Patient supervised automatic sedation control
Researchers: Teresa Mendonça (FCUP-SYSTEC), Paula Rocha (FEUP-SYSTEC), Bertinho Costa (IST-INESC-ID); Manuel Seabra (USLM-Hospital Pedro Hispano); Pedro Gambús (Hospital Clinic de Barcelona)
Institutions: UPorto-SYSTEC, UL-INESC; Unidade Local de Saúde de Matosinhos-Hospital Pedro Hispano; Hospital Clinic de Barcelona.
The purpose of sedation and analgesia during a medical examination is to relieve patient anxiety and discomfort, improve the outcome of the examination, and diminish the patient’s memory of the event. At the level of moderate sedation, the patient, while maintaining ventilator and cardiovascular function, is able to make purposeful responses to verbal or tactile stimulation. Typically, diagnostic and uncomplicated therapeutic upper endoscopy and colonoscopy are successfully performed with moderate sedation. Studies have demonstrated an advantage of sedation with propofol for endoscopy due to more rapid onset of action and shorter recovery time compared with traditional sedative regimens. However the narrow therapeutic window of propofol increases the risk for cardiopulmonary complications if it is not administered appropriately. Hence, specific training in the administration of propofol and patient monitoring during the use of this agent are required. The amount of dosing and depth of sedation are titrated as appropriate for the procedural goals. It is important to note that propofol does not possess analgesic properties so that, if it is administered as the sole agent, deep sedation may be required to keep the patient comfortable. Both for moderate and deep sedation, the level of consciousness must be periodically assessed in addition of heart rate, blood pressure, respiratory rate, and oxygen saturation. The constant need for monitoring and consequent possible drug dose adaptation motivates the design of an automatic system for the monitoring and controlling the sedation procedure. More concretely, the idea is to develop a device to control the administration of an hypnotic (propofol) drug, receiving inputs from both patient and clinician, allowing an adequate state of semi-unconsciousness, able to respond to some stimulus, but insensitive to pain. This requires the use of non-classical models as well as new identification techniques that enable robust model-based control.