An infrared camera of the video pupillometer measures the pupillary dilation reflex (PDR) in response of a nociceptive stimulus. This autonomic reflex, parasympathetic mediated in sedated patients, can be generated by various pain stimuli (built in standardized protocol, surgical incision, …) The PDR is a robust reflex, even in patients under general anesthesia, and provides a potential evaluation of the autonomous circuit within the nociceptive evaluation based on pupil dilation upon A-delta and C fibers in both electrical or mechanic stimulation. This mono-centric project involving American Society of Anesthesiologists (ASA) classification I-II patients undergoing elective abdominal surgery under general anesthesia are recruited. Enrolled patients perioperative undergo PDR measurements at four different standardized times.
In this study, the pupillary dilation reflex is measured as a nociceptive indicator during elective abdominal surgery under general anesthesia.