Introduction
Thyroid surgeries have evolved into safe procedures with low morbidity and mortality.1 Concerns with surgery are most commonly associated with postoperative pain, which results from extensive tissue dissection and tension. Opioids are the most potent analgesics in clinical anesthesia; however, prescription opioids are a substantial contributor to drug-related adverse effects and the risk of dependence and abuse.2 Thus, reducing postsurgical pain using opioid-sparing techniques can have long-term benefits.3 Multimodal analgesia is useful in reducing opioid consumption following myriad surgeries, including orthopedic, gynecologic, colorectal, and bariatric surgery. Nonetheless, the adoption of multimodal analgesia in head and neck surgeries has lagged.
Ketamine inhibits N-methyl-d-aspartate (NMDA) receptor activation and attenuates the wind-up and central sensitization associated with hyperalgesia, opioid tolerance, and chronic pain.4Numerous publications have stated that adjuvant ketamine reduces postoperative pain and opioid consumption postoperatively.5-8 However, the psychotomimetic effects of ketamine, such as visual disturbances and dizziness, can compromise patient satisfaction. Esketamine, the left-handed optical isomer of racemic ketamine, is purported to have higher potency and a lower incidence of adverse events than racemic ketamine.9 In this randomized controlled trial, we evaluated the opioid-sparing effect of esketamine during thyroid surgery. The primary outcome was perioperative sufentanil consumption. Pain and sleep quality during the first 24 h postoperatively were recorded as secondary outcomes. We hypothesized that the administration of esketamine would reduce perioperative sufentanil consumption, along with better pain control and sleep quality 24 h after surgery.