291: NIRS to Compare the Regional Cerebral Oxygen Saturation : opioid and opioid sparing anesthesia

Topic: Clinical Science
Subtopic: Non-specific to any diagnosis, Psychology, Pain in Special Populations , Imaging (e.g. fMRI, PET, MRS)

Background and Aims: Near-infrared spectroscopy (NIRS) is widely used as a surrogate marker for cerebral perfusion, particularly during cardiac and non-cardiac surgeries, where decreases in cerebral oxygen saturation (rSO₂) have been linked to poor outcomes, including postoperative cognitive dysfunction (POCD). POCD, affecting up to 40% of non-cardiac surgery patients, is a significant concern, especially among elderly patients undergoing laparoscopic gastrointestinal surgeries. The cognitive risks associated with opioids have spurred interest in opioid-free anesthesia (OFA), which utilizes non-opioid adjuncts to reduce opioid consumption, potentially improving postoperative outcomes.

Methods: ). On inclusion, consent obtained and preoperatively, cognitive dysfunction assessed using ACE-III scale of patients over 60 years undergoing laparoscopic abdominal surgeries and randomised into two groups, in group A, where fentanyl and morphine was used and group B, where lignocaine (1.5 mg/kg was given over 30 minutes) and dexmedetomidine (0.3-0.8 mg/kg/hr) used intraoperatively, with paracetamol and NSAIDs common in both groups for analgesia. The NIRS sensor was attached to the forehead of the patient just below the hairline and its baseline (on room air) readings of cerebral oxygenation on the right and left frontal regions were noted. Using NIRS machine, cerebral oxygen saturation in right and left frontal region was noted every 10 minutes using INVOS 5100 device. The regional cerebral tissue oxygen saturation was recorded as mean value.

Results: ACE-III scores revealed no significant gender differences preoperatively or at 30 days in both groups. However, at 24 hours postoperatively, females in the opioid group had significantly lower scores (p=0.008), indicating greater early cognitive decline, while a non-significant trend toward lower scores in males was observed in the OFA group (p=0.053). NIRS values were plotted and compared between the two groups. The mean NIRS values did not differ significantly as determined by repeated-measures ANOVA F (120,100) = 2.66, p = 0.253). Patients with POCD at 30 days postoperatively had slightly higher intraoperative rSO₂ values (59.84 ± 1.57) than those without POCD (58.95 ± 2.44); however, this difference was not statistically significant (p = 0.435). In contrast, patients with early POCD (within 24–48 hours) demonstrated significantly higher intraoperative rSO₂ values (60.41 ± 1.81) compared with those without POCD (58.54 ± 1.19, p = 0.023).

Conclusions: Our study found no significant association between intraoperative rSO₂ levels and POCD at 30 days, not between anaesthesia type (opioid vs. opioid-free) and rSO₂. These findings suggest that intraoperative rSO₂ monitoring alone may not be a reliable predictor of long-term postoperative cognitive outcomes in elderly patients.
Trial Registration: CTRI/2023/04/051526.
Key words: Opioid free anaesthesia (OFA), Laparoscopy, Postoperative cognitive decline (POCD), Postoperative neurocognitive disorders (PND), Near Infrared Spectroscopy (NIRS), cerebral oxygen saturation (rSO₂).

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Presenting Author: PUNEET KHANNA
Submitting Author: Puneet Khanna

Senior Author: PUNEET KHANNA

IASP 2026 Global Year theme of Neuropathic Pain: No

• DIPAYAN MISTRY: MD - AIIMS, ND