经皮无创血气监测在儿童危重症中的应用价值评估

Vaule of applying transcutaneous blood gas monitoring in critical ill children

目的:分析不同血循环状态下经皮氧分压(transcutaneous oxygen pressure,PctO_2)与血氧分压(partial pressure of oxygen in arterial blood,PaO_2)、经皮二氧化碳分压(transcutaneous carbon dioxide pressure,PctCO_2)与血二氧化碳分压(partial pressure of oxygen in arterial blood,PaCO_2)的相关性及差异性,从而了解PctO_2及PctCO_2在微循环障碍时的监测意义。方法:对2014年11月至2015年3月在重庆医科大学附属儿童医院重症医学科住院的56例患儿进行PctO_2/PctCO_2监测,因病情需要,部分患儿不同时段予动态监测,共采集110份数据。分析微循环正常组(n=75)、轻度障碍组(n=20)及重度障碍组(n=15)间PctO_2与PaO_2及PctCO_2与PaCO_2的相关性及差异性。用受试者工作特征曲线(receiver operating characteristics curve,ROC curve)评价PctO_2、PctCO_2诊断低氧血症及二氧化碳潴留的敏感度及特异度。结果:相关性分析:在微循环正常组(n=75),PctO_2与PaO_2、PctCO_2与PaCO_2均有良好相关性(r=0.937、0.569,均P<0.05);在微循环轻度障碍组(n=20)及重度障碍组(n=15),患儿PctCO_2与PaCO_2均具有良好的相关性(r=0.718、0.679,均P<0.05),而PctO_2与PaO_2无相关性(P=0.175、0.074)。氧分压差(△PO2):微循环正常组(n=75)、轻度障碍组(n=20)和重度障碍组(n=15)的△PO2分别为:(0.24±1.08)、(7.99±7.99)和(9.71±5.15)k Pa。ROC曲线分析:微循环正常组(n=75)中,PctO_2在ROC曲线下面积(area under the ROC curve,AUC)为0.89(95%CI=0.82~0.96,P=0.036),PctO_2=10.25 k Pa时诊断缺氧的敏感度是81.5%,特异度是83.3%。PctCO_2的AUC为0.77(95%CI=0.65~0.88,P=0.000),PctCO_2=5.45 k Pa时诊断二氧化碳潴留的敏感度是81.5%,特异度是66.7%。结论:在微循环正常时,PctO_2/PctCO_2监测在一定程度上可预测PaO_2/PaCO_2。在微循环轻度障碍及重度障碍时,PctCO_2监测可预测PaCO_2。PctO_2与PaO_2差别明显时往往提示微循环灌注不良,对于此类危重症患者,可结合PctO_2/PctCO_2监测与血气分析中PaO_2/PaCO_2综合判断。

Objective：To assess the correlation of transcutaneous oxygen pressure（PctO2）and partial pressure of oxygen in arterial blood（PaO2）,transcutaneous carbon dioxide pressure（PctCO2）and partial pressure of carbon dioxide in arterial blood（PaCO2）under different circulation states and to know the significance of PctO2/PctCO2 under micro-circulatory disorder. Methods：Totally 110 sampling of PctO2/PctCO2 and arterial blood gases（ABG）from November 2014 to March 2015 in 56 cases were collected;the correlation and difference between PctO2 and PaO2,PctCO2 and PaCO2 under different circulation states were analyzed and the sensitivity and specificity of oxygen and carbon dioxide retention by PctO2 and PctCO2 under ROC curve were evaluated. Results：In the normal microcirculation group（n=75）,PctO2 and PaO2,PctCO2 and PaCO2 were in good correlation（r=0.937,0.569,P〈0.05）. In the mildly and seriously micro-circulation disorder group（n=20,15）,PctCO2 and PaCO2 were in good correlation（r=0.718,0.679,P〈0.05）;PctO2 had no relation with PaO2（P=0.175,0.074）. The △PO2（PaO2-PctO2）in the normal micro-circulation group（n=75）,the mildly micro-circulation disorder group（n=20）and the seriously microcirculation disorder group（n=15）were（0.24 ±1.08）,（7.99 ±7.99）,（9.71±5.15）k Pa respectively. In the normal micro-circulation group（n=75）,the AUC of PctO2 was 0.89（95%CI=0.82 to 0.96,P=0.036）. PctO2 can predict hypoxia with the optimal threshold value given by ROC analysis at 10.25 k Pa（Sen：81.5%,Spe：83.3%）. The AUC of PctCO2 was 0.77（95%CI=0.65 to 0.88,P=0.000）. PctCO2 can predictCO2 retention with the optimal threshold value given by ROC analysis at 5.45 k Pa（Sen：81.5%,Spe：66.7%）. Conclusion：In the normal micro-circulation,PctO2/PctCO2 monitoring can predict the PaO2/PctCO2 to some degree. Under the mildly and seriously micro-circulation disorder,PctCO2 can predict the PctCO2 to some degree. The obvious difference between PctO2 and PaO2 suggests poor micro-circulation perfusion,therefore,PctO2/PctCO2 monitoring combined with PaO2/PaCO2 is needed for critically ill patients who need ABG.