Jones A W
J Appl Physiol Respir Environ Exerc Physiol. 1983 Oct;55(4):1237-41. doi: 10.1152/jappl.1983.55.4.1237.
To settle certain discrepancies about the correct value of the blood-breath ratio of ethanol, I analyzed samples of end-expired air, rebreathed air, and venous blood during the postabsorptive phase of ethanol metabolism in healthy men. Ethanol was determined in blood and breath by gas chromatography. After rebreathing one to five times the concentrations of ethanol rose by 5.3, 11.2, 13.7, 14.8, and 16.9%, respectively, above the levels in end-expired air. The average increase after three cycles of rebreathing was about 10% after adjusting for the higher airway temperatures associated with rebreathing. Both methods of breath sampling correlated well with blood ethanol. The mean blood-breath ratio of ethanol was 2,225 +/- 111 (SD, n = 23) for end-expired breath and this value decreased by 5.7%/1 degree C rise in expired air temperature (P less than 0.05). The ratio was 1,947 +/- 110 (n = 23) after five cycles of rebreathing, and it was not significantly influenced by temperature, 0.5%/1 degree C (P greater than 0.05). Ethanol vapor is highly soluble in water and can rapidly equilibrate between airway fluids and respiratory air. During rebreathing the concentration of ethanol in breath rises leading to lower blood-breath partition ratios.
为解决乙醇血-气比值正确值的某些差异问题，我分析了健康男性乙醇代谢吸收后阶段的终末呼出气体、重复吸入气体和静脉血样本。通过气相色谱法测定血液和呼出气体中的乙醇含量。重复吸入一至五次后，乙醇浓度分别比终末呼出气体中的水平升高了5.3%、11.2%、13.7%、14.8%和16.9%。在对与重复吸入相关的较高气道温度进行校正后，三次重复吸入循环后的平均升高约为10%。两种呼出气体采样方法与血液乙醇含量均具有良好的相关性。终末呼出气体中乙醇的平均血-气比值为2225±111（标准差，n = 23），该值随呼出气体温度每升高1℃下降5.7%（P<0.05）。重复吸入五次后的比值为1947±110（n = 23），且不受温度显著影响，为0.5%/1℃（P>0.05）。乙醇蒸汽高度溶于水，可在气道液体和呼吸气体之间迅速达到平衡。重复吸入期间，呼出气体中乙醇浓度升高，导致血-气分配比值降低。
