RESUMO
Objective To evaluate the effect of velocity of inspiratory flow on the severe asthma patients.Methods Twenty patients were ventilated thirty minutes respectively when the peak velocity of flow was 40L/min,60 L/min,80 L/min,100 L/min and 120 L/min,and then we measured their airway peak pressure(Ppeak),plateau pressure(Pplat)and intrinsic positive end expiratory pressure(PEEPi)and arterial blood gas analysis,accounting shunt fraction(QS/QT)and Dead space value(VD/VT).Results When velocity of flow enhanced from 40L/min to 60L/min,Ppeak increased while Pplat,PEEPi,VD/VT decreased obviously.When velocity of flow enhanced from 60L/min to 80L/min,Ppeak increased also but Pplat,PEEPi,QS/QT and VD/VT changed no significant.When velocity of flow enhanced from 60L/min to 100L/min,Pplat and PEEPi increased indistinctly while Ppeak,QS/QT and VD/VT increased distinctly.Conclusions The velocity of inspiratory flow,60~80L /min,can reduce PEEPi、QS/QT 及VD/VT and improve respiratory status.