机械通气患者呼出气冷凝液pH值测定的临床意义

Clinical significance of exhaled breath condensate pH in mechanical ventilated patients

目的研究机械通气患者呼出气冷凝液(Exhaled breath condensate,EBC)pH值的临床意义。方法纳入31例ICU中行机械通气患者,按预后分为生存和死亡组,在病程第1、第5天使用改进的EcoScreen冷凝器收集EBC标本。分析两组患者EBC-pH的差异及其与临床指标的相关性。结果机械通气患者EBC-p H较正常降低,死亡组患者EBC-pH在第1天与第5天均低于生存组。EBC-p H值与PaO_2/FiO_2正相关(r=0.319,P<0.05)。结论机械通气患者EBC-p H的降低与肺脏氧合功能障碍相关,持续较低的EBCp H可能提示预后不良。

Objective To study the clinical significance of exhaled breath condensate pH in mechanical ven-tilated patients. Methods 31 ventilated patients in ICU were divided into the survival and the death group based on their prognosis. EBC samples were collected by modified EcoScreen condenser at the 1st and 5th days. The difference of EBC-pH between the two groups was observed, and the relationships between EBC-pH and clinical parameters were analyzed. Results The value of EBC-pH was lower in ventilated patients than in normal people, and it was lower in the death group than in the survival group at the 1st and 5th days. The value of EBC-pH was positively correlated with PaO2/FiO2（r=0. 319, P〈0. 05）. Conclusion The decrease of EBC-pH value in ventilated patients is related with lung oxygenation dysfunction, and the continuing lower EBC-pH value can indicate a poor prognosis.