MRC Centre for Inflammation Research, Room C2.17, University of Edinburgh, Edinburgh EH16 4TJ, UK.
Thorax. 2010 Mar;65(3):201-7. doi: 10.1136/thx.2009.122291. Epub 2009 Oct 12.
Ventilator-associated pneumonia (VAP) is the most commonly fatal nosocomial infection. Clinical diagnosis of VAP remains notoriously inaccurate. The hypothesis was tested that significantly augmented inflammatory markers distinguish VAP from conditions closely mimicking VAP.
A prospective, observational cohort study was carried out in two university hospital intensive care units recruiting 73 patients with clinically suspected VAP, and a semi-urban primary care practice recruiting a reference group of 21 age- and sex-matched volunteers. Growth of pathogens at >10(4) colony-forming units (cfu)/ml of bronchoalveolar lavage fluid (BALF) distinguished VAP from "non-VAP". Inflammatory mediators were quantified in BALF and serum. Mediators showing significant differences between patients with and without VAP were analysed for diagnostic utility by receiver operator characteristic (ROC) curves.
Seventy-two patients had recoverable lavage-24% had VAP. BALF interleukin-1beta (IL-1beta), IL-8, granulocyte colony-stimulating factor and macrophage inflammatory protein-1alpha were significantly higher in the VAP group (all p<0.005). Using a cut-off of 10 pg/ml, BALF IL-1beta generated negative likelihood ratios for VAP of 0.09. In patients with BALF IL-1beta <10 pg/ml the post-test probability of VAP was 2.8%. Using a cut-off value for IL-8 of 2 ng/ml, the positive likelihood ratio was 5.03. There was no difference in cytokine levels between patients with sterile BALF and those with growth of <10(4) cfu/ml.
BALF IL-1beta and IL-8 are amongst the strongest markers yet identified for accurately demarcating VAP within the larger population of patients with suspected VAP. These findings have potential implications for reduction in unnecessary antibiotic use but require further validation in larger populations.
呼吸机相关性肺炎（VAP）是最常见的医院获得性感染，致死率高。临床诊断 VAP 的准确率通常较低。本研究旨在验证一个假设，即显著增加的炎症标志物能够将 VAP 与临床表现类似的疾病区分开来。
本研究采用前瞻性、观察性队列研究，在两家大学附属医院的重症监护病房（ICU）和一家半城市基层医疗机构招募了 73 名疑似患有 VAP 的患者，以及 21 名年龄和性别相匹配的志愿者作为参考组。支气管肺泡灌洗液（BALF）中病原体生长超过 10（4）菌落形成单位（cfu）/ml 可将 VAP 与“非 VAP”区分开来。在 BALF 和血清中定量检测炎症介质。通过接收者操作特征（ROC）曲线分析在 VAP 患者和非 VAP 患者之间具有显著差异的介质的诊断效用。
72 名患者的 BALF 可用于检测，其中 24%患有 VAP。VAP 组的 BALF 白细胞介素-1β（IL-1β）、白细胞介素-8（IL-8）、粒细胞集落刺激因子和巨噬细胞炎症蛋白-1α明显升高（均 p<0.005）。BALF IL-1β的截断值为 10pg/ml 时，VAP 的阴性似然比为 0.09。在 BALF IL-1β<10pg/ml 的患者中，VAP 的后验概率为 2.8%。当 IL-8 的截断值为 2ng/ml 时，阳性似然比为 5.03。BALF 无菌和生长<10（4）cfu/ml 的患者之间的细胞因子水平没有差异。
BALF 的 IL-1β和 IL-8 是迄今为止在疑似 VAP 患者群体中准确区分 VAP 的最强标志物之一。这些发现可能对减少不必要的抗生素使用有影响，但需要在更大的人群中进一步验证。
