The influence of dexmedetomidine on remifentanil_induced hyperalgesia and the sex differences

Authors
H Qiu, Z Sun, F Shadhiya, R Arulthas, et al

Lab
Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China, Department of International Medical School, Tianjin Medical University, Tianjin 300070, P.R. China

Journal
Experimental and Therapeutic Medicine

Abstract
In the clinical settings, patients often develop opioid_induced hyperalgesia (OIH) after utilization of high dose intra_operative remifentanil. Systemic _2 agonists, including dexmedetomidine, are believed to reduce pain and opioid requirements after surgery, thus decreasing the incidence of hyperalgesia. The present study aimed to investigate the effect of dexmedetomidine on remifentanil_induced hyperalgesia and explored the sex differences. A total of 48Êpatients (24 male, 24 female) with an American Society of Anesthesiologists physical status of I_II that were undergoing thyroidectomy were randomly assigned to one of the following six groups: Male controlled group (MC) and female controlled group (FC) (group MC, n=8 and group FC, n=8), which received a preoperative placebo of 0.2ʵg.kg_1 normal saline and intraoperative remifentanil 0.2ʵg.kg_1.min_1; male and female group with low_dose dexmedetomidine (group MD1, n=8 and group FD1, n=8), which received preoperative dexmedetomidine 0.2ʵg.kg_1 and intraoperative remifentanil 0.2ʵg.kg_1.min_1; and male and female groups with high_dose dexmedetomidine (group MD2, n=8 and group FD2, n=8), which received dexmedetomidine 0.6ʵg.kg_1 and intraoperative remifentanil 0.2ʵg.kg_1.min_1. Result indicated that the visual analog scale (VAS) scores and morphine dosing frequency were significantly higher in MC and FC groups compared with the other same sex groups. Furthermore, the mechanical hyperalgesia threshold and patients analgesia satisfaction score after surgery were significantly lower in MC and FC groups. Notably, the frequency of post_operative chills, nausea and vomiting were significantly lower in groups MD1, MD2, FD1 and FD2. The present findings indicated that low_ and high_dose dexmedetomidine injection significantly decreased the patient's risk of enhanced pain intensity and increased postoperative morphine dosing caused by remifentanil_induced hyperalgesia. These findings suggest that the influence of dexmedetomidine displayed minimal significant differences between sex.

BIOSEB Instruments Used:
Von Frey Filaments (Bio-VF-M)