Towards Monitoring of the Anesthetic Drug Propofol: Design, Development, and Characterization of an Automated Flow Analytical System

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University of Memphis, 2012
Propofol is an intravenous anesthetic drug commonly used for the maintenance of sedation for critically ill patients in the ICU. Current standard dosing paradigms, which use weight, age, and sex to determine dosage amounts, are not universal to all patients. Consequently, some patients may be under-sedated, while others may be over-sedated. Patient under-sedation can affect patient comfort, proper patient-ventilator synchronization, and blood oxygenation. Patient over-sedation can result in the development of Propofol Infusion Syndrome (PRIS). PRIS can cause many physiological dysfunctions, even death, especially in children. To address this issue, an electrochemical propofol sensor and an automated flow analytical system (AFAS) have been designed in our lab. The AFAS is aimed toward the feedback controlled monitoring of propofol using microfabricated planar electrochemical sensors. The AFAS is composed of a flow-through electrochemical cell, computer controlled actuator, multi-position valve, peristaltic pump, and potentiostat. The system allows the user to implement complex analytical tasks, including flow injection analysis, continuous monitoring, and multipoint calibration with sample measurements. Measurements can be performed under varied experimental conditions, including a wide range of electrode configurations, sampling schemes, sample volumes, and sample concentrations. A membrane coated sensor for the measurement of propofol has been developed. The AFAS was used to characterize the response of the membrane coated electrode in repeated measurements, using ferrocenemethanol as a model compound. The influence of the thickness of the membrane on the measured electrochemical signal was also examined. Finally, the AFAS was used to demonstrate the performance characteristics of a membrane coated sensor for the measurement of propofol. The AFAS was used to determine the precision and accuracy of propofol measurement in the physiologically relevant concentration range, and the effect of interfering compounds on propofol measurement.

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