title: Individuality of breathing during volitional moderate hyperventilation.
abstract: OBJECTIVE
  The aim of this study is to investigate the individuality of airflow shapes during volitional hyperventilation.
  
  
  METHODS
  Ventilation was recorded on 18 healthy subjects following two protocols: (1) spontaneous breathing (SP1) followed by a volitional hyperventilation at each subject's spontaneous (HVSP) breathing rate, (2) spontaneous breathing (SP2) followed by hyperventilation at 20/min (HV20). HVSP and HV20 were performed at the same level of hypocapnia: end tidal CO2 (FETCO2) was maintained at 1% below the spontaneous level. At each breath, the tidal volume (VT), the breath (TTOT), the inspiratory (TI) and expiratory durations, the minute ventilation, VT/TI, TI/TTOT and the airflow shape were quantified by harmonic analysis. Under different conditions of breathing, we test if the airflow profiles of the same individual are more similar than airflow profiles between individuals.
  
  
  RESULTS
  Minute ventilation was not significantly different between SP1 (6.71 ± 1.64 l·min(-1)) and SP2 (6.57 ± 1.31 l·min(-1)) nor between HVSP (15.88 ± 4.92 l·min(-1)) and HV20 (15.87 ± 4.16 l·min(-1)). Similar results were obtained for FETCO2 between SP1 (5.06 ± 0.54 %) and SP2 (5.00 ± 0.51%), and HVSP (4.07 ± 0.51%) and HV20 (3.88 ± 0.42%). Only TI/TTOT remained unchanged in all four conditions. Airflow shapes were similar when comparing SP1-SP2, HVSP-HV20, and SP1-HVSP but not similar when comparing SP2-HV20.
  
  
  CONCLUSIONS
  These results suggest the existence of an individuality of airflow shape during volitional hyperventilation. We conclude that volitional ventilation alike automatic breathing follows inherent properties of the ventilatory system. Registered by Pascale Calabrese on ClinicalTrials.gov, # NCT01881945.
authors.affiliation: Department of Human Physiology and Biophysics, State Medical and Pharmaceutical University "Nicolae Testemitanu", Chisinau, Republic of Moldova.
authors.forename: Tudor
authors.initials: T
authors.lastname: Besleaga
authors.affiliation: UJF-Grenoble 1/CNRS/TIMC-IMAG UMR 5525/BCM Team, 38041, Grenoble, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Blum
authors.affiliation: UJF-Grenoble 1/CNRS/TIMC-IMAG UMR 5525/PRETA Team, 38041, Grenoble, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Briot
authors.affiliation: Department of Human Physiology and Biophysics, State Medical and Pharmaceutical University "Nicolae Testemitanu", Chisinau, Republic of Moldova.
authors.forename: Victor
authors.initials: V
authors.lastname: Vovc
authors.affiliation: Department of Human Physiology and Biophysics, State Medical and Pharmaceutical University "Nicolae Testemitanu", Chisinau, Republic of Moldova.
authors.forename: Ion
authors.initials: I
authors.lastname: Moldovanu
authors.affiliation: UJF-Grenoble 1/CNRS/TIMC-IMAG UMR 5525/PRETA Team, 38041, Grenoble, France. pascale.calabrese@imag.fr.
authors.forename: Pascale
authors.initials: P
authors.lastname: Calabrese
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D007206:Individuality; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology*; D012119:Respiration; D013990:Tidal Volume / Q000502:physiology*; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Breathing pattern; Healthy subjects; Individuality; Volitional hyperventilation