Clustering of recreational divers by their health conditions in a database of a citizen science project.

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.

The demographics and diving behaviour of DAN Asia-Pacific members with and without pre-existing medical conditions.

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.

Toxicidad pulmonar asociada al empleo de oxígeno hiperbárico: procedimientos de cálculo / Pulmonary toxicity is associated with the hyperbaric oxygen: methods of calculation

OBJETIVOS: Estudiar si una exposición hiperbárica de larga duración motivada por la aparición de una enfermedad descompresiva bajo presión, presenta alteraciones espirométricas y si éstas están acompañadas de sintomatología clínica pulmonar compatible con toxicidad pulmonar por oxígeno. PACIENTES Y MÉTODO: 3 buceadores profesionales que durante una inmersión a 100 metros de profundidad, uno de ellos presenta, antes de terminar la inmersión una patología descompresiva que requiere aumentar los tiempos de respiración de oxígeno, se realizan espirometrías pre- y post-inmersión midiendo: FVC, FEV1, PEF, FEV1/FVC, FEF25-75, FEF 75-85, FEF 25, FEF 50, FEF 75. RESULTADOS: Los resultados post-inmersión demuestran un descenso global de todos los parámetros estudiados destacando el descenso de PEF (12.8%), FEF 50 (9,3%) y FEV1 (8.8%), de forma individual 2 buceadores mostraron descenso de todos los parámetros mientras que un buceador de los nueve parámetros estudiados solo experimentó descenso en cinco. Estos resultados no estuvieron acompañados de sintomatología pulmonar y carecieron de significado estadístico. CONCLUSIONES: Tras esta exposición hiperbárica se alteró el flujo y la capacidad sin la presencia de sintomatología clínica pulmonar y papel importante de la susceptibilidad individual. Los estudios de función pulmonar se deberían extender a colectivos sometidos a: cambios constantes de presión y a la respiración de oxígeno, gas con efectos tóxicos agudos y a largo plazo (AU)

INTRODUCTION: We studied if one hyperbaric exposition in the long term with decompression sickness under pressure causes disturbances in the pulmonary functions and if they are related with clinical manifestations which are compatibles with pulmonary oxygen toxicity. PATIENTS AND METHOD.-Three professional divers carried out one immersion at 100 meters of deep, only one person displayed, before the immersion was finished, one decompression pathology which need increase the times breathing of oxygen, we valued the pulmonary functions pre and post immersion so we measured: FVC, FEV1, PEF, FEV1/FVC, FEF25-75, FEF 75-85, FEF 25, FEF 50 and FEF 75. RESULTS: The post immersion results showed one total decline of all studied parameters showed the decrease of PEF (12.8%), FEF 50 (9.3%) and FEV1 (8.8%), two divers showed one decline of all parameters meanwhile that one diver registered decrease only in five parameters. These results are not accompanied of pulmonary symptoms and of significant statistic. CONCLUSIONS: After this hyperbaric exposure, the flow and the capacity were disturbed but they did not show neither clinic pulmonary symptoms nor had one important role in the personal susceptibility. The studies of pulmonary function should include group with constant pressure changes and the breathing of oxygen, this gas have acute toxic effects in the long term (AU)

Direct ascent from air and N2-O2 saturation dives in humans: DCS risk and evidence of a threshold.

To estimate the risk of decompression sickness (DCS) for direct ascents from depth to the sea surface for personnel who are saturated with hyperbaric nitrogen, we analyzed 586 experimental air or nitrogen-based saturation dives. No DCS occurred on shallow saturation dives between 12.0 and 20.5 feet of seawater, gauge (fswg) but incidence of DCS rose abruptly when depth was deeper than 20.5 fswg, reaching 27% at 30 fswg. This is evidence of a threshold for clinical DCS. A model based on a Hill function that provides for a threshold predicts the observations better than a model having no threshold provision; the no-threshold model overestimates risk shallower than 20.5 fswg and underestimates risk between 20.5 and 30 fswg. For situations such as submarine rescues, we recommend our threshold model when the exposure pressure is 33 fswg or less. We also discuss deeper dives where there are no human data; extrapolations can be quite different for models that provide for a threshold than for models that do not.

Diving accident management, with special emphasis on the situation in the Red Sea.

Accident management is a concept commonly misunderstood, frequently confused with accident treatment. The situation in the Sinai and the Red Sea makes a broad definition of the term "management" necessary. Management encompasses the whole spectrum: from recognition of the need for a hyperbaric facility, establishing one, education of dive center management, instructors, boat skippers and deck hands, to actual contingency plans set according to the different geographical sites. The essential elements of communication, oxygen first aid, transportation, and actual recompression therapy or other treatments and follow-up must be included. Furthermore, a link to the international organisations involved with diving accident management is an essential and desired backup.