Bain呼吸环路防治单肺通气犬肺内分流量增加的实验研究

Study of the Bain Respiratory Cycle Used to Prevent Increase of Intrapulmonary Shunt and Reduce Hypoxemia during One-Lung Ventilation in Canine Models

对15条单肺通气(OLV)犬模型进行实验,观察手术侧肺加用或不用Bain环路对犬肺分流量和氧合的影响。结果提示:与双肺通气(TLV)相比,不用Bain的OLV犬,动、静脉氧分压(PAO_2、P(?)O_2),动、静脉血氧饱和度(SaO_2、S(?)O_2)分别降低了49％、11％、8％、14％;肺泡气与动脉血氧分压差(_(A-a)DO_2),肺毛细血管-动脉血氧含量差(C_cO_2-CaO_2),肺毛细血管-静脉血氧含量差(C_cO_2-C(?)O_2)和肺分流量(Q_(?)/Q_t),分别增加了39％、350％、50％和190％(均为P<0.01)。提示低氧血症与OLV时严重肺内分流、静脉血掺杂有关。而使用Bain的OLV犬氧合良好,PaO_2、P(?)O_2稍有增高,^(A-a)DO_2和Q_(?)/Q-t分别降低了19.3％和8％(均为P>0.05)。Bain环路能将氧气以一定的压力和流速持续吹入肺泡,使其扩张并行气体交换,达到改善术侧肺功能和防治肺内分流量增加的目的。

15 dogs in one-lung ventilation (OLV) were used, to observe whether oxygen insufflation in-to the upper nonventilated lung at 0. 5 bar CPAP via Bain respiratory cycle during one-lung anesthesia would diminish transpulmonary right-to-left shunt and also improve oxygenation. Significant differences were deter-mined in arterial and venous oxygen tension (PaO2 and PvO2), arterial and venous oxygen saturation(SaO2and SvO2), alveolar-arterial oxygen tension difference (DO2) and Q./Qt between dogs in whpm oxygen was not insufflated (only OLV), and those in which oxygen via Bain Cycle in nonventilated lung was insufflated (OLV + Bain). When the nonventilation lung of the dog was deflated, it had significantly lower PaO2 ,PvO2,SaO2and SvO2(about 49 %, 11 %, 8 % and 14 %), higher ADO2, CcO2-CaO2, CcO2-C,O2 and Q/Q,(39 %, 350 %, 50 % and 190 % ) (P<0. 01 ) compared to two-lung ventilation (TLV). The results indicated that hypoxemia was due to a greatly increased venous admixture through the nonventilated upper lung. How-ever, the above parameter by OLV + Bain was slightly variable and no significant differences were observed when compared with the TLV treated dogs. Since oxygen could be continuously insufflated into the pul-monary alveoli through the Bain cycle and gas exchange was completed at the expansive alveoli, obvious ef-fects could be obtained of reducing intrapulmonary shunt and improving pulmonary function during OLV.