The Effect of Subclinical Doses of Ketamine on Early Postoperative Pain Sensitivity in Patients Undergoing Salpingectomy: a Prospective, Double-blind, Randomized Controlled Clinical Trial

Ectopic pregnancy (EP) refers to the implantation and development of a fertilized egg outside the uterine cavity, and is one of the common acute abdominal conditions in obstetrics and gynecology. Among them, tubal pregnancy is the most common type, with the highest incidence rate among all ectopic pregnancies. After falling ill, it is easy for patients to experience symptoms such as vaginal bleeding, abdominal pain, and amenorrhea, and even infertility, which seriously affects their physical and mental health. After diagnosis, patients often experience negative emotions such as anxiety, fear, and depression. A history of preoperative anxiety and depression can lower the patient's pain threshold, leading to poor postoperative pain control. In gynecological laparoscopic surgery, ectopic pregnancy surgery is also a relatively painful type of surgery, and the establishment of pneumoperitoneum during surgery can easily cause postoperative pain and affect the patient's prognosis and quality of life. And the patient's preoperative preparation time is limited, leading to a decrease in pain tolerance and an increased demand for postoperative analgesia . Therefore, the issue of increased postoperative pain sensitivity in patients with ectopic pregnancy deserves attention.

Ketamine is an N-methyl-D-aspartate (NMDA) receptor inhibitor that can effectively inhibit NMDA receptor-mediated central sensitization. As an adjuvant analgesic for preventing postoperative hyperalgesia induced by remifentanil, it has a definite therapeutic effect . Esketamine, also known as right ketamine, has pharmacological characteristics similar to racemic ketamine while enhancing analgesic and sedative effects, helping to reduce perioperative opioid use. It has also shown significant advantages in the treatment of pain sensitivity, depression, and epilepsy . However, there are relatively few studies on the postoperative pain sensitivity of subclinical doses of ketamine and ectopic pregnancy patients in clinical practice, and whether it can improve postoperative pain sensitivity in such patients still needs further research and exploration.