降钙素原对呼吸机相关性肺炎的诊断意义

目的评价血清降钙素原（PCT）水平对呼吸机相关性肺炎（VAP）的诊断价值。方法用半定量固相免疫测定法测定62例呼吸机辅助通气患者血清PCT水平,按照机械通气时间〉7 d是否发生VAP分为VAP组和非VAP组。于机械通气前及机械通气7 d后（非VAP组）或患VAP（VAP组）时测定血清PCT水平,PCT水平分为〈0.5μg/L,0.5～2.0μg/L,2.1～10.0μg/L和≥10.0μg/L 4个等级。同时检测血清C反应蛋白（CRP）及白细胞（WBC）计数。结果 CRP与WBC计数对VAP的诊断敏感性分别为81.2%和86.5%;特异性分别为55.3%和57.8%,阳性预测值分别为61.4%和67.9%;阴性预测值分别为67.9%和64.4%。PCT对VAP诊断敏感性为87.5%,特异性为70.0%,阳性预测值为80.0%,阴性预测值为77.8%。结论血清PCT对VAP的诊断有较高敏感性,监测血清PCT可有助于VAP的早期诊断。

Diagnostic value of procalcitonin in ventilator associated pneumonia

Objective To assess the diagnostic value of procalcitonin(PCT) level in ventilator associated pneumonia(VAP).Methods Sixty-two patients treated with ventilators were divided into two groups:VAP group and non-VAP group,depending on whether the patients developed VAP in 7 days or not.The PCT levels were determined with the method of semi-solid phase immunoassay before and 7 days after instillation of mechanical ventilation in these patients.The PCT levels were graded into four categories,i.e.<0.5 μg/L,0.5~2.0 μg/L,2.0~10.0 μg/L and 10.0 μg L.At the same time,C reactive protein(CRP) and white blood cell(WBC) count were also detected.Results The diagnostic sensitivity of CRP and WBC count for VAP were 81.2% and 86.5% respectively.Their specificity was 55.3% and 57.8%,respectively.Their positive prediction rates were 61.4% and 67.9%,respectively and their negative prediction rates were 67.9% and 64.4%,respectively.The sensitivity of serum PCT determination for the diagnosis of VAP was 87.5% with specificity rate of 70.0%.The positive prediction rate was 80.0%,and the negative prediction rate was 77.8%.Conclusion The value of serum PCT has high sensitivity rate in diagnosing VAP,so that timely surveillance of serum PCT change is helpful for the diagnosis of VAP in the early stage.