Corbo Jill, Bijur Polly, Lahn Michael, Gallagher E John
Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Ann Emerg Med. 2005 Oct;46(4):323-7. doi: 10.1016/j.annemergmed.2004.12.005.
We examine the concordance between end-tidal partial pressure of CO2 (PetCO2) measured by capnography and arterial partial pressure of carbon dioxide (PaCO2) obtained by arterial blood gas in acute asthmatic patients presenting to the emergency department.
This was a prospective observational cohort study of acutely ill adult asthmatic patients undergoing an arterial blood gas measurement as part of their evaluation. PetCO2 was recorded during exhalation into a capnograph while arterial blood was pulsing in the arterial blood gas tubing. Concordance between PetCO2 and PaCO2 was displayed as a Bland-Altman matrix, using prespecified limits of agreement of +/-5 mm Hg difference between PetCO2 and PaCO2 in each patient.
The mean difference between the PetCO2 and PaCO2 levels was 1.0 mm Hg (95% confidence interval -0.1 to 2.0 mm Hg), with a median of 0 mm Hg. Of the 39 patients enrolled, 37 (95%) fell within the a priori limits of agreement.
In adult asthmatic patients with acute exacerbations, concordance between PetCO2 measured by capnography and PaCO2 measured by arterial blood gas was high. These findings must be validated before capnography replacement of arterial blood gas as an accurate means of assessing alveolar ventilation in acute asthma is recommended.
我们研究了在急诊科就诊的急性哮喘患者中，通过二氧化碳波形图测量的呼气末二氧化碳分压（PetCO2）与通过动脉血气分析获得的动脉二氧化碳分压（PaCO2）之间的一致性。
这是一项前瞻性观察性队列研究，研究对象为病情严重的成年哮喘患者，他们接受动脉血气分析作为评估的一部分。在呼气至二氧化碳波形图的过程中记录PetCO2，同时动脉血在动脉血气分析管中搏动。PetCO2与PaCO2之间的一致性以Bland-Altman矩阵表示，使用预先设定的每位患者PetCO2与PaCO2差值的一致性界限为±5mmHg。
PetCO2与PaCO2水平的平均差值为1.0mmHg（95%置信区间为-0.1至2.0mmHg），中位数为0mmHg。在纳入的39例患者中，37例（95%）落在预先设定的一致性界限内。
在急性加重的成年哮喘患者中，通过二氧化碳波形图测量的PetCO2与通过动脉血气分析测量的PaCO2之间的一致性较高。在推荐将二氧化碳波形图替代动脉血气分析作为评估急性哮喘肺泡通气的准确方法之前，这些发现必须得到验证。
