低温体外循环心脏瓣膜置换手术胃粘膜pH、胃粘膜PCO_2的变化

Changes of gastric intramucosal PCO_2 and gastric intramucosal pH during hypothermic cardiopulmonary bypass in cardiac valve replacement

目的研究低温体外循环(CPB)心脏瓣膜置换术中胃粘膜pH(pHi)和胃粘膜PCO2(PiCO2)的变化。方法17例心脏瓣膜置换术患者,分别于CPB转机前(T1)、转机30 min(T2)、循环恢复后15 min(T3)、停机前(T4)、停机60 min(T5)、术后6h(T6)测定PaCO2和PiCO2,计算pHi。结果与T1比较,T3、T4、T5时间点PiCO2明显增高,pHi明显降低(P<0.01或P<0.05)。结论低温体外循环期间存在胃粘膜低灌流和酸中毒,胃粘膜产生CO2增加。pHi和PiCO2能反映CPB期间存在胃粘膜低灌流和酸中毒。

Objective To investigate the changes of gastric intramucosal PCO2 （PiCO2） and gastric intramucosal pH（pHi） during hypothermic cardiopulmonary bypass（CPB） of cardiac valve replacement. Methods 17 patients undergoing cardiac valve replacement under CPB were selected. PaCO2 and PiCO2 were measured and pHi were calculated before CPB（T1 ）, at 30 rain after intermission of CPB （T2）, 15 rain after the cirulation recovery, the end of CPB （T4）, 60 rain after completion of CPB（T5 ） and 6h after the surgery（T6 ） respectively. Results The PiCO2 increased and pHi decreased significantly at T3 ,T4 and T5 compared with T1 （ P 〈0.01or P 〈0.05）. Conclusion There were gastric mucosal hypoperfusion and acidosis during hypothermic CPB. The increased PiCO2 was primarily related to an increased production of CO2 in the gastric mucosal. The gastric mucosal hypoperfusion and acidosis during CPB might be reflected by pHi and PiCO2.