Patterns of wet suit diving in Korean women breath-hold divers

Work shifts, diving pattern, diving lung volumes, and counterweights were studied in professional Korean women breath-hold divers wearing wet suits. One of the major differences, compared with their diving pattern only a few years ago when wearing cotton suits, is the prolongation of the diving shifts from 70 to 180 min in the summer and 10 to 120 min in the winter. In sustained diving the average dive and surface times in a 5-m dive are 32 and 46 s, and in a 10-m dives, 43 and 85 s, respectively. During a 3-h shift the total bottom time for harvesting is 37 min in 5-m dives and 17 min in 10-m dives. Rates of descent and ascent are 0.55 and 0.84 m/s. The wet suit divers adjust their counterweights to obtain a 12% positive buoyancy at the surface of sea water in contrast to the 8% positive buoyancy of cotton suit divers. The average lung volumes before and after a dive are 79% and 64% of their vital capacities, values similar to those of previous cotton suit divers.     

Daily diving pattern of Korean and Japanese breath-hold divers (ama).

Daily diving patterns and thoracic skin and sea-water temperatures were recorded during the entire work shift of Korean female unassisted (cachido) and Japanese male unassisted and partly assisted (funado) divers using Underwater Physiological Data Loggers developed in Buffalo and Japan. All 3 groups of divers were studied during the summer of 1989 and 1990. Additional studies were conducted during the winter of 1991 on Korean female divers who, unlike Japanese divers, dive all year round. The water temperature of the diving grounds in summer was 24 degrees C in both Korea and Japan, and 10 degrees C during winter in Korea. Both Korean female and Japanese male cachido divers made 113-138 dives a day and stayed in the water a total of 170-200 min.day-1, of which only 52-63 min were spent diving submerged, and the remaining time at the water surface. These diving patterns were not different between female and male cachido divers. Compared with Japanese male divers, Korean female divers dived to a shallower depth (3.7 vs. 6.9 m) with shorter dive time (29 vs. 37 s) and shorter bottom time (14 vs. 18 s). Velocities of descent (0.72 vs. 0.47 m.s-1) and ascent (0.77 vs. 0.56 m.s-1) were also slower in female divers than in male divers. The diving pattern of Korean female divers was similar in both summer and winter. Although all cachido divers wore wet suits and thus were protected from severe cold stress, thoracic skin temperature decreased during a work shift by 7 degrees C in winter (vs. 1 degree C in summer) in Korean divers. Compared with Japanese male cachido divers, Japanese male funado divers stayed in the diving ground (including time in the boat) longer (201 vs. 305 min.day-1) but performed only 23 dives per day. The average diving depth (9.7 m), duration (69 s), and bottom time for each dive (45 s), however, were significantly greater in funados. The velocity of vertical descent (1.0 m.s-1) was also significantly greater in funados because they descend with a weight (8-12 kg). The rate of ascent was not different.     

Divers' lung function: small airways disease?

Pulmonary function was measured in 152 professional saturation divers and in a matched control group of 106 subjects. Static lung volumes, dynamic lung volumes and flows, transfer factor for carbon monoxide (T1CO), transfer volume per unit alveolar volume (KCO), delta-N2, and closing volume (CV) were measured and compared with reference values from recent Scandinavian studies, British submariners, and the European Community for Coal and Steel (ECCS) recommended reference values. Diving exposure was assessed as years of diving experience, total number of days in saturation and depth, and as the product of days in saturation and mean depth. Divers had significantly lower values for forced expired volume in one second (FEV1), FEV1/forced vital capacity (FVC) ratio, FEF25-75%, FEF75-85%, FEF50%, FEF75%, T1CO, and KCO compared with the controls and a significantly higher CV. There was a positive correlation between diving exposure and CV, whereas the other variables had negative correlations with diving exposure. Values for the control group were not different from the predictive values of Scandinavian reference studies or British submariners, although the ECCS standard predicted significantly lower values for the lung function variables both in divers and the control group. The pattern of the differences in lung function variables between the divers and controls is consistent with small airways dysfunction and with the transient changes in lung function found immediately after a single saturation dive. The association between reduced pulmonary function and previous diving exposure further indicates the presence of cumulative long term effects of diving on pulmonary function.     

Divers' lung function: small airways disease?

Pulmonary function was measured in 152 professional saturation divers and in a matched control group of 106 subjects. Static lung volumes, dynamic lung volumes and flows, transfer factor for carbon monoxide (T1CO), transfer volume per unit alveolar volume (KCO), delta-N2, and closing volume (CV) were measured and compared with reference values from recent Scandinavian studies, British submariners, and the European Community for Coal and Steel (ECCS) recommended reference values. Diving exposure was assessed as years of diving experience, total number of days in saturation and depth, and as the product of days in saturation and mean depth. Divers had significantly lower values for forced expired volume in one second (FEV1), FEV1/forced vital capacity (FVC) ratio, FEF25-75%, FEF75-85%, FEF50%, FEF75%, T1CO, and KCO compared with the controls and a significantly higher CV. There was a positive correlation between diving exposure and CV, whereas the other variables had negative correlations with diving exposure. Values for the control group were not different from the predictive values of Scandinavian reference studies or British submariners, although the ECCS standard predicted significantly lower values for the lung function variables both in divers and the control group. The pattern of the differences in lung function variables between the divers and controls is consistent with small airways dysfunction and with the transient changes in lung function found immediately after a single saturation dive. The association between reduced pulmonary function and previous diving exposure further indicates the presence of cumulative long term effects of diving on pulmonary function.     

Acute otitis externa in divers working in the North Sea: a microbiological survey of seven saturation dives.

Saturation diving is an important and widely used technique in the Offshore Oil Industry. During 1974-5 two saturation dives in the North Sea were terminated because of outbreaks of incapacitating otitis externa, and others were disrupted. Pseudomonas aeruginosa was consistently isolated from the ears of affected divers. Because complex work schedules were threatened seven subsequent dives were subjected to microbiological monitoring and control. Colonization of ear canal with P. aeruginosa or with other gram-negative bacilli occurred in 39 (67%) of the 58 divers studied, usually within 7 days of starting the dive. Data obtained by serotyping this isolations of P. aeruginosa suggested that a single infected diver may be the source of organisms which rapidly spread to his colleagues and throughout the living chambers, that the living chambers may constitute a reservoir of infection during and between dives, and that certain serotypes of P. aeruginosa are more likely than others to colonize the ear canal in the conditions of a saturation dive. The control measures used during the dives were only partially effective, but none of the divers suffered severe pain and all the dives were an operational success.     

Evaluation of noise within the MK 12 SSDS helmet and its effect on divers' hearing

The noise inside the U.S. Navy MK 12 SSDS helmet was measured and its effect on the hearing of divers assessed. Seven male divers completed 20 dives while breathing air at simulated depths ranging from 1.8 to 30.5 msw with dive durations ranging from 40 to 120 min. Microphones recorded sound pressure levels inside the helmet while the diver was in the water and exercising. Average corrected sound intensity levels in the helmet ranged from 90.5 dB(A) at 1.8 msw to 97.3 dB(A) at 30.5 msw. Diver hearing threshold level shifts were recorded as a function of helmet noise exposure; moderate threshold shifts were observed at depths of 9.1 msw or deeper after 120-min dives. The hearing of all divers completing dives up to 120 min returned to predive levels within 24 h after noise exposure. However, dive durations in excess of 120 min at 9.1 and 20.1 msw resulted in substantial auditory shifts in 1 diver, which required 2-3 d to recover to predive levels. These results suggest that the impact of helmet noise on diver hearing should be included in planning operations using the MK 12 SSDS.     

Diving pattern of Tsushima male breath-hold divers (Katsugi)

The present study was undertaken to investigate the diving pattern, buoyancy-mass relationship, and some respiratory functions in professional male breath-hold divers in Tsushima Island, Japan. These divers always wear neoprene wet suits and use fins and 4-kg counterweights. They usually dive to 3-10 m depths. The rate of descent was 1.12 m/s for deeper dives (greater than 10 m), which is nearly twofold greater than that of Korean female divers also wearing wet suits and fins. However, the rate of ascent (0.8 m/s) was comparable to that of Korean women divers. On a typical summer day, they spend nearly 4 h in the water and perform 175 dives. The average dive and surface time were 39 and 42 s, respectively. The total bottom time was estimated to be 67 min/d, nearly twice that of Korean women divers. These divers do not adjust the counterweight and all are using a 4-kg weight. Nevertheless, the buoyancy-mass relationship revealed that they maintain the same degree of positive buoyancy (approximately 10% above the neutral level) at surface as do Korean women divers who adjust counterweights. The vital capacity was significantly greater in the diver than in the control (P less than 0.05), which was largely due to the greater expiratory reserve volume in the diver. The end-tidal O2 and CO2 pressures of the diver resting in air were not different from those of the control. These results indicate that, while the basic diving pattern is similar in both male and female breath-hold divers, the overall efficiency of diving (in terms of the rate of descent and the bottom time) appears to be superior in male divers.     

Diving profiles and work loads of fishermen's "Oikomi Gyoho" diving

Diving profiles of fishermen divers in the Izu Islands were investigated and recorded by DDR (Diving Data Recorder). Consumed air volume during diving work was also checked in each dive and the work load was measured by VO2 during diving. It was recognized that divers repeatedly experienced extreme descents and ascents, that were accompanied by increases of oxygen consumption. This suggested that the load of their work was far beyond that of sports divers. The particular diving method used, called the "Oikomi Gyoho method" is to repeatedly dive several times to catch fish. Each bottom (diving) time is rather short and the dept changes from deeper to shallower areas gradually. This profile is considered to be a safe diving method for the prevention of DCS (Decompression Sickness). However, stopping for decompression during ascent is sometimes required to prevent DCS according to analysis of the diving profiles. It is pointed out that the risk of DCS still remains with this diving method.     

Neuropsychologic effects of saturation diving

Neuropsychologic status of saturation divers was assessed before and after 300-500 msw dives (deep saturation diving--DSD group) and before and after 3.5 yr of ordinary saturation diving (saturation diving--SD group). Average baseline results showed the divers to be slightly superior to nondiving controls. Mild-to-moderate neuropsychologic changes (greater than 10% impairment) were found in measures of tremor, spatial memory, vigilance, and automatic reactivity in 20% of the divers after deep dives (DSD group). One year postdive no recovery was observed except for a vigilance test. In the SD group, 20% of the divers showed greater than 10% impairment after 3.5 yr of ordinary saturation diving. Significant reduction in autonomic reactivity was also found and there was a relationship between low autonomic reactivity before saturation diving and number of greater than 10% impairments. For the whole group (DSD + SD divers), negative correlations were found between saturation experience and results on memory and complex visuomotor tests. Years of diving from first to last examination was positively correlated with number of greater than 10% impairments and with reduction in autonomic reactivity. No similar correlations were found to dive variables after about 3 yr of air diving. The mild-to-moderate changes seen in some divers, therefore, seem to be the effects of saturation diving. Since one deep dive may cause an effect similar to the effect of 3.5 yr of ordinary saturation diving, there is reason to believe that repeated deep diving may lead to more pronounced neuropsychologic impairment.     

Correlation between 99Tcm-HMPAO-SPECT brain image and a history of decompression illness or extent of diving experience in commercial divers.

OBJECTIVES: To explore the use of 99technetiumm-hexamethyl propylene amine oxime single photon computed tomography (HMPAO-SPECT) of the brain as a means of detecting nervous tissue damage in divers and to determine if there is any correlation between brain image and a diver's history of diving or decompression illness (DCI). METHODS: 28 commercial divers with a history of DCI, 26 divers with no history of DCI, and 19 non-diving controls were examined with brain HMPAO-SPECT. Results were classified by observer assessment as normal (I) or as a pattern variants (II-V). The brain images of a subgroup of these divers (n = 44) and the controls (n = 17) were further analysed with a first order texture analysis technique based on a grey level histogram. RESULTS: 15 of 54 commercial divers (28%) were visually assessed as having HMPAO-SPECT images outside normal limits compared with 15.8% in appropriately identified non-diver control subjects. 18% of divers with a history of DCI were classified as having a pattern different from the normal image compared with 38% with no history of DCI. No association was established between the presence of a pattern variant from the normal image and history of DCI, diving, or other previous possible neurological insult. On texture analysis of the brain images, divers had a significantly lower mean grey level (MGL) than non-divers. Divers with a history of DCI (n = 22) had a significantly lower MGL when compared with divers with no history of DCI (n = 22). Divers with > 14 years professional diving or > 100 decompression days a year had a significantly lower MGL value. CONCLUSIONS: Observer assessment of HMPAO-SPECT brain images can lead to disparity in results. Texture analysis of the brain images supplies both an objective and consistent method of measurement. A significant correlation was found between a low measure of MGL and a history of DCI. There was also an indication that diving itself had an effect on texture measurement, implying that it had caused subclinical nervous tissue damage.     

Extremely deep recreational dives: the risk for carbon dioxide (CO(2)) retention and high pressure neurological syndrome (HPNS)

Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) caused by a direct compression effect, presumably on the lipid component of cell membranes of the central nervous system. In deep professional diving, divers use a mixture of helium and oxygen to decrease gas density, and nitrogen is used only in some cases for decreasing the signs and symptoms of HPNS. The same approach with decreasing the nitrogen content in the breathing mixture can also be observed nowadays in deep recreational diving. Moreover, in extremely deep professional diving, hydrogen has been used successfully both for decreasing the density of the breathing gas mixture and amelioration of HPNS signs and symptoms. It is fair to assume that the use of hydrogen will be soon "re-invented" by extremely deep recreational divers. So the scope of modern diving medicine for recreational divers should be expanded also to cover these problems, which previously were assigned exclusively to professional and military divers.     

Relations of smoking and diving experience to pulmonary function among U.S. Navy divers

The relations of 4 pulmonary function parameters (measured from the forced expiratory spirogram) with diving experience (in years) and indices of cigarette smoking were examined in a group of 93 healthy U.S. Navy divers. Years of diving was not significantly related to lung function. The value for pack-years of smoking was inversely associated with both percentage of predicted forced expiratory volume in 1 s (FEV1) and percentage of predicted maximal midexpiratory flow rate (MMFR). Divers who have relatively heavy smoking histories may be at greater risk for developing significant decline in pulmonary function, and diving exposure factors other than years of diving may contribute to this risk.     

Western Australian recreational scuba diving fatalities, 1992 to 2005

Objective: To investigate recreational scuba diving fatalities within Western Australia (WA) between 1992 and 2005.
Methods: Coroners reports for 24 diving fatalities were reviewed to determine anthropometry, certification status and breaches of safe practices for each.
Results: Certification status was known for 20 divers and of these six (30%) were uncertified. Certified divers breached significantly fewer safe diving practices than uncertified divers ( p <0.01). Existing regulatory mechanisms require training certification only for dives made from commercial dive boats, yet the number of deaths involving shore dives or private craft (n=15) were triple the number diving from commercial boats (n=5).
Conclusion: Uncertified divers are less regulated and breach more safe practices than certified divers.
Implications: We recommend changes to existing regulations governing dives made from shore and private craft in WA, requiring that all divers be certified.     

Identification of infectious Pseudomonas aeruginosa strains in an occupational saturation diving environment

OBJECTIVES: Occupational saturation divers have various skin disorders, of which skin infections are the most serious and frequent. Pseudomonas aeruginosa is the microbe most often isolated from skin infections in divers. The purpose of the present work was (a) to report the occurrence of P aeruginosa in skin infections in operational saturation diving in the North Sea from 1987 to 1995; (b) to report the environmental occurrence of P aeruginosa in saturation diving systems, and finally (c) to identify possible relations between infection related to strains of P aeruginosa and environmental isolates of the microbe. RESULTS: During the period 1987-95, P aeruginosa was isolated from 257 skin infections in operational saturation divers. Most of the isolates related to infection by P aeruginosa show a unique growth inhibition pattern towards the normal skin flora, and the serotype pattern of P aeruginosa from skin infections is limited compared with similar infections in non-divers. In a mini-epidemiological study on board one diving vessel during one operational diving period, five significantly different DNA fragment profiles were found among the 12 isolates related to infection by P aeruginosa obtained from the saturation system. In two cases the infectious genotypes were detected in the fresh water for the saturation chambers weeks before the arrival of the infected diver. CONCLUSIONS: The most commonly used epidemiological marker for P aeruginosa world wide, also used in earlier studies, is serotyping, but with pulsed field gel electrophoresis (PFGE) miniepidemiology it was shown to be insufficient for epidemiological purposes in saturation environments. PFGE analyses were shown to be superior both to antibacterial factor and to serotyping in epidemiological analyses of P aeruginosa infections in saturation diving.     

Aseptic bone necrosis among U.S. Navy divers: survey of 934 nonrandomly selected personnel

Nine hundred thirty-four U.S. Navy divers were selected and surveyed radiographically using standard techniques developed for detecting aseptic bone necrosis (ABN). X rays were read by qualified radiologists. A total of 16 positive cases was detected, and another 11 were interpreted as doubtful. ABN was found to be related to age and number of months in diving. After controlling for these factors, ABN could not be related to any of seven indices of diving activity. Divers with ABN did, however, have a history of more treatments for decompression sickness (DCS) than did divers without ABN. Implications of these findings are discussed, and the suggestion is made that ABN and DCS may not be related causally, but may be related to a third common factor. The need for controlled studies is discussed. The conclusion is made that the low prevalence rates of ABN among U.S. Navy divers cannot be related to any specific index of diving activity, and may not be causally related to DCS.     

Objective neuropsychological test performance of professional divers reporting a subjective complaint of "forgetfulness or loss of concentration"

OBJECTIVE: This study attempted to determine whether the higher prevalence of reported "forgetfulness or loss of concentration" among professional divers can be confirmed using objective neuropsychological tests. Secondary aims were to qualify the functional nature of the complaints and to ascertain whether reduced performance was linked to diving history. METHODS: In a case-control study, the neuropsychological test performance of divers complaining of moderate or severe "forgetfulness or loss of concentration" was compared with two age-matched control groups reporting no or slight "forgetfulness or loss of concentration" ("nonforgetful" divers and "nonforgetful" nondivers). The group differences were analyzed using a multivariate analysis of co-variance, followed by canonical discriminant function analysis. Altogether 102 divers with a complaint, 100 nonforgetful divers, and 100 nonforgetful nondivers completed the study. RESULTS: The overall neuropsychological performance differed significantly between the groups [Pillai's trace: F(24,484)=2.04, P=0.003]. Verbal memory (Logical Memory and the California Verbal Learning Test), current intelligence (Wechsler Abbreviated Scale of Intelligence), and sustained attention (rapid visual processing) were poorer among the divers with a complaint than among the nonforgetful divers or the nonforgetful nondivers. The tests of memory, but not those of executive function, differentiated the divers with complaints from the two control groups. Mixed gas bounce diving and surface oxygen decompression diving, but not other techniques, were negatively associated with memory performance. CONCLUSIONS: A cognitive complaint of divers was confirmed using objective tests of neuropsychological performance. Memory, rather than executive function, was affected at the group level, but only to a mild degree. The relationships between diving experience and neuropsychological test performance were small and only seen with diving techniques used in the offshore oil and gas industry.     

Diving accidents in sports divers in Orkney waters

Scapa Flow in Orkney is one of the major world centres for wreck diving. Because of the geography of Orkney and the nature of the diving, it is possible to make relatively accurate estimates of the number of dives taking place. The denominator of dive activity allows the unusual opportunity of precise calculation of accident rates. In 1999, one in every 178 sports divers visiting Orkney was involved in a significant accident, in 2000 the figure was one in 102. Some of these accidents appear to have been predictable and could be avoided by better education and preparation of visiting divers.     

An audiometric survey of Navy divers.

The pure tone audiograms of a diverse group of U.S. Navy divers were examined across four major variables: (1) number of years of Navy diving experience, (2) previous noise exposure history, (3) previous history of barotrauma, and (4) type of equipment used, i.e. scuba and helmet. The results obtained suggest that these variables had only minimal effects on auditory sensitivity and that when the hearing of these divers was compared to a normal population of nondivers, no significant differences were detected. A comparison of these findings with those in the existing diving literature was then made.     

Characteristics of the response to exercise in professional saturation divers

Exercise testing with measurements of expired minute ventilation (VE), oxygen uptake (VO2), and carbon dioxide elimination (VCO2) was done in 63 professional saturation divers, in the screening programs for selection of divers, to 10 different experimental and operational saturation dives. Their experience as divers averaged 9.8 yr (range 1-20), and they averaged 276 days (range 5-900) in saturation. The maximal pressure they had ever been exposed to averaged 2.01 MPa (range 0.8-5.1). The divers were compared with a control group of 47 offshore workers and policemen matched for age, height, and smoking habits and with reference values for the general healthy population. There were no significant differences in peak work load achieved, VO2peak and VCO2peak. VE at VO2peak and the corresponding ventilatory equivalents for oxygen uptake (VE(peak)/VO2peak) and carbon dioxide elimination (VE(peak)/VCO2peak) were significantly higher in divers (P less than 0.05), but VE, VE/VO2 and VE/VCO2 were not different at lower work loads. VE(peak)/VCO2peak correlated positively with years of diving experience when corrected for age (P less than 0.01). Divers had higher tidal volumes and lower breathing frequencies at ventilations lower than 40% of VE(peak), but maximal tidal volumes were not different. Tidal volume at a VE of 30 liter.min(-1) correlated negatively with FEV1 (P less than 0.05). The results are in agreement with the transient changes in pulmonary function and exercise tolerance demonstrated after a single saturation dive, and indicate that these changes may not be completely reversible.     

戴口罩前后细菌培养和肺活量检测结果分析

目的探讨戴口罩对护士健康的影响。方法对医院30名急诊科护士连续戴口罩2h前后的鼻咽部样本做了细菌学培养．并测定戴口罩前后的肺活量。结果连续戴口罩2h后的菌落数为（105．10±72．23）CFU／cm^2，高于戴口罩前的（37．17±25．14）CFU／cm^2，差异有统计学意义（t=-5．99，P〈0．01）；戴口罩后的肺活量为（2193．10±281．73）mL．低于戴口罩前的（3170．00±291．40）mL，差异有统计学意义（t=32．75，P〈0．01）。结论长时间戴口罩增加了呼吸道自身感染的机会，使护士的肺活量下降，可能影响护士的身体健康，同时影响护患交流的效果。