目的 通过一种新型单腔肺隔离导管通气工具对开胸手术犬行控制性肺萎陷通气的肺保护作用。 方法 实验犬18只，采用随机数字表法分为3组（每组6只），全身麻醉后经口插入控制肺内平衡分气肺隔离导管，行股动脉穿刺、置管，右颈内静脉穿刺置入Swan?蛳Ganz漂浮导管。首先均行双肺通气（two?蛳lung ventilation, TLV）20 min，后进行左侧单肺通气（one?蛳lung ventilation, OLV），右肺萎陷程度依次为100%（完全肺萎陷组，A组），90%（90%肺萎陷组，B组），50%（50%肺萎陷组，C组），各组均在肺萎陷前1 min（T1）、肺萎陷后30 min（T2）、肺萎陷后60 min（T3）、肺萎陷后120 min（T4）经股动脉和颈内静脉取血行血气分析测定肺内分流率（intrapulmonary shunt rate, Qs/Qt）、测定细胞间黏附分子?蛳1（intercellular adhesion molecule 1, ICAM?蛳1）及丙二醛（malondialdehyde, MDA）含量、超氧化物歧化酶（superoxide, SOD）活性。实验过程中持续监测HR、股动脉血压（arterial blood pressure, ABP）、平均肺动脉压（mean pulmonary arterial pressure, MPAP）、PETCO2、肛温等生命体征。 结果 各组在TLV时测得的各方面生理指标差异均无统计学意义（P＞0.05）；OLV后，各组MPAP在T2、T3、T4时较T1时均升高（P＜0.05）；与A组比较，B组、C组MPAP较为平稳，差异有统计学意义（P＜0.05），B组、C组间各方面生理指标差异无统计学意义（P＞0.05）；与T1时比较，3组肺内分流率Qs/Qt在T2、T3、T4时明显升高（P＜0.05），血清ICAM?蛳1、MDA含量在T2、T3、T4时升高（P＜0.05），SOD活性在T2、T3、T4时下降（P＜0.05）；在T2、T3、T4时，B组、C组Qs/Qt低于A组（P＜0.05），血清ICAM?蛳1、MDA含量低于A组（P＜0.05），SOD活性高于A组（P＜0.05）；C组血清ICAM?蛳1、MDA含量低于B组（P＜0.05），SOD活性高于B组（P＜0.05）。 结论 与完全肺萎陷（萎陷程度100%）相比，控制性肺萎陷（萎陷90%和萎陷50%）更利于减轻OLV的肺损伤，对肺具有保护作用。萎陷50%与萎陷90%相比作用明显，提示萎陷50%可能具有更显著的肺保护作用。
Ｏｂｊｅｃｔｉｖｅ To investigate the protective effect of controlled lung collapse using a new type single-cavity lung isolation catheter ventilation tool in dogs undergoing thoracotomy. Methods Eighteen dogs were randomly divided into three groups (n=6). After induction of general anesthesia, all dogs were intubated with the controlled intrapulmonary balanced gas lung isolation catheter, and then two Swan-Ganz floating catheters were inserted into the femoral artery and the right internal jugular vein respectively for blood pressure monitoring and blood sample collection. After 20 min of two-lung ventilation (TLV), one-lung ventilation (OLV) was performed to collapse the right lung. The degree of collapse in the right lung in group A, B and C was respectively maintained at 100%, 90% and 50% by a microcapsule. Blood samples from the femoral artery and jugular vein were collected at the following time points: 1 min before OLV (T1), 30 min (T2), 60 min (T3) and 120 min (T4) after OLV. The intrapulmonary shunt rate (Qs/Qt) was determined by blood gas analysis, and serum levels of intercellular adhesion molecule 1 (ICAM-1), malondialdehyde (MDA) and superoxide (SOD) were analyzed by ELISA. HR, femoral arterial blood pressure (ABP), mean pulmonary arterial pressure (MPAP), PEtCO2, rectal temperature and other vital signs were continuously monitored during the whole procedure. Results All physiological indices did not differ in all groups during TLV (P>0.05). OLV significantly elevated Qs/Qt, reduced production of serum ICAM-1 and MDA, and increased serum SOD production in a time dependent manner among all groups. The dogs with 90% and 50% lung collapse showed reduced MPAP, lower serum ICAM-1 and MDA, higher SOD production and lower Qs/Qt as compared to dogs with complete one lung collapse. Furthermore, when compared with 90% lung collapse, 50% lung collapse induced better lung protection as indicated by lower production of serum ICAM-1 and MDA and higher serum SOD production. Conclusions Controlled one lung collapse has beneficial effect on acute lung injury by minimizing inflammatory responses and attenuating impairment of lung function. Especially, 50% one lung collapse has better lung protective effect than 90% collapse.
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