Ketamine infiltration improves analgesia after thyroid surgery

Background: Postoperative pain increases the risk of postoperative complications and may predispose patients to chronic post-surgical pain. This study aims to evaluate the impact of ketamine wound infiltration versus placebo at the end of thyroid surgery on postoperative pain and analgesic requirements. Methods: In this randomized controlled trial, we prospectively studied patients who underwent thyroid surgery. Patients were randomized into two groups: group S, where local infiltration was performed using 10 ml of a physiological saline solution; and group K, where 10 ml of a solution containing 2 mg/kg ketamine was infiltrated. Standardized thyroidectomies were performed in the 2 groups. Pain perception was measured using a visual analog scale (VAS) every 10 minutes in the post-anesthetic care unit (PACU) for 2 hours and thereafter every 6 hours during the first 24 hours. The opioid requirement in the PACU was evaluated. A comparison between the 2 groups was carried out. Results: Postoperatively, the mean VAS was higher in group S compared to group K during all PACU stay periods and the first 24 hours. Pain scores during swallowing were significantly lower for group K in the PACU at 0, 10, and 20 minutes. The mean morphine consumption in the PACU was 0.71 mg and 0 mg respectively in group S and group K (p=0.03). The incidence of nausea and vomiting was similar in both groups. Conclusions: Ketamine wound infiltration is an efficient modality to reduce postoperative opioid consumption compared to a placebo after thyroid surgery.