Standardizing the collection and measurement of glucose in exhaled breath and its relationship to blood glucose concentrations
Abstract
Blood glucose level control (glycemic control) is crucial in diabetes. Limitations in current commercially available monitoring devices include causing patient pain leading to poor blood glucose level management. The development of a non-invasive measurement system may lead to improved patient glycemic control, reducing unwanted side-effects and complications of poor blood glucose level maintenance. This work explores the use of glucose within exhaled breath in attempt to establish an indirect method of blood glucose level measurement. Specifically, exhaled breath condensate (EBC) is examined. A breath condensing unit was designed to measure the temperature of the system, flow rate, volume of expired air, ambient humidity, and remove exhaled dead volume before condensing breath. A fluorometric assay was used to analyze and measure the glucose concentrations in the EBC samples. The results directly relate to the feasibility of developing a noninvasive EBC-based glucose measuring device. A nebulizer study was performed to verify that the amount of glucose present in the condensate was predictable, given a known concentration of aerosolized glucose. The nebulizer study revealed that some glucose interferent is present in the ambient air. Further exploration allowed for a humidity based model to be developed that can accurately and consistently predict the concentration of the condensate. An IRB approved study, using a total of five human subjects, was employed to quantitatively evaluate the change in both blood and EBC glucose levels associated with the intake of either food or water. The human subject study results indicate that, with the use of the humidity based model derived from the nebulizer study, it is possible to predict blood glucose levels from EBC glucose levels. These results provide motivation for the further exploration of an EBC-based non-invasive blood monitoring device.
Degree
M.S.B.M.E.
Advisors
Rundell, Purdue University.
Subject Area
Biomedical engineering
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