Objective: Oxycodone or dexmedetomidine (DEX) alone are widely used in clinical practice. The aim of this study was to observe the effect of 2 oxycodone and DEX combinations on postoperative sleep quality.
Methods: This was a prospective and randomized clinical study. A total of 99 patients underwent laparoscopic-assisted operations on stomach and intestines with general anesthesia were enrolled and randomly divided into 3 groups according to postoperative analgesic protocol (n=33 each). The analgesic protocols were as follows after the surgery. In group C, 0.6 mg/kg oxycodone alone was diluted to 100 mL in 0.9% saline. In group D1 or D2, 0.6 mg/kg oxycodone combined with 2.4 μg/kg or 4.8 μg/kg DEX was diluted to 100 mL in 0.9% saline, respectively. The intravenous patient-controlled analgesia device was set up to deliver a continuous infusion of 3 mL/h and a bolus of 1 mL, with a 12-minute lockout interval. The primary outcome was the percentage of stage 2 nonrapid eye movement (stage N2) sleep. Polysomnography was performed the night before operation (PSG-night0), the first (PSG-night1) and second (PSG-night2) nights after surgery.
Results: A total of 97 patients were included in the final analysis. Compared with group C, N2 sleep were higher in groups D1 and D2 on PSG-night1 (54±9% and 53±10%, respectively) and PSG-night2 (55±7% and 56±8%, respectively) (P<0.001 for all comparisons). No differences were observed regarding N1 and N2 sleep between groups D1 and D2 on PSG-night1 and PSG-night2 (P>0.05). Group C had higher percentage of N1 sleep on PSG-night1 (37±5%) and PSG-night2 (33±3%) when compared with groups D1 and D2 (P<0.001 for the comparisons). Groups D1 and D2 required lower rates of rescue analgesia (5% and 4.7%, respectively; P=0.012) and effective pressing times (10.7±4.8 times and 9.9±2.6 times, respectively; P<0.05) when compared with group C, whereas no statistical significance was found between groups D1 and D2. Furthermore, there were no significant difference about resting visual analogue scales at 4, 6, and 12 hours postoperatively between groups D1 and D2. In comparison with the other 2 groups, group D2 had a higher occurrence of postoperative hypotension (24.2%) (P<0.05), though without significant sinus bradycardia.
Discussion: DEX combined with oxycodone can improve sleep quality and provide good visceral analgesia. However, larger doses of DEX does not further improve sleep but increases the risk of hypotension.