胎龄≤34周早产儿生后1周内血清降钙素原日龄百分位曲线及其对早发型脓毒症的诊断价值

Serum procalcitonin concentrations in preterm infants less than 34 weeks during the first week after birth and its diagnostic value for sepsis

目的探讨胎龄≤34周早产儿生后1周内降钙素原(procalcitonin,PCT)生理性波动规律及其对早发型脓毒症(early-onset sepsis,EOS)的诊断价值。方法选择2017年1月至2018年12月山东省立医院东院区新生儿重症监护病房收治的胎龄≤34周早产儿进行回顾性分析。入选早产儿生后均进行PCT动态监测,根据是否发生EOS分为EOS组和非EOS组(无感染)。非EOS组早产儿应用多元线性回归分析围产期因素对PCT的影响,构建PCT日龄百分位参考曲线;并进一步按照胎龄分为<30周、30~31周、32~34周3个亚组进行PCT分层比较。EOS组早产儿应用贝叶斯定理计算PCT第95百分位数诊断EOS的敏感度、特异度、阳性预测值和阴性预测值。结果研究期间共纳入胎龄≤34周早产儿216例,其中EOS组54例(25.0%),非EOS组162例(75.0%)。多元回归分析显示胎龄≤34周早产儿PCT水平与检测日龄及胎龄相关,PCT在生后第1天达峰值(中位数5.38 ng/ml)后逐渐下降,至第4天降至儿童正常值(中位数0.44 ng/ml);胎龄<30周组生后5 d内PCT水平(0~5 d中位数分别为0.35、6.98、5.64、2.74、0.87、0.50 ng/ml)明显高于胎龄30~31周组(0~5 d中位数分别为0.25、4.21、2.98、0.88、0.38、0.36 ng/ml)和胎龄32~34周组(0~5 d中位数分别为0.19、2.67、2.42、0.87、0.37、0.18 ng/ml),生后6 d降至正常范围(中位数0.33 ng/ml)。日龄百分位曲线显示,生后1~3 d PCT第95百分位数分别为25.00、10.00、6.01 ng/ml,诊断EOS的特异度、阳性预测值均处于较高水平,其中第2天PCT为10.00 ng/ml的诊断价值最高(特异度99.1%、阳性预测值94.7%、敏感度33.3%、阴性预测值75.0%)。结论胎龄≤34周早产儿生后PCT水平的生理性波动受胎龄、日龄影响,其中胎龄<30周早产儿生后5 d内PCT水平明显高于30~34周早产儿;生后第2天PCT界值为10.00 ng/ml诊断EOS的价值最高。

Objective To study the physiological concentrations of procalcitonin(PCT)in preterm infants with gestational age(GA)less than 34 weeks(w)during the first week after birth and to assess its accuracy in detecting early-onset sepsis(EOS).Method From January 2017 to December 2018,preterm infants with GA less than 34 w admitted to neonatal intensive care unit(NICU)of our hospital were included in this study.The preterms were assigned into EOS group and non-EOS group according to the diagnosis criteria of EOS.In the non-EOS group,multiple linear regression analysis was used to analyze the influence of perinatal factors on PCT,and a postnatal age-specific percentile-based reference curve for PCT from birth to 7 days after birth was established.Then PCT was compared among three subgroups according to GA(<30 w,30~31 w,32~34 w).The sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)of the 95th percentile(P95)of PCT for the diagnosis of EOS in the EOS group were calculated.Result A total of 216 preterms were enrolled in the study,including 162(75.0%)in the non-EOS group and 54(25.0%)in the EOS group.Multiple linear regression analysis indicated that PCT concentration was correlated with sampling time(postnatal age)and GA.The PCT concentration peaked on the first day after birth(median 5.38 ng/ml)and decreased thereafter to the normal range on the fourth day(median 0.44 ng/ml).Within the first 5 days after birth,the PCT concentration in GA<30 w subgroup(median PCT on 0~5 d were 0.35,6.98,5.64,2.74,0.87,and 0.50 ng/ml,respectively)were significantly higher than the 30~31w subgroup(median PCT on 0~5 d were 0.25,4.21,2.98,0.88,0.38,and 0.36 ng/ml,respectively)and the 32~34 w subgroup(median PCT on 0~5 d were 0.19,2.67,2.42,0.87,0.37,and 0.18 ng/ml,respectively),which decreased to the normal range on the 6th day after birth(median 0.33 ng/ml).The age-specific percentile-based reference curve showed high specificity and high PPV at P95 on the first(25.00 ng/ml),second(10.00 ng/ml)and third(6.01 ng/ml)day after birth.Among them,P95(10.00 ng/ml)on the second day had the highest diagnostic value with specificity 99.1%,PPV 94.7%,sensitivity 33.3%,and NPV 75.0%.Conclusion The physiological concentrations of PCT in preterms less than 34 w were correlated with GA and postnatal age.PCT concentration in preterms less than 30 w was significantly higher than 30~34 w within 5 days after birth.The PCT is 10.00 ng/ml on the second day after birth has the highest diagnostic value for EOS.