title: Doppler detection in Ama divers of Japan.
abstract: OBJECTIVE
  Symptoms consistent with neurological decompression sickness (DCS) in commercial breath-hold (Ama) divers has been reported from a few districts of Japan. The aim of this study was to detect circulating intravascular bubbles after repetitive breath-hold diving in a local area where DCS has been reported in Ama divers.
  
  
  METHODS
  The participants were 12 partially assisted (descent using weights) male Ama divers. The equipment (AQUALAB system) consisted of continuous-wave Doppler with a 5-MHz frequency, and the Doppler probe was placed in the precordial site with the ultrasonic wave directed into the pulmonary infundibulum. We carried out continuous monitoring for 10 minutes at the end of the series of repetitive dives, and the recordings were made on numerical tracks and graded in a blind manner by 2 experienced investigators, according to the Spencer Doppler code.
  
  
  RESULTS
  Depths and number of dives were 8 to 20 m and 75 to 131 times. Mean diving duration and surface interval were 64 ± 12 seconds and 48 ± 8 seconds, respectively (mean ± SD). We detected the lowest grade of intravascular bubbles (Spencer's grade I) in an Ama diver whose mean surface interval was only 35.2 ± 6.2 seconds. His mean descending, bottom, and ascending times were 10.4 ± 1.6 seconds, 39.2 ± 8 seconds, and 18.2 ± 3.0 seconds, respectively, over the course of 99 dives.
  
  
  CONCLUSIONS
  Intravascular bubbles may be formed after repetitive breath-hold dives with short surface intervals or after a long breath-holding session in Ama divers. Symptoms consistent with neurological accidents in repetitive breath-hold diving may be caused in part by the intravascular presence of bubbles, indicating the need for safety procedures.
authors.affiliation: Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS, EA 3832), Faculté des Sciences du Sport, Université de Rouen, France (Drs Lemaître and Costalat); Association pour la Recherche sur l'Apnée et les Activités Subaquatiques (APRAAS; Drs Lemaître and Gardette). Electronic address: frederic.lemaitre@univ-rouen.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lemaître
authors.affiliation: Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan (Drs Kohshi, Tamaki, Satou, Hoshiko, and Ishitake).
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Kohshi
authors.affiliation: Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan (Drs Kohshi, Tamaki, Satou, Hoshiko, and Ishitake).
authors.forename: Hideki
authors.initials: H
authors.lastname: Tamaki
authors.affiliation: Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Tochigi, Japan (Drs Nakayasu, Harada, and Masanobu).
authors.forename: Kasuo
authors.initials: K
authors.lastname: Nakayasu
authors.affiliation: Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Tochigi, Japan (Drs Nakayasu, Harada, and Masanobu).
authors.forename: Mesanori
authors.initials: M
authors.lastname: Harada
authors.affiliation: Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Tochigi, Japan (Drs Nakayasu, Harada, and Masanobu).
authors.forename: Masanobu
authors.initials: M
authors.lastname: Okayama
authors.affiliation: Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan (Drs Kohshi, Tamaki, Satou, Hoshiko, and Ishitake).
authors.forename: Yuka
authors.initials: Y
authors.lastname: Satou
authors.affiliation: Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan (Drs Kohshi, Tamaki, Satou, Hoshiko, and Ishitake).
authors.forename: Michiko
authors.initials: M
authors.lastname: Hoshiko
authors.affiliation: Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan (Drs Kohshi, Tamaki, Satou, Hoshiko, and Ishitake).
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ishitake
authors.affiliation: Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS, EA 3832), Faculté des Sciences du Sport, Université de Rouen, France (Drs Lemaître and Costalat).
authors.forename: Guillaume
authors.initials: G
authors.lastname: Costalat
authors.affiliation: Association pour la Recherche sur l'Apnée et les Activités Subaquatiques (APRAAS; Drs Lemaître and Gardette); Comex S.A., Marseille, France (Dr Gardette).
authors.forename: Bernard
authors.initials: B
authors.lastname: Gardette
mesh_terms: D000368:Aged; D003665:Decompression Sickness / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D004242:Diving / Q000009:adverse effects / Q000502:physiology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000378:metabolism*; D013997:Time Factors; D018608:Ultrasonography, Doppler
chemical_list: D009584:Nitrogen
keywords: Ama divers; bubbles; decompression sickness