Measurements on biological fluids form the mainstay of routine clinical investigations. Samples of blood, urine, etc are, generally, easily obtainable and measurements can be interpreted directly. On the other hand, alveolar epithelial lining fluid (ELF) is relatively inaccessible but offers valuable insight into pathogenesis and pharmacokinetics relating to diseases affecting the alveolus. The lung is frequently described as having the surface area of a tennis court. When folded up to fit into the volume of an average thorax, it creates a complex maze that represents a significant obstacle to accessing ELF. The difficulty of gaining access safely and without disrupting the alveolar milieu is complicated by the delicate structure and function of the gas exchange membrane. Different approaches have been adopted including the use of a bronchoscopic microsample (PMS) probe,1 which allows direct measurements from ELF, or bronchoalveolar lavage (BAL), which requires a correction method to adjust for the dilutional effects of the lavage fluid. Urea (or albumin or creatinine) has been commonly used as an endogenous marker to estimate the volume of ELF2–5: by measuring the urea in BAL aspirate and plasma, a ratio can be calculated allowing an estimate of the dilution of apparent volume of ELF. ‘Contamination’ from lavage of the larger airways is also an issue that is influenced by the method of BAL sampling. This is not particularly important in routine clinical BAL, and guidelines do not stipulate the order of …

中文翻译：

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定量 BAL：评估 α-1 抗胰蛋白酶缺乏症上皮衬里液的合适方法？


生物体液测量是常规临床检查的主要内容。血液、尿液等样本通常很容易获得，并且可以直接解释测量值。另一方面，肺泡上皮衬里液 （ELF） 相对难以获得，但为与影响肺泡的疾病相关的发病机制和药代动力学提供了有价值的见解。肺经常被描述为具有网球场的表面积。当折叠起来以适应普通胸部的体积时，它会形成一个复杂的迷宫，这是访问 ELF 的重大障碍。由于气体交换膜的精细结构和功能，很难在不破坏肺泡环境的情况下安全进入。已经采用了不同的方法，包括使用支气管镜微量样本 （PMS） 探针，1 允许直接从 ELF 进行测量，或者支气管肺泡灌洗液 （BAL），这需要一种校正方法来调整灌洗液的稀释效果。尿素（或白蛋白或肌酐）通常用作估计 ELF2-5 体积的内源性标志物：通过测量 BAL 抽吸物和血浆中的尿素，可以计算出一个比率，从而估计 ELF 表观体积的稀释度。较大气道灌洗的“污染”也是一个受 BAL 采样方法影响的问题。这在常规临床 BAL 中并不是特别重要，指南也没有规定 ...