Bhat Y R, Abhishek N
Department of Paediatrics, Kasturba Medical College, Manipal University, Manipal 576104, Karnataka, India.
Singapore Med J. 2008 Mar;49(3):199-203.
Continuous noninvasive monitoring of the partial pressure of arterial carbon dioxide (PaCO2) in ventilated neonates would help clinicians to reduce arterial blood sampling. Our objective was to determine the correlation and agreement between end-tidal carbon dioxide (EtCO2) and PaCO2 in newborns ventilated for various clinical situations.
This prospective study was undertaken over 15 months in a teaching hospital. Simultaneous end-tidal and arterial CO2 pairs were obtained from ventilated neonates who were monitored by mainstream capnography and had indwelling arterial catheter. The correlation coefficient and degree of bias between EtCO2 and PaCO2 were assessed for various clinical situations.
A total of 133 end-tidal and arterial CO2 pairs were analysed from 32 ventilated newborns. The mean gestational age was 34.6 +/- 3.8 weeks and birth weight was 2,200 +/- 780 g. The overall coefficient of correlation (r) was 0.73 (p-value is less than 0.001). The EtCO2 value was lower than the corresponding PaCO2 value in 86.5 percent pairs, with a mean bias of -6.65 +/- 7.54 mmHg (95 percent CI, - 7.9 to - 5.35). The r-value was more than or equal to 0.92 in neonates ventilated for sepsis, asphyxia and apnoea of prematurity, 0.67 in hyaline membrane disease (HMD) and 0.69 in meconium-aspiration syndrome. In HMD, neonates who received surfactant had a better r-value than those who did not (0.76 vs. 0.6).
The correlation between mainstream EtCO2 and PaCO2 is good. Neonates with pulmonary disease will have a lower correlation. Surfactant therapy improves the correlation. EtCO2 monitoring is helpful in trending or screening for abnormal PaCO2 values.
对接受通气治疗的新生儿进行动脉血二氧化碳分压（PaCO2）的连续无创监测，将有助于临床医生减少动脉采血。我们的目的是确定在各种临床情况下接受通气治疗的新生儿中，呼气末二氧化碳分压（EtCO2）与PaCO2之间的相关性和一致性。
这项前瞻性研究在一家教学医院进行了15个月。从接受通气治疗的新生儿中获取同步的呼气末和动脉血二氧化碳样本，这些新生儿通过主流二氧化碳监测仪进行监测，并留置动脉导管。针对各种临床情况评估EtCO2与PaCO2之间的相关系数和偏差程度。
共分析了32例接受通气治疗的新生儿的133对呼气末和动脉血二氧化碳样本。平均胎龄为34.6±3.8周，出生体重为2200±780克。总体相关系数（r）为0.73（p值小于0.001）。在86.5%的样本对中，EtCO2值低于相应的PaCO2值，平均偏差为-6.65±7.54 mmHg（95%置信区间，-7.9至-5.35）。在因败血症、窒息和早产儿呼吸暂停接受通气治疗的新生儿中，r值大于或等于0.92；在透明膜病（HMD）中为0.67，在胎粪吸入综合征中为0.69。在HMD中，接受表面活性剂治疗的新生儿的r值高于未接受治疗的新生儿（0.76对0.6）。
主流EtCO₂与PaCO₂之间的相关性良好。患有肺部疾病的新生儿相关性较低。表面活性剂治疗可改善相关性。EtCO₂监测有助于追踪或筛查异常的PaCO₂值。
