【論文摘要】Evaluation of the Negative Arterial to end-tidal CO_2 pressure gradient as a predictor of survival in acute respiratory failure

【論文摘要】負向動脈對呼氣末CO_2壓力梯度的評估作為急性呼吸衰竭患者存活預測指標

葉美華(Mei-Hua Yeh) ； 柯祈化(Ko-Chi-Hua)

《呼吸治療》 17卷1期 (2018/07) Pp. 37-37

https://doi.org/10.6269/JRT.201807_17(1).0009

摘要

Background：Measurement of CO_2 concentrations in the expired air directly indicates changes in the elimination of CO_2 from the lungs. In a healthy person, end tidal CO_2 (elimination of PCO_2 from alveolar) is lower than PaCO_2 (arterial PCO_2) by 2-5 mmHg. The Arterial to end-tidal CO_2 pressure gradient [(a-ET) PCO_2 ]is dependent on the amount of alveolar dead space. Negative (a-ET) PCO_2 values were observed with increased cardiac output and increased CO_2 production, reduced FRC and low compliance. Thus, (a-ET) PCO_2 monitoring can be used as a simple index of pulmonary blood flow. Objectives：The objective of this study was to investigate the association between (a-ET) PCO_2 and mortality in patients with acute respiratory failure. Methods：We retrospective studied 197 intubated patients undergoing mechanical ventilation due to acute respiratory failure patients between 2014 and 2015 in Chang Gung Memorial Hospital. PaCO_2 to end-tidal CO_2 pressure gradient with clinical data and outcomes were measured after admission. Result：Forty patients with negative (a-ET) PCO_2 values had lower mortality, lower FiO_2 setting, lower respiratory rate and higher blood pressure (Table.1).Odds ratios (95% confidence intervals) associated with Age(＜65yr), gender(male),PaO_2/FiO_2(＜300) and minute volume(＞8L/min) were 0.078(0.010-0.624),0.148 (0.042-0.521), 0.089(0.011-0.701)and 0.229(0.075-0.698), respectively(Table2). Negative (a-ET) PCO_2 was strongly associated with good outcome and were significantly associated with overall survival (figure 1). Conclusion：In conclusion, the negative arterial to end-tidal CO_2 pressure gradient may predict patient survival in some subgroups.

關鍵字

end-tidal CO_2 pressure gradient ； survival ； acute respiratory failure.