Measuring airway exchange of endogenous acetone using a single-exhalation breathing maneuver

Abstract

Exhaled acetone is measured to estimate exposure or monitor diabetes and congestive heart failure. Interpreting this measurement depends critically on where acetone exchanges in the lung. Health professionals assume exhaled acetone originates from alveolar gas exchange, but experimental data and theoretical predictions suggest that acetone comes predominantly from airway gas exchange. We measured endogenous acetone in the exhaled breath to evaluate acetone exchange in the lung. The acetone concentration in the exhalate of healthy human subjects was measured dynamically with a quadrupole mass spectrometer and was plotted against exhaled volume. Each subject performed a series of breathing maneuvers in which the steady exhaled flow rate was the only variable. Acetone phase III had a positive slope (0.054+/-0.016 liter-1) that was statistically independent of flow rate. Exhaled acetone concentration was normalized by acetone concentration in the alveolar air, as estimated by isothermal rebreathing. Acetone concentration in the rebreathed breath ranged from 0.8 to 2.0 parts per million. Normalized end-exhaled acetone concentration was dependent on flow and was 0.79+/-0.04 and 0.85+/-0.04 for the slow and fast exhalation rates, respectively. A mathematical model of airway and alveolar gas exchange was used to evaluate acetone transport in the lung. By doubling the connective tissue (epithelium+mucosal tissue) thickness, this model predicted accurately (R2=0.94+/-0.05) the experimentally measured expirograms and demonstrated that most acetone exchange occurred in the airways of the lung. Therefore, assays using exhaled acetone measurements need to be reevaluated because they may underestimate blood levels.

Quantitative breath analysis of volatile organic compounds of lung cancer patients

“…As shown in Fig. 1, N,N-dimethylacetamide (C 4 H 9 NO, retention time 9.02 min) and phenol (C 6 H 6 O, retention time 11.33 min) were two of the most abundant VOCs in human breath besides acetone (C 3 H 6 O, retention time 1.71 min) and isoprene (C 5 H 8 , retention time 1.87 min) [32,33]. The two VOCs were considered as pollutants [30].…”

A fully integrated standalone portable cavity ringdown breath acetone analyzer

“…Gas chromatographymass spectrometry (GC-MS) [5][6][7][8][9][10] has been regarded as a gold-standard method for trace gas analysis for its high sensitivity and high accuracy. However, the GC-MS method is not suitable for breath analysis using a large number of samples due to its complicated sample preparation procedure, time-consuming test process, and high instrumentation and operational costs.…”

Detection of disease markers in human breath with laser absorption spectroscopy

“…Acetone can occur in the exhaled air of healthy man with a concentration of 0.39 to 0.85 ppm [66,[83][84][85]. The concen− tration exceeding the value of 1.4 ppm might suggest diabetes, but it also occurs in breath of children who are on a high−fat diet for the treatment of epilepsy [86].…”