Objective  To evaluate the safety and effectiveness of esketamine in painless colonoscopy and its effects on dreams and mood.

  Methods  A total of 230 patients who received painless colonoscopy were selected as study subjects. After two cases were excluded, the patients were randomly divided into experimental group and control group, with 114 cases in each group. The experimental group was anesthetized with 0.5 mg/kg esketamine combined with 2 mg/kg propofol, while the control group was anesthetized with 1 μg/kg fentanyl combined with 2 mg/kg propofol. The average blood pressure (MBP), heart rate (HR), blood oxygen saturation (SpO₂) at the three time points of admission (T₁), first administration (T₂) and end of examination (T₃), awakening time and recovery time of orientation were observed in the two groups. The character of dreams and emotional state after operation were also observed.

  Results  HR and MBP at T₂ in the experimental group were significantly higher than those at T₁, while HR and MBP at T₂ in the control group were significantly lower than those at T₁ (P < 0.05). Awakening time and recovery time of orientation in the experimental group were significantly shorter than those in the control group (P < 0.05). The incidence of positive dreams in the experimental group was significantly higher, and the number of patients with excellent and best mood scores after operation were significantly more than that in the control group (P < 0.05).

  Conclusion  Single time administration of 0.5 mg/kg esketamine combined with propofol is safe for patients undergoing painless colonoscopy, which is more conducive to the recovery of patients, and can produce better emotion.