[The Japanese Law Regulating Underwater and Caisson Work: Current Issues and Future Developments].

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.

Severe immersion pulmonary edema in a novice elderly scuba diver after heavy alcohol intake.

BACKGROUND: There are no reports of immersion pulmonary edema induced by excessive alcohol intake. We describe the case of a novice scuba diver who developed apnea due to immersion pulmonary edema during scuba diving after heavy alcohol intake. CASE PRESENTATION: A 71-year-old hypertensive man, without regular antihypertensive therapy, performed diving after excessive alcohol intake (total amount, approximately 253 g) until the night before. When swimming at a depth of 12 m, the patient experienced chest discomfort and ascended immediately but became unconscious. Respiratory arrest was confirmed, and he spat pink foamy sputum. On hospital admission, hypoxemia was confirmed, and chest radiography revealed butterfly-shaped shadows. Therefore, mechanical ventilation was initiated. The next day, his blood oxygenation level improved, and the radiographic shadows disappeared. He was discharged on day 7 of hospitalization without sequelae. CONCLUSION: A scuba diver with untreated hypertension might develop immersion pulmonary edema during diving after heavy alcohol intake.

[What is the Best Therapeutic Strategy for Decompression Illness? First Aid Oxygen Inhalation and Hyperbaric Oxygen Therapy].

Decompression illness (DCI), a syndrome following inadequate reduction in environmental pressure, has two forms: decompression sickness and arterial gas embolism after pulmonary barotrauma. Recompression therapy using oxygen, a kind of hyperbaric oxygen therapy, has been considered the gold standard treatment for DCI, although there is no randomized controlled trial evidence for its use. We evaluated the effectiveness of recompression therapy in treating DCI by reviewing the reported therapeutic results of serious DCI, especially neurological disorders. Early or ultra-early recompression therapy did not dramatically improve clinical recovery from DCI symptoms, including spinal cord disorders. In contrast, early first aid normobaric oxygen inhalation highly improved or stabilized clinical conditions of DCI. Based on these clinical results, the international committee for hyperbaric and diving medicine has stated that cases of mild DCI may be managed without recompression therapy. Further work is needed to clarify the clinical utility of recompression therapy for spinal injury as a common symptom of DCI. We also point out that the Japanese decree "Ordinance on Safety and Health of Work under High Pressure", which describes work under hyperbaric environments, has some serious issues and should be amended on the basis of scientific evidence.