title: Estimation of arterial PCO2 from a lung model during ramp exercise in healthy young subjects.
abstract: The aim of this study is to propose a new approach to estimate non-invasively arterial carbon dioxide partial pressure (P(a)CO2) approach was based on the reconstruction of alveolar gas composition over each breath from a tidally ventilated lung model (P(M)(CO2)). Eight healthy young subjects were studied during a ramp exercise test on a cycle ergometer. Arterial samples were drawn at rest and every minute during the exercise test for determination of P(a)CO2 . P(a)CO2 was compared with indirect estimates of P(CO2) : P(M)(CO2), end-tidal P(CO2) (P(ET)(CO2)) and an empirical equation involving P(ET)(CO2) and tidal volume (P(J)(CO2)). The difference between estimated and measured P(a)CO2 on the whole ramp exercise was -0.3+/-1.9mmHg for P(M)(CO2), 1.0+/-2.2mmHg for P(ET)(CO2) and -1.7+/-1.7mmHg for P(J)(CO2) . P(ET)(CO2) and P(J)(CO2) were significantly different from actual P(a)CO2 (P<0.001). It is concluded that, on the basis of the bias, the breathing lung model gave better estimates of P(a)CO2 than the two other indirect methods during ramp exercise.
authors.affiliation: Unité de Recherche: Physiologie et Physiopathologie de l'Exercice et Handicap, Université Jean Monnet, Saint-Etienne, France. vincent.thomas@univ-st-etienne.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Thomas
authors.forename: Frédéric
authors.initials: F
authors.lastname: Costes
authors.forename: Thierry
authors.initials: T
authors.lastname: Busso
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D010101:Oxygen Consumption / Q000502:physiology; D011650:Pulmonary Alveoli / Q000378:metabolism; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015203:Reproducibility of Results; D012129:Respiratory Function Tests
chemical_list: D002245:Carbon Dioxide