This observational cohort study (n=236) in China examined the effect of low-dose esketamine combined with propofol on depressive mood in paediatric tumour patients undergoing general anaesthesia for bone marrow puncture. Children aged 4 to 16 years of both sexes were included, with 118 participants in the observation group and 118 in the control group. The study focused on anaesthesia in paediatric oncology patients and compared outcomes between groups receiving the anaesthetic regimen versus standard management, although the trial record does not specify a detailed comparator intervention. The primary outcome was depression score, assessed in the perioperative period, with the timing of measurement not further specified in the available record. Secondary outcomes included the incidence of hypoxaemia and emergence time, indicating that the study also evaluated safety and recovery after anaesthesia. No Phase designation was provided. Sponsored by Children’s Hospital of Soochow University, this study adds to clinical evidence from China on the potential psychological and anaesthetic effects of esketamine in children undergoing painful diagnostic procedures.