title: Periodic Breathing in Heart Failure Explained by Dynamic and Static Properties of Respiratory Control.
abstract: OBJECTIVE
  The respiratory operating point is determined by the interplay between the controller and plant subsystem elements within the respiratory chemoreflex feedback system. This study aimed to establish the methodological basis for quantitative analysis of the open-loop dynamic properties of the human respiratory control system and to apply the results to explore detailed mechanisms of the regulation of respiration and the possible mechanism of periodic breathing in chronic heart failure.
  
  
  RESULTS
  In healthy volunteers, we measured arterial CO2 partial pressure (PaCO2) and minute ventilation [Formula: see text] to estimate the dynamic properties of the controller ( [Formula: see text] relation) and plant ( [Formula: see text] relation). The dynamic properties of the controller and plant approximated first- and second-order exponential models, respectively, and were described using parameters including gain, time constant, and lag time. We then used the open-loop transfer functions to simulate the closed-loop respiratory response to an exogenous disturbance, while manipulating the parameter values to deviate from normal values but within physiological ranges. By increasing both the product of gains of the two subsystem elements (total loop gain) and the lag time, the condition of system oscillation (onset of periodic breathing) was satisfied.
  
  
  CONCLUSIONS
  When abnormality occurs in a part of the respiratory chemoreflex system, instability of the control system is amplified and may result in the manifestation of respiratory abnormalities such as periodic breathing.
authors.affiliation: Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka City, Osaka, Japan.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Miyamoto
authors.affiliation: Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka City, Osaka, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Nakahara
authors.affiliation: Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka City, Osaka, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ueda
authors.affiliation: Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka City, Osaka, Japan.
authors.forename: Kou
authors.initials: K
authors.lastname: Manabe
authors.affiliation: Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka City, Osaka, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Kawai
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Suita City, Osaka, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Inagaki
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Suita City, Osaka, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kawada
authors.affiliation: Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Suita City, Osaka, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugimachi
keywords: chemoreflex; negative feedback; respiratory abnormality; systems analysis