A Scheme-Based Closed-Loop Anesthesia System

Many aspects of modern medicine, including the administration of anesthetic agents during general surgery, remain unautomated and reliant on the vigilance of the attending clinicians. In other fields where failures can have catastrophic consequences, such as the aviation and nuclear power industry, automated control regimens have been adopted to reduce the risks and improve performance. In this paper we discuss many aspects of the implementation of a complete automated system for intravenous anesthetic drug infusion based on feedback from electroencephalography (EEG) readings. The system software in its entirety consists of approximately 22K lines of Scheme code and features a client-server implementation interfacing medical devices with a portable graphical user interface. The user interface runs on both mobile devices and dedicated medical flat panel displays. The strengths of the Scheme functional language have been leveraged to build a robust maintainable modular system with extensive testing facilities to mitigate the inherent safety hazards associated with the application.