title: Body Mass Index-Dependent Ventilatory Parameters From Respiratory Inductive Plethysmography During 6-Minute Walk Test.
abstract: BACKGROUND
  Walking is part of obesity management. Assessment of ventilatory impairments and consequences for gait induced by obesity could be clinically helpful. We aimed to develop a method to accurately monitor ventilation with respiratory inductive plethysmography (RIP) in subjects with high body mass indices (BMIs) during a 6-min walk test (6MWT).
  
  
  METHODS
  25 volunteers were divided into 2 groups based on BMI (<25 or >30 kg/m2) and performed a 6MWT with a calibrated RIP. Ventilatory parameters (tidal volume [V(T)], inspiratory [T(I)] and expiratory [T(E)] times, V(T)/T(I) ratio, and T(I)/Ttot ratio) were determined after processing RIP signals with a custom-made algorithm designed to discriminate tissue motion artifacts and respiratory cycles in the time domain. Six-min walk distance and average speed by minute were collected.
  
  
  RESULTS
  The number of artifacts removed by the algorithm used for artifact removal was higher for high-BMI subjects and was correlated to their individual values (r = 0.66, P < .001). Six-min walk distance was lower for the group with a higher BMI (P = .001). ANOVA revealed effects of exercise for V(T), T(I), and T(E) (P < .001) and also BMI effects in the course of the 6MWT for V(T), T(I), T(E), V(T)/T(I), and T(I)/Ttot (P < .001 for each of them).
  
  
  CONCLUSIONS
  This respiratory monitoring method is sufficiently sensitive to point out differences between rest and exercise as well as locomotor and ventilatory differences relative to BMI during the 6MWT. Thus, this system gives useful information from the 6MWT for clinicians who want to assess respiratory patterns of patients during this commonly used test.
authors.affiliation: Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France. yann.retory@aphp.fr.
authors.forename: Yann
authors.initials: Y
authors.lastname: Retory
authors.affiliation: Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France.
authors.forename: Carole
authors.initials: C
authors.lastname: de Picciotto
authors.affiliation: Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Niedzialkowski
authors.affiliation: Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Petitjean
authors.affiliation: Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France.
authors.forename: Marcel
authors.initials: M
authors.lastname: Bonay
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D010993:Plethysmography, Whole Body / Q000379:methods*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012119:Respiration; D012146:Rest / Q000502:physiology; D013990:Tidal Volume; D000070857:Walk Test / Q000379:methods*
keywords: 6-min walk test; artifacts; body mass index; respiratory inductive plethysmography; submaximal exercise; tidal ventilation