Please confirm that an ethics committee approval has been applied for or granted: Not relevant

Background and Aims Peripheral nerve blocks are commonly practiced in anesthesia practice to provide post operative analgesia. Ketamine is a NMDA antagonist which possesses anti-nociceptive and local anesthetic properties. The aim of the meta-analysis is to assess the analgesic efficacy of perineural ketamine as an adjuvant to local anesthetic solution compared to local anesthetics alone for peripheral nerve blocks during surgical procedures

Methods Randomized controlled trials (RCT) comparing ketamine as adjuvant to local anesthetic solution in peripheral nerve blocks in adult patients undergoing elective surgeries were systematically searched from databases – Pubmed, Embase, CENTRAL from inception till May 2023. The primary objective was analgesic efficacy in terms of duration of analgesia and opioid requirement. Secondary objectives included onset and duration of nerve block

Results A total of 12 RCT (539 patients) were included. Duration of analgesia was significantly longer when ketamine was used as adjuvant for peripheral nerve block [SMD – 1.88; 95% CI (1.01-2.76); P < 0.0001]. Opioid requirement was also lower when ketamine was used [SMD – 1.4; 95% CI (2.00-0.80); P <0.0001]. The duration of sensory and motor block were similar in both the groups. The onset of sensory block was similar while onset of motor block was slightly delayed with use of ketamine.

Conclusions The use of ketamine as an adjuvant to local anesthetics in peripheral nerve blocks for surgeries leads to longer duration of analgesia and lower opioid requirement. The duration of sensory and motor block remains similar compared to use of local anesthetics alone.