UNASSIGNED: This is a review of commercial heliox saturation decompression procedures. The scope does not include compression, storage depth or bell excursion dive procedures. The objectives are to: identify the sources of the procedures; trace their evolution; describe the current practice; and detect relevant trends.
UNASSIGNED: Eleven international commercial diving companies provided their diving manuals for review under a confidentiality agreement.
UNASSIGNED: Modern commercial diving saturation procedures are derived from a small number of original procedures (United States Navy, Comex, and NORSOK). In the absence of relevant scientific studies since the late 80\'s, the companies have empirically adapted these procedures according to their needs and experience. Such adaptation has caused differences in decompression rates shallower than 60 msw, decompression rest stops and the decision to decompress linearly or stepwise. Nevertheless, the decompression procedures present a remarkable homogeneity in chamber PO2 and daily decompression rates when deeper than 60 msw. The companies have also developed common rules of good practice; no final decompression should start with an initial ascending excursion; a minimum hold is required before starting a final decompression after an excursion dive. Recommendation is made for the divers to exercise during decompression.
UNASSIGNED: We observed a trend towards harmonisation within the companies that enforce international procedures, and, between companies through cooperation inside the committees of the industry associations.

UNASSIGNED: Performance of routine Chest X-rays (CXRs) in asymptomatic individuals to assess hyperbaric exposure risk is controversial. The radiation risk may overshadow the low yield in many settings. However, the yield may be higher in certain settings, such as tuberculosis-endemic countries. We evaluated the utility of routine CXR in diving and submarine medical examinations in South Africa.
UNASSIGNED: Records of 2,777 CXRs during 3,568 fitness examinations of 894 divers and submariners spanning 31 years were reviewed to determine the incidence of CXR abnormality. Associated factors were evaluated using odds ratios and a binomial logistic regression model, with a Kaplan-Meier plot to describe the duration of service until first abnormal CXR.
UNASSIGNED: An abnormal CXR was reported in 1.1% per person year of service, yielding a cumulative incidence of 6.5% (58/894) of the study participants. Only four individuals had a clinical indication for the CXR in their medical history. A range of potential pathologies were seen, of which 15.5% were declared disqualifying and the rest (84.5%) were treated, or further investigation showed that the person could be declared fit.
UNASSIGNED: In South Africa, a routine CXR has a role to play in detecting abnormalities that are incompatible with pressure exposures. The highest number of abnormalities were found during the initial examinations and in individuals with long service records. Only four individuals had a clinical indication for their CXR during the 31-year span of our study. Similar studies should be performed to make recommendations in other countries and settings.

UNASSIGNED: There is an increasing interest in \'transfer under pressure\' (TUP) decompression in commercial diving, bridging traditional surface-oriented diving and saturation diving. In TUP diving the diver is surfaced in a closed bell and transferred isobarically to a pressure chamber for final decompression to surface pressure.
UNASSIGNED: Tables for air diving and air and oxygen decompression have been compared for total decompression time (TDT), oxygen breathing time as well as high and low gradient factors (GF high and low). These have been considered surrogate outcome measures of estimated decompression sickness probability (PDCS).
UNASSIGNED: Six decompression tables from DadCoDat (DCD, The Netherlands), Defence and Civil Institute of Environmental Medicine (DCIEM, Canada), Comex MT92 tables (France) and the United States Navy (USN) have been compared. In general, USN and DCD procedures advised longer TDT and oxygen breathing time and had a lower GF high compared to MT92 and DCIEM tables. GF low was significantly higher in USN procedures compared to DCD and one of the MT92 tables due to a shallower first stop in many USN profiles compared to the two others. Allowance and restrictions for repetitive diving varied extensively between the six procedures. While USN procedures have been risk-assessed by probabilistic models, no detailed documentation is available for any of the tables regarding validation in experimental and operational diving.
UNASSIGNED: Absence of experimental testing of the candidate tables precludes firm conclusions regarding differences in PDCS. All candidate tables are recognised internationally as well as within their national jurisdictions, and final decisions on procedure preference may depend on factors other than estimated PDCS. USN and DCD procedures would be expected to have lower PDCS than MT92 and DCIEM procedures, but the magnitude of these differences is not known.

The Japan \"Ordinance on Safety and Health of Work under High Pressure\", which is the law regulating health conditions for workers under high pressure environments, was amended in 2014. The revised regulations have highlighted other difficulties and new problems, but they have not yet written an appropriate amendment based on the aspect of occupational and environmental health. Health management for occupational divers and caisson workers in accordance with the new regulations has not determined the best approach to reducing related disorders and will cause other legal problems. This paper presents some issues in the new regulations for hyperbaric workers, which directly or indirectly involve occupational health physicians. Health checkups and work limitations should be done in consideration of the occupational characteristics of the undersea and hyperbaric environment. Regular examinations using specific studies are useful to diagnose the early stages of chronic conditions for workers, and are also useful for determining the hiring suitability for hyperbaric workers. Work limitations should be decided by the conditions that induce serious accidents or disorders that result from exposure to hyperbaric environments, and depend on the obstacles for work due to sequelae of decompression sickness. The new regulations need to be properly revised, based on scientific evidence, to include health management for workers in undersea and hyperbaric environments.

BACKGROUND: This study identified characteristics and diving practices of victims of fatal surface supplied breathing apparatus (SSBA) incidents in Australia from 1965-2019 to determine underlying factors and risks associated with these activities, better educate the diving community and prevent such deaths.
METHODS: A hand search was made of \'Project Stickybeak\' reports from 1965-2000 and SSBA fatality data were compared to the Australasian Diving Safety Foundation fatality database. The National Coronial Information System was searched to identify SSBA diving deaths for 2001-2019. Extracted data were collated and analysed using descriptive statistics and Poisson Regression. A chain of events analysis was used to determine the likely sequence of events.
RESULTS: There were 84 identified SSBA-related deaths during the study period. Most victims were relatively young, healthy males (median age 33 years). At least 50% of victims were undertaking work-related diving, and 37% were recreational diving. Equipment issues, mainly compressor-related, were the main contributor, identified as a predisposing factor in 48% of incidents and as triggers in 24%.
CONCLUSIONS: Preventable surface-supplied diving deaths still occur in both occupational and recreational diving, often from poor equipment maintenance and oversight. Incorrect configuration of the SSBA and lack of training remain on-going problems in recreational users. These could be addressed by improved education, and, failing this, regulatory oversight. The increase in health-related incidents in older participants may be controlled to some extent by greater medical oversight, especially in recreational and non-certified occupational divers who should be encouraged to undergo regular diving medical assessments.

Diving challenges the respiratory system because of the pressure changes, breathing gases, and cardiovascular effects. We aimed to analyse the long term effect of occupational diving on pulmonary functions in terms of diving experience (year), smoking history, and occupational groups (commercial divers and SCUBA instructors).
We retrospectively analysed respiratory system examination results of the experienced occupational divers who were admitted to the Undersea and Hyperbaric Medicine Department for periodic medical examination between January 1, 2013 and February 28, 2019.
Sixty-four divers applied to our department. Candidate divers were not included in our study. The mean diving experience (year) was 13.6 ± 7.3. None of the divers complained of pulmonary symptoms. Pulmonary auscultation and chest radiography were normal in all cases. In divers with 20 years or more experience, the FEV1/FVC ratio and FEF25-75(%) was significantly lower (p < 0.001, p < 0.05, respectively). In addition, there was a statistically significant negative correlation between FEV1/FVC ratio and FEF25-75(%) and diving experience (year) (p < 0.05, r = -0.444, p < 0.05, r = -0.300, respectively). As the diving experience increase per 1 year, the FEF25-75(%) value decreases by 1.04% according to linear regression analyses. However, smoking and occupational groups did not show any significant influence on pulmonary function test parameters.
Occupational diving seems to create clinically asymptomatic pulmonary function test changes related to small airway obstruction after long years of exposure.

BACKGROUND: Adult attention-deficit/hyperactivity disorder (ADHD) is associated with increased chance of workplace accidents, psychiatric comorbidities, other risky behaviours and sophisticated psychopharmacological treatment. These factors all contribute to a potentially complex risk profile within the commercial diving context. In order to make informed decisions regarding ADHD and commercial diving, further description of this condition among commercial divers is required. This paper reports on a study that aimed to determine the prevalence of adult ADHD among commercial divers.
METHODS: The study used a self-reporting survey-type questionnaire to determine likely diagnosis, based on Diagnostic and Statistical Manual of Mental Disorders, 5th ed. criteria, in a group of 245 commercial divers in South Africa.
RESULTS: Fourteen cases (5.7% of the sample) met criteria for ADHD. The majority of the cases presented with combined type, and reflected mild forms of ADHD. Adult ADHD did not appear to occur in significantly different proportions across the biographical variables of age, education or diving qualification.
UNASSIGNED: Based on this small survey, adult ADHD may be over-represented in commercial diving in South Africa, compared to general workplace populations. However, ADHD may not necessarily be a contra-indication to commercial diving.

BACKGROUND: Professional divers, like many other specialised occupational groups, are subject to regulatory constraints that include mandatory initial medical certification and routine recertification. The New Zealand system of diver certification and health surveillance has undergone modifications in recent years, but its acceptance among end-users has never been formally assessed. Because of the wide variety of tasks, circumstances and personalities encountered in the diving industry, unanimous satisfaction is an unrealistic expectation, but establishing the current mood of divers in this regard and canvassing opinions on possible improvements is an important step towards optimising the certification process.
METHODS: A multi-choice satisfaction questionnaire was added, as a quality assurance measure, to the on-line health questionnaire completed annually by all New Zealand professional divers. A complete 12-month dataset was analysed to determine levels of satisfaction, areas of dissatisfaction and suggestions for improvement. Comparison of the opinions of various diver groups was achieved by stratification into employment-type sub-groups and those working locally, overseas or both.
RESULTS: The responses of 914 divers who completed the survey established an 85% satisfaction rate with the existing diver certification system. Dissatisfaction was independent of diving locality. Compliance cost was the most common area of dissatisfaction, particularly among recreational diving instructors.
CONCLUSIONS: Most New Zealand professional divers consider the current certification system satisfactory. Effective communication between the regulating authority and divers was identified as an important area for further development.

BACKGROUND: Approximately 77% of professional divers leave the industry within five years of entry, for reasons that are uncertain. One possibility is that attrition is due to ill-health. The health of New Zealand occupational divers is surveyed by a comprehensive medical examination every five years and by a health questionnaire in the intervening years. Divers are thereby confirmed \'fit\' annually. The aim of this study was to determine if divers quit the industry due to a health problem not identified by this health surveillance system.
METHODS: 601 divers who had left the industry within five years of entry medical examination (\'quitters\') were identified from a computerised database. One hundred and thirty-six who could be contacted were questioned about their principal reason for quitting. Comparison was made between the health data of all those defined as \'quitters\' and a group of 436 \'stayers\' who have remained active in the industry for over 10 years.
RESULTS: Health was the principal reason for abandoning a diving career for only 2.9% of quitters. The overwhelming majority (97.1%) quit because of dissatisfaction with aspects of the work, such as remuneration and reliability of employment. Besides gender, the only significant difference between the health data of quitters and stayers was that smoking was four times more prevalent among quitters.
CONCLUSIONS: The key determinant of early attrition from the New Zealand professional diver workforce is industry-related rather than health-related. The current New Zealand diver health surveillance system detects the medical problems that cause divers to quit the industry.

BACKGROUND: Surveillance of professional divers\' hearing is routinely undertaken on an annual basis despite lack of evidence of benefit to the diver. The aim of this study was to determine the magnitude and significance of changes in auditory function over a 10-25 year period of occupational diving with the intention of informing future health surveillance policy for professional divers.
METHODS: All divers with adequate audiological records spanning at least 10 years were identified from the New Zealand occupational diver database. Changes in auditory function over time were compared with internationally accepted normative values. Any significant changes were tested for correlation with diving exposure, smoking history and body mass index.
RESULTS: The audiological records of 227 professional divers were analysed for periods ranging from 10 to 25 years. Initial hearing was poorer than population norms, and deterioration over the observation period was less than that predicted by normative data. Changes in hearing were not related to diving exposure, or smoking history.
CONCLUSIONS: Audiological changes over 10 to 25 years of occupational diving were not found to be significantly different from age-related changes. Routine annual audiological testing of professional divers does not appear to be justifiable.