目的 观察不同剂量艾司氯胺酮复合丙泊酚静脉推注应用于儿科患者增强计算机断层扫描（CT）检查的有效性和安全性，阐明艾斯氯胺酮与丙泊酚镇静配伍的最佳临床剂量。 方法 本研究为随机对照、双盲（受试者和评估者盲）和单中心临床试验。选取行增强CT检查的学龄前儿童120例，采用随机数字表法随机分为丙泊酚组（P组）、丙泊酚+0.3 mg·kg^-1艾司氯胺酮组（P+K3组）和丙泊酚+0.5 mg·kg^-1艾司氯胺酮组（P+K5组），每组40例。所有患儿均给予丙泊酚2 mg·kg^-1，根据镇静效果追加丙泊酚，每次1 mg·kg^-1直至达到入CT室镇静标准［改良警觉/镇静（MOAA/S）评分≤3分］。观察并记录所有患儿镇静前（T₀）、镇静满意时（T₁）、注入造影剂时（T₂）和苏醒时（T₃）的生命体征；记录各组患儿检查时间、镇静满意时间（镇静开始至MOAA/S 评分≤3分）和苏醒时间（检查结束至MOAA/S评分>4分）；比较各组患儿丙泊酚的总量及追加丙泊酚例数占比；比较各组患儿诱导时、检查过程中和苏醒后不良反应发生情况。 结果 3组患儿一般情况比较差异无统计学意义（P>0.05），具有可比性。血流动力学指标，在T₂时刻，与P组比较，P+K3组和P+K5组患儿脉搏血氧饱和度（SpO₂）升高（P<0.05）；在T₁时刻，与P组比较，P+K3组和P+K5组患儿动脉收缩压（SBP）升高（P<0.05）。3组患儿检查时间比较差异无统计学意义（P>0.05）。与P组和P+K3组比较，P+K5组患儿镇静满意时间更短（P<0.05）。与P组比较，P+K3组和P+K5组患儿苏醒时间更短（P<0.05）。与P组和P+K3组比较，P+K5组患儿丙泊酚总量减少（P<0.05），追加丙泊酚例数占比降低（P<0.05）。不良反应指标，与P组比较，P+K3组和P+K5组患儿呼吸抑制发生率降低（P<0.05），恶心呕吐发生率降低（P<0.05）；与P组和P+K3组比较，P+K5组患儿体动发生率降低（P<0.05），眩晕发生率升高（P<0.05）；3组患儿气道分泌物增加发生率比较差异无统计学意义（P>0.05）。 结论 0.5 mg·kg^-1艾司氯胺酮复合2 mg·kg^-1丙泊酚静推用于儿童增强CT检查镇静，可提高此类检查效率，具有较高安全性和有效性。

Objective To observe the effectiveness and safety of different doses of esketamine combined with propofol for intravenous administration in the child patients undergoing enhanced computed tomography （CT） examination， and to clarify the optimal clinical dose of esketamine in combination with propofol for sedation. Methods This study is a randomized， controlled， double-blind （blinded to subjects and evaluators）， and single-center clinical trial. A total of 120 preschool children undergoing enhanced CT examination were randomly divided into propofol group （P group）， propofol+0.3 mg·kg^-1 esketamine group （P+K3 group）， and propofol+0.5 mg·kg^-1 esketamine group （P+K5 group）， and there were 40 cases in each group. All the children were given 2 mg·kg^-1 propofol， and additional propofol was administered in increments of 1 mg·kg^-1 until the sedation criteria for entering the CT room were met ［Modified Observer’s Assessment of Alertness/Sedation （MOAA/S） score ≤3］. The vital signs of the children were observed and recorded at four time points： before sedation （T₀）， when sedation was satisfactory （T₁）， during contrast agent injection （T₂）， and upon awakening （T₃）. The examination time， time to satisfactory sedation （from the start of sedation to MOAA/S score≤3）， and awakening time （from the end of the examination to MOAA/S score>4） of the children in various groups were recorded. The total dose of propofol and the proportion of cases requiring additional propofol were compared among various groups. Adverse reactions during induction， examination， and after awakening were also compared among various groups. Results There were no significant differences in general conditions of the children in three groups （P>0.05）. Hemodynamic parameters： at T₂， compared with P group， the SpO₂ levels of the children in P+K3 group and P+K5 group were increased （P<0.05）； at T₁， compared with P group， the SBP levels of the children in P+K3 group and P+K5 group were increased （P<0.05）. There were no significant differences in examination time of the children in three groups （P>0.05）. Compared with P group and P+K3 group， the time to satisfactory sedation of the children in P+K5 group was shorter （P<0.05）. Compared with P group， the awakening time of the children in P+K3 group and P+K5 group was shorter （P<0.05）. Compared with P group and P+K3 group， the total dose of propofol of the children in P+K5 group was decreased （P<0.05）， and the proportion of cases requiring additional propofol was lower （P<0.05）. Adverse reaction indicators： compared with P group， the incidence of respiratory depression of the children in P+K3 group and P+K5 group was lower （P<0.05）， and the incidence of nausea and vomiting was lower （P<0.05）. Compared with P group and P+K3 group， the incidence of movement during the examination of the children in P+K5 group was lower （P<0.05）， and the incidence of dizziness was higher （P<0.05）. There were no significant differences in the incidence of increased airway secretions of the children in three groups （P>0.05）. Conclusion The use of 0.5 mg·kg^-1 esketamine combined with 2 mg·kg^-1 propofol for intravenous administration in the child patients for enhanced CT examination sedation can improve the efficiency of such examinations and offers high safety and effectiveness.