单肺通气时两种通气模式对PetCO2与PaCO2相关性的影响

目的：探讨胸科开胸手术单肺通气定容通气模式下和定压通气模式下PetC02（呼气末二氧化碳分压）与PaCO2（动脉二氧化碳分压）的相关性。方法：选择40例择期左侧开胸手术单肺通气成年患者，ASAI～II级，随机分为A组（n=20）采用VCV（容量控制通气）模式通气、B组（n=20）采用PCV（压力控制通气）模式通气。比较两组各时段的PaCO2和PetCO2的差异及相关性。结果：经统计学分析，除第一时间点，两组同一时间点的PetC02比较及PaCO2比较差异均有统计学意义（P〈O．05），A组PetC02四个时间点比较及PaCO2四个时间点比较差异均有有统计学意义（P〈0．001），B组除PetCO2第三与第四个时间点比较差异无统计学意义外，余PetCO2各时间点相比较及PaCO2各时间点相比较差异均有统计学意义（P〈0．05）。单肺通气定压通气模式下PetCO2与PaCO2在各个时间点的相关系数均大于定容通气模式时。无论是定容还是定压通气模式，单肺通气时间越长，其PetCO2与PaCOz的相关系数也越小。结论：1．同双肺通气相比，单肺通气时定压通气模式下PaCO2及PetCO2的改变小于定容通气模式时。2．单肺通气时，定压通气模式下PetCO2与PaCO2的相关性好于定容通气模式时。3．在这两种通气模式下PetCO2与PaCO2的相关性与单肺通气的时间成反比。

Effect of the Correlation between PetCO2 and PaCO2 on one Lung Ventilation during Two Different Ventilation Modes

Objective： To compare with the impacts of Pressure controlled ventilation （PCV） and volume controlled ventilation （VCV） on the correlation between PetCO2 and PaCO2 during One-lung ventilation for Thoracic surgery. Methods： 40 ASA I - II adult patients undergoing lobectomy with one lung ventilation were randomized to receive VCV （group A, n=20）, or PCV（group B, n=20）, Pet- CO2and PaCO2 were determined at different points in both groups. Results： The statistical analysis show that compare with the same time point PetCOz and PaCO2 were statistical difference （P〈0.05） but the first point between the two groups, compare with each time points PetCOz and PaCOz were statistical difference （P〈0.05） in the group A, compare with each time points PetCO2 and PaCO2 were statistical difference （17〈0.05） but PetCO2 compare with the third and the fourth time point in the group B .The correlation coefficient between Pet- CO2 and PaCO2 is larger at each time point during PCV than VCV on OLV. Either PCV and VCV, the correlation coefficient between PetCO2and PaCO： is getting smaller during OLV for a long time. Conclusion： 1. Compare with TLV, the change of PaCO2 and PetCO2 is less during PCV than VCV on OLV. 2. During OLV in Thoracic surgery, PCV is superior to VCV on the correlation between PetCO2 and PaCO2. 3. PaCO2 is needed to monitor intermittent during OLV for a long time.