Abstract:Objective To explore the effects of different doses of esketamine (ESK) during anesthesia induction and maintenance in patients undergoing abdominal surgery, so as to provide a reference for clinical selection of the appropriate dose of ESK. Methods A total of 80 patients scheduled for abdominal surgery under general anesthesia in Zhongshan Hospital Xiamen University from May to November 2023 were selected as the research objects. They were randomly divided into three groups using a random number table: control group (CON group, n=20), low-dose ESK group (L-ESK group, n=30), and medium-dose ESK group (M-ESK group, n=30). Anesthesia induction: all three groups were intravenously injected with midazolam 1-3 mg, sufentanil 0.3-0.6 μg/kg, propofol 2-3 mg/kg, and cisatracurium 0.2 mg/kg, followed by tracheal intubation. Immediately after intubation, patients in the L-ESK group and M-ESK group were intravenously injected with ESK 0.25 mg/kg and 0.5 mg/kg, respectively, while patients in the CON group were given the same volume of normal saline. Anesthesia maintenance: the CON group was continuously infused with propofol 4-6 mg/ (kg·h) and cisatracurium 0.05 mg/ (kg·h) by pump. The L-ESK group and M-ESK group were additionally given continuous pump infusion of ESK 0.125 mg/ (kg·h) and 0.25 mg/ (kg·h), respectively, on the basis of the CON group. Postoperatively, all patient received sufentanil by patient controlled intravenous analgesia. Hemodynamic parameters (blood pressure and heart rate), anesthesia recovery indicators, pain degree [Visual Analogue Scale (VAS)] at different time points, and the incidence of postoperative adverse reactions were compared among the three groups. Results Compared with the pre - anesthesia values in the same group, the heart rate, diastolic blood pressure (DBP), and systolic blood pressure (SBP) in the three groups were significantly decreased before intubation (P<0.05), and significantly increased after intubation (P<0.05). There was no statistically significant difference in heart rate, DBP, and SBP between post-extubation and pre-anesthesia (P>0.05). Compared with the CON group, the anesthesia recovery time, extubation time, consciousness recovery time, and spontaneous breathing recovery time in the L-ESK group and M-ESK group were significantly shorter (P<0.05), while the VAS scores on the postoperative day 1 and 2 were significantly lower (P<0.05). Compared with the L-ESK group, the anesthesia recovery time, extubation time, consciousness recovery time, and spontaneous breathing recovery time in the M - ESK group were further shorter (P<0.05), while the VAS scores on the postoperative day 1 and 2 were significantly lower (P<0.05). The overall incidence of adverse reactions was 65.00% (13/20) in the CON group, 23.33% (7/30) in the L-ESK group, and 26.67% (8/30) in the M-ESK group while the difference among three groups was significant (χ²=10.623,P=0.005), with the CON group being higher than both the L-ESK group and M-ESK group (P<0.017). However, there was no statistically significant difference between the L-ESK group and the M-ESK group (P>0.017). Conclusion The combined application of ESK during the anesthesia induction and maintenance stages in patients undergoing abdominal surgery can effectively shorten the postoperative recovery time and alleviate the degree of postoperative pain. Compared with the dose of 0.125 mg/ (kg·h), dose of 0.25 mg/ (kg·h) ESK can further shorten the recovery time and relieve pain without increasing the incidence of adverse reactions.