Effect of Esketamine on Anxiety State in Patients Undergoing Abdominal Tumor Surgery

Inclusion Criteria: * Patients undergoing abdominal tumor surgery; * older than 18 years old and younger than 70 years old; * ASA grade I-III； * Hamilton anxiety scale ≥ 8. Exclusion Criteria: * Having serious mental illness before surgery or on antipsychotic medication in the two weeks before screening; * Severe organ function lesions such as heart failure (left ventricular ejection fraction \<30%), myocardial infarction, kidney failure (requiring kidney replacement therapy), liver function impairment (Child-Pugh grade C), etc. * Patients arranged to receive general anesthesia combined with epidural anesthesia patients; * Patients who cannot communicate, read or write due to visual, auditory, language or other reasons; * Patients allergic to ketamine; * Patients refused to use postoperative self-controlled intravenous analgesia pump; * Patients refused to participate in the study.