title: Volume and flow dependence of respiratory mechanics in mechanically ventilated COPD patients.
abstract: Volume and flow dependencies of respiratory mechanics are examined in 10 COPD patients under mechanical ventilation (MV) at 3 levels of externally applied PEEP (PEEPe). Airways pressure (Paw), flow (V') and volume (V) data are analyzed according to (1) the linear and (2) a non-linear model, accounting for volume dependence of elastance and for flow and volume dependence of resistance. The models' fitness to data is assessed by the regression errors. Non-linear modelling fits significantly better to data, while the difference of fitness decreases with PEEPe. Linear mechanics are not significantly different between the 3 levels of PEEPe. A positive volume dependence of elastance observed at 0, decreases at 5 and increases again at 10 hPa of PEEPe. A seriously negative volume dependence of resistance at 0 turned to positive with PEEPe. These dependencies of respiratory mechanics during COPD under MV, show that the present non-linear respiratory mechanical monitoring may help for better and less risky adjustment of PEEPe.
authors.affiliation: The Pneumonology Department, Medical School, University of Ioannina, Ioannina, Greece. mvassil@cc.uoi.gr
authors.forename: Miltos P
authors.initials: MP
authors.lastname: Vassiliou
authors.forename: Argyro
authors.initials: A
authors.lastname: Amygdalou
authors.forename: Charalampos J
authors.initials: CJ
authors.lastname: Psarakis
authors.forename: Yotanna
authors.initials: Y
authors.lastname: Dalavanga
authors.forename: Pericles M
authors.initials: PM
authors.lastname: Vassiliou
authors.forename: Kostas E
authors.initials: KE
authors.lastname: Mandragos
authors.forename: Stavros H
authors.initials: SH
authors.lastname: Constantopoulos
authors.forename: Panagiotis K
authors.initials: PK
authors.lastname: Behrakis
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011175:Positive-Pressure Respiration / Q000379:methods; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000628:therapy; D012123:Pulmonary Ventilation / Q000502:physiology*; D012121:Respiration, Artificial