Trichloroethene levels in human blood and exhaled breath from controlled inhalation exposure.
Trichloroethene levels in human blood and exhaled breath from controlled inhalation exposure.
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DOI：
10.1289/ehp.98106573
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发表时间：
1998-09
影响因子：
10.4
通讯作者：
Lindstrom AB
中科院分区：
文献类型：
--
作者：
Pleil JD;Fisher JW;Lindstrom AB
呼出的人类呼吸的有机成分代表通过肺中的血液/呼吸界面中的气体交换的血源性浓度。特定化合物的存在可以是近期暴露的指示或代表受试者的生物反应。对于挥发性有机化合物，呼吸的采样和分析优选于直接从血液样品进行测量，因为呼吸收集是非侵入性的，避免了潜在的传染性废物，样品供应基本上是无限的，并且气相分析物的测量在气体基质中比在复杂的生物组织如血液中简单得多。然而，为了评估污染物在体内的分布，需要对血液水平进行合理的估计。我们在一项受控暴露实验中研究了使用无创呼吸测量作为血液测量的替代品来测量（高）职业水平的三氯乙烯。受试者被放置在一个曝光室24小时，他们暴露于100百万分之一体积的三氯乙烯为最初的4小时和净化空气为其余20小时。匹配的呼吸和血液样本定期收集在实验过程中。我们对产生的浓度数据进行了时间过程建模，并评估了暴露（摄取）期间和暴露后（消除）期间的血液/呼吸关系。根据呼吸数据计算峰值血液水平、房室分布和时间常数的估计值，并与直接血液测量值进行比较，以评估呼吸测量方法的有效性。在吸收和消除过程中研究了血液/呼吸分配系数。在暴露结束时的平衡条件下，我们可以使用呼吸消除曲线计算和文献值分配系数预测实际血液水平，所有受试者的平均计算值：测量值比值为0.98，标准误（SE）= 0.12。平衡时的血液/呼吸比较导致计算出的体内分配系数，所有受试者和实验的平均值为10.8，SE = 0.60，仅消除实验的平均值为9.69，SE = 0.93。我们发现，在吸入暴露过程中进入人体的三氯乙烯中，约有78%通过呼气以外的途径代谢、储存或排泄。
The organic constituents of exhaled human breath are representative of bloodborne concentrations through gas exchange in the blood/breath interface in the lungs. The presence of specific compounds can be an indicator of recent exposure or represent a biological response of the subject. For volatile organic compounds, sampling and analysis of breath is preferred to direct measurement from blood samples because breath collection is noninvasive, potentially infectious waste is avoided, the sample supply is essentially limitless, and the measurement of gas-phase analytes is much simpler in a gas matrix rather than in a complex biological tissue such as blood. However, to assess the distribution of a contaminant in the body requires a reasonable estimate of the blood level. We have investigated the use of noninvasive breath measurements as a surrogate for blood measurements for (high) occupational levels of trichloroethene in a controlled exposure experiment. Subjects were placed in an exposure chamber for 24 hr; they were exposed to 100 parts per million by volume trichloroethene for the initial 4 hr and to purified air for the remaining 20 hr. Matched breath and blood samples were collected periodically during the experiment. We modeled the resulting concentration data with respect to their time course and assessed the blood/breath relationship during the exposure (uptake) period and during the postexposure (elimination) period. Estimates for peak blood levels, compartmental distribution, and time constants were calculated from breath data and compared to direct blood measurements to assess the validity of the breath measurement methodology. Blood/breath partition coefficients were studied during both uptake and elimination. At equilibrium conditions at the end of the exposure, we could predict actual blood levels using breath elimination curve calculations and a literature value partition coefficient with a mean ratio of calculated:measured of 0.98 and standard error (SE) = 0.12 across all subjects. blood/breath comparisons at equilibrium resulted in calculated in vivo partition coefficients with a mean of 10.8 and SE = 0.60 across all subjects and experiments and 9.69 with SE = 0.93 for elimination-only experiments. We found that about 78% of trichloroethene entering the body during inhalation exposure is metabolized, stored, or excreted through routes other than exhalation.