摘要
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.
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 were studied before and after OA infusion at intervals,during an observation period lasting 4h,using curve-fitting method,interrupter technique and pressure-volume (PV) loops measurement.The main findings are listed as follows:(1)Compliance and functional residual capacity (FRC) showed a marked decrease,while Pao and Ptp showed a marked increase within 2h after OA.(2) Airflow resistance at expiratory phase estimated by the curve-fitting method showed a marked increase after OA.(3)PV loops of the lungs or total respiratory system showed similar changes 4h after OA,characterized by the presence of an inflexion point at the inflation 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 PV loop for the total respiratory system would be more appropriate for monitoring lung mechanics during mechanical ventilatory support of ARDS patients.
