Thrifty effect of subanesthetic‐dose S‐ketamine on postoperative opioids and its safety and analgesic effectiveness: A prospective, triple‐blind, randomized controlled, polycentric clinical trial

Aim To investigate the thrifty effects of subanesthetic‐dose S‐ketamine on postoperative opioids and its safety and analgesic efficacy. Methods Four‐hundred and twenty patients were divided into the control group (CON group), the S‐ketamine 0.2 mg/kg group (ES0.2 group), and the S‐ketamine 0.3 mg/kg group (ES0.3 group) randomly. Major indicators include the Visual Analogue Scale (VAS), the times of compression with analgesic pumps after surgery, and analgesic drug consumption from anesthesia induction to 48 h after surgery. Minor records include vital signs, the use of vasoactive drugs, the Ramsay scores, the occurrence of adverse events including nervous system reaction, and the patient's satisfaction with anesthesia. Results Compared with the CON group, VAS scores decreased in the ES0.2 and ES0.3 groups (p