Reliability of thoracic gas volume derived from mechanical impedance at different levels of the vital capacity

Citation
R. Peslin et C. Duvivier, Reliability of thoracic gas volume derived from mechanical impedance at different levels of the vital capacity, RESPIRATION, 66(4), 1999, pp. 323-331
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cardiovascular & Respiratory Systems","da verificare
Journal title
RESPIRATION
ISSN journal
0025-7931 → ACNP
Volume
66
Issue
4
Year of publication
1999
Pages
323 - 331
Database
ISI
SICI code
0025-7931(199907/08)66:4<323:ROTGVD>2.0.ZU;2-M
Abstract
Thoracic gas volume (TGV) may be estimated during spontaneous breathing by measuring simultaneously respiratory impedance (Zrs) and alveolar gas compr ession (Vpl) at several oscillation frequencies [Peslin and Duvivier: J App l Physiol 1998;84:862-867]. Objective: The aim of the study was to test the validity of that approach at different levels of the vital capacity (VC). Methods: We measured Zrs and Vpl at frequencies ranging from 6 to 29 Hz in 10 healthy subjects rebreathing BTPS gas in a constant volume body plethysm ograph, In a first series, the subjects were asked to breathe voluntarily a t different levels of the VC and oscillation TGV (TGVos) was compared to st andard plethysmographic TGV (TGVst) assessed immediately after TGVos measur ements, In a second series, the subjects were asked to change stepwise thei r lung volume in the middle of the forced oscillation recording, and the ch anges in TGVos (Delta TGVos) were compared to the changes in lung volume (D elta V) computed from the integrated flow signal, Results: In most subjects TGVos and TGVst were highly correlated and the slopes of the relationships did not differ significantly from unity. Delta TGVos a nd Delta V were a I so high ly correlated both in individuals and in the group (r = 0,97), and their signless differences averaged 0.23 +/-: 0.20 liter, Conclusion: We co nclude that forced oscillation estimates of TGV a re reliable in healthy su bjects over a large part of the VC.