Afessa Bekele, Hubmayr Rolf D, Vetter Emily A, Keegan Mark T, Swanson Karen L, Baddour Larry M, Cockerill Franklin R, Peters Steve G
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Am J Respir Crit Care Med. 2006 Jun 1;173(11):1229-32. doi: 10.1164/rccm.200512-1899OC. Epub 2006 Mar 9.
Although the serial dilution technique for quantitative culture of bronchoalveolar fluid is considered to be the gold standard for the diagnosis of ventilator-associated pneumonia, it is more labor intensive than the calibrated loop technique.
We sought to determine the agreement between the calibrated loop and serial dilution techniques in the diagnosis of ventilator-associated pneumonia.
We prospectively measured bacterial colony counts by the serial dilution and calibrated loop techniques in 121 bronchoalveolar lavage samples of 104 patients with suspected ventilator-associated pneumonia.
At the time of bronchoscopy, patients had received mechanical ventilation for a median of 8 d. Patients were receiving antibiotics when 90 of the 121 (74.4%) bronchoalveolar samples were obtained. The colony counts of 13 bacterial isolates were too numerous to count by the calibrated loop technique; by serial dilution technique, their counts ranged from 4.70 to 6.74 log10 cfu/ml. Fifty other bacteria had paired colony counts measured by each of the two techniques: the bias (95% confidence interval) between the two techniques was -0.380 (-0.665 to -0.095) log10 cfu/ml, with precision of 1.002 log10 cfu/ml and 95% limits of agreement of -2.344 to 1.584 log10 cfu/ml. Using the threshold of 4 log10 cfu/ml as a criterion for the diagnosis of ventilator-associated pneumonia, there was discordance only for one bacterial organism between the two techniques.
The calibrated loop technique can be used for the diagnosis of ventilator-associated pneumonia using bronchoalveolar lavage fluid.
虽然支气管肺泡灌洗液定量培养的连续稀释技术被认为是诊断呼吸机相关性肺炎的金标准，但它比校准环技术劳动强度更大。
我们试图确定校准环技术和连续稀释技术在诊断呼吸机相关性肺炎方面的一致性。
我们前瞻性地采用连续稀释技术和校准环技术对104例疑似呼吸机相关性肺炎患者的121份支气管肺泡灌洗样本进行细菌菌落计数。
在支气管镜检查时，患者接受机械通气的中位时间为8天。在获取的121份（74.4%）支气管肺泡样本中，有90份样本采集时患者正在接受抗生素治疗。13种细菌分离株的菌落计数太多，无法用校准环技术计数；通过连续稀释技术，其计数范围为4.70至6.74 log10 cfu/ml。另外50种细菌通过两种技术分别测量了配对菌落计数：两种技术之间的偏差（95%置信区间）为-0.380（-0.665至-0.095）log10 cfu/ml，精密度为1.002 log10 cfu/ml，95%一致性界限为-2.344至1.584 log10 cfu/ml。以4 log10 cfu/ml作为诊断呼吸机相关性肺炎的阈值标准，两种技术之间仅对一种细菌存在不一致。
校准环技术可用于通过支气管肺泡灌洗液诊断呼吸机相关性肺炎。
