Rosier Sébastien, Launey Yoann, Bleichner Jean-Paul, Laviolle Bruno, Jouve Alice, Malledant Yannick, Seguin Philippe
Département d'Anesthésie Réanimation, Hôpital Pontchaillou, Rennes.
Département d'Anesthésie Réanimation, Hôpital Pontchaillou, Institut National de la Santé et de la Recherche Médicale U991, and Université Rennes.
Respir Care. 2014 Aug;59(8):1242-7. doi: 10.4187/respcare.02726. Epub 2013 Dec 10.
In patients suffering from brain injury, end-tidal PCO2 (PETCO2 ) monitoring is controversial, but transcutaneous PCO2 (PtcCO2 ), which is noninvasive and utilizes immediate display, may be an alternative method. We hypothesized that PtcCO2 would be more accurate than PETCO2 for monitoring PaCO2 in patients with severe brain injury.
A prospective observational study included consecutive mechanically ventilated adult subjects who had acute brain injury and an arterial catheter in place. When an arterial blood gas analysis was required, the PETCO2 and PtcCO2 values were simultaneously recorded. The agreement between the PETCO2 , PtcCO2 , and PaCO2 measurements (reference) was determined using the Bland-Altman method. The number of outliers defined by the formula ([PETCO2 or PtcCO2 ] - PaCO2 ) > ± 4 mm Hg indicated the proportion of measurements that were considered clinically unacceptable.
A total of 25 subjects were included in the study, and 85 simultaneous measurements of PaCO2 , PtcCO2 , and PETCO2 were obtained. The bias and precision between PaCO2 and PtcCO2 were -0.75 and 6.23 mm Hg, respectively. The limits of agreement ranged from -12.97 to 11.47 mm Hg. The bias and precision between PaCO2 and PETCO2 were 0.68 and 5.82 mm Hg, respectively. The limits of agreement ranged from -10.72 to 12.08 mm Hg. There were 34 (40%) outliers for the PtcCO2 sensor and 34 (40%) outliers for the PETCO2 sensor (P > .99).
The accuracy of PtcCO2 was not superior to that of PETCO2 for assessing PCO2 levels and should not be used to monitor these levels in subjects with severe brain injury.
在脑损伤患者中，呼气末二氧化碳分压（PETCO2）监测存在争议，但经皮二氧化碳分压（PtcCO2）监测具有无创性且能即时显示结果，可能是一种替代方法。我们推测在重度脑损伤患者中，PtcCO2在监测动脉血二氧化碳分压（PaCO2）方面比PETCO2更准确。
一项前瞻性观察性研究纳入了连续的成年机械通气患者，这些患者患有急性脑损伤且已留置动脉导管。当需要进行动脉血气分析时，同时记录PETCO2和PtcCO2值。使用Bland - Altman方法确定PETCO2、PtcCO2与PaCO2测量值（参考值）之间的一致性。由公式（[PETCO2或PtcCO2] - PaCO2）> ± 4 mmHg定义的异常值数量表明被认为临床上不可接受的测量比例。
该研究共纳入25名受试者，同时获得了85次PaCO2、PtcCO2和PETCO2测量值。PaCO2与PtcCO2之间的偏差和精密度分别为 - 0.75和6.23 mmHg。一致性界限范围为 - 12.97至11.47 mmHg。PaCO2与PETCO2之间的偏差和精密度分别为0.68和5.82 mmHg。一致性界限范围为 - 10.72至12.08 mmHg。PtcCO2传感器有34个（40%）异常值，PETCO2传感器有34个（40%）异常值（P > 0.99）。
在评估二氧化碳分压水平方面，PtcCO2的准确性并不优于PETCO2，不应用于监测重度脑损伤患者的这些水平。
