新西兰大白兔PetCO2与PaCO2相关性的研究

目的观察新西兰大白兔的呼气末二氧化碳分压（partial pressure of carbon dioxide at end-trial,PetCO2）和动脉血二氧化碳分压（arterial carbon dioxide partial pressure,PaCO2）的关系,探讨无创PetCO2监测用于新西兰大白兔的可行性和准确性。方法新西兰大白兔33只,麻醉后行气管切开插管后机械通气,呼吸次数40/min,调整潮气量使PetCO2在25～35 mmHg（1 mmHg=0.133 kPa）,每增加1 mmHg为1组,共11组,每组3只动物。持续监测有创血压（blood pressure,BP）、心电图（electrocardiogram,ECG）和PetCO2。PetCO2数值稳定30 min后行动脉血气分析,记录pH值、PaCO2、HCO3-、P（a-et）CO2P（a-et）CO2=PaCO2-PetCO2]。结果新西兰大白兔在PetCO2为25～35 mmHg区间时,PetCO2与PaCO2呈高度正相关（P〈0.01）,相关系数r=0.905。线性方程为y=1.87 x-15.85,其中y为PaCO2,x为PetCO2。P（a-et）CO2=（9.72±3.97）mmHg。结论持续无创的PetCO2监测能有效反映新西兰大白兔动脉血PaCO2,可用于指导新西兰大白兔机械通气,其合理的PetCO2在28～32 mmHg。

Correlation of PaCO2 and PetCO2 in New Zealand White Rabbits

Objective To observe the correlation between partial pressure of carbon dioxide at end-trial(PetCO2) and arterial carbon dioxide partial pressure(PaCO2),and explore the feasibility and accuracy of PetCO2 monitoring in New Zealand white rabbits.Methods Thirty-three anesthetized New Zealand white rabbits underwent tracheotomy,intubation and mechanical ventilation.The respiration rate was 40 breaths/min and the tidal volume was adjusted to maintain PetCO2 at 25-35 mmHg(11 groups,n=3 each).The arterial pressure,electrocardiogram(ECG) and PetCO2 were monitored.The arterial blood gas analysis was performed when PetCO2 had been stable for 30 minutes,and pH,PaCO2,HCO3-,P(a-et)CO2(PaCO2-PetCO2) were recorded.Results PetCO2 and PaCO2 had positive correlation when PetCO2 was 25-35mmHg in New Zealand white rabbits(r=0.905)(P<0.01).y=1.87x-15.85,where y was PaCO2,and x was PetCO2.P(a-et) CO2=(9.72±3.97)mmHg.Conclusion Continuous noninvasive monitoring of PetCO2 can effectively reflect the arterial PaCO2 and can be used to guide the mechanical ventilation in New Zealand white rabbits.The optimal PetCO2 is 28-32 mmHg.