ABSTRACT
Objective Comparing the influence on cardiac-pulmonary function of health and acute lung injury (ALI)dogs by proportional assist ventilation(PAV)and pressure support ventilation(PSV)modes.Methods Use intermittent positive pressure ventilation(IPPV)mode in health and ALI dogs,calculate elastance(Ers)and resistance(Rrs),then change to PAV,set the assist ratio 60%.Then change the mode into PSV,set the inspiratory pressure(IPAP)according to PAV,so that tidal volume(VT)and peak pressure(Ppeak)were the sanle as that of PSV respectively.Observe the changes of respiratory mechanics,blood gas analysis and hemodynamics during mechanical ventilation.Results For health dogs,compared with PAV,mean airway pressure(mPaw)and work of breath of ventilator(WOBv)of PSV was higher than those of PAV when VT were similar,the difference was remarkable;while the influence on hemodynamics was not different.For ALI dogs,compared with PAV,Ppeak,mPaw and pulmonary capillary wedge pressure(PCWP)of PSV was higher than those of PAV when VT were similar,the difference was remarkable.Conclusion For health and ALI dogs,compared with PSV,PAV has lower airway pressure and less influence on hemodynamies.