title: Increased ventilatory variability and complexity in patients with hyperventilation disorder.
abstract: It has been hypothesized that hyperventilation disorders could be characterized by an abnormal ventilatory control leading to enhanced variability of resting ventilation. The variability of tidal volume (VT) often depicts a nonnormal distribution that can be described by the negative slope characterizing augmented breaths formed by the relationship between the probability density distribution of VT and VT on a log-log scale. The objectives of this study were to describe the variability of resting ventilation [coefficient of variation (CV) of VT and slope], the stability in respiratory control (loop, controller and plant gains characterizing ventilatory-chemoresponsiveness interactions) and the chaotic-like dynamics (embedding dimension, Kappa values characterizing complexity) of resting ventilation in patients with a well-defined dysfunctional breathing pattern characterized by air hunger and constantly decreased PaCO2 during a cardiopulmonary exercise test. Compared with 14 healthy subjects with similar anthropometrics, 23 patients with hyperventilation were characterized by increased variability of resting tidal ventilation (CV of VT median [interquartile]: 26% [19-35] vs. 36% [28-48], P = 0.020; slope: -6.63 [-7.65; -5.36] vs. -3.88 [-5.91; -2.66], P = 0.004) that was not related to increased chemical drive (loop gain: 0.051 [0.039-0.221] vs. 0.044 [0.012-0.087], P = 0.149) but that was related to an increased ventilatory complexity (Kappa values, P < 0.05). Plant gain was decreased in patients and correlated with complexity (with Kappa 5 - degree 5: Rho = -0.48, P = 0.006). In conclusion, well-defined patients suffering from hyperventilation disorder are characterized by increased variability of their resting ventilation due to increased ventilatory complexity with stable ventilatory-chemoresponsiveness interactions.
authors: AP-HP, Hôpital Européen Georges Pompidou, Service de Physiologie, Clinique de la Dyspnée, Paris, and Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France;
authors: Plamen
authors: P
authors: Bokov
authors: Sorbonne Universités, UPMC Université Paris 06, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France;
authors: Marie-Noëlle
authors: MN
authors: Fiamma
authors: AP-HP, Hôpital Européen Georges Pompidou, Unité d'Épidémiologie et de Recherche Clinique, Paris, France;
authors: Brigitte
authors: B
authors: Chevalier-Bidaud
authors: Sorbonne Universités, UPMC Université Paris 06, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale, Paris, France;
authors: Cécile
authors: C
authors: Chenivesse
authors: Sorbonne Universités, UPMC Université Paris 06, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service d'Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée, Paris, France.
authors: Christian
authors: C
authors: Straus
authors: Sorbonne Universités, UPMC Université Paris 06, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale, Paris, France;
authors: Thomas
authors: 0000-0003-2868-9279
authors: T
authors: Similowski
authors: AP-HP, Hôpital Européen Georges Pompidou, Service de Physiologie, Clinique de la Dyspnée, Paris, and Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France; christophe.delclaux@aphp.fr.
authors: Christophe
authors: C
authors: Delclaux
mesh_terms: D000368:Aged; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012119:Respiration; D012146:Rest / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology*
keywords: chaotic-like ventilation; controller gain; loop gain; plant gain; ventilatory control