OBJECTIVETo explore feasible and reliable methods for estnbolishment and of acute lung injury model in animal models.

METHODSTwenty-four healthy adult mongrel dogs with oleic acid-induced acute lung injury were evaluated for early-stage physiological response to acute lung injury using a balloon catheter system for measuring esophageal and gastric pressure.

RESULTSIn canine models of early-stage oleic acid-induced acute lung injury that sustained spontaneous breathing, in terms of respiratory mechanics, some parameters obviously increased including the respiratory rate (RR), minute ventilation (VE), peak inspiratory volume (Vinsp, peak), mean inspiratory volume (VT/Ti), inspiratory airway resistance (Raw, insp) (P<0.001 for all the parameters), with also significantly increased peak transdiaphragmatic pressure (Pdi, peak, P=0.0185). The tidal volume (VT) and dynamic lung compliance (CL,dyn), however, were significantly decreased (P<0.001), and significant variation occurred in the ratio of inspiratory time to duration of one breath (Ti/Ttot, P=0.163). In terms of gas exchange, the pH, PaO(2), SaO(2), PaO(2)/FiO(2), and end tidal partial pressure of carbon dioxide (PETCO(2)) all evidently declined (P<0.001), but PaCO(2) and ratio of alveolar dead space to tidal volume [VD(alv)/VT] increased significantly (P<0.001).

CONCLUSIONApplication of balloon catheter system for measuring esophageal and gastric pressures allows objective evaluation of the various physiological responses in early stage of acute lung injury.