Dexmedetomidine as an Adjuvant for Sub-Tenon's Anesthesia

Background: The investigator evaluated the motor and sensory block durations and the postoperative analgesic effects of adding dexmedetomidine to levobupivacaine for sub-Tenon's anesthesia in patients undergoing vitreoretinal surgery. Motor and sensory block durations were considered as a primary endpoint.

Methods: The investigator investigated 60 patients subjected to vitreoretinal surgery under sub-Tenon's anesthesia. The patients were randomly divided equally into 1 of 2 groups conferring to the local anesthesia (LA) solution used to receive either 4 mL of levobupivacaine 0.75% plus hyaluronidase 15 IU diluted with 1mL normal saline (group L) or 4 mL of levobupivacaine 0.75% plus hyaluronidase 15 IU and dexmedetomidine 20 μg diluted with 1mL normal saline (group LD). The total volume of the LA solution used was 5 mL. Motor block (akinesia) and sensory block durations were evaluated until the return of normal motor and sensory function. The sedation level was assessed during the surgery period and 24 hours postoperatively together with the degree of postoperative pain and the efficiency of postoperative analgesia. The sleep quality of the first postoperative night was assessed using the Consensus Sleep Diary (CSD).

Inclusion criteria

• satisfactory akinesia
• predictable surgical time to be less than 3 hours were inclusion criteria for this study

Exclusion criteria

• incorporated patients younger than 18 years,
• patients with a single eye,
• history of sleep apnea,
• severe cardiac disease, and
• drug abuse or
• if there was any contraindication to LA.