Friesen R H, Alswang M
Department of Anesthesiology and Pediatrics (Critical Care), Children's Hospital, Denver, Colorado 80218, USA.
J Clin Monit. 1996 Mar;12(2):155-9. doi: 10.1007/BF02078136.
To assess the correlation and accuracy of end-tidal PCO2 (PetCO2) sampled via nasal cannulae in pediatric patients by comparison to the criterion standard PaCO2, and to identify sources of error during PetCO2 monitoring via nasal cannulae.
PetCO2 was monitored continuously by sampling end-tidal gas through nasal cannulae that had been designed and manufactured for this purpose in spontaneously breathing children undergoing conscious or deep sedation during either cardiac catheterization (n = 43) or critical care (n = 54). When both the capnographic wave form and the PetCO2 value had been stable for at least 10 minutes, the PetCO2 value was recorded while blood was drawn from an indwelling arterial line for PaCO2 measurement. The effects of age, weight, respiratory rate, oxygen delivery system, airway obstruction, mouth breathing, and cyanotic heart disease were evaluated by linear regression analysis and calculation of absolute bias (PaCO2-PetCO2).
Mouth breathing, airway obstruction, oxygen delivery through the ipsilateral nasal cannula, and cyanotic heart disease adversely affected accuracy. In patients without those factors, PetCO2 correlated well with PaCO2 (R2 = 0.994), and absolute bias was 3.0 +/- 1.8 mmHg.
Several factors-some controllable and all recognizable-affect the accuracy of PetCO2 monitored via nasal cannulae in pediatric patients. When these factors are not present, PetCO2 correlates well with PaCO2 and appears to be a useful monitor of ventilatory status during conscious or deep sedation.
通过与标准的动脉血二氧化碳分压（PaCO2）进行比较，评估经鼻导管采集的小儿患者呼气末二氧化碳分压（PetCO2）的相关性和准确性，并确定经鼻导管监测PetCO2期间的误差来源。
在43例接受心导管插入术或54例接受重症监护的清醒或深度镇静的自主呼吸儿童中，通过为此目的设计和制造的鼻导管对呼气末气体进行采样，连续监测PetCO2。当二氧化碳波形图和PetCO2值至少稳定10分钟后，记录PetCO2值，同时从留置动脉导管抽取血液测量PaCO2。通过线性回归分析和计算绝对偏差（PaCO2 - PetCO2）评估年龄、体重、呼吸频率、输氧系统、气道阻塞、口呼吸和紫绀型心脏病的影响。
口呼吸、气道阻塞、同侧鼻导管输氧和紫绀型心脏病对准确性有不利影响。在没有这些因素的患者中，PetCO2与PaCO2相关性良好（R2 = 0.994），绝对偏差为3.0±1.8 mmHg。
几个因素——有些是可控的，有些是可以识别的——影响小儿患者经鼻导管监测PetCO2的准确性。当不存在这些因素时，PetCO2与PaCO2相关性良好，似乎是清醒或深度镇静期间通气状态的有用监测指标。
