Role of the pupillometer in the assessment of pain in the sedation of pediatric patients

OBJECTIVE: Pupillometry has been used to assess pain intensity and response to analgesic drugs in adults. The aim of this study was to verify the usefulness and effectiveness of the pupillometer to assess pain and depth of sedation in pediatric patients undergoing painful procedures and to optimize pain management by observing pupillary variations induced by opioids. PATIENTS AND METHODS: This is a prospective, monocentric study conducted in the sedation room of the Pediatric Intensive Care Unit of Fondazione Policlinico A. Gemelli in Rome. A population of 22 pediatric patients who underwent painful procedures was enrolled. Eleven children were sedated by opioid drugs. Heart rate, systolic blood pressure, diastolic blood pressure, bispectral index, maximum pupil size (Size), pupil change (CH), Neurological Pupil Index (NPi) were collected over four times: before starting the procedure; before the painful stimulus (when the patient was sedated); when the painful stimulus was applied; at the end of the procedure. A NeurOptics NPi-200 pupillometer was used for the study. RESULTS: Statistical significance in the varia- tion of haemodynamic parameters was less significant than the variation obtained by analyzing the pupillary parameters: a significant change in NPi and CH in the transition from wakefulness to sedation and from the application of the painful stimulus to awakening was found in both study populations, patients who have received opioids and patients who have not received opioids. Changes in the mean CH of the pupil diameter correlate with the depth of sedation and the size values vary in relation to the administration of opioids. CONCLUSIONS: Our findings highlight the potential role of pupillometry as a non-invasive method to objectively quantitate pain response in children to reach an efficient analgesic ap- proach.