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At least 361 records · Page 20Linked to original sources
PubMed1998

Atopy, airway reactivity and compressed air diving in males.

A decline in expiratory flow rates in divers has recently been attributed to chronic exposure to hyberbaric air. Airway hyperresponsiveness (AHR) to stimuli due to a hyperbaric environment may play a certain role in this context. The aim of this study was to determine the prevalence of AHR in compressed air divers and to assess the value of bronchial challenges for prediction of fitness to dive. A cross-sectional sample of 59 healthy male volunteers--28 divers and 31 diving candidates (controls)--who had been found fit to dive in a diving medical examination underwent additional allergy screening (skin prick and serum IgE) and a histamine bronchial challenge. Pre- and postchallenge body plethysmography was completed to assess AHR. AHR to histamine was significantly increased among divers and positively related to diving experience whereas divers and controls did not differ significantly with respect to age, anthropometric data, current smoking habits, skin prick reaction, and elevated serum IgE. Our results indicate an increased prevalence of AHR to nonspecific inhalation stimuli in experienced divers. Bronchial challenge tests may be helpful to detect asthmatics in the medical assessment of fitness to dive and for follow-up examinations during a diver's career.

Adult↗
PubMed1985

Parasympathetic activity assessed by diving reflex and by airway response to methacholine in bronchial asthma and rhinitis.

It has been suggested that airway hyperreactivity in asthma is associated with increased parasympathetic tone. We have accordingly assessed parasympathetic responsiveness in five groups of subjects (17 normal controls, 8 patients with extrinsic rhinitis, 6 with intrinsic rhinitis, 10 extrinsic asthmatic patients, 7 intrinsic asthmatic patients) by examining their responses to both diving reflex and methacholine inhalation challenge. The mean fall in heart rate during the diving test was significantly greater in asthmatic subjects than in normal controls and in patients with rhinitis. The diving-induced bradycardia was significantly greater in intrinsic than in extrinsic asthmatic subjects. There was a good correlation between the drop in heart rate during diving test and the provocation dose of methacholine producing a 45% decrease in specific airway conductance both in patients with rhinitis and in asthmatic patients. There was a less good correlation between diving response and clinical severity score in the same asthmatic patients. These results indicate that intrinsic asthma is associated with a marked degree of cholinergic hyperreactivity. The diving test seems to provide an accurate method for the analysis of the parasympathetic system in asthma.

Adult↗
PubMed1991

Pressure chamber tympanometry in diving candidates.

The currently recommended examination for diving fitness ascertains middle ear autoinflation ability only under surface pressure conditions. The purpose of our study was to document and quantify middle ear pressure equalization failure during simulated dives among diving candidates who had otherwise met the otologic criteria for diving fitness. Forty-two candidates for regular naval diving activity were included in the study. Tympanograms of both ears at 1 and 1.1 absolute atmospheres (ATA) were taken inside a pressure chamber with the subjects in two positions: seated and supine. At a pressure of 1 ATA, type A tympanograms were found in all 84 ears examined. At a pressure of 1.1 ATA, with subjects in the upright position, 19 (22.9%) of the ears had type C and 2 (2.4%) type B tympanograms, while with subjects recumbent during descent, 6 of the ears (7.2%) had type C and 7 (8.4%) type B. Our results suggest that successful autoinflation at surface ambient pressure does not necessarily reflect middle ear pressure equalization ability during descent in a dive.

Acoustic Impedance Tests↗
PubMed2000

Skin temperatures during free-ranging swimming and diving in antarctic fur seals.

This study tests the hypothesis that an endothermic homeotherm should minimise heat flux in cold polar waters by minimising skin temperature. Temperature variability was measured at the surface of the skin of three Antarctic fur seals (Arctocephalus gazella) at intervals of 2 s over a total of 9.7 days while they were swimming and diving freely in polar waters at temperatures of 1.5-4 degrees C. The temperature difference ( capdelta T) between skin on the dorsal thorax and the water varied from more than 20 degrees C to close to equality over periods of less than 1 h. Shorter-term variations in capdelta T of up to 5 degrees C occurred in association with diving, although these types of variations also occurred without diving. In general, capdelta T began to decline during the descent phase of a dive and began to increase again during the ascent or at the end of the dive. One of the three individuals examined showed little variation in capdelta T, which remained low (approximately 3 degrees C) throughout the experiment. In the other two fur seals, capdelta T tended to decline during periods of sustained diving and usually increased during periods spent at the surface. Mean calculated heat flux varied from 95 to 236 W m(-)(2) depending on the individual. Metabolic rates based on these calculated heat fluxes were towards the lower end of those measured in previous studies using different methodologies. The study has shown that Antarctic fur seal skin temperature is highly dynamic and suggests that the thoracic surface is an organ used for active thermoregulation.

Animals↗
PubMed2002

Changes in sleep patterns during simulated nitrox saturation diving to 20 and 30 meters.

This study assessed the effect of a nitrogen-oxygen (N2-02) saturation diving environment on nocturnal sleep and the differences in sleep on diving depth. We measured and recorded the standard polysomnograph and heart rate for a total of 459 nights on 27 divers who performed the N2-O2 saturation simulation dive an 20- and 30-m equivalent depths as well as their subjective feelings of fatigue. From the last half of the period on the bottom to the postdive period of both saturation diving depths, our main findings included a prolongation of sleep latency, shortened total sleep time, a decreased sleep efficiency index, and increased feelings of fatigue. During the bottom period and decompression period, the total number of awakenings and the awakenings from rapid eyes movement (REM) sleep increased. This was slightly greater at the 30-m equivalent depth. From these facts, we assumed that the deterioration of sleep at the 20- and 30-m nitrox saturation dives was predominantly relative to being restricted in a closed environment for a long time and the lack of physical activity of the divers. No recovery of sleep was observed in the postdive period. A difference in the effects on sleep by the dive depth was not found.

Adult↗
PubMed2004

Oral and maxillofacial aspects of diving medicine.

Sport diving has witnessed explosive growth in the past decade, as 8.5 million people are certified in the United States alone. Even though scuba diving is a relatively safe sport, there are serious risks that all divers must consider. Beyond the better-known sequelae such as decompression sickness, middle ear dysfunction, and potential central nervous system effects, scuba diving also carries inherent risk to the maxillofacial region. Atypical facial pain, temporomandibular joint dysfunction, sinus barotraumas, and barodontalgia have all been reported by dentists and physicians treating military, commercial, and sport divers. Additionally, clinicians must address anatomic concerns for would-be divers, including cleft lip and palate, edentulism, or patients with pre-existing temporomandibular dysfunction, midfacial trauma, or craniomaxillofacial surgery. Health care professionals should have a thorough understanding of the implications of scuba diving for consultation and recommendation regarding diving fitness and the treatment of adverse effects of scuba diving to the maxillofacial region.

Barotrauma↗
PubMed1999

Electroencephalography and magnetic resonance imaging after diving and decompression incidents: a controlled study.

Electroencephalography and magnetic resonance imaging after diving and decompression incidents: a controlled study. Undersea Hyper Med 1999.; 26(2):61-65.--Diving incidents with symptoms of decompression sickness (DCS) and/or arterial gas emboli (AGE) might increase the degree of pathologic change in the electroencephalogram (EEG) or magnetic resonance imaging (MRI) of the supraspinal central nervous system (CNS). Diving itself, even without known symptoms of DCS and/or AGE, has been proposed to increase the number of CNS lesions using either EEG or MRI. In the first part of a two-part study we examined the effects of recompression treatment on EEG in decompression incidents in a group of sport and professional divers compared with a control group of healthy naval divers. In the second part we recorded brain MRI from three groups of volunteers: 1) divers who were treated for DCS in pressure chamber, 2) divers who had never had symptoms of DCS (and/or AGE), and 3) healthy normal controls who were not divers. Our results indicate that DCS increases the incidence of pathologic EEG recordings, whereas recompression treatment decreases them. The results of MRI do not verify evidence of increased numbers of CNS lesions in normal divers as compared to non-diving, healthy control subjects, whereas some of the divers treated for DCS in a pressure chamber had hyperintense lesions in brain white matter. None of them had any abnormalities in EEG, neurologic performance, or psychologic behavior. Both EEG and MRI are sensitive and non-specific methods for judging suspected evidence of brain lesions from diving or diving accidents.

Adult↗
PubMed1975

Hematology and blood chemistry in saturation diving: II. Open-sea vs. hyperbaric chamber.

Hematograms, platelet function, and blood-enzyme chemistry were compared in two similar saturation-excursion dives, one conducted in a hyperbaric chamber and the other in the open sea. The chamber dive was more stressful in that it was preceded by a series of bounce decompression dives (one of which produced a 100% incidence of cutaneous pruritus in four subjects) and in that the excursions from saturation depth (60 fsw or 2.818 ATA) were longer and deeper (producing one case of O2 convulsions, one of confirmed decompression sickness, and several of Doppler-detected vascular bubbles). The chamber dive was associated with a marked and significant reduction in circulating platelet count; significant increases in plasma enzyme activities in the victim of O2 toxicity (LDH, CPK) and in one subject with Doppler bubbles and questionable bends symptoms (LDH, GOT, GPT) but not in another; and mild but significant anemia. In the open-water dive, one subject, who developed symptoms of gastroenteritis, showed moderate elevation of LDH, GOT, and GPT activity. No significant change in platelet counts occurred. Both dives were associated with elevated white-cell counts, apparently as a result of numerous minor infections, and reduced sensitivity of platelets of ADP-induced aggregation.

Alanine Transaminase↗
PubMedDate not supplied

[ENT examination in SCUBA divers and ENT pathologies restricting diving].

SCUBA diving can be safely performed if a careful pre-dive examination regarding the medical standards of diving is performed, and if all necessary precautions are taken with attention being paid to the potential risks of diving. The most frequent medical problems arising from SCUBA diving fall into the otolaryngology discipline; thus, candidates should be examined in terms of ENT disorders that may prevent them from diving. This article aims to review particular aspects of ENT examination, investigation methods, and criteria for candidates

Barotrauma↗
PubMed2002

[Scuba diving: practical aspects].

Keeping in mind some fundamental physic's laws permits to better understand the risks of scuba diving. Essentially, it concerns Boyle's-Mariotte's law (pressure/volume relationship), Dalton's and Henry's laws on the gases partial pressures. Contra-indications of scuba diving depend on the possibility of accidents due to preexisting diseases. The most frequent accidents occur in the O.R.L. and pulmonary systems with the risk of barotraumas, and also in the cardiovascular system with the risk of fainting, uncontrolled ascent to the surface and even drowning. The aptitude test is essential to evaluate and minimize these risks with judicious advices. Generally, complementary tests are performed. In some cases, diving must be limited to "recreational diving", and sporting deep diving, where the conditions are more tiring and hard, must be discouraged. A list is added to the paper, to assist those with any medical problem related with scuba diving, to find informations and advices.

Accident Prevention↗
PubMed2002

The incidence of venous gas emboli in recreational diving.

From 1989-91, the Divers Alert Network monitored recreational divers for Doppler-detected venous gas emboli (VGE) and depth-time profiles following multi-day, repetitive, multi-level exposures. A Spencer score >0 occurred in 61 of 67 subjects (91%) and 205 of 281 dives (73%). No subject developed decompression sickness (DCS) on monitored days although 102 dives (36.3%) scored at Spencer Grades 2 or 3 (High Bubble Grade, HBG). We recorded the depth-time profiles with Suunto dive computers and estimated exposure severity with a probabilistic decompression algorithm. The HBG incidence increased 53% over the range of exposure severity (p < 0.001) in the divers, was approximately 20% higher for repetitive dives than for first dives, and decreased approximately 25% over the 6-8 days of multi-day diving (p < 0.001) suggesting a phenomenon similar to DCS adaptation. The observed HBG incidence was approximately 20% higher for males than females. Older male divers had a 25% increase in observed incidence of HBG while older female divers showed a 55% increase when compared to their younger counterparts.

Adult↗
PubMed2003

[Changes of serum IL-1, IL-2R and TNF-alpha levels in divers after 150 m Heliox saturation -182 m excursion in the open sea diving].

OBJECTIVE: To observe the change of the serum IL-1, IL-2R and TNF-alpha levels in divers after deep saturation in the open sea diving. METHOD: Eight divers experienced 150 in Heliox saturation -182 in excursion diving. Serum levels of IL-1, IL-2R and TNF-alpha level before and after diving were measured by ELISA. RESULTS: There was no significant change of serum TNF-alpha level after saturation diving, but serum levels of IL-1, IL-2R increased significantly after saturation diving. CONCLUSION: Deep open sea saturation diving had significant effects on serum IL-6, IL-2R levels of the divers.

Adult↗
PubMed2003

Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox.

Many divers report less fatigue following diving breathing oxygen rich N2-O2 mixtures compared with breathing air. In this double blinded, randomized controlled study 11 divers breathed either air or Enriched Air Nitrox 36% (oxygen 36%, nitrogen 64%) during an 18 msw (281 kPa(a)) dry chamber dive for a bottom time of 40 minutes. Two periods of exercise were performed during the dive. Divers were assessed before and after each dive using the Multidimensional Fatigue Inventory-20, a visual analogue scale, Digit Span Tests, Stroop Tests, and Divers Health Survey (DHS). Diving to 18m produced no measurable difference in fatigue, attention levels, ability to concentrate or DHS scores, following dives using either breathing gas.

Adult↗
PubMed2005

[Diving fitness for scuba divers--what the primary care physician should know].

The diving fitness medical examination serves to show and reveal medical conditions that are a contraindication for diving or to evaluate the risk of preexisting conditions. For this reason, it should never have the character of a certification given as a matter of courtesy. Fitness to dive is given if the candidate is healthy and when there are no pathological findings. Even with deviations from the norm, diving is still possible, but with restrictions. Important organ systems for the diving fitness examination are the cardiovascular system, the respiratory organs and the ears. In addition, adequate eyesight is important. The German Society of Diving and Hyperbaric Medicine (GTOUM) has drawn up recommendations on the examination of scuba divers to assist the physician (www.gtuem.org).

Diving↗
PubMedDate not supplied

Pulmonary effects of submerged oxygen breathing: 4-, 6-, and 8-hour dives at 140 kPa.

Elevated inspired oxygen partial pressures (PO2) may cause pulmonary oxygen toxicity (PO2T). However, normal variability and water immersion also cause pulmonary function (PF) changes. In 21 subjects, we measured the variability of flow-volume parameters and diffusing capacity for carbon monoxide (DLCO) for six weeks without diving. In 24 divers, we compared the effects of air (P(I)O2 = 0.3 atm = 30 kPa) and oxygen (P(I)O2 = 1.4 atm = 140 kPa) during paired resting dives of 4, 6, or 8 hours in a freshwater pool 4.6 m deep. Without diving, median coefficients of variation (CV) were: vital capacity, 3.2%; FEV1, 3.5%; peak flow, 7.0%; and DLCO, 5.9%. Measurements within 2.4.CV of baseline were considered unchanged. After 4-, 6-, and 8- hour air dives, PF decreased in one, one, and four subjects, respectively, and three, one, and two, respectively, reported symptoms. After the oxygen dives, PF decreased in two, three, and four subjects, respectively, and two, four, and seven, respectively, reported symptoms. PO2T persisted for several days after 8-hour oxygen dives.

Adult↗
PubMedDate not supplied

Blood biochemical parameters in women during long-term simulated hyperoxic diving up to 8 ATA.

Nowadays an increasing number of women are participating in recreational diving. A special recompression treatment table for delayed pulmonary barotrauma or decompression sickness was developed by V.V. Smolin in the Institute for Biomedical Problems (IBMP, Russia). The aim of our study was to investigate the effect of simulated dives (similar to this recompression treatment table) on biochemical parameters of healthy women. Three healthy female volunteers participated in long-term simulated diving to 8 ATA (0.8 MPa). Blood samples for determination of the biochemical substrate levels and activity of blood enzymes using a Reflotron analyzer were obtained at the control period, at the beginning of decompression and at the post dive period. No significant changes of serum levels of glucose, triglycerides, cholesterol, HDL cholesterol and urea were found during this experimental period or in comparison with the predive values. There were no significant changes in ALT activity in two volunteers but there was some tendency for an insignificant decrease in AST activity. One of the volunteers had a considerable increase in AST and ALT activities 15 h after the dive, probably due to a modified diet outside the experiment conditions. Thus, the long-term simulated diving recompression treatment table did not lead to a shift in the woman's serum biochemical status. However, it remains necessary to consider probable dysfunction of liver due to hyperbaric exposure.

Adult↗
PubMed1991

[Diving of patients with spinal cord injuries].

Three patients with traumatic spinal cord injuries of a level below Th 5 have been certified as sports divers in Norway, and an increasing number of other paraplegics and tetraplegics have shown an interest for diving. The article reviews possible complications for these patients during diving. It is concluded that diving is not unsuitable for patients with spinal cord injuries, even for tetraplegics, but these persons run greater risk of complications than healthy divers do. However, on the basis of present knowledge, we have prohibited diving to below 20 m, and patients with spinal cord injuries over Th 5 have so far been advised not to dive. All diving must be performed only after comprehensive training and adaptation.

Adult↗
PubMed1990

Respiratory changes with deep diving.

Deep diving refers to saturation diving to a depth of more than 180 m (1.9 MPa ambient pressure). In the 1990s diving to 400 m may be necessary on the Norwegian continental shelf. The safety margins are narrow and the respiratory system is subject to great strain at such depths. The respiratory resistance increases and the dynamic lung volumes are reduced as the pressure increases due to enhanced gas density. Helium is used together with oxygen as breathing gas and its lower density partly normalises the dynamic lung volumes. The respiratory system puts clear limitations on intensity and duration of physical work in deep diving. Systematic studies of lung mechanics, gas exchange and respiratory regulation in the different phases of deep dives are lacking. Detection of occupational respiratory disorder following diving are dependent on long-term follow-up.

Diving↗