To evaluate the efficacy of dexmedetomidine(Dex) combined with oxycodone(OD) for patient-controlled intravenous analgesia(PCIA) after spine surgery.

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.

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). Compared with group OD₁, the incidences of nausea, somnolence,bradycardia and pruritus were significantly decreased in groups OD₂ and OD₃, while patient′s satisfaction towards analgesia was significantly improved in group OD₂(P<0.05) but decreased in group OD₃(P<0.05). Compared with group OD₂, no significant difference was found in the incidence of side effects in group 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).

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.

Oxycodone; Dexmedetomidine; Patient-controlled intravenous analgesia