Τίτλος:
Volume dependence of respiratory system resistance during artificial
ventilation in rabbits
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The volume dependence of respiratory resistance (Rrs), usually observed
during normal breathing, is expected to be accentuated during expiratory
flow limitation (EFL). In order to quantify this dependence we studied
the pressure, flow and volume data obtained from eight New Zealand
rabbits, artificially ventilated at different levels of applied
expiratory pressure (0-10 hPa), before and during histamine i.v.
infusion. EFL was provoked by lowering the expiratory pressure and was
detected by the application of an additional negative expiratory
pressure and by forced oscillations. The analysis of respiratory system
mechanics was performed by multiple regression, using the classical
linear first-order model and also a nonlinear model, accounting for
volume dependence of Rrs. Both models satisfactorily fitted the data in
the absence of EFL. The nonlinear model proved to be more appropriate in
the presence of EFL. The coefficient expressing the volume dependence of
Rrs (Rvd) was significantly more negative during EFL. Rvd values were
highly correlated with the fraction of the tidal volume left to be
expired at the onset of EFL. A threshold Rvd value of -1,000
(hPa(.)s(.)l(-2)) detected EFL with high sensitivity and specificity. We
conclude that a strongly negative volume dependence of Rrs is a reliable
and noninvasive index of EFL during artificial ventilation.
Συγγραφείς:
Vassiliou, M
Saunier, C
Duvivier, C
Behrakis, P
Peslin,
R
Περιοδικό:
Intensive Care Medicine Experimental
Λέξεις-κλειδιά:
expiratory flow limitation; linear regression; volume dependence of
resistance; respiratory impedance; respiratory elastance; respiratory
resistance; mechanical ventilation
DOI:
10.1007/s001340100939
