Effect of dexmedetomidine on Nociception Level Index-guided remifentanil antinociception: A randomised controlled trial.

Coeckelenbergh, Sean; Doria, Stefano; Patricio, Daniel; Perrin, Laurent; Engelman, Edgard; Rodriguez, Alexandra; Di Marco, Livia; Van Obbergh, Luc; Estebe, Jean-Pierre; Barvais, Luc; Kapessidou, Panayota

BACKGROUND The effect of dexmedetomidine on Nociception Level Index (Medasense, Israel) antinociception to reduce intra-operative opioid requirements has not been previously investigated. OBJECTIVE We aimed to determine if low-dose dexmedetomidine would reduce remifentanil requirements during Nociception Level Index-guided antinociception without increasing complications associated with dexmedetomidine. DESIGN Double-blind randomised controlled trial. SETTING Two university teaching hospitals in Brussels, Belgium. PATIENTS American Society of Anesthesiologists 1 and 2 patients (n = 58) undergoing maxillofacial or cervicofacial surgery under propofol--remifentanil target-controlled infusion anaesthesia. INTERVENTIONS A 30 min infusion of dexmedetomidine, or equal volume of 0.9% NaCl, was infused at 1.2 μg kg h immediately preceding induction and then decreased to 0.6 μg kg h until 30 min before ending surgery. Nociception Level Index and frontal electroencephalogram guided the remifentanil and propofol infusions, respectively. MAIN OUTCOMES The primary outcome was the remifentanil requirement. Other outcomes included the propofol requirement, cardiovascular status and postoperative outcome. RESULTS Mean ± SD remifentanil (3.96 ± 1.95 vs. 4.42 ± 2.04 ng ml; P = 0.0024) and propofol (2.78 ± 1.36 vs. 3.06 ± 1.29 μg ml; P = 0.0046) TCI effect site concentrations were lower in the dexmedetomidine group at 30 min postincision and remained lower throughout surgery. When remifentanil (0.133 ± 0.085 vs. 0.198 ± 0.086 μg kg min; P = 0.0074) and propofol (5.7 ± 2.72 vs. 7.4 ± 2.80 mg kg h; P = 0.0228) requirements are represented as infusion rates, this effect became statistically significant at 2 h postincision. CONCLUSION In ASA 1 and 2 patients receiving Nociception Level Index-guided antinociception, dexmedetomidine decreases intra-operative remifentanil requirements. Combined frontal electroencephalogram and Nociception Level Index monitoring can measure dexmedetomidine's hypnotic and opioid-sparing effects during remifentanil-propofol target-controlled infusion anaesthesia. TRIAL REGISTRATIONS Clinicaltrials.gov: NCT03912740, EudraCT: 2018-004512-22.