title: Ventilatory oscillations at exercise in hypoxia: A mathematical model.
abstract: We evaluated the mechanisms responsible for the instability of ventilation control system under simultaneous metabolic (exercise) and environmental (hypoxia) stresses, promoting the genesis of periodic breathing. A model following the main concepts of ventilatory control has been tested, including cardiovascular and respiratory parameters, characteristics of peripheral and central chemoreceptors, at mild exercise in hypoxia (FIO2=0.145). Interaction between O2and CO2sensing was introduced following three different modalities. A sensitivity and multivariate regression analyses closely matched with physiological data for magnitude and period of oscillations. Low FIO2and long circulatory delay from lungs to peripheral chemoreceptors (DeltaTp) lengthen the period of oscillations, while high peripheral and central chemoresponses to O2and CO2, low FIO2and high DeltaTp increased their magnitude. Peripheral and central O2/CO2interactions highlight the role of CO2on peripheral gain to O2and the contribution of peripheral afferences on central gain to CO2. Our model supports the key role of peripheral chemoreceptors in the genesis of ventilatory oscillations. Differences in the dynamics of central and peripheral components might be determinant for the system stability.
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et poumons", EA2363, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France. Electronic address: eric.hermand17@gmail.com.
authors.forename: Eric
authors.initials: E
authors.lastname: Hermand
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et poumons", EA2363, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France.
authors.forename: François J
authors.initials: FJ
authors.lastname: Lhuissier
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et poumons", EA2363, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Voituron
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et poumons", EA2363, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France. Electronic address: richalet@univ-paris13.fr.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Richalet
mesh_terms: D000465:Algorithms; D002245:Carbon Dioxide / Q000378:metabolism*; D003198:Computer Simulation; D015444:Exercise / Q000502:physiology*; D006801:Humans; D000860:Hypoxia; D007700:Kinetics; D008168:Lung / Q000378:metabolism / Q000502:physiology; D008962:Models, Theoretical; D010100:Oxygen / Q000378:metabolism*; D015656:Respiratory Mechanics / Q000502:physiology*; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: CO(2); Chemoreflex; Delays; Exercise; Gain; Hypoxia; Modeling; O(2); Periodic breathing; Ventilatory oscillations