title: [New parameters "average flow" and "acceleration wave": comparison with current parameters in the flow volume curve].
abstract: OBJECTIVE
  The flow volume curve is an essential test method for diagnosis and treatment of the respiratory diseases. However, this curve depends on patient's continuous effort toward optimal expiration and it has been reported that differences in this effort may possibly result in error in flow speed. To overcome the potential error, we devised the "average flow" and the "acceleration wave" that comprehends the overall data of the expiration flow speed, and have done comparative analysis with the current parameters.
  
  
  METHODS
  The average flow is derived by taking the integration from the beginning of the expiration to the end, and divides the integrated value by the number of data counts. Additionally, the acceleration wave is derived by taking the second degree derivative of the flow volume curve.
  
  
  RESULTS
  The average flow showed strong correlation among healthy male and healthy female V50, obstructive index and criteria for COPD severity patients. Also, we were able to obtain the maximum acceleration from the acceleration wave. Significantly, this value showed strong correlation with the COPD patient's peak flow and average flow/peak flow.
  
  
  CONCLUSIONS
  If the ratio of the average flow and the peak flow is below a fixed criterion, it is an obstructive lung disease, if it is above, it is possible to detect restrictive lung disease. Since the maximum acceleration rate of the acceleration wave is derived by the start of the expiration nearly up to 100 ml, it is especially possible to detect minute changes of the flow speed in large respiratory tract.
authors.affiliation: Department of Medical Technology, Graduate School of Kagawa Prefectural University of Health Sciences, Takamatsu, Japan. imai@chs.pref.kagawa.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Imai
authors.forename: Katashi
authors.initials: K
authors.lastname: Satoh
authors.forename: Noriko
authors.initials: N
authors.lastname: Manabe
authors.forename: Makoto
authors.initials: M
authors.lastname: Miyoshi
authors.forename: Naoto
authors.initials: N
authors.lastname: Ichihara
authors.forename: Risa
authors.initials: R
authors.lastname: Ozaki
authors.forename: Miho
authors.initials: M
authors.lastname: Kato
authors.forename: Arisa
authors.initials: A
authors.lastname: Miki
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yokoo
authors.forename: Miyoko
authors.initials: M
authors.lastname: Kasai
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hose
authors.forename: Michiko
authors.initials: M
authors.lastname: Takagi
authors.forename: Nobuto
authors.initials: N
authors.lastname: Kishimoto
mesh_terms: D000054:Acceleration; D000368:Aged; D000375:Aging / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology; D012140:Respiratory Tract Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014797:Vital Capacity