The Medasense Study

Despite various efforts there is still the need for adequate monitoring of pain and nociception during anesthesia. In a previous protocol the investigators measured pain responses during anesthesia based on single end-points, eg heart rate,blood pressure and pulse transit time. None of these parameters provided sufficient information regarding nociception. The investigators therefore want to further investigate this matter using a composite parameter, the Nociception Level or NoL. The NoL is a novel index that measures the magnitude of the autonomic response to painful stimuli. The NoL combines information from several physiological parameters, which represent different autonomic pathways. The multi-parameter approach empowered with state-of-the-art signal processing and machine learning techniques. In the current study the investigators will measure the NoL in ASA 1-3 patients undergoing elective surgery under general anesthesia. The investigators will measure NoL responses and the occurrence of patient movement upon the administration of a painful stimulus: Introduction of the laryngoscope, Insertion of the endotracheal tube, Insertion of the gastric tube, Insertion of the bladder catheter and Skin incision.