Ohlsson J, Ralph D D, Mandelkorn M A, Babb A L, Hlastala M P
Department of Physiology, University of Washington, Seattle 98195.
J Stud Alcohol. 1990 Jan;51(1):6-13. doi: 10.15288/jsa.1990.51.6.
The importance of interaction of exhaled air with the airway surface was evaluated by comparing the effects of different breathing maneuvers and inhaled air temperature on the relationship between breath alcohol concentration (BRAC) and blood alcohol concentration (BAC). Breath alcohol was measured with an infrared absorption unit. Blood and simulator liquid alcohol concentrations were measured by gas chromatography. Breath samples were measured after both low and high exhaled volumes and after rebreathing. Breathing maneuvers were performed after either hyperventilation, breathhold or normal breathing. Inspired air temperature was varied between 0 degree C and 40 degrees C. The rebreathing method for sampling alveolar alcohol samples was evaluated with a new isothermal rebreather that was designed to provide a substantial amount of heat to the rebreathed air in order to heat the airway surfaces. Using a single breath test, the indicated BAC values vary from 14% above the actual BAC to as low as 55% below the actual BAC. Hyperventilation caused a significant decrease in BRAC and breathhold caused a significant increase in BRAC. When isothermal rebreathing is applied to such tests, the breath test results were always within +/- 10% of the true BAC, even with an altered breathing pattern. Isothermal rebreathing provided an accurate sample of alveolar air that was not affected by altered breathing pattern or air temperature.
通过比较不同呼吸动作和吸入空气温度对呼气酒精浓度（BRAC）与血液酒精浓度（BAC）之间关系的影响，评估呼出空气与气道表面相互作用的重要性。使用红外吸收装置测量呼气酒精。通过气相色谱法测量血液和模拟液体中的酒精浓度。在低呼出量和高呼出量后以及重复呼吸后测量呼气样本。在过度通气、屏气或正常呼吸后进行呼吸动作。吸入空气温度在0摄氏度至40摄氏度之间变化。使用一种新型等温重复呼吸器评估用于采集肺泡酒精样本的重复呼吸方法，该呼吸器旨在为再呼吸空气提供大量热量，以加热气道表面。使用单次呼吸测试时，指示的BAC值比实际BAC高出14%至比实际BAC低55%不等。过度通气导致BRAC显著降低，屏气导致BRAC显著升高。当将等温重复呼吸应用于此类测试时，即使呼吸模式改变，呼气测试结果始终在真实BAC的±10%范围内。等温重复呼吸提供了不受呼吸模式改变或空气温度影响的准确肺泡空气样本。
