人工心肺机对P_((a-E^1))CO_2的影响

Effects of artificial cardiopulmonary bypass on P(a-E^1)CO_2

本文观察了34例心脏手术患者在人工心肺机(CPB)转流前后的动脉二氧化碳分压与呼吸末二氧化碳分压之差〔P_(a-E^1)CO_2〕的变化,按转流时间长短将患者分为3组。各组CPB转流后P_(a-E^1)CO_2均有增大趋势,且C组(CPB转流158～186min)较A组(CPB转流82～106min)相差显著(P<0.05)。观察结果表明:CPB停机后P_(E^1)CO_2可进一步低估PaCO_2,且低估程度随CPB转流时间延长而增加,提示CPB停机后以P_(E^1)CO_2代替PaCO_2是不可靠的,及时的血气分析仍然很重要。

The difference between the arterial and the end-tidal carbon dioxide tension [P(a-E1)CO2] was observed before and after cardiopulmonary bypass(CPB)was performed in 34 patients,who were divided into 3 groups according to the duration of CPB.It was found that there was an increase of P(a-E1)CO2 after CPB in all the patients and the increase was more significant in Group C(CPB duration of 158 to 186 minutes)than in Group A(CPB duration of 82 to 106 minutes)(P<0.05).It was also found that after the stopping of CPB,the readings of PE1CO2 could not accurately reflect PaCO2 and usually underestimated PaCO2 especially in case the duration of CPB was prolonged.These findings imply that after the stopping of CPB,the determination of PE1 CO2 connot be used to substitute that of PaCO2 since it is not reliable,and prompt gas analysis is imperative.