Efficacy of dexmedetomidine combined with oxycodone for patient-controlled intravenous analgesia after spine surgery

Objective To evaluate the efficacy of dexmedetomidine(Dex) combined with oxycodone(OD) for patient-controlled intravenous analgesia(PCIA) after spine surgery. Methods A total of 100 ASA Ⅰ or Ⅱ patients were scheduled for spine surgery under general anesthesia were enrolled into the current study. They were randomly divided into four groups(n=25): group OD, a 1.0 mg/kg oxycodone combined with 2.5 μg/kg Dex group(group OD1), a 0.8 mg/kg OD combined with 2.5 μg/kg Dex group(group OD2) and 0.6 mg/kg OD combined with 2.5 μg/kg Dex group(group OD3). Normal saline was used to reach a total volume of 200 ml for each group. Then, 15 min before the end of surgery, 0.1 mg/kg OD was intravenously injected followed by connection to a PCIA pump. The PCIA pump was set up a background infusion rate of 3.5 to 4.5 ml/h to deliver a bolus dose of 2 ml within 20 min. Furthermore, 0.05 mg/kg OD was injected intravenously for rescue analgesia, where VAS was maintained≤4. Rescue analgesia was recorded within 48 h after surgery. The number of effective delivery and the incidences of side effects such as bradycardia, hypotension, nausea, vomiting, over-sedation, somnolence, pruritus and respiratory depression were recorded. Patient′s satisfaction towards analgesia was assessed 72 h after surgery. Results No patients required rescue analgesia, while no over-sedation, vomiting, respiratory depression and hypotension was found in the four groups. Compared with group OD, the incidence of somnolence was significantly increased in group OD1, while the incidences of nausea, somnolence, bradycardia and pruritus were decreased in groups OD2 and OD3. Patient′s satisfaction towards analgesia was improved in groups OD1, OD2, and OD3(P 0.05), and patient′s satisfaction towards analgesia was decreased in group OD3(P<0.05). The number of effective delivery was higher in group OD3 than those in groups OD, OD1 and OD2 groups(P<0.01). Conclusions The combined use of 2.5 μg/kg Dex and 0.8 mg/kg OD is an effective approach for intravenous analgesia after spine surgery. It can significantly reduce the consumption of OD, decrease the incidence of side effects and improve the overall patient′s satisfaction of analgesia. Key words: Oxycodone; Dexmedetomidine; Patient-controlled intravenous analgesia