This Small Business Innovation Research Phase I project proposes to develop a clinical monitor for propofol (2,6-diisopropylphenol), an intravenous anesthetic drug widely used in general surgery and as a sedative agent in the intensive care unit (ICU) because of its favorable safety profile and rapid onset and weaning characteristics. Currently, the effectiveness of propofol-induced anesthesia is only assessed symptomatically. Two independent research groups have recently demonstrated that propofol concentrations in human exhaled breath following intravenous administration are proportional to the blood concentrations. Therefore, pulmonary propofol concentrations could be used as a control variable for closed-loop anesthesia. This Phase I project proposes to study the feasibility of monitoring pulmonary propofol concentrations with a compact and real-time optical device by directly measuring the characteristic spectral features of propofol. The work will focus on a proof-of-principle demonstration and a determination of the ultimate sensitivity of the technique. The possibility of chemical interferences will also be studied. The ability to quantify propofol concentrations reliably and economically could also have broad applications in propofol pharmacokinetics and many clinical investigations.
The current technique for monitoring propofol levels in anesthetized patients is by blood samples analysis; a technique that is not only expensive and invasive, but does not provide real-time feedback. If successful, the proposed work will lead to a real time monitor of propofol levels in the bloodstream that could be deployed in hospitals, medical centers and even individual physician offices in order to improve the efficacy of the anesthesia and decrease the risk of sudden patient mortality. Compared to the expensive and bulky proton transfer mass spectrometer, which has been used in research to detect pulmonary propofol, the proposed device is expected to be smaller, less expensive, easier to operate and maintain, and comparable in sensitivity.
