[Lung collapse during one lung ventilation does not change low frequency respiratory mechanics].
The present study was carried out to clarify the effects of lung collapse for one lung ventilation on respiratory system impedance during thoracic surgery. We measured the impedances of respiratory system (RS) in eight paralyzed subjects under anesthesia employing a pseudorandom noise forced volume oscillation technique. These measurements were performed before and after the one lung ventilation. The impedance values were fitted to a mathematical model consisting of a single conduit connected with a viscoelastic parenchyma. Lung collapse did not affect resistance and reactance in RS after the re-expansion. The mathematical modeling showed no significant effect of one lung ventilation on all the parameters of airway and parenchyma. There was no difference in model fit of the parameters, indicated by the presence of the goodness-of-fit parameter (chi 2), before and after lung collapse. In conclusion, lung collapse during one lung ventilation does not change low frequency respiratory mechanics.
Oka
T
T
Department of Anesthesia, Tochigi Cancer Center, Utsunomiya.
Ozawa
Y
Y
Sato
J
J
D000368:Aged; D000768:Anesthesia, General; D004548:Elasticity; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011031:Pneumothorax, Artificial; D012121:Respiration, Artificial; D015656:Respiratory Mechanics; D019616:Thoracic Surgical Procedures; D013997:Time Factors