Smart Portable Pen for Continuous Monitoring of Anaesthetics in Human Serum with Machine Learning
Abstract : Continuous monitoring of anaesthetics infusion is demanded by anaesthesiologists to help in defining personalized dose, hence reducing risks and side effects. We propose the first piece of technology tailored explicitly to close the loop between anaesthesiologist and patient with continuous drug monitoring. Direct detection of drugs is achieved with electrochemical techniques, and several options are present in literature to measure propofol (widely used anaesthetics). Still, the sensors proposed do not enable in-situ detection, they do not provide this information continuously, and they are based on bulky and costly lab equipment.
In this paper, we present a novel smart pen-shaped electronic system for continuous monitoring of propofol in human serum. The system consists of a needle-shaped sensor, a quasi digital front-end, a smart machine learning data processing, in a single wireless battery-operated embedded device featuring Bluetooth Low Energy (BLE) communication. The system has been tested and characterized in real, undiluted human serum, at 37C. The device features a limit of detection of 3.8M, meeting the requirement of the target application, with an electronics system 59% smaller and 81% less power consuming w.r.t. the state-of-the-art, using a smart machine learning classification for data processing, which guarantees up to twenty continuous measure.
? Interoperative anaesthetics involves the patient monitoring and drug control management during surgery.
? It requires very accurate and controlled doses of drugs to be administered in a timely fashion. Any errors in any aspect of the process are extremely dangerous.
? Target-controlled infusion (TCI) is part of anaesthesia delivery in many countries, resulting in the precision, reliability, efficacy, and safety of intravenous (IV) anaesthesia delivery.
? Advancement in drug development has primarily modifying the chemical structures of existing drugs to improve their pharmacodynamic, pharmacokinetic, and side effect properties.
o Propofol is a widely used anesthetic thanks to its many pharmacological properties such as rapid distribution, short action and reduced side effects in post-operative recovery.
• This is known as Pain On Propofol Injection (POPI) and it is still among the most critical problems in the anesthesia current practices.
• To reduce POPI effects, other compounds, e.g., paracetamol, are usually administered in combination with propofol to exploit their antipyretic and analgesic effects.
• The proposed system, on the other hand, is not programmed in this sense at all. Instead, it is "trained", by exposing it to an extensive set of example "inputs" and "desired outputs".
• These data are generated by logging all the data from a large number of real operations carried out in the past, under the supervision of human anaesthesiologists.
• Using a neural network training algorithm, the system learns to map the inputs into the desired output responses.
• The American Society of Anaesthesiologists (ASA) has proposed a widely-accepted classification scheme to aid pre-operative assessment.
• We have redesigned the front-end hardware of our previous implementation by improving its performances with the aim of providing a robust system for human serum detection.
• In particular, we have re-implemented the analog read-out by introducing a 4th-order filtering block as second amplification stage in cascade with respect to the Trans-Impedance Amplifier (TIA) stage.
• The exchange of the fluxing solutions was done in the 10 s of mixing in order to not interrupt the procedure.
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