主流和旁流呼气末二氧化碳与动脉二氧化碳一致性研究

目的 评估主流和旁流呼气末二氧化碳分压(PETCO2)与PaCO2的一致性.方法 前瞻性收集228例接受有创机械通气患者的临床资料,每例患者进行动脉血气分析时,同时分别采用主流和旁流PETCO2监测仪采集数据并记录,用Bland-Altman方法评估主流和旁流PETCO2与PaCO2的一致性,一致性界限设定在±5 mmHg.结果 患者年龄(60.43±14.28)岁,PaCO2值为(50.64±24.98) mmHg,主流PETCO2为(46.18±24.45) mmHg,旁流PETCO2均值为(44.36±23.36) mmHg.Bland-Altman一致性分析显示,PaCO2与主流PETCO2均值相差4.5 mmHg(95％ CI-1.6～10.5 mmHg),具有一致性.PaCO2与旁流PETCO2均值相差6.3 mmHg(95％ CI-0.1～12.7 mmHg),不具有一致性.主流与旁流PETCO2均值相差1.8 mmHg(95％ CI-0.4～4.0 mmHg),一致性良好.受试者工作曲线分析,主流和旁流PETCO2正常范围截断值分别是31.90～39.20 mmHg和30.68～37.70 mmHg.结论 接受有创机械通气的患者主流PETCO2与PaCO2、主流与旁流PETCO2具有一致性,旁流PETCO2与PaCO2不具有一致性.

Disparity between mainstream and sidestream end-tidal carbon dioxide values and arterial carbon dioxide levels

Objective To assess the agreement between the PaCO2 values and end-tidal carbon dioxide (PETCO2) performed by mainstream and sidestream.Methods A total of 228 subjects with invasive mechanical ventilations were enrolled in a prospective observational study.PETCO2 measured by mainstream and sidestream methods were performed when arterial blood gas were analysed.Agreements between PETCO2 and PaCO2 values were evaluated using the Bland-Altman method.The acceptable limit of agreemems was determined to be 5 mmHg.Results The mean age was (60.43 ± 14.28) years.The mean PaCO2 was (50.64±24.98) mmHg.The mainstream PETCO2 was (46.18 ± 24.45) mmHg,and the sidestream PETCO2 was (44.36±23.36) mmHg.Bland-Altman analysis showed an average difference of 4.5 mmHg (95％ limits of agreement-1.6 to 10.5) between mainstream PETCO2 and PaCO2 values.The average difference was 6.3 mmHg (95％ limits of agreement-0.1 to 12.7 mmHg) between the sidestream PETCO2 and PaCO2 values.The average difference was 1.8 mmHg (95 ％ limits of agreement-0.4-4.0 mmHg) between the mainstream PETCO2 and sidestream PETCO2.Conclusions This study revealed an agreement between noninvasive PETCO2 measurements and PaCO2 values,but no agreement between sidestream methods and PaCO2 values.