血清降钙素原在新生儿呼吸机相关性肺炎诊治中的意义

The value of procalcitonin in diagnosis and treatment of neonatal ventilator associated pneumonia

目的 探讨血清降钙素原（procalcitonin,PCT）在新生儿呼吸机相关性肺炎（ventilator associated pneumonia,VAP）诊治中的价值.方法 按照7d内是否发生VAP,将2012年1月至2013年12月入住我院NICU需有创机械通气的60例患儿分为VAP组（30例）和非VAP组（30例）,VAP组患儿再按照随机数字表法随机分为PCT组（15例）和对照组（15例）.两组患儿于机械通气前及机械通气后测定血清PCT、C反应蛋白（C-reactive protein,CRP）及WBC计数,比较各炎症指标对VAP诊断的敏感性、特异性、阳性预测值和阴性预测值.结果 VAP组患儿机械通气前后血清PCT水平比较差异有统计学意义（t=1.58,P=O.000）,分别为（0.37±0.25） μg/L和（2.17±1.46） μg/L;非VAP组机械通气前后PCT水平无明显变化（t=3.67,P=0.055）.两组患儿机械通气前后血清CRP与WBC计数差异均无统计学意义（P均＞0.05）.以PCT≥0.40 μg/L、CRP≥28 mg/L、WBC≥10×109/L为阳性阈值,三指标对诊断VAP的敏感性分别为93.3％、73.3％、66.7％,其中PCT的特异性为73.3％,阳性预测值为77.8％,阴性预测值为91.7％.PCT组和对照组抗生素使用时间分别为（12.6±5.6）d和（15.1±9.1）d,两者差异有统计学意义（P=0.018）.结论 血清PCT在VAP诊断中有较高的敏感性和特异性,PCT联合临床肺部感染评分可以提高VAP诊断的准确性,及时监测血清PCT有助于VAP的早期诊断,以血清PCT指导抗生素治疗可缩短抗生素疗程.

Objective To explore the value of procalcitonin （PCT） in diagnosis and treatment of neonatal ventilator associated pneumonia（VAP）. Methods Sixty neonates needed invasive mechanical ven- tilation admitted to our NICU from Jan 2012 to Dec 2013 were divided into VAP group （30 cases） and non- VAP group （30 cases）, depending on whether the neonates developed to VAP or not in 7 days. The VAP group then was randomly divided into PCT group （ 15 cases） and control group（ 15 cases） according to ran- dom number table. The levels of serum PCT,C-reactive protein（CRP） and WBC count were detected when the neonates suspected VAP before and after mechanical ventilation. Besides, the sensitivity, specificity, posi- tive and negative predictive values for PCT, CRP and WBC were calculated in the diagnosis of VAP. Results The serum levels of PCT in VAP group had significant difference before and after mechanical ventilation （ t = 1.58 ,P =0. 000） ,the levels of PCT were （0. 37 ± 0. 25 ） μg/L and （2. 17 ± 1.46） μg/L respective- ly. The levels of PCT in non-VAP group had no significant difference （ t = 3.67, P = 0. 055 ）. The levels of CRP and WBC showed no significant differences between VAP and non-VAP group before mechanical venti- lation（P 〉0. 05 ）. Taking PCT≥0. 40 μg/L,CRP≥28 mg/L and WBC≥10 x 109/L as the cut off value,the sensitivity of the three indicators diagnosis of VAP were 93.3% ,73. 3% and 66.7% respectively. PCT had the highest sensitivity 93.3% ,specificity 73. 3% ,positive predictive 77. 8% and negative predictive 91.7%. The antibiotic duration of PCT group was （ 12.6 ± 5.6） d compared with （ 15.1± 9. 1 ） d in control group （P = 0. 018）. Conclusion Serum PCT has high sensitivity and specificity in the diagnosis of VAP, PCT combined with clinical pulmonary infection score can improve the diagnostic accuracy of VAP, early diagno- sis and timely monitoring of serum PCT is helpful in VAP. PCT guidance substantially reduces antibiotic use in VAP, so that timely surveillance of PCT is necessary for patients on ventilator.