降钙素原、C反应蛋白、白细胞计数联合检测在ICU医院获得性细菌性肺炎鉴别诊断中的价值

The combined determination of procalcitonin,C-reactive protein and white blood cell count for the diagnosis of hospital-acquired bacterial pneumonia in ICU

目的探讨降钙素原(PCT)、C反应蛋白(CRP)、白细胞(WBC)计数联合检测在重症监护病房(ICU)医院获得性细菌性肺炎(简称获得性肺炎)早期诊治中的价值。方法选取ICU收治的获得性肺炎患者69例,同期选取非细菌性肺炎患者(病原体包括真菌、支原体、寄生虫、立克次体等)71例,分别于入院时、治疗第2天、治疗第7天及治疗结束时检测痰液PCT、血清PCT、血清CRP及WBC计数,同时进行痰涂片及病原学培养。采用受试者工作特性(ROC)曲线评价各检测指标早期诊断获得性肺炎的临床价值。结果与非细菌性肺炎组比较,获得性肺炎组治疗第2天时血清PCT明显升高,治疗第7天时CRP明显升高,治疗结束时WBC计数明显降低;其余各时间点2个组之间各项指标比较,差异均无统计学意义(P>0.05)。获得性肺炎组入院时及治疗结束时WBC分类计数(以中性粒细胞百分率>70%为阳性)的阳性率与非细菌性肺炎组比较,差异均有统计学意义(P<0.05)。获得性肺炎组痰液PCT 4个时间点之间差异均无统计学意义(P>0.05);治疗第2天的血清PCT明显高于其他时间点(P<0.001);血清CRP入院时最高,随着治疗时间延长,其浓度逐渐下降,各时间点间比较,差异均有统计学意义(P<0.001);WBC计数入院时明显高于其他时间点(P<0.001),治疗第2天与治疗第7天比较,差异无统计学意义(P>0.05),治疗结束时恢复正常。非细菌性肺炎组痰液PCT和血清PCT 4个时间点之间差异均无统计学意义(P>0.05),血清CRP和WBC计数的变化与获得性肺炎组一致。获得性肺炎组分离培养居前3位的细菌分别为铜绿假单胞菌、鲍曼不动杆菌和大肠埃希菌,治疗第2天时大肠埃希菌感染者血清PCT明显高于铜绿假单胞菌和鲍曼不动杆菌感染者(P<0.05),WBC计数明显高于鲍曼不动杆菌感染者(P<0.05);其余项目3种细菌感染者之间差异均无统计学意义(P>0.05)。治疗第2天血清PCT的ROC曲线下面积为0.921(P<0.05),敏感性为87.5%,特异性为93.7%。结论血清PCT在ICU获得性肺炎早期诊断中有较好的敏感性和特异性,联合检测血清PCT、CRP和WBC计数在鉴别诊断获得性肺炎中有较高的临床价值。

Objective To investigate the combined determination of procalcitonin(PCT),C-reactive protein(CRP) and white blood cell(WBC) count for the early diagnosis and treatment of hospital-acquired bacterial pneumonia(acquired pneumonia) in intensive care unit(ICU). Methods A total of 69 patients with acquired pneumonia in ICU were enrolled,and 71 patients with non-bacterial pneumonia(pathogens including fungus,mycoplasma,parasite,rickettsia and so on)were enrolled as control group. Sputum PCT,serum PCT,serum CRP and WBC count were determined in admission,after treatment for 2 d,after treatment for 7 d and at the end of treatment,and sputum smear and culture etiology were performed simultaneously. Receiver operating characteristic(ROC) curve was used to evaluate the significance of each parameter for the diagnosis of acquired pneumonia. Results Compared with non-bacterial pneumonia group,serum PCT in acquired pneumonia group increased after treatment for 2 d,CRP increased after treatment for 7 d,WBC count reduced at the end of treatment. There was no statistical significance for the other parameters between 2 groups at different time points(P>0.05). For acquired pneumonia group in admission and at the end of treatment,WBC count(neutrophil percentage >70% as positive)had statistical significance compared with non-bacterial pneumonia group(P<0.05). Sputum PCT in acquired pneumonia group had no statistical significance for the 4 time points(P>0.05),and serum PCT after treatment for 2 d was higher than those in the other time points(P<0.001). Serum CRP in admission was the highest,with treatment,the concentration decreased,and the difference among the 4 time points were statistically significant(P<0.001). WBC count was higher in admission than at the other time points(P<0.001),there was no statistical significance between after treatment for 2 d and 7 d(P>0.05),and WBC count returned to normal at the end of treatment. In non-bacterial pneumonia group,the difference of sputum and serum PCT at the 4 time points was not statistically significant(P>0.05),and the changes of serum CRP and WBC count were consistent with those in acquired pneumonia group. The top 3 isolates in acquired pneumonia group were Pseudomonas aeruginosa,Acinetobacter baumannii and Escherichia coli. After treatment for 2 d,serum PCT in patients infected with Escherichia coli was higher than those in patients infected with Pseudomonas aeruginosa and Acinetobacter baumannii(P<0.05),and WBC count in patients with Escherichia coli was higher than that in patients with Acinetobacter baumannii(P<0.05). There was no statistical significance among the 3 kinds of isolates for sputum PCT and serum CRP(P>0.05). The area under ROC curve of serum PCT was 0.921(P<0.05),with a sensitivity of 87.5% and a specificity of 93.7%. Conclusions Serum PCT in the early diagnosis of acquired pneumonia in ICU has good sensitivity and specificity,and the combined determination of serum PCT,CRP and WBC count is of clinical significance in the diagnosis of acquired pneumonia.