pet(CO2)和V(CO2)的改变对患者容量反应性的预测

目的:探讨呼气末CO2分压(end-tidal carbon dioxide partial pressure,pet(CO2))及患者单次呼吸呼出CO2气体的体积(volumetric carbon dioxide,V(CO2))的改变是否能有效预测心脏前负荷(在舒张末期心室所承受的容量负荷或压力)后患者的液体反应性.方法:对患者进行被动抬腿试验(passive leg raising,PLR)或者输液500 mL,通过心排量监护仪观察其每搏指数,若增加超过10％就定义为患者有液体反应.通过监护仪测量pet(CO2)和V(CO2).对机械通气患者,潮气量控制在8 mL/kg,分钟通气量恒定.结果:54％的患者对静脉液体量的增加有反应,pet(CO2)增加(5.9±7.6)％,V(CO2)增加(11.1±8.6)％;而没有液体反应的患者,pet(CO2)增加(1.4±4.4)％,V(CO2)增加(0.8±5.6)％.两两比较差异有统计学意义(P＜0.05).因此,对于没有肺部疾病的患者,pet(CO2)和V(CO2)可以预测患者的液体反应性.有液体反应的患者,每搏量变化是(15.8±3.7)％,而没有液体反应的患者,每搏量变化是(13.6±4.8)％(P=0.15).结论:对于没有肺部疾病的患者,pet(CO2)和V(CO2)的动态变化可以作为液体反应性的辅助预测指标.

Changes of patient in end-tidal carbon dioxide and volumetric carbon dioxide as predictors of volume responsiveness

Objective To determine whether changes in Pet（CO2） （partial pressure of C02 at the end of an exhaled breath） and exhaled CO2 V（CO2） can predict fluid responsiveness after a preload challenge, Methods FlUid responsiveness was determined by a passive leg raising （PLR） maneuver and/or a 500 mL crystalloid challenge. An increase in the stroke volume index 〉10% as measured by a NICOM bioreactance cardiac output monitor （Cheetah Medical） was used to made clear fluid responsiveness, Pet（CO2） and volumetric capnography V（CO2） were monitored via a combined CO2 and flow sensor capnostat （Respironics NM3 Monitor; Philips Healthcare）. Patients were mechanically ventilated with tidal volumes controlled at 8 mL/kg, allowing for consistent minute ventilation. Results During the study period, 44 challenges （10 PLR and 34 fluid boluses） were performed on 34 patients. There were 24（54%） positive fluid responses, Pet（CO2） increased by （5.9±7.6）% in the responders compared with （1.4±4.4）% in the nonresponders （P=0.02）. Similarly, V（CO2） increased by （11.0±8.6）% in the responders compared with （0.8±5.6）% in the nonresponders （P=0.001）. pet（CO2） and V（CO2） were predictive of fluid responsiveness only in those patients without underlying lung disease. The stroke volume variation was （15.8±3.7）% in the responders compared with （13.6±4.8）% in the nonresponders （P=0.15）. Conclusion Dynamic changes in Pet（CO2） and V（CO2） may be used as adjunctive indicators of fluid responsiveness in Datients without under-lying lung disease.