<正> In mechanically ventilated anesthetized dogs （pentobarbital sodium

30mg/kg） with acute lung injury induced by intravenous infusion of oleic acid（OA）

changes in airflow

lung volume

and tracheal （Pao）

transpulmonary （Ptp）and esophageal （Pes） pressures were measured.Changes in lung mechanics werestudied before and after OA infusion at intervals

during an observation periodlasting 4h

using curve-fitting method

interrupter technique and pressure-volume（PV） loops measurement.The main findings are listed as follows:（1）Complianceand functional residual capacity （FRC） showed a marked decrease

while Pao andPtp showed a marked increase within 2h after OA.（2） Airflow resistance atexpiratory phase estimated by the curve-fitting method showed a marked increaseafter OA.（3）PV loops of the lungs or total respiratory system showed similarchanges 4h after OA

characterized by the presence of an inflexion point at theinflation limb

increased hysteresis and rightward and downward shift of the loop.It is suggested that use of the curve-fitting method in combination with the PVloop for the total respiratory system would be more appropriate for monitoringlung mechanics during mechanical ventilatory support of ARDS patients.