A small fraction of alcohol, typically less than 5%, is excreted intact through sweat, urine, and breath (4, 32); Figure 2). One important application for the excretion of alcohol in the breath is that given the high blood flow of the lungs, end-expiratory breath alcohol concentration closely follows arterial blood alcohol concentration (see (100) as an example), which allowed the development of the “breathalyzer” to non-invasively estimate brain and blood alcohol concentrations. A second potential application of this pathway is to accelerate ethanol excretion in cases of severe intoxication. Results from an innovative proof-of-concept pilot study support this concept (154). Since ethanol elimination via exhaled air is proportional to BAC and minute ventilation, increasing minute ventilation—while maintaining constant carbon dioxide levels—could enhance ethanol excretion in cases of extreme intoxication. To test the hypothesis, the investigators used a device to facilitate isocapnic hyperventilation, a technique previously shown to speed up the elimination of vapor anesthetics. In this pilot study, participants consumed a moderate alcohol dose during two separate visits. Using a counterbalanced design, their BrAC was measured under normal breathing (control)
