高频喷射通气(HFJV)气流运输和效应的动物实验研究

Study of Gas Transprot Combined with Effects of Ventilation during HFJV in Experimental Dogs

犬8条,分油酸组(C_L)和非油酸组(C_N),每组4条。根据正交实验设计表L_9(4~3)分9种状态作HFJV,应用热线呼吸测速仪测定0级气管内的气流速度,并于30min后作动脉血气分析。结果显示,两组在f 15时,吸气和呼气末的气流都能降到零,曲线上出现两个峰,f 60和120时,整个呼吸周期均有气流存在,一个双峰,呼气末速度不能降到零,这有利于气体的对流。V_T·f乘积计算证明f 60、120大于f 15.即高频的对流效应好于常频。然而,血气分析提示,随频率升高,PaCO_2也有升高趋势,特别是C_L组。所以,不能认为对流效应好,通气效应就一定好。对此,作者从气流动力学角度作了阐述,认为临床上应对频率加以限制。

8 anesthesia dogs were divided into 2 groups. One was normal (C_N) and other was low compliance (C_L) in- duced by injecting 0.1 ml/kg oleic acid. HFJV performed in 9 states according to orthogonal design L_9(4~3). Gas transport in tracheal (0) was measured with hot wire anemometer and blood gas analysis was observed after 30 min HFJV. The results showed the flow was found during whole respiratory period with double peak curve during f 60 or 120, flow decreased to zero in end-expiration with two single-peak curves during f 15 in both groups. The prod- uct of V_T f, as sign of convective effect, was less in f 15 than in f 60 or 120, Howerver, blood gas analysis showed that PaCO_2 tended to increase as the f increasing, especially in C_L group. So it is concluded that f must be limitted in clinical practice. The reasons were interpreted by aerodynamics.