Effect of Dexmedetomidine on Nol-Index Guided Remifentanil Analgesia

Effect of Dexmedetomidine vs 0.9% Sodium Chloride on Nol-Index Guided Remifentanil Analgesia: a Double-blinded Bicenter Randomized Controlled Trial

Background:

Analgesia remains to this day a challenge for anesthesiologists. Dexmedetomidine, a potent central alpha-2 agonist, has been shown to have analgesic and opioid sparing effects. The classic analgesic strategy focuses on opioid administration guided by estimated time of elimination and hemodynamic response (increase in blood pressure and heart rate). This technique is not sensitive and forces the anesthesiologist to be one step behind nociception, the patient's unconscious response to pain.

PMD-200 (Medasense, Israel) displays the Nociceptive level (NOL)-Index as marker of nociception. The NOL-Index ranges from 0 (no nociception) to 100 (intense nociception) and the recommended analgesic range during surgery is from 10 to 25 (Medasense recommendations).

The goal of this study is to compare two analgesia strategies guided by the NOL Index (range 10-25) using either remifentanil TCI (target controlled infusion) alone or remifentanil TCI associated with a continuous dexmedetomidine infusion.

Methods:

A total of 100 patients will be included and informed consent will be acquired. This bi-center study will take place at Erasme University Hospital (primary center) and Saint-Pierre University Hospital. Patients will be randomized into either two groups: remifentanil and placebo versus remifentanil and dexmedetomidine. Both groups will be monitored using the PMD-200 that will guide the analgesic therapy strategy. Investigators and patients will be blinded to dexmedetomidine and placebo administration. The primary outcome will be intraoperative remifentanil consumption. Secondary outcomes will include postoperative opioid administration, opioid associated complications, hemodynamics, and hospital length of stay.

Inclusion Criteria:

- American Society of Anesthesiologists (ASA) grades 1-2 undergoing scheduled stomatological, cervical, and thyroid surgery anticipated to last at least two hours

Exclusion Criteria:

• ASA score >2
• Preoperative organ dysfunction
• Patients with non-regular cardiac rhythm
• Implanted pacemakers
• Emergent surgery
• Pregnancy or lactation
• Allergy or intolerance to any of the study drugs
• Participation in another interventional study
• Patient refusal