The investigators aim through the use of proton-transfer-reaction mass spectrometry to perform comprehensive breath analysis to identify compounds of interest associated with glucose fluctuations. More than 500 different volatile organic compounds can be detected in human breath. Compounds such as ethane, pentane and isoprene (hydrocarbons), as well as acetone, acetaldehyde, methanol, ethanol, 2-propanol (oxygen-containing compounds), are most likely to be relevant and measurable in our study population. Hydrocarbons are stable end-products of lipid peroxidation and show only low solubility in blood and therefor are excreted into breath within minutes of their formation in tissues. There is evidence for increased hydrocarbon production in states of oxidative stress. Oxygen-containing compounds such as acetone/acetaldehyde (ketones) are also clinically relevant in the measurement of insulin deficient states of catabolism in patients with diabetes. A previous study of exhaled isoprene was found to be elevated during hypoglycemia. This study aims to expand on this to characterize the full range of changes in concentrations of volatile organic compounds in human breath during glucose fluctuations.~Characterizing this biochemical fingerprint of hypoglycemia may provide clues about what so-called diabetes alert dogs are detecting as well as improve our understanding of hypoglycemia, the physiology behind hypoglycemia unawareness, and potentially identify a novel non-invasive measure of blood glucose.
The investigators are investigating the biochemical fingerprint of hypoglycemia (low blood sugar) in the breath of people with type 1 diabetes.