Effects of Dexmedetomidine for postoperative pain management in elderly patients with femoral head replacement

Objective To investigate the effects of different doses of dexmedetomidine combined with sufentanil for postoperative pain management in elderly patients with femoral head replacement(FHR). Methods Between January 2016 and August 2016, 160 elderly patients(>65 years and BMI 20-28 kg/m2)with American Society of Anesthesiologists(ASA)physical classification Ⅰ-Ⅲ scheduled for elective FHR under spinal anesthesia were randomly allocated into four groups(n=40 for each group). Forty patients, who received patient-controlled intravenous analgesia(PCIA)with sufentanil(1.5 μg/kg)and tropisetron(5 mg)diluted by normal saline to 100 ml, were assigned to the control group.The other 120 patients who received Dexmedetomidine in addition to PCIA were allocated to the experimental group.Based on the dose of dexmedetomidine used in PCIA, the experimental group was divided into three subgroups: Group D1(1.0 μg/kg), D2(1.5 μg/kg)and D3(2.0 μg/kg). The background infusion rate was 2 ml/h, demand dose 0.5 ml and lockout interval 15 min.Pain scores at rest were evaluated with a visual analogue scale(VAS)and Ramsay sedation scores were recorded at 4 h, 8 h and 24 h after surgery.Effects of post-operative analgesia and sedation, supplementary doses of analgesics, and adverse events were also recorded and compared. Results Compared with Control group, VAS was significantly lower at 4 h, 8 h and 24 h after surgery in Group D1, D2, and D3(P 0.05). Meanwhile, there were no significant differences in Ramsay scores among the four groups.Doses of supplementary analgesics and rates of adverse events were markedly lower in Group D1, D2 and D3 than in Control group(P<0.05 for all). Conclusions Dexmedetomidine may enhance the analgesic effects of PCIA with sufentanil and reduce the side effects of opioids in elderly patients with FHR. Key words: Dexmedetomidine; Arthroplasty, replacement; Femoral head; Analgesia