Background: Postoperative pain often remains underestimated due to challenges in its evaluation. Traditional assessment methods like pain scales and hemodynamic indicators may be complex and occasionally unreliable. The perfusion index (PI), derived from Masimo pulse oximetry, offers a rapid, non-invasive, and objective approach for assessing pain in post-surgical patients.

Objective: To determine the effectiveness of perfusion index as an objective marker for evaluating pain relief following rescue analgesia in postoperative individuals.

Materials and Methods: A total of 120 extubated postoperative patients aged 18–80 years were observed. A Masimo pulse oximeter probe was applied, and data on PI, BPS-NI score, and hemodynamic variables were recorded at the first request for analgesia (T1). Rescue analgesia was administered at this point, and all parameters were reassessed 30 minutes later (T2).

Results: Significant elevation in PI values was noted post analgesia, accompanied by notable reductions in BPS-NI scores, mean arterial pressure (MAP), and heart rate. However, no statistically significant changes were observed in axillary temperature or oxygen saturation.

Conclusion: The pulse oximeter-derived perfusion index is a quick, easy-to-use, and non-invasive tool for evaluating pain and monitoring the effectiveness of rescue analgesia in postoperative settings.