Effect of Intrathecal Fentanyl on Spinal Anesthesia During Dexmedetomidine Infusion

Effect of Intrathecal Fentanyl on Spinal Anesthesia During Dexmedetomidine

Intravenous infusion of dexmedetomidine during procedure was known to be associated prolonged duration of spinal anesthesia. In patients receiving dexmedetomidine infusion during procedure, it has been not evaluated whether use of adjuvant intrathecal fentanyl had additional prolonging effect on duration of spinal anesthesia or not. Therefore, the investigators planned this trial to compare clinical outcomes in patients receiving spinal anesthesia with heavy bupivacaine only and heavy bupivacaine plus fentanyl adjuvant.

Inclusion Criteria:

• Adult patients undergoing total knee replacement arthroplasty under spinal anesthesia

Exclusion Criteria:

• Contraindication of spinal anesthesia
• inability to communicate
• morbid obesity (BMI > 30kg/m2)
• spine abnormality
• severe cardiac dysfunction
• Height <155cm, or > 180cm
• contraindication to fentanyl