title: End-tidal CO2relates to seasickness susceptibility: A study in Antarctic voyages.
abstract: OBJECTIVE
  To investigate the relationship between end-tidal CO2(EtCO2) and seasickness (motion sickness at sea) during an Antarctic voyage.
  
  
  METHODS
  In this study, we measured EtCO2and severity of seasickness using the subjective symptoms of motion sickness (SSMS). We sampled EtCO2and SSMS every 3-4h for 3 days from the date of sail in 16 healthy subjects. This experiment was performed on an icebreaker (standard displacement: 12,650t).
  
  
  RESULTS
  Since 2 subjects dropped out because of severe motion sickness, available data were collected from 14 subjects. On analysis of all data of all subjects grouped together, there seemed to be a significant negative correlation between EtCO2and SSMS (R=-0.27, P=0.0005). However, in individual subjects, this correlation was not obvious. During the voyage, EtCO2level in the seasickness susceptible group was lower than that in the non-susceptible group (P=0.018). Both EtCO2increasing in the non-susceptible group and decreasing in the susceptible group contribute to the difference in EtCO2levels. We suggest that the cause of this increase in EtCO2level in the non-susceptible group was unwitting slow and deep breathing to resist seasickness.
  
  
  CONCLUSIONS
  We revealed that for seasickness during an Antarctic voyage, EtCO2level relates to susceptibility, but not occurrence or severity. Measurement of EtCO2levels may be useful to identify seasickness-susceptible persons and to efficiently prevent seasickness.
authors.affiliation: National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, Japan; Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, Japan; Department of Otolaryngology, Ayabe City Hospital, 20-1 Ootsuka, Aono-cho, Ayabe, Kyoto, Japan. Electronic address: hasegawa@koto.kpu-m.ac.jp.
authors.forename: Tatsuhisa
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Oe
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, Japan.
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Taki
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sakaguchi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hirano
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan; Wada Ear, Nose and Throat Clinic, 4-7-15 Komagawa, Higashisumiyosi-ku, Osaka, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Wada
mesh_terms: D000328:Adult; D000864:Antarctic Regions; D002245:Carbon Dioxide / Q000032:analysis*; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009041:Motion Sickness; D012720:Severity of Illness Index; D012767:Ships; D013990:Tidal Volume; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Antarctic voyage; End-tidal CO(2); Motion sickness; Susceptibility