对机械通气患者呼出气冷凝液中过氧化氢的研究

目的 探讨呼吸重症加强治疗病房(RICU)机械通气患者呼出气冷凝液(EBC)中过氧化氢(H2O2)浓度与呼吸道炎症反应及预后的关系.方法 采用自行设计的EBC收集器,对36例机械通气患者在通气1、3、5和7 d收集呼气端的EBC,应用化学荧光法测定EBC中H2O2浓度,并进行统计学分析.结果 存活组机械通气3、5和7 d EBC中H2O2浓度较1 d明显降低,差异有统计学意义(0.105±0.032)μmol/L、(0.072±0.034)μmol/L、(0.047±0.029)μmol/L比(O.192±0.135)μmol/L,P均O.05).死亡组机械通气7 d EBC中H2O2浓度较1、3和5 d明显升高,差异有统计学意义(0.234±0.152)μmol/L比(0.055±0.029)μmol/L、(0.088±0.040)μmol/L、(0.150±0.134)μmol/L,P均0.05).与存活组比较,死亡组机械通气1 d EBC中H2O2浓度明显降低(PO.05);5 d和7 d时明显增高,差异有统计学意义(P均<0.05).存活组和死亡组机械通气患者EBC中H2O2浓度与APACHEⅡ、Ⅲ评分均无相关性(P均>O.05).结论 EBC中H2O2水平的高低与病情严重程度有关,故可作为机械通气患者气道炎症反应的重要监测指标,并可作为评估机械通气患者治疗和预后的重要监测指标.

Determination of the hydrogen peroxide level in exhaled breath condensate of patients under mechanical ventilation

OBJECTIVE: To determine hydrogen peroxide (H(2)O(2)) content in condensate of exhaled breath (EBC) in order to explore its relation with intensify of inflammation of the respiratory tract and prognosis of the patients under mechanical ventilation in respiratory intensive care unit (RICU). METHODS: Thirty-six patients undergoing mechanical ventilation were studied. EBC was collected on the 1,3,5,7 days after mechanical ventilation. H(2)O(2) in EBC was measured fluorimetrically. RESULTS: A significantly lowered H(2)O(2) level in the survivors was observed on day 3 (0.105+/-0.032)micromol/L], day 5 (0.072+/-0.034)micromol/L] and day 7 (0.047+/-0.029)micromol/L] compared with day 1 (0.192+/-0.135) micromol/L] after mechanical ventilation (all P<0.05). A significantly lowered H(2)O(2) level was observed on day 7 compared with day 3 (P<0.05) after mechanical ventilation. There was no difference in the H(2)O(2) level on day 7 compared with day 5 (P>0.05). A significant lower H(2)O(2) level was observed in non-survivors on day 1 (0.055+/-0.029)micromol/L], and day 3 (0.088+/-0.040)micromol/L] and day 5 (0.150+/-0.134)micromol/L] compared with day 7 (0.234+/-0.152)micromol/L] after mechanical ventilation (all P<0.05). A significantly lower H(2)O(2) level was observed on day 1 compared with day 5 (P<0.05) after mechanical ventilation. There was no difference in the H(2)O(2) level on day 1 compared with day 3 (P>0.05). A significantly lower H(2)O(2) level in non-survivor compared with survivors on day 1 after mechanical ventilation (P<0.05);There was no difference in the H(2)O(2) level between non-survivors and survivors on day 3 after mechanical ventilation (P>0.05).A significantly higher H(2)O(2) level in non-survivors compared with that of survivors on day 5 and day 7 after mechanical ventilation (P<0.05, respectively). The levels of H(2)O(2) in EBC in survivors and non-survivors undergoing mechanical ventilation showed no correlation with acute physiology and chronic health evaluation II (APACHEII) and APACHEIII scores (both P>0.05). CONCLUSION: The findings suggest that the level of H(2)O(2) in EBC is correlated with severity of patients under mechanical ventilation, and it may prove to be useful in monitoring of inflammatory reaction in the airway after mechanical ventilation to be used as a guidance of therapy and prognosis in patients under mechanical ventilation.