Sport Scuba Divers Research Articles

A Doppler ultrasound self-monitoring approach for detection of relevant individual decompression stress in scuba diving

Observing modern decompression protocols alone cannot fully prevent diving injuries especially in repetitive diving. Professional audio Doppler bubble measurements are not available to sports scuba divers. If those non-professionals were able to learn audio Doppler self-assessment for bubble grading, such skill could provide significant information on individual decisions with respect to diving safety. We taught audio Doppler self-assessment of subclavian and precordial probe position to 41 divers in a 45-min standardized, didactically optimized training. Assessment before and after air dives within sports diving limits was made through 684 audio Doppler measurements in dive-site conditions by both trained divers and a medical professional, plus additional 2D-echocardiography reference. In all dives (average maximum depth 22 m; dive time 44 min), 33% of all echocardiography measurements revealed bubbles. The specificity of audio bubble detection in combination of both detection sites was 95%, and sensitivity over all grades was 40%, increasing with higher bubble grades. Dive-site audio-Doppler-grading underestimated echo-derived bubble grades. Bubble detection sensitivity of audio Doppler self-assessments, compared to an experienced examiner, was 62% at subclavian and 73% at precordial position. 6 months after the training and 4.5 months after the last measurement, the achieved Doppler skill level remained stable. Audio Doppler self-assessment can be learned by non-professionals in a single teaching intervention. Despite accurate bubble grading is impossible in dive-site conditions, relevant high bubble grades can be detected by non-professionals. This qualitative information can be important in self-evaluating decompression stress and assessing measures for increased diving safety.

Abstract 11790: Echocardiography is Able to Detect Morphological and Functional Changes of the Right Heart in Sport Scuba Divers

Introduction: Scuba diving represents stressful event for cardiovascular system. Breathing with compressed air, hyperbaric environment and microbubbles formation are the main factors are the most influencing factors for pulmonary circulation. Hypothesis: The aim of the study was to evaluate the change in morphology and function of the right heart after scuba dive with compressed air. Methods: Ten healthy sport divers (2 woman, 8 men, average age 42.1 ± 4.1 yrs., 21-52yrs) performed one scuba dive with compressed air (the depth was 20 meters, bottom tine 20 minutes, one safety stop at 3 m, water temperature 15°C). Echocardiography was performed just before and immediately after the dive, and every 60 minutes after surfacing with the aim to evaluate the presence of microbubbles (iVivid, GE). Results: After the dive, left atrium, right ventricle and inferior vena cava diameters significantly decreased (LA: 30.4±2.1 vs. 27.1±1.2 mm, p<0.05; RV: 27.8±2.1 vs. 25.2±1.1mm, p<0.05; IVC: 19.3±1.1 vs. 17.6±0.9 mm, p<0.05). LV ejection fraction, fractional shortening and myocardial performance index remained unchanged (LVEF: 65.7±7.1 vs. 62.2±10, p ns; FS: 40.9±6.1 vs.38.9±9.9, p ns; LV MPI: 0.50±0.15 vs. 0.48±0.14, p ns). We found significant decrease in mitral E/A (E/A 1.37±0.18 vs. 1.19±0.15 m/s, p<0.05). Right ventricle functional parameters decreased (TAPSE: 29.9±2.1 vs. 26.1±2.2 mm, p<0.05; RV MPI: 0.58±0.18 vs. 0.43±0.16mm, p<0.05). Analysis of the pulsed tissue Doppler velocities of the tricuspid annulus showed significant decrease in S’ parameter (S’lat 16.1±1.1 vs. 13.9±2.3, p<0.05). In 8 divers (80%), microbubbles were detected in right heart. They were detectable in pulmonary circulation for 3 hours. Due to this fact, the Doppler estimates of pulmonary artery pressure were not possible. Conclusions: Scuba dive with compressed air is associated with decrease of the both ventricle and atria diameters. It is associated with the decreased diastolic LV function and global RV function. These changes can be associated with the presence of microbubbles in lung circulation. This study showed echocardiography is able to detect changes of the circulation which are associated with the recreational dive.

Demographics and Respiratory Illness Prevalence of Sport Scuba Divers

Demographics and Respiratory Illness Prevalence of Sport Scuba Divers

Demographics and Respiratory Illness Prevalence of Sport Scuba Divers

This study aimed to establish epidemiological data on diving habits and outcome of subjects with respiratory diseases who are considered at increased risk for diving injuries. We conducted a cross-sectional demographics and prevalence study by distribution of an anonymous questionnaire with an issue of a widespread sport diving magazine. The questionnaire was designed to obtain medical and diving history data with an emphasis on respiratory diseases and complaints. The investigational population comprised sport scuba divers of any age and gender from Austria, Germany, and Switzerland. Two hundred and twenty-six male and 96 female divers sent completed questionnaires. Of the respondents 8.7 % indicated that they currently have asthma. Two thirds of asthmatics complained about regular dyspnoea. However, only 42.4 % used drugs relieving or controlling their symptoms regularly and 27.3 % used them in a prophylactic manner before diving. Five percent and 4.7 % of all divers reported a history of respiratory disease other than asthma or dyspnoea respectively. The divers with respiratory illness or complaints had logged a total of 17,386 dives. There were no cases of serious diving injuries. Despite the well-known limitations of postal surveys assessing self reported data, this study indicates that there is a population of subjects diving uneventfully with respiratory diseases that are considered medical contraindications to diving. These subjects deserve particular guidance on related risks and disease management.

Resting Pulmonary Ventilation in Sports Scuba Divers

It should be investigated whether the traditional dependency between respiratory and systemic measures is preserved during scuba diving, and whether the diving experience would affect respiration. Additionally, respiration data were analyzed for gender differences (118 sports divers). Respiratory variables were assessed at poolside and during diving in the pool. The respiration pattern at poolside was significantly different from the pattern during diving, where respiration rate (RR) decreased (11.8± 3.8 vs. 7.8± 2.9 min−1; −34%) and tidal volume increased (1.1± 0.5 vs. 1.6± 0.6L; +45%). This produced a decrease in respiratory minute volume (RMV) from 12.4± 4.7 to 11.2± 3.8L/min (−10%). Respiratory Minute Volume and vital capacity correlated at poolside. This physiologic correlation was lost while diving. Instead, RMV and number of dives (=diver's experience) correlated negatively. Because RMV at both poolside and during diving correlates with RR, an increased RMV in diving beginners can be estimated via RR. Thus, close observation of RR could help improve safety during a regular dive, avoiding hazardous hyperventilation. Female divers, irrespective of body height and weight, need less air during diving.

Evaluation of Predive Parameters Related to Eustachian Tube Dysfunction for Symptomatic Middle Ear Barotrauma in Divers

Eustachian tube dysfunction plays an important role in the pathogenesis of middle ear barotrauma. This investigation evaluates the predictive value of several parameters related to tubal dysfunction, in relation to symptomatic middle ear barotrauma in divers. Prospective and blinded. Thirty-one sport scuba divers with normal predive audiometry, tympanometry, and general and otorhinolaryngologic examination. After an occurrence of middle ear barotrauma, the individual diver predive data on smoking, mild septal deviation, otitis media history, rhinosinusitis history, Valsalva, Toynbee, and nine-step inflation/deflation tympanometric test, as well as degree of mastoid pneumatization were registered for calculation of predictive value in relation to the barotrauma. All symptomatic ears were examined within 24 hours of diving by the investigator, who was blinded to the predive findings. Barotraumas that occurred during an upper respiratory tract infection were excluded. Divers completed a total of 774 dives (median, 25; range, 3-100). Symptomatic middle ear barotrauma occurred in 19 ears (31%) of 14 divers (45%) at one time or another. The rate of tubal dysfunction measured by the nine-step test and a mastoid pneumatization below average were significantly higher in divers (p <0.05) as well as in ears (p <0.005) with barotrauma. Positive and negative predictive values of both parameters for subsequent barotrauma were between 69% and 76%. Combining the results into a two-test battery in a strict approach (positive on both) increased the positive predictive value to 86%. Eustachian tube dysfunction measured by the nine-step test and a small size of the mastoid cell system seem to be risk factors for symptomatic middle ear barotrauma in otherwise healthy sport scuba divers. Evaluation of these factors in the predive examination of diving candidates may be useful in the determination of fitness to dive.

Relationship Between Mastoid Pneumatization and Middle Ear Barotrauma in Divers

Previous studies have shown a relationship between eustachian tube function and size of mastoid pneumatization, as well as eustachian tube function and middle ear (ME) barotrauma. The purpose of this study is to investigate a possible relationship between size of mastoid pneumatization and ME barotrauma in sports scuba (self-contained underwater breathing apparatus) divers. Prospective, blinded. Twenty-four sports scuba divers (48 ears), who were fit to dive in the predive and otolaryngologic examination, were included in the study. Size of mastoid pneumatization was measured by simplified rectangular dimension method on a mastoid x-ray taken at Schüller's view. Divers were counseled to refer to the investigators if any symptoms occurred during and/or after diving. All symptomatic ears were examined within 24 hours of diving by the same investigator, who was blinded to the degree of pneumatization. ME barotrauma occurred in 15 ears (31%) of 11 divers (46%) at one time or another. The median degree of pneumatization in ears with barotrauma (22.9 cm2) was significantly smaller than that in unaffected ears (34.1 cm2; (P <.001). Furthermore, findings showed that with increasing degree of pneumatization, there was a decreasing risk of symptomatic barotrauma (P <.001). No barotrauma occurred in ears with a pneumatization greater than 34.7 cm2. However, barotrauma occurred in all 3 ears with a pneumatization degree smaller than 13.6 cm2. Our findings indicate an inverse relationship between size of pneumatization and risk of symptomatic ME barotrauma in sport scuba divers.

The roentgenographic findings associated with air embolism in sport scuba divers.

Records on all patients with arterial gas embolism (AGE) presenting to UCSD from 1982-1989 and for whom chest radiographs were available were reviewed. Of the 31 patients, 13 roentgenograms (42%) showed evidence of pulmonary barotrauma demonstrated by pneumomediastinum (N = 8), subcutaneous emphysema (N = 3), pneumocardium (N = 2), pneumoperitoneum (N = 1), or pneumothorax (N = 1). Pneumopericardium was not seen. Sixteen (52%) of the 31 patients had pulmonary infiltrates. Radiographic evidence of barotrauma was on occasion subtle, and in four cases was overlooked. Evidence of barotrauma (i.e., extra-alveolar air) was often identified along the left cardiac border, aortic arch, descending aorta, and hilar vessels. Subtle findings of ectopic air can confirm the clinical diagnosis of AGE; however, radiographic evidence of concomitant near drowning occurs more frequently.

Decompression sickness and arterial gas embolism in sports scuba divers.

Diving underwater with breathing apparatus is an increasingly popular sport. Consequently, the number of diving-related accidents, including both decompression sickness and arterial gas embolism, have increased. Though both involve bubbles, decompression sickness is a disease which involves gas bubbles forming in tissues and venous blood, while arterial gas embolism results from the introduction of gas bubbles directly into the arterial circulation. Although the pathologies and natural histories of decompression sickness and arterial gas embolism are different, the treatment of these conditions is essentially the same. Compression in a recompression chamber is the definitive treatment of both decompression sickness and arterial gas embolism, and any delay before treatment must be minimised if a good outcome is desired.

Dysbaric cerebral air embolism in Hawaii

Cerebral air embolism is a major cause of death and disability among sport scuba divers. To better define the epidemiologic and clinical manifestations of this infrequently encountered disorder, the records of all recompression treatments in Hawaii from 1976 through 1979 were reviewed. Forty-two cases of dysbaric air embolism (DAE) were identified on the basis of clinical criteria, accounting for 18% of the patients undergoing recompression treatment for diving-related disorders during this four-year period. In 22 patients (52%), DAE was part of a dysbarism syndrome that involved one or more forms of decompression sickness and/or in which DAE could not be differentiated from neurologic decompression sickness. The presenting signs and symptoms varied, with asymmetric multiplegia being the most common finding. Two patients died, giving a case fatality rate of 5% for those who survived until reaching the recompression chamber. Overall, 78% of the cases manifested either complete (61%) or substantial (17%) recovery with recompression and adjunctive medical measures. Traditional concepts of dysbaric cerebral air embolism are not adequate to explain the spectrum of clinical manifestations encountered in this condition.

Training in Sport Diving: Can Improving Written Tests Improve Safety?

A survey aimed at assessing the adequacy of the written testing materials used in certifying sport SCUBA divers was administered to 11 student divers. The results indicated that the areas of training concerned with the diving environment and with diving procedures were in need of improvement. Since these topics are critical to dive safety, it was concluded that improving the written training materials might have a positive impact on diving accidents and injuries.

Otolaryngology and Sport Scuba Diving

There are over a million certified sport scuba divers in the United States today. The sport is growing at an average annual rate of 7%. The vast majority of medical problems associated with scuba diving are related to the head and neck area, especially the ears. This paper provides an update on the physiology and pathophysiology of sport scuba diving. It also offers guidelines for the physician who may be called upon to examine candidates for the sport or to make decisions on continued diving for trained sport divers.

Cognitive Performance in Sports Scuba Divers

7 subjects completed four cognitive tests at depth in the open water. Analysis indicated that cognitive impairment can occur at depths experienced by sports divers.

Otolaryngologic aspects of scuba diving.

Among the most common injuries encountered by the 700,000 active sport scuba divers in the United States are sinus and otitic barotrauma. The management of these injuries and the identification of high-risk patients during their required pretraining physical examination are discussed.

SCUBA Diving and the Bends

To the Editor: —One omission from the excellent remarks on medical aspects of SCUBA diving by Drs. Salzman and Jung in the Oct. 27 issue ofThe Journal( 182 :34) was underscored by the sentence: By using compressed air a diver can descend without too much danger to a depth of 125 feet. The omission, of course, is discussion of decompression sickness or the bends. Diving to 125 ft and surfacing without decompression is limited to 10 min of according to Navy diving tables. Repetitive diving reduces this safe bottom time to even briefer periods. During the past 2 yr, 23 civilian sport SCUBA divers have been treated for decompression sickness in the recompression-decompression chambers of the submarine base at Pearl Harbor. Next to drowning, this disease is the most common serious misfortune encountered in diving. It can be prevented by informing SCUBA divers of the limitations of