Self-contained Underwater Breathing Apparatus Divers Research Articles

Prevalence of Airway Obstruction in Recreational SCUBA Divers

The prevalence of airflow obstruction in recreational self-contained underwater breathing apparatus (SCUBA) divers is unknown. Since airflow obstruction is a relative contraindication for diving, we conducted a study to determine its prevalence and magnitude in a cohort of recreational divers in Saba, Netherlands Antilles. Prior to diving, divers were asked to complete a diving/health questionnaire and then to perform spirometry administered by trained dive store personnel. Spirometry instrumentation provided immediate feedback regarding test quality. Of 8365 eligible divers during the study period (November 1997-March 1999), 668 enrolled and completed questionnaires. Of those completing questionnaires, 46% reported a history of smoking, 13% were current smokers, 15% wheezed, 6% had asthma, 4% used bronchodilators, and 3% took oral steroids. Of 654 completing spirometry, 231 had acceptable spirometry quality and complete questionnaires. By forced expiratory volume in 1 second/forced vital capacity, 10% had mild, 1.7% had moderate, and 0.4% had severe airflow obstruction. The prevalence of airflow obstruction was 6% to 15% by report and 12% by spirometry, approximating the combined prevalence of asthma and chronic obstructive pulmonary disease in the general population. Study limitations include possible self-selection and low enrollment rate. Prospective lung function testing can be conducted at remote sites using nonmedical personnel as "testers." This study could guide future investigations to determine if asthma is a risk factor for decompression illness.

Using underwater cameras to assess the effects of snorkeler and SCUBA diver presence on coral reef fish abundance, family richness, and species composition

The results of underwater visual fish censuses (UVC) could be affected by fish changing their behavior in response to the snorkeler or diver conducting the survey. We used an underwater video camera to assess how fish abundance, family richness, and community composition were affected by the presence of snorkelers (n = 12) and self-contained underwater breathing apparatus (SCUBA) divers (n = 6) on a coral reef in Thailand. The total number of families, abundance of some fish families, and overall species composition showed significant differences before and during snorkeling disturbances. We did not detect significant and consistent changes to these parameters in the presence of a SCUBA diver; however, this could be a result of lower statistical power. We suggest that the use of a stationary video camera may help cross-check data that is collected through UVC to assess the true family composition and document the presence of rare and easily disturbed species.

The Prevalence of Orofacial Pain and Tooth Fracture (Odontocrexis) Associated with SCUBA Diving

To assess the prevalence of orofacial complications associated with SCUBA (self-contained underwater breathing apparatus) diving. Main outcome measures were prevalence of orofacial pain and odontocrexis. Two hundred divers at four dive centres on the north-east coast of Australia were asked to complete a questionnaire that requested information regarding diving experience and facial pain and dental symptoms experienced during diving. One hundred and twenty-five completed questionnaires were returned (63% response rate). The prevalence of reported orofacial pain was 44%. Twenty-one per cent reported toothache, 27% sinus pain, 16% jaw pain, and 12% other pain. The prevalence of odontocrexis was less than 1%. Less than 1% had lost a filling when diving. No divers reported a crown or bridge being dislodged during diving. Among those who returned questionnaires, orofacial pain in divers was common and odontocrexis was rare.

Low-back problems in recreational self-contained underwater breathing apparatus divers: Prevalence and specific risk factors

Low-back problems (LBP) are one of the most common musculoskeletal disorders in the general population, with reported lifetime prevalences of 50% to 80%. Also, certain sports participants (e.g. gymnasts, alpine skiers, runners) are at risk of LBP and its repercussions. This epidemiological study was undertaken to examine the lifetime and 1-year prevalence of LBP among recreational Flemish self-contained breathing apparatus (scuba) divers and to identify general and sport-specific risk factors associated with the occurrence of LBP. A retrospective self-assessment questionnaire was developed and assessed for validity and reliability, to gather data concerning demographics, LBP prevalence and associated risk factors and injuries among active scuba divers. A total of 181 recreational scuba divers (men: n = 138, mean age 40.3 ± 12.8 years; women: n = 43, mean age 35.0 ± 10.9 years) from 10 randomly selected internationally recognised scuba diving clubs participated in the study. Lifetime and 1-year prevalence of LBP among recreational Flemish scuba divers were 55.8% and 50.3%, respectively. General risk factors for LBP were found to include prior history of LBP, structural abnormalities, heavy workload, pregnancy and parturition, general fatigue and bending forwards and backwards. Scuba divers suffering from LBP generally had a significantly higher dive certificate than those without LBP (p = 0.007). Symptomatic scuba divers also used significantly more weights on their weight belts during indoor training (p = 0.003) and during outdoor dives with a dry suit (p = 0.044) as compared to asymptomatic scuba divers. In scuba diving, reliable sport-specific risk factors for LBP were found to be scarce. Further biomechanical research is required to point out whether or not scuba diving characteristics actually contribute to LBP.

Paranasal sinus barotrauma in sports self-contained underwater breathing apparatus divers

TO evaluate potential pre-dive parameters in relation to paranasal sinus barotrauma in sports self-contained underwater breathing apparatus divers. The pre-dive and follow-up records of 46 healthy sports self-contained underwater breathing apparatus divers were analysed. In the routine pre-dive examination of diving candidates with no symptoms of rhino-sinus disease, rhinoscopy, sinus radiography and nasal endoscopy indicated no signs of rhinitis and/or sinusitis. Any signs of paranasal sinus barotrauma were noted, and several parameters were evaluated in relation to occurrence of barotrauma. Of the studied parameters, a history of sinusitis and of middle-ear barotrauma was significantly more frequent in divers in the barotrauma group (p < 0.05). In divers undergoing a routine pre-dive examination, paranasal sinus barotrauma was not related to sex, alcohol consumption, smoking, decongestant use, mild nasal septal deviation, or inability to perform the Valsalva or Toynbee manoeuvres. However, divers with a history of sinusitis or middle-ear barotrauma may be more prone to paranasal sinus barotrauma. A more detailed pre-dive examination may be useful for such individuals.

Prevalence and severity of external auditory exostoses in breath-hold divers

To explore the prevalence and severity of external auditory exostoses in a population of experienced breath-hold divers, and to compare these to the same parameters within surfing and self-contained underwater breathing apparatus diving populations. A stepwise, multiple regression analysis of cross-sectional data examining the relative contributions of sea surface temperature, latitude of exposure and years of exposure to the prevalence and severity of stenosis due to external auditory exostoses. A chi-square analysis of the prevalence and severity of external auditory exostosis stenosis in the breath-hold divers was compared with previously published data for surfers and self-contained underwater breathing apparatus divers. Seventy-six male and thirty-five female breath-hold divers attending an international 'freedive' competition completed a questionnaire describing aquatic sports habits, geography of participation and symptomatology. Those completing the questionnaire (111/154 attendees) were examined otoscopically for evidence of external auditory exostoses. Images were digitally recorded, scored and graded. Exostoses were evident in 87.7 per cent of the 204 ears scored and graded for severity of stenosis due to external auditory exostoses. The prevalence of exostoses was no different from that found in previous studies of surfers and self-contained underwater breathing apparatus divers (p = 0.101). However, the pattern of affliction was more similar to that found in surfers. The severity of exostoses was significantly less than that found in surfing populations (p < or = 0.001 to 0.007), but greater than that found in self-contained underwater breathing apparatus diving populations (p < or = 0.001). Sea surface temperature at the location of open-water exposure was the most significant predictor of the prevalence and severity of external auditory exostoses in breath-hold divers (p = 0.019). The prevalence and severity patterns of stenosis due to external auditory exostoses in breath-hold divers are more similar to previously published results for surfing populations than to previously published results for self-contained underwater breathing apparatus diving populations. In breath-hold divers, sea surface temperature is the strongest predictor of severity of stenosis due to external auditory exostoses.

The evolution of colony-level development in the Siphonophora (Cnidaria:Hydrozoa)

Evolutionary developmental biology has focused almost exclusively on multicellular organisms, but there are other relevant levels of biological organization that have remained largely neglected. Animal colonies are made up of multiple physiologically integrated and genetically identical units called zooids that are each homologous to solitary, free-living animals. Siphonophores, a group of pelagic hydrozoans (Cnidaria), have the most complex colony-level organization of all animals. Here the colony-level development of five siphonophore species, strategically sampled across the siphonophore phylogeny, is described from specimens collected using deep-sea submersibles and by self-contained underwater breathing apparatus diving. These species include three cystonects, Bathyphysa sibogae, Rhizophysa filiformis, and Rhizophysa eysenhardti, and two "physonects", Agalma elegans and Nanomia bijuga. These data, together with previous findings, are analyzed in a phylogenetic framework to reconstruct key features of the history of colony-level organization and development in the Siphonophora. It is shown that gonodendra and gastrozooids of the examined cystonects arise as independent buds directly on the stem, whereas probud subdivision (the origin of feeding, reproductive, and other zooids from a single bud) is a synapomorphy of the Codonophora. The origin of probud subdivision is associated with the origin of cormidia as integrated units of colony organization, and may have allowed for greater morphological and ecological diversification in the Codonophora relative to the Cystonectae. It is also found that symmetry is labile in siphonophores, with multiple gains and/or losses of directional asymmetry in the group. This descriptive work will enable future mechanistic and molecular studies of colony-level development in the siphonophores.

SCUBA Diving for Individuals with Disabilities

Self-contained underwater breathing apparatus (SCUBA) diving has become an increasingly popular recreational activity, enjoyed by millions of individuals. There has also been a growing interest in SCUBA diving in the disabled population for rehabilitation and recreation. This review discusses medical issues relevant to individuals with disabilities who wish to participate in SCUBA diving. In addition, specialized equipment, adaptations in techniques, and additional precautions will be presented. SCUBA diving can be an enriching experience, potentially helping to improve self-image and quality of life. Knowledgeable healthcare professionals can help to guide their patients who are interested in SCUBA diving.

Airway reactivity and diving in healthy and atopic subjects.

The short- and long-term effects of self-contained underwater breathing apparatus (SCUBA) dives on airway responsiveness in nonasthmatic atopic subjects have not been systematically investigated. To compare the effect of SCUBA diving at 50-m depth on lung function and airway responsiveness to methacholine (MCh) in atopic nonasthmatics and healthy subjects. We studied 15 atopic nonasthmatic subjects and 15 controls who underwent the visit for the professional SCUBA-diving license at the Navy Medical Center, La Spezia, Italy. All subjects underwent spirometry and skin-prick test for common environmental allergens. MCh challenge was performed 24 h before, and 20 min and 24 h after a standardized SCUBA-dive test and after hyperbaric-chamber test. At 20 min, the provocative dose of MCh causing 20% fall of the forced expiratory volume at the first second (MCh PD20 - FEV1) was significantly reduced in atopic, asymptomatic subjects from 1712 x 2.6 microg (mean x geometric standard deviation) to 1202 x 2.2 microg (P < 0.0005) after the hyperbaric-chamber test and to 1204 x 2.3 microg (P < 0.005) after SCUBA diving. In healthy subjects, the baseline value of MCh PD20 was 2977 x 1.1 microg, and this value did not change significantly after the hyperbaric-chamber test (2575 x 1.4 microg) and after SCUBA dives (2553 x 1.4 microg, P > 0.1 for both comparisons). In atopic subjects, the MCh PD20 returned near to the baseline value 24 h after the hyperbaric-chamber test (1776 x 2.4 microg) and after the SCUBA test (1500 x 2.67 microg). No significant change in FEV1 was observed after the tests in both groups. SCUBA diving is associated with development of early airway hyperresponsiveness to MCh in atopic subjects.

Asthma and recreational SCUBA diving: a systematic review.

Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity.There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making.

Medicine at a Glance

<b>Underwater accidents</b>remain relatively rare, but Duke University Medical Center clinicians—who operate a Divers Alert Network from Durham, NC—note that about 300,000 new divers are trained each year in this country. Thus, they say, there may be as many as 3 million active sport SCUBA (self-contained underwater breathing apparatus) divers "who make an undetermined number of dives yearly," and among whom about 500 may encounter problems. To assist with these specialized injuries, the Duke team maintains a 24-hour emergency hotline at (919) 684-8111 that accepts collect calls about diving accidents. A nonemergency information line is available at (919) 684-2948 for medical questions related to diving, Monday through Friday, 9 AM to 5 PM EST. The program originally was federally funded (<i>JAMA</i>[MEDICAL NEWS] 1981;246:1879). Now it relies on contributions from sport divers and medical groups and offers memberships at $10 per year that include a manual, newsletter, and other information.

SCUBA Diving for Blind and Visually Impaired People

An orientation to SCUBA (self-contained underwater breathing apparatus) diving as a leisure and career activity, by a trained SCUBA diver who is severely visually impaired. Provides a detailed description of the factors involved in underwater activity at depth and discusses the multifaceted underwater experience and the requisite skills and adaptations necessary for blind and visually impaired divers to function adequately with SCUBA.

Ventilatory response of SCUBA divers to CO2 inhalations.

A study was made to compare the minute ventilatory response of SCUBA (self-contained underwater breathing apparatus) divers and nondivers to CO2 inhalations under ambient conditions at rest and during light exercise. Furthermore, other respiratory parameters and lung function measurements were made for comparison with published reports of apneustic divers. The SCUBA diver and the nondiver in this study were similar with respect to basal ventilation, divisions of the lung volume, and spirographic functions. There was some tendency for the SCUBA divers to have a slightly diminished ventilatory response to CO2 inhalations during rest compared to the nondivers, but this was not a clear-cut phenomena. Furthermore, the ventilatory response to CO2 bore no relation to time spent in diving. The respiratory adaptations which have been described in the literature for the apneustic diver under ambient conditions were not present in the SCUBA diver. Note: (With the Technical Assistance of Christa McReynolds, Mabel Pearson and Roy Engstrom) Submitted on June 3, 1960