Bacterial ventilator-associated pneumonia: bronchoalveolar lavage results are not influenced by dilution
Bacterial ventilator-associated pneumonia: bronchoalveolar lavage results are not influenced by dilution
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DOI：
10.1007/s00134-009-1417-4
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发表时间：
2009-07-01
影响因子：
38.9
通讯作者：
Papazian, Laurent
中科院分区：
文献类型：
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作者：
Baldesi, Olivier;Michel, Fabrice;Papazian, Laurent
本研究旨在确定支气管肺泡灌洗（BAL）定量培养结果是否可以自信地用于诊断细菌性呼吸机相关性肺炎（VAP），而无需考虑稀释。对127例疑似VAP的患者进行了呼吸机监测（3份50 mL），如果临床疑似VAP，则纳入所有连续通气超过48 h的成人。根据以下公式开发稀释因子k：稀释因子k =血浆中尿素浓度/回收灌洗液中尿素浓度。使用该稀释因子，相应地解释定量细菌计数，校正阳性阈值为10（5）菌落形成单位（CFU）mL（-1）。89份BAL中至少有1种微生物检出率为千分之10（4）CFU mL（-1）（37%）。在176例BAL（73%）中，k范围为10 - 100。VAP组中位k为24.4（9.7-40.2），无肺炎（NS）组中位k为24.6（13.1-57.8）。在25份微生物计数为10（4）CFU mL（-1）的BAL中，3份的稀释因子低于10，导致校正计数低于阈值10（5）CFU mL（-1）。在15例微生物计数10（3）CFU mL（-1）的患者中，有2例校正后的微生物计数为10（5）CFU mL（-1）。最后，只有5个BAL（2.1%）被错误分类时，稀释校正因子applied.Using尿素作为稀释因子，我们表明，BAL稀释的变化并没有改变BAL定量细菌培养的解释时，给予三等份的50毫升的盐水。
This study was designed to determine if bronchoalveolar lavage (BAL) quantitative culture results can be used confidently for the diagnosis of bacterial ventilator-associated pneumonia (VAP) without taking dilution into account.Prospective observational cohort study.A 12-bed medical ICU in a teaching hospital.A total of 241 BAL (three 50-mL aliquots) were performed in 127 patients presenting a suspicion of VAP.All consecutive adults who were ventilated more than 48 h were included if VAP was clinically suspected. A dilution factor, k, was developed according to the formula: dilution factor k = concentration of urea in plasma/concentration of urea in lavage fluid recovered. Using this dilution factor, the quantitative bacterial counts were interpreted accordingly with a corrected positive threshold at 10(5) colony forming unit (CFU) mL(-1).Eighty-nine BAL with at least one micro-organism a parts per thousand yen10(4) CFU mL(-1) were identified (37%). In 176 BAL (73%), k ranged from 10 to 100. Median k was 24.4 (9.7-40.2) in VAP group and 24.6 (13.1-57.8) in patients without pneumonia (NS). Among the 25 BAL with micro-organism counts of 10(4) CFU mL(-1), 3 had a dilution factor lower than 10, resulting in corrected counts below the threshold of 10(5) CFU mL(-1). Two out of 15 patients with micro-organism counts of 10(3) CFU mL(-1) had corrected micro-organism counts of 10(5) CFU mL(-1). Finally, only five BAL (2.1%) were misclassified when the dilution correction factor was applied.Using urea as dilution factor, we showed that BAL dilution variations did not alter the interpretation of BAL quantitative bacterial culture when administrating three aliquots of 50 mL of saline.