Objectives: To evaluate the accuracy and safety of measurements of transcutaneous carbon dioxide partial pressure (TcPCO2) and transcutaneous oxygen partial pressure (TcPO2) at electrode temperatures lower than the value used in clinical practice in very low birth weight infants.
Methods: A total of 45 very low birth weight infants were enrolled. TcPCO2 and TcPO2 measurements were performed in these infants. Two transcutaneous monitors were placed simultaneously for each subject. One electrode was set and maintained at 42℃ used in clinical practice for neonates (control group), and the other was successively set at 38℃, 39℃, 40°C, and 41℃ (experimental group). The paired t-test was used to compare the measurement results between the groups. A Pearson correlation analysis was used to analyze the correlation between the measurement results of the experimental group and control group, and between the measurement results of experimental group and arterial blood gas parameters.
Results: There was no significant difference in TcPCO2 between each experimental subgroup (38-41℃) and the control group. TcPCO2 in each experimental subgroup (38-41℃) was strongly positively correlated with TcPCO2 in the control group (r>0.9, P<0.05) and arterial carbon dioxide partial pressure (r>0.8, P<0.05). There were significant differences in TcPO2 between each experimental subgroup (38-41℃) and the control group (P<0.05), but TcPO2 in each experimental subgroup (38-41℃) was positively correlated with TcPO2 in the control group (r=0.493-0.574, P<0.05) and arterial oxygen partial pressure (r=0.324-0.399, P<0.05). No skin injury occurred during transcutaneous measurements at all electrode temperatures.
Conclusions: Lower electrode temperatures (38-41℃) can accurately measure blood carbon dioxide partial pressure in very low birth weight infants, and thus can be used to replace the electrode temperature of 42°C. Transcutaneous measurements at the lower electrode temperatures may be helpful for understanding the changing trend of blood oxygen partial pressure.
目的: 评估在低于临床常用的电极温度下进行经皮二氧化碳分压（transcutaneous carbon dioxide partial pressure，TcPCO2）和经皮氧分压（transcutaneous oxygen partial pressure，TcPO2）监测在极低出生体重儿应用中的准确性和安全性。方法: 对45名极低出生体重儿进行TcPCO2和TcPO2监测，每个研究对象同时放置两个经皮监测仪，其中一个电极温度设置并保持临床常用于新生儿监测的42℃（对照组），另一个电极温度依次设置为38℃、39℃、40℃和41℃（试验组），通过配对t检验对各组监测结果进行比较，并通过Pearson相关性分析法对试验组和对照组的监测结果进行相关性分析，以及对试验组的监测结果与动脉血气分析值进行相关性分析。结果: 在38℃、39℃、40℃和41℃各电极温度下的TcPCO2与对照组比较差异均无统计学意义（P>0.05），且各电极温度（38~41℃）试验组的TcPCO2与对照组TcPCO2（r>0.9，P<0.05）及动脉血二氧化碳分压（r>0.8，P<0.05）均呈极强的正相关。在38℃、39℃、40℃和41℃各电极温度下的TcPO2与对照组比较差异有统计学意义（P<0.05），但与对照组TcPO2（r=0.493~0.574，P<0.05）及动脉血氧分压（r=0.324~0.399）均呈显著正相关（P<0.05）。在所有电极温度下经皮监测均未发生皮肤损伤。结论: 较低电极温度（38~41℃）可准确监测极低出生体重儿血二氧化碳分压，可以取代临床常用的42℃；对于血氧分压，较低电极温度经皮监测可能有助于了解其变化趋势。.
Keywords: Carbon dioxide partial pressure; Electrode temperature; Oxygen partial pressure; Transcutaneous measurement; Very low birth weight infant.