Association between Perioperative Pupillary Parameters and Opioid Analgesic Requirements in Adult Spine Surgery A Prospective Observational Study

Pupil size reflects the balance between sympathetic and parasympathetic systems. Nociceptive stimulation increases sympathetic discharge which in turn dilates pupil and increases pupillary size that is inhibited by opioids in dose dependent fashion.The pupil diameter increases in response to pain regardless of gender and anxiety level. Clinically measured pupillary size is subjective and has interobserver variability . Hence hand held pupillometer is used. More the pupillary size more the analgesics required in intraoperative period to manage pain.

The aim of this study is to evaluate the association between perioperative pupillometry changes (delta pupillometry is equal to post-operative minus pre-operative pupillometry values) and the total dose of  intra-operative opioids and perioperative analgesics[ opioid and non opioid]