sixteen patients were treated for DCI during the study period. The precipitating dive was a single deep decompression dive in seven cases, multiday repetitive dive sequences in eight and a non-decompression dive in one. Three of the 16 cases of DCI involved dives in excess of 90 metres' fresh water (mfw) using trimix. As the total estimated number of dives in the study period was approximately 57,000 the incidence of DCI in Australian cave divers was estimated to be 2.8:10,000 (0.028%). It is possible that the overall incidence of DCI is as high as 0.05%, and even higher when dives to depths greater than 90 mfw are involved. CONCLUSIONS The estimated incidence of DCS in this series is lower than expected but consistent with other series describing DCI in cold-water recreational diving.
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Affiliation(s)
- Richard Jd Harris
- Hyperbaric Medicine Unit, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia, Phone: +64-(0)8-8222-5116 E-mail:
| | - Geoffrey Frawley
- Department of Intensive Care and Hyperbaric Medicine, The Alfred Hospital, Melbourne
| | - Bridget C Devaney
- Department of Intensive Care and Hyperbaric Medicine, The Alfred Hospital, Melbourne
| | - Andrew Fock
- Department of Intensive Care and Hyperbaric Medicine, The Alfred Hospital, Melbourne
| | - Andrea B Jones
- Hyperbaric Medicine Unit, Royal Adelaide Hospital, North Terrace, Adelaide
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Lippmann J, Lawrence C, Fock A, Wodak T, Jamieson S, Harris R, Walker D. Provisional report on diving-related fatalities in Australian waters 2010. Diving Hyperb Med 2015; 45:154-175. [PMID: 26415067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/01/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION An individual case review was conducted of known diving-related deaths that occurred in Australia in 2010. METHOD The case studies were compiled using statements from witnesses and reports of the police and coroners. In each case, the particular circumstances of the accident and details from the post-mortem examination, where available, are provided. A root cause analysis was made for each case. RESULTS There were 20 reported fatalities, one less than the previous year. Five of the victims were female (four scuba divers) and 15 were males. Twelve deaths occurred while snorkelling and/or breath-hold diving, seven while scuba diving (one of whom was using a rebreather), and one diver died while using surface supplied breathing apparatus. At least two breath-hold divers likely drowned as a result of apnoeic hypoxia. Cardiac-related issues were thought to have contributed to the deaths of at least three and possibly five snorkellers, and of at least one, possibly two compressed gas divers. CONCLUSIONS Snorkelling or diving alone, poor supervision, apnoeic hypoxia, pre-existing medical conditions, lack of recent experience and unfamiliar and/or poorly-functioning equipment were features in several deaths in this series. Reducing delays to CT-scanning and autopsy and coroners' reports documenting that the victim of a drowning was snorkelling or scuba diving at the time are aspects of the investigation of these fatalities that could be improved.
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Affiliation(s)
- John Lippmann
- Divers Alert Network (DAN) Asia-Pacific, Ashburton, Victoria, Deakin University, Victoria, P O Box 384 Ashburton VIC 3147, Australia, Phone: +61-(0)3-9886-9166, E-mail:
| | | | - Andrew Fock
- Departments of Hyperbaric Medicine and Intensive Care Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | | | - Scott Jamieson
- Divers Alert Network (DAN) Asia-Pacific, Ashburton, Victoria, Australia
| | - Richard Harris
- Department of Diving and Hyperbaric Medicine, Royal Adelaide Hospital, South Australia
| | - Douglas Walker
- Retired general practitioner, Sydney, New South Wales, Australia
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Huchim-Lara O, Salas S, Chin W, Montero J, Fraga J. Diving behavior and fishing performance: the case of lobster artisanal fishermen of the Yucatan coast, Mexico. Undersea Hyperb Med 2015; 42:285-296. [PMID: 26403014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An average of 209 cases of decompression sickness (DCS) have been reported every year among artisanal fishermen. divers of the Yucatan Peninsula, Mexico. DCS is a major problem among fishermen divers worldwide. This paper explores how diving behavior and fishing techniques among fishermen relate to the probability of experiencing DCS (Pdcs). Fieldwork was conducted in two communities during the 2012-2013 fishing season. Fishermen were classified into three groups (two per group) according to their fishing performance and followed during their journeys. Dive profiles were recorded using Sensus Ultra dive recorders (Reefet Inc.). Surveys were used to record fishing yields from cooperative and individual fishermen along with fishing techniques and dive behavior. 120 dives were recorded. Fishermen averaged three dives/day, with an average depth of 47 ± 2 feet of sea water (fsw) and an average total bottom time (TBT) of 95 ± 11 minutes. 24% of dives exceeded the 2008 U.S. Navy no-decompression limit. The average ascent rate was 20 fsw/minute, and 5% of those exceeded 40 fsw/minute. Inadequate decompression was observed in all fishermen. Fishermen are diving outside the safety limits of both military and recreational standards. Fishing techniques and dive behavior were important factors in Pdcs. Fishermen were reluctant to seek treatment, and symptoms were relieved with analgesics.
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Gunepin M, Derache F, Dychter L, Blatteau JE, Nakdimon I, Zadik Y. Dental Barotrauma in French Military Divers: Results of the POP Study. Aerosp Med Hum Perform 2015; 86:652-5. [PMID: 26102147 DOI: 10.3357/amhp.4197.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The aim of the POP (odontological problems among divers) study was to assess dental barotrauma among French military divers exposed to an underwater environment. METHODS A questionnaire on dental barotrauma was completed by the divers who presented at the SMHEP (Centre for Hyperbaric Medicine and Diving Expertise) for their quadrennial medical exam from March 2011 to July 2014. RESULTS There were 1317 questionnaires completed, representing 60.6% of all French military divers. A total of 5.3% of divers had a dental barotrauma (70/1317), mainly fracture and/or loss of dental restoration. Dental barotrauma disrupted diving in 34.3% of cases. A total of 76.4% of divers were informed by a military physician of the importance of maintaining good oral health and 88.5% of divers consult their dentist at least once a year. Of the participants, 82.5% made their dentist aware they are divers, but only 4.9% of the dental practitioners advised their patient not to dive after some types of dental treatments and 12.8% indicated that, as divers, they need adapted dental treatments. CONCLUSIONS Dental barotrauma was experienced by 1 in 19 military divers. Nevertheless, a contradiction exists between the frequency of dental barotraumas and the rigorous medical and dental follow-up of military divers. We note that there is inadequate dental management of divers when dental issues are identified. To avoid this unsatisfactory situation, "diving dentistry" should be taught to military and civilian dentists and physicians to make them aware of the potential dental complications and preventive measures associated with operating in a subaquatic environment.
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Janisch T, Kopp R. Blood lead levels in scuba divers: a pilot study. Diving Hyperb Med 2014; 44:241-242. [PMID: 25596838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
INTRODUCTION Lead is a toxic element which is known to accumulate in the body. Nevertheless, it is very widely used as a diving weight. METHODS Blood samples were taken from 20 recreational scuba divers to assess blood lead concentrations. RESULTS The last dive before blood sampling was an average of 4.8 weeks previously (range 1-18 weeks). All the samples were within the normal background range, the highest lead concentration being 44.8 µg∙L⁻¹ with an average concentration of 26.5 µg∙L⁻¹ (range 11.7-44.8 µg∙L⁻¹). CONCLUSIONS The results show no elevated blood lead concentrations in this group of divers compared to background levels. However, owing to the small number of divers studied and the variable, often long interval between the last dive and blood sampling, the results cannot be generalized.
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Affiliation(s)
- Thorsten Janisch
- Specialist anaesthetist, Department of Intensive Care, University Hospital RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany, Phone: +49-(0)241-80-35385, Fax: +49-(0)241-80-3380444, E-mail:
| | - Rüdger Kopp
- Specialist anaesthetist in the Department of Intensive Care, University Hospital RWTH Aachen, Germany
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Kot J. Diving deeper and higher: an editorial perspective. Undersea Hyperb Med 2014; 41:489-491. [PMID: 25562939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Egi SM, Pieri M, Marroni A. Diving at altitude: from definition to practice. Undersea Hyperb Med 2014; 41:495-503. [PMID: 25562941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms.
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Affiliation(s)
- S Murat Egi
- Galatasaray University, MTF, Computer Engineering Department, Istanbul, Turkey.
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Sayer MDJ, Azzopardi E. The silent witness: using dive computer records in diving fatality investigations. Diving Hyperb Med 2014; 44:167-169. [PMID: 25311326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/30/2014] [Indexed: 06/04/2023]
Abstract
Downloaded data from diving computers can offer invaluable insights into diving incidents resulting in fatalities. Such data form an essential part of subsequent investigations or in legal actions related to the diving incident. It is often tempting to accept the information being displayed from a computer download without question. However, there is a large variability between the makes and models of dive computer in how the data are recorded, stored and re-displayed and caution must be employed in the interpretation of the evidence. In reporting on downloaded data, investigators should be fully aware of the limitations in the data retrieved. They should also know exactly how to interpret parameters such as: the accuracy of the dive profile; the effects of different mode settings; the precision of displayed water temperatures; the potential for misrepresenting breathing rates where there are data from integrated monitoring systems, and be able to challenge some forms of displayed information either through re-modelling based on the pressure/time profiles or by testing the computers in standardised conditions.
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Affiliation(s)
- Martin D J Sayer
- UK National Facility for Scientific Diving, Scottish Association for Marine Science, Dunstaffnage Marine Laboratories, Dunbeg, Oban, Argyll PA37 1QA, Scotland, Phone: +44-(0)1631-559236, E-mail:
| | - Elaine Azzopardi
- UK NERC National Facility for Scientific Diving, Scottish Association for Marine Science, Oban, Scotland
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Cummings B, Wilson C. British sub-aqua club (BSAX) diving incidents report 2013. Diving Hyperb Med 2014; 44:170-171. [PMID: 25872232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Myznikov IL, Polishchuk YS. [Health status, morbidity and injury rate in divers serving in the Kola North]. Gig Sanit 2014:61-66. [PMID: 25842499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The authors analyzed the health status of military personnel (males) of the Northern Fleet who did call-up military service (n = 420) and served on contract (n = 1370) in special diving positions in the Kola Arctic over the past few years. For the comparison of the rate of the decline of health level in different conditions of service the authors presented the averaged results of studies previously performed in the same period of time in the service personnel of coastal military units in the European North, troops from the surface ship crews and crew nuclear submarine. In the article there are considered the features of the primary disease and injury. Research and monitoring of causative-consecutive relationships between the features of military professional activity and the level and structure of primary morbidity rate allow to form the main directions of vocational rehabilitation for fleet specialists.
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Thorrold SR, Afonso P, Fontes J, Braun CD, Santos RS, Skomal GB, Berumen ML. Extreme diving behaviour in devil rays links surface waters and the deep ocean. Nat Commun 2014; 5:4274. [PMID: 24983949 PMCID: PMC4102113 DOI: 10.1038/ncomms5274] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 06/02/2014] [Indexed: 11/26/2022] Open
Abstract
Ecological connections between surface waters and the deep ocean remain poorly studied despite the high biomass of fishes and squids residing at depths beyond the euphotic zone. These animals likely support pelagic food webs containing a suite of predators that include commercially important fishes and marine mammals. Here we deploy pop-up satellite archival transmitting tags on 15 Chilean devil rays (Mobula tarapacana) in the central North Atlantic Ocean, which provide movement patterns of individuals for up to 9 months. Devil rays were considered surface dwellers but our data reveal individuals descending at speeds up to 6.0 m s(-1) to depths of almost 2,000 m and water temperatures <4 °C. The shape of the dive profiles suggests that the rays are foraging at these depths in deep scattering layers. Our results provide evidence of an important link between predators in the surface ocean and forage species occupying pelagic habitats below the euphotic zone in ocean ecosystems.
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Affiliation(s)
- Simon R. Thorrold
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
- These authors contributed equally to this work
| | - Pedro Afonso
- IMAR (Institute of Marine Research) at the University of the Azores, Department of Oceanography and Fisheries, Horta 9901-862, Portugal
- LARSyS—Laboratory of Robotics and Systems in Engineering and Science, Lisboa 1049-001, Portugal
- These authors contributed equally to this work
| | - Jorge Fontes
- IMAR (Institute of Marine Research) at the University of the Azores, Department of Oceanography and Fisheries, Horta 9901-862, Portugal
- LARSyS—Laboratory of Robotics and Systems in Engineering and Science, Lisboa 1049-001, Portugal
- These authors contributed equally to this work
| | - Camrin D. Braun
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Ricardo S. Santos
- IMAR (Institute of Marine Research) at the University of the Azores, Department of Oceanography and Fisheries, Horta 9901-862, Portugal
- LARSyS—Laboratory of Robotics and Systems in Engineering and Science, Lisboa 1049-001, Portugal
| | - Gregory B. Skomal
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
- Massachusetts Marine Fisheries, 1213 Purchase Street, New Bedford, Massachusetts 02740, USA
| | - Michael L. Berumen
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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Ranapurwala SI, Bird N, Vaithiyanathan P, Denoble PJ. Scuba diving injuries among Divers Alert Network members 2010-2011. Diving Hyperb Med 2014; 44:79-85. [PMID: 24986725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Scuba diving injuries vary greatly in severity and prognosis. While decompression sickness (DCS) and arterial gas embolism can be tracked easily, other forms of diving injury remain unaccounted for. PURPOSE The purpose of this paper is to assess rates of overall self-reported scuba-diving-related injuries, self-reported DCS-like symptoms, and treated DCS and their association with diver certification level, diving experience and demographic factors. METHODS We analyzed self-reported data from a Divers Alert Network membership health survey conducted during the summer of 2011. Poisson regression models with scaled deviance were used to model the relative rates of reported injuries. Models were adjusted for sex, age, body mass index (BMI) and average annual dives, based on the bias-variance tradeoff. RESULTS The overall rate of diving-related injury was 3.02 per 100 dives, self-reported DCS symptoms was 1.55 per 1,000 dives and treated DCS was 5.72 per 100,000 dives. Diving-related injury and self-reported DCS symptom rates decreased for higher diver certification levels, increasing age, increasing number of average annual dives and for men; they increased for increasing BMI. CONCLUSIONS Diving injury rates may be higher than previously thought, indicating a greater burden on the diving community. Self-reported DCS-like symptoms are a small fraction of all dive-related injuries and those receiving treatment for DCS are an even smaller fraction. The small number of divers seeking treatment may suggest the mild nature and a tendency towards natural resolution for most injuries.
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Affiliation(s)
- Shabbar I Ranapurwala
- Divers Alert Network, Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA, Divers Alert Network, 6 West Colony Place, Durham, NC 27705, USA, E-mail:
| | - Nicholas Bird
- Duke Urgent Care, Duke University Health System, Durham, NC, USA
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Haas RM, Hannam JA, Sames C, Schmidt R, Tyson A, Francombe M, Richardson D, Mitchell SJ. Decompression illness in divers treated in Auckland, New Zealand, 1996-2012. Diving Hyperb Med 2014; 44:20-25. [PMID: 24687481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
INTRODUCTION The treatment of divers for decompression illness (DCI) in Auckland, New Zealand, has not been described since 1996, and subsequent trends in patient numbers and demographics are unmeasured. METHODS This was a retrospective audit of DCI cases requiring recompression in Auckland between 01 January 1996 and 31 December 2012. Data describing patient demographics, dive characteristics, presentation of DCI and outcomes were extracted from case notes and facility databases. Trends in annual case numbers were evaluated using Spearman's correlation coefficients (ρ) and compared with trends in entry-level diver certifications. Trends in patient demographics and delay between diving and recompression were evaluated using regression analyses. RESULTS There were 520 DCI cases. Annual caseload decreased over the study period (ρ = 0.813, P < 0.0001) as did entry level diving certifications in New Zealand (ρ = 0.962, P < 0.0001). Mean diver age was 33.6 (95% confidence limits (CI) 32.7 to 34.5) years and age increased (P < 0.0001) over the study period. Median (range) delay to recompression was 2.06 (95% CI 0.02 to 23.6) days, and delay declined over the study period (P = 0.005). CONCLUSIONS Numbers of DCI cases recompressed in Auckland have declined significantly over the last 17 years. The most plausible explanation is declining diving activity but improvements in diving safety cannot be excluded. The delay between diving and recompression has reduced.
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Affiliation(s)
- Rachel M Haas
- School of Medicine, University of Auckland, New Zealand
| | - Jacqueline A Hannam
- Department of Anaesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Christopher Sames
- Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand
| | - Robert Schmidt
- Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand
| | - Andrew Tyson
- Hyperbaric Health, Quay Park, Auckland, New Zealand
| | - Marion Francombe
- Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand
| | - Drew Richardson
- Professional Association of Diving Instructors, Rancho Santa Margarita, CA, USA
| | - Simon J Mitchell
- Slark Hyperbaric Unit, Waitemata District Health Board, Department of Anaesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand, E-mail: , Phone: +64-(0)9-373-7599, Fax: +64-(0)9-373-7970
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Doolette DJ, Gault KA, Gutvik CR. Sample size requirement for comparison of decompression outcomes using ultrasonically detected venous gas emboli (VGE): power calculations using Monte Carlo resampling from real data. Diving Hyperb Med 2014; 44:14-19. [PMID: 24687480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 01/05/2014] [Indexed: 06/03/2023]
Abstract
INTRODUCTION In studies of decompression procedures, ultrasonically detected venous gas emboli (VGE) are commonly used as a surrogate outcome if decompression sickness (DCS) is unlikely to be observed. There is substantial variability in observed VGE grades, and studies should be designed with sufficient power to detect an important effect. METHODS Data for estimating sample size requirements for studies using VGE as an outcome is provided by a comparison of two decompression schedules that found corresponding differences in DCS incidence (3/192 [DCS/dives] vs. 10/198) and median maximum VGE grade (2 vs. 3, P < 0.0001, Wilcoxon test). Sixty-two subjects dived each schedule at least once, accounting for 183 and 180 man-dives on each schedule. From these data, the frequency with which 10,000 randomly resampled, paired samples of maximum VGE grade were significantly different (paired Wilcoxon test, one-sided P ⋜ 0.05 or 0.025) in the same direction as the VGE grades of the full data set were counted (estimated power). Resampling was also used to estimate power of a Bayesian method that ranks two samples based on DCS risks estimated from the VGE grades. RESULTS Paired sample sizes of 50 subjects yielded about 80% power, but the power dropped to less than 50% with fewer than 30 subjects. CONCLUSIONS Comparisons of VGE grades that fail to find a difference between paired sample sizes of 30 or fewer must be interpreted cautiously. Studies can be considered well powered if the sample size is 50 even if only a one-grade difference in median VGE grade is of interest.
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Affiliation(s)
- David J Doolette
- Navy Experimental Diving Unit, 321 Bullfinch Road, Panama City, FL 32407, USA, Phone: +1-(0)850-230-3100, E-mail:
| | - Keith A Gault
- Navy Experimental Diving Unit, Panama City, Florida, USA
| | - Christian R Gutvik
- Technology Transfer Office, Norwegian University of Science and Technology (NTNU)
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Denoble PJ, Nelson CL, Ranapurwala SI, Caruso JL. Prevalence of cardiomegaly and left ventricular hypertrophy in scuba diving and traffic accident victims. Undersea Hyperb Med 2014; 41:127-133. [PMID: 24851550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Although frequently asymptomatic, left ventricular hypertrophy (LVH) is an independent predictor of sudden cardiac death (SCD). We hypothesized that diving may increase the propensity for pre-existent LVH to cause a lethal arrhythmia (and SCD) and therefore the prevalence of LVH may be greater among scuba fatalities than among traffic fatalities. We compared autopsy data for 100 scuba fatalities with 178 traffic fatalities. Extracted data contained information on age, sex, height, body mass, heart mass (HM), left ventricular wall thickness (LVWT), interventricular wall thickness (IVWT), and degree of coronary artery stenosis. A case was classified as LVH if the LVWT was > 15 mm. Log risk models were used to compare HM and LVWT in two groups while controlling for body mass, body length, age and sex. The prevalence of LVH was compared using Pearson's test. The mean HM was 428.3 +/- 100 for divers and 387 +/- 87 for controls. The crude HM ratio for scuba fatalities vs. controls was 1.11 (1.05, 1.17), and when controlled for sex, age and body mass the ratio was 1.06 (1.01, 1.09). The mean LVWT was 15 +/- 3.5 for divers and 14 +/- 2.7 for controls (p = 0.0017). HM and LVWT measured at autopsy were greater in scuba than in traffic fatalities.
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Chng J, Chan G, Tang KC. Does diving affect the hearing of Asian military divers? A study in the Republic of Singapore Navy. Undersea Hyperb Med 2014; 41:41-47. [PMID: 24649716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVE This study examined whether military diving during a National Serviceman's two-year term of service affected his hearing threshold levels. METHODS A retrospective cohort study was designed to examine the hearing thresholds of divers (mean age 20.9 years) who enlisted between 2001 and 2010 (n = 748). Their pre-enlistment and pre-discharge audiograms were collected. All made dives using scuba dive sets, averaged 200 dives over two years and depths of 30 meters of sea water/msw or less. RESULTS The divers' hearing levels in the left ear were not affected except for a marginal decrease in hearing level at the 2kHz level. There was a marginal decrease in hearing level in 0.5, 1 and 2 kHz in the right ear. These changes are physiologically insignificant. There were more low-frequency (0.5, 1 and 2 kHz) changes compared to high-frequency (4 and 8 kHz) changes in both ears, with a larger number of changes noted in the right ear, as compared to the left. However, no diver had a hearing threshold increase greater than 20dB or exceeded the hearing threshold levels required of military divers. CONCLUSION There was no decrease of clinical significance in hearing function of the Republic of Singapore Navy national serviceman naval divers after diving for two years.
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