Evaluation of the effect of diagnostic methodology on the reported incidence of ventilator-associated pneumonia
Evaluation of the effect of diagnostic methodology on the reported incidence of ventilator-associated pneumonia
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DOI：
10.1136/thx.2008.110239
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发表时间：
2009-06-01
期刊：
影响因子：
10
通讯作者：
Walsh, T. S.
中科院分区：
文献类型：
--
作者：
Morris, A. Conway;Kefala, K.;Walsh, T. S.
背景：呼吸机相关肺炎(VAP)的最佳诊断方法存在争议，其对报告发病率的影响尚不确定。本研究旨在模拟气管内吸入或支气管肺泡灌洗对肺炎报告发病率的影响，并在临床实践中检验理论模型所提出的效果。首先，使用来自53名疑似VAP患者的配对样本比较了抽吸和灌洗的诊断性能。其次，感染监测数据被用来模拟单独使用吸入物或灌洗来调查疑似肺炎(643名患者；110例临床疑似肺炎病例)对肺炎发病率和抗生素使用的潜在影响。结果：吸入物误诊VAP与灌洗相比较(%vs21%临床疑似病例，p<；0.0001)。模型表明，从完全抽吸改为灌洗诊断将使肺炎报告发病率降低76%(95%可信区间为67%至87%)，抗生素使用率降低30%(95%可信区间为20%至42%)。在实践改变倡议后，灌洗使用率从37%增加到58%。虽然临床疑似肺炎的发生率没有变化，但微生物确诊的呼吸机相关性肺炎病例从每千个呼吸机日18例下降到9例(p=0.001；相对风险降低0.61(95%可信区间0.46~0.82))，平均抗生素使用量从9.1%下降到7.2d(减少21%，p=0.08)。
Background: The optimal method for diagnosing ventilator-associated pneumonia (VAP) is controversial and its effect on reported incidence uncertain. This study aimed to model the impact of using either endotracheal aspirate or bronchoalveolar lavage on the reported incidence of pneumonia and then to test effects suggested from theoretical modelling in clinical practice.Methods: A three-part single-centre study was undertaken. First, diagnostic performance of aspirate and lavage were compared using paired samples from 53 patients with suspected VAP. Secondly, infection surveillance data were used to model the potential effect on pneumonia incidence and antibiotic use of using exclusively aspirate or lavage to investigate suspected pneumonia (643 patients; 110 clinically suspected pneumonia episodes). Thirdly, a practice change initiative was undertaken to increase lavage use; pneumonia incidence and antibiotic use were compared for the 12 months before and after the change.Results: Aspirate overdiagnosed VAP compared with lavage (89% vs 21% of clinically suspected cases, p < 0.0001). Modelling suggested that changing from exclusive aspirate to lavage diagnosis would decrease reported pneumonia incidence by 76% (95% CI 67% to 87%) and antibiotic use by 30% (95% CI 20% to 42%). After the practice change initiative, lavage use increased from 37% to 58%. Although clinically suspected pneumonia incidence was unchanged, microbiologically confirmed VAP decreased from 18 to 9 cases per 1000 ventilator days (p = 0.001; relative risk reduction 0.61 (95% CI 0.46 to 0.82)), and mean antibiotic use fell from 9.1 to 7.2 antibiotic days (21% decrease, p = 0.08).Conclusions: Diagnostic technique impacts significantly on reported VAP incidence and potentially on antibiotic use.