Clinical Diagnostic Study On The Accuracy And Reliability Of Transcutaneous Blood Gas Monitoring Of Neonatal Infectious Pneumonia

Objective1.To compare and analyze the accuracy of TcPO₂in diagnosing hypoxemia in NIP neonates and TcPCO₂in diagnosing hypercapnia in NIP neonates.2.To compare and analyze the reliability of TcPO₂and TcPCO₂monitoring results in NIP neonates3.To explore the relevant factors affecting the reliability of TcPO₂and TcPCO₂monitoring results in NIP neonates deeply.MethodsIn this study,we selected the neonates with infectious pneumonia in the NICU of a tertiary hospital in Chengdu from March 2021 to October 2021.We performed the transcutaneous blood gas monitoring before collecting the blood of the patients with infectious pneumonia who were ordered to have arterial blood gas analysis according to their condition.Then compared the results of stable TcPO₂and TcPCO₂monitoring with the results of the arterial blood gas analysis during the same period.The accuracy of TcPO₂and TcPCO₂in predicting hypoxemia and hypercapnia in patient was analyzed by ROC curve.Pearson correlation analysis and Bland-Altman plot were used to analyze the reliability between the two variables.To explore the influencing factors of the reliability of monitoring results of TcPO₂and TcPCO₂by multiple regression analysis.Results（1）Analysis the general characteristics of the NIP neonatesEighty neonates with NIP were included in this study.The gestational age was38.21（35.61,39.82）weeks,ranging from 30.71 to 41.43 weeks,and the birth weight was 2.88±0.73kg,ranging from 1.70 to 4.47kg.There were more males,accounting for 67.50%;There were many infants AGA,accounting for 87.50%;Cesarean section was slightly more than spontaneous labor,accounting for 56.25%;Most of the complications were myocardial damage,accounting for 50.00%.（2）The comparison of TcPO₂and PaO₂,TcPCO₂and PaCO₂levels127 pairs of ABG and TCM results were obtained in this study.TcPO₂,PaO₂,TcPCO₂and PaCO₂were 68.73±9.77（mm Hg）,75.65±13.74（mm Hg）,37.90±7.79（mm Hg）and 36.02±6.43（mm Hg）respectively.TcPO₂was significantly lower than PaO₂,TcPCO₂was significantly higher than PaCO₂,and the differences were statistically significance（P<0.01）.（3）Accuracy evaluation1.The accuracy of TcPO₂in predicting hypoxemiaThe analysis of ROC curve showed that TcPO₂could predict accurately hypoxemia（the area under the ROC curve was 0.837,95%CI 0.764～0.908）.When TcPO₂was 71.5mm Hg,the sensitivity and specificity were 82.28%and 72.92%respectively,and the Youden index was 0.552.2.The accuracy of TcPCO₂in predicting hypercapniaThe analysis of ROC curve showed that TcPCO₂could predict accurately hypercapnia（the area under the ROC curve was 0.974,95%CI 0.949～0.999）.When TcPCO₂was 46.25mm Hg,the sensitivity and specificity were 100.00%and 92.24%respectively,and the Youden index was 0.922.（4）Reliability evaluation1.The correlation analysis between TcPO₂and PaO₂,TcPO₂and PaO₂Pearson correlation analysis showed that there was a positive correlation between TcPO₂and PaO₂,TcPCO₂and PaCO₂,and the correlation coefficients were r=0.612and r=0.764 respectively.In hypoxemia group,the correlation between TcPO₂and PaO₂was poor（r=0.364,P<0.01）.In hypercapnia group,the correlation between TcPO₂and PaO₂was better（r=0.880,P<0.01）.In the hypoxemia with hypercapnia group,there was no significant correlation between TcPO₂and PaO₂（r=-0.092,P=0.828）.There was a good correlation between TcPCO₂and PaCO₂in hypoxemia group,hypercapnia group and hypoxemia with hypercapnia group.The correlation coefficients were r=0.766,r=880 and r=0.733 respectively.2.The consistency analysis of TcPO₂and PaO₂,TcPCO₂and PaCO₂Through the Bland-Altman plot,it is found that 95.30%of the points between TcPO₂and PaO₂are within the 95%Lo A confidence interval,but the 95%Lo A confidence interval of the mean difference between TcPO₂and PaO₂is-31.67～17.84（mm Hg）,which is beyond the clinically acceptable range.It is considered that the consistency between the two is poor.96.10%of the points between TcPCO₂and PaCO₂are within the 95%Lo A confidence interval,and the 95%Lo A confidence interval of the mean difference between TcPCO₂and PaCO₂is-9.53～13.31（mm Hg）.Within the clinically acceptable range,it is considered that the consistency between the two is good.In hypoxemia group,hypercapnia group and hypoxemia with hypercapnia group,the 95%Lo A confidence interval of the mean difference between TcPO₂and PaO₂exceeded the clinically acceptable range.In hypoxemia group,hypercapnia group and hypoxemia with hypercapnia group,the 95%Lo A confidence interval of the mean difference between TcPCO₂and PaCO₂was within the clinically acceptable range.（5）The analysis of influencing factors1.The influencing factors of TcPO₂reliabilityUnivariate analysis showed that the significance of gestational age,birth weight and BMI was P<0.1,which could be included in multivariate regression analysis.At the same time,Apgar score≤7 at birth and ARDS were included in the multiple linear regression equation（Stepwise method）.It was found that gestational age（B=0.706,P=0.019）was an independent factor affecting the reliability of TcPO₂.R²=0.036 after model adjustment,indicating that the adjusted model explains 3.6%variation of TcPO₂reliability.2.The influencing factors of TcPCO2 reliabilityUnivariate analysis showed that the significance of vasoactive drugs was P<0.1,which could be included in multivariate regression analysis.At the same time,gestational age,birth weight and ARDS were included in the multiple linear regression equation（backward method）.It was found that the use of vasoactive drugs（B=2.776,P=0.025）was an independent factor affecting the reliability of TcPCO₂.R²=0.037 after model adjustment,indicating that the adjusted model explains 3.7%variation of TcPCO₂reliability.Conclusions1.Both TcPO₂and TcPCO₂can accurately predict the occurrence of hypoxemia/hypercapnia in children,and the accuracy of TcPCO₂is better than that of TcPO₂.2.The reliability of TcPCO₂is good.In patients with hypoxemia,hypercapnia and hypoxemia with hypercapnia,TcPCO₂can reflect the level of PaCO₂to a certain extent,but the use of vasoactive drugs may reduce the reliability of TcPCO₂;TcPO₂has certain reliability.It has good a correlation and consistency in patients with hypercapnia,but there is no significant correlation in patients with hypoxemia.Moreover,TcPO₂is greatly affected byO₂dispersion rate.It is necessary to judge the oxygenation of patients by SpO₂ and collect PaO₂ if necessary.