Comparison of Remifentanil and Dexmedetomidine for Monitored Anaesthesia Care During Vertebroplasty and Kyphoplasty

All patients fasted for 8 h before the procedure and were premedicated with midazolam 0.02 mg/kg. In the prone position, patients were monitored by ECG, non-invasive blood pressure, and pulse oximetry, and received supplemental oxygen (3 L/min) via a nasal cannula during the procedure.

Study drugs were prepared in 20 mL and 50 mL syringes to maintain a double-blind design. One anaesthesiologist administered normal saline or dexmedetomidine contained in the 20-mL syringe during the initial 10 min for loading dose of dexmedetomidine. Then, another investigator who did not know which syringes contained remifentanil or dexmedetomidine adjusted the infusion rate with a 50-mL syringe according to patients' response. After all patients in both groups received a bolus dose of propofol 0.3 mg/kg, patients given remifentanil received continuous infusion of the drug at 1-5 µg/kg/h, and patients receiving dexmedetomidine were given that drug at 0.3-0.4 µg/kg over 10 min, followed by continuous infusion of dexmedetomidine 0.2-1 µg/kg/h throughout the procedure. Levels of patient sedation were checked during the procedure and infusion rates of the study drugs were adjusted to maintain alertness/sedation below 4 on the OAA/S scale.

Mean arterial pressure (MAP), heart rate (HR), oxygen saturation (SpO2), respiratory rate (RR), and adverse effects of the study drugs were recorded during the procedure. Ephedrine 5 mg was injected when systolic blood pressure decreased below 90 mmHg. Duration of PACU stay was also recorded.

Operator satisfaction score and patient's overall pain experience were also recorded.

Inclusion criteria

• patients who are scheduled for vertebroplasty or kyphoplasty under monitored anesthesia care
• ASA status I-III
• aged more than 65 years old.

Exclusion criteria

• obesity (BMI > 30 kg/m2)
• hypotension (systolic blood pressure < 100 mmHg)
• bradycardia (heart rate < 60 bpm)
• heart block
• baseline oxygen desaturation (SpO2 < 90%)
• sleep apnea
• asthma, or chronic obstructive pulmonary disease
• those who refused to give informed consent