Malewicz-Oeck NM et al.
European Journal of Anaesthesiology. 2025 Jul;42(7):587–598.
This randomized, placebo-controlled study investigated whether pupillary reflex dilation (PRD), a tool traditionally used in anesthetized patients to guide analgesia, could differentiate between painful and nonpainful stimuli in awake individuals. Thirty healthy volunteers received four types of forearm stimuli: unannounced painful (UPS), announced painful (APS), nonpainful (NPS), and placebo.
Key findings include:
-
PRD was significantly higher with painful stimuli (UPS and APS) compared to NPS and placebo.
-
The greatest PRD was recorded with UPS (25%), while APS showed elevated responses similar to placebo and NPS.
-
Subjective pain ratings correlated with PRD (r = 0.35, P < 0.0001).
The study concludes that PRD can reliably distinguish between painful and nonpainful stimuli in awake subjects, supporting its potential as a noninvasive nociception monitor in conscious patients.
We would like to thank the European Journal of Anaesthesiology for allowing us to share this article. If you’re not already a member, we encourage you to join this excellent organization and support its commitment to advancing safe and evidence-based anesthesia care.