Reduction of correlation dimension in human respiration by inhaling a mixture gas of 5% carbon dioxide and 95% oxygen.
In order to investigate the effect of the respiratory control system on deterministic behavior in respiration, we used nonlinear analysis in subjects breathing a mixture gas of 5% carbon dioxide (CO2) and 95% oxygen (O2) (CO2-mixed gas). The respiratory movements during breathing air or CO2-mixed gas in eight healthy volunteers were measured. We estimated the values of the correlation dimension (D2) in respiratory movement using Grassberger-Procaccia algorithm. The respiratory movements during inhaling either air or CO2-mixed gas showed a nonlinear behavior using surrogate data method. The values of D2 in respiratory movement during inhaling CO2-mixed gas (1.77 +/- 0.17) were significantly smaller than those during inhaling air (2.52 +/- 0.60) (P < 0.05). This might be related to a prompt change in the nonlinear signal from the central respiratory chemical system.
Third Department of Internal Medicine, Faculty of Medicine, Tottori University, 36-1 Nishimachi, Yonago 683-8504, Japan. suyamahi@grape.med.tottori-u.ac.jp
Hisashi
H
Suyama
Naoto
N
Burioka
Takanori
T
Sako
Masanori
M
Miyata
Eiji
E
Shimizu
D000328:Adult; D002245:Carbon Dioxide / Q000737:chemistry / Q000493:pharmacokinetics / Q000502:physiology*; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology; D010100:Oxygen / Q000737:chemistry / Q000493:pharmacokinetics / Q000502:physiology*; D010991:Plethysmography / Q000379:methods; D012143:Respiratory Physiological Phenomena / Q000187:drug effects; D012272:Ribs / Q000502:physiology; D013223:Statistics as Topic / Q000379:methods
D002245:Carbon Dioxide; D010100:Oxygen