Intravenous versus perineural dexmedetomidine as adjuvant in adductor canal block for total knee arthroplasty.

BACKGROUND

The shivering effect after spinal anesthesia in total knee arthroplasty (TKA) is challenging for anesthesiologists. This study aimed to compare two administration routes of dexmedetomidine as a post-neuraxial shivering prevention measure and an adjunctive analgesic and sedative agent.

METHODS

Fifty-six patients were randomly allocated into two equal groups. The intravenous dexmedetomidine (IV dex) group received an IV infusion of 0.5 µg/kg dexmedetomidine diluted in 20 ml saline and an adductor canal block (ACB) consisting of 20 ml of 0.25% levobupivacaine and 1 ml saline. The adductor canal block dexmedetomidine (ACB dex) group received a 20 ml IV infusion of saline and an ACB consisting of 20 ml 0.25% levobupivacaine and 1 ml of 0.5 µg/kg dexmedetomidine.

RESULTS

The incidence of shivering 1 h post spinal anesthesia was equal in both groups (50%); however, the shivering grade was significantly lower in the IV dex group 1 h postoperatively. The onset of sensory block was significantly later in the IV dex group (22.14 ± 2.52 min) than in the ACB dex group (12 ± 3.31 min). Postoperative analgesic duration (h) was significantly longer in the ACB dex group (12.28 ± 4.47) compared to the IV dex group (9.28 ± 1.90). The sedation scores were also significantly higher in the IV dex group in the preoperative, intraoperative, and immediate postoperative periods.

CONCLUSIONS

While perineural ACB dexmedetomidine had similar intraoperative anti-shivering with less sedative effects as IV dexmedetomidine, it was associated with both less shivering control and superior analgesia post-TKA under spinal anesthesia.