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

@article{citeulike:1285466, 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. 10.1152/japplphysiol.00868.2005}, author = {Anderson, Joseph C. and Lamm, Wayne J. and Hlastala, Michael P.}, citeulike-article-id = {1285466}, citeulike-linkout-0 = {http://dx.doi.org/10.1152/japplphysiol.00868.2005}, citeulike-linkout-1 = {http://jap.physiology.org/cgi/content/abstract/100/3/880}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/16282431}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=16282431}, day = {1}, doi = {10.1152/japplphysiol.00868.2005}, journal = {J Appl Physiol}, keywords = {50071065, acetone, endogenous, exhalation}, month = {March}, number = {3}, pages = {880--889}, posted-at = {2007-05-09 21:34:39}, priority = {5}, title = {Measuring airway exchange of endogenous acetone using a single-exhalation breathing maneuver}, url = {http://dx.doi.org/10.1152/japplphysiol.00868.2005}, volume = {100}, year = {2006} }

TY - JOUR ID - citeulike:1285466 L3 - citeulike-article-id:1285466 N2 - 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. 10.1152/japplphysiol.00868.2005 IS - 3 JF - J Appl Physiol EP - 889 TI - Measuring airway exchange of endogenous acetone using a single-exhalation breathing maneuver VL - 100 SP - 880 KW - 50071065 KW - acetone KW - endogenous KW - exhalation AU - Anderson, Joseph AU - Lamm, Wayne AU - Hlastala, Michael PY - 2006/03/01/ UR - http://dx.doi.org/10.1152/japplphysiol.00868.2005 ER -