Anderson Joseph C, Hlastala Michael P
Department of Bioengineering, University of Washington , Seattle, Washington.
Department of Physiology and Biophysics, University of Washington , Seattle, Washington.
J Appl Physiol (1985). 2019 Jun 1;126(6):1630-1635. doi: 10.1152/japplphysiol.00726.2018. Epub 2019 Apr 11.
Alcohol breath test (ABT) measurements are sensitive to the volume of the exhaled breath. Although a minimum breath volume is required for a legally acceptable sample, any additional increase in the volume of exhaled air increases the measurement of breath alcohol concentration (BrAC). Using a sample of 115 ABTs collected by police agencies for evidentiary purposes, we studied the influence of exhaled air volume on the measurement of BrAC. The 115 ABTs were performed on 30 different Alcotest 9510s. Each of the tests included paired, time series measurements of exhaled breath flow rates and breath alcohol content. The exhalation flow rates and exhalation times were used to create exhalation volume-BrAC plots. On average, exhaled air volumes were ~50% of the subjects' age-, height-, race-, and sex-predicted vital capacities (VC). More than 80% of the samples had exhaled air volumes ranging between 30 and 70% of the subject's predicted VC. Breath volumes for duplicate breath samples were similar. For all breath samples, BrAC increased with exhalation volume, an expected behavior for any very high blood solubility compound such as alcohol. Beyond the legally accepted minimum expiratory volume, BrAC increased, on average, at a rate of 9.2 ± 2.8%/liter air exhaled. As a result, a person who exhales just beyond the minimum volume will have a lower BrAC compared with a person who exhales a full VC. Exhaled volume materially impacts the measurement of an ABT. Subjects who provide breath samples for evidentiary alcohol breath tests exhale, on average, about half of their predicted vital capacity. Because breath alcohol concentration increases with greater exhaled air volume, subjects who exhale more than average volume will have a greater breath alcohol concentration, whereas subjects who exhale less than average volume will have a lesser breath alcohol concentration. A quantification of air volume impact on breath alcohol concentration is provided.
酒精呼气测试（ABT）测量结果对呼出气体的体积很敏感。虽然法定可接受的样本需要最小呼气量，但呼出空气量的任何额外增加都会提高呼气酒精浓度（BrAC）的测量值。我们使用警方机构为取证目的收集的115份ABT样本，研究了呼出空气量对BrAC测量的影响。这115份ABT测试在30台不同的Alcotest 9510仪器上进行。每次测试都包括对呼出气流速率和呼气酒精含量的配对时间序列测量。呼气流量速率和呼气时间用于创建呼气量-BrAC图。平均而言，呼出空气量约为受试者根据年龄、身高、种族和性别预测的肺活量（VC）的50%。超过80%的样本呼出空气量在受试者预测肺活量的30%至70%之间。重复呼气样本的呼气量相似。对于所有呼气样本，BrAC随呼气量增加，这是任何血液溶解度非常高的化合物（如酒精）的预期行为。超过法定可接受的最小呼气量后，BrAC平均以每呼出1升空气9.2±2.8%的速率增加。因此，与呼出全部肺活量的人相比，呼气量刚超过最小量的人BrAC会更低。呼出量对ABT测量有重大影响。为酒精呼气取证测试提供呼气样本的受试者，平均呼出量约为其预测肺活量的一半。由于呼气酒精浓度随呼出空气量增加而升高，呼出量超过平均量的受试者呼气酒精浓度会更高，而呼出量低于平均量的受试者呼气酒精浓度会更低。本文提供了空气量对呼气酒精浓度影响的量化结果。
