Sedative effect and safety of different doses of S-ketamine in combination with propofol during gastro-duodenoscopy in school-aged children: a prospective, randomized study

BACKGROUND: Propofol combined with opioids can reduce the dosage of propofol and improve the safety of endoscopy. However, there are few studies on propofol combined with S-ketamine in children undergoing gastro-duodenoscopy. We aim to determine the sedative effect and safety of different doses of S-ketamine in combination with propofol in school-aged children undergoing gastro-duodenoscopy. METHODS: This is a prospective, randomized trial. Totally, 120 school-aged children who underwent gastro-duodenoscopy were randomly allocated into Group P, Group S(0.3), Group S(0.5) and Group S(0.7). During induction, children in Group P, Group S(0.3), Group S(0.5) and Group S(0.7) received 0, 0.3 mg.kg(−1), 0.5 mg.kg(−1) and 0.7 mg.kg(−1) S-ketamine, respectively, following 3 mg.kg(−1) propofol injection. During gastro-duodenoscopy, 1 mg.kg(−1) of propofol was added according to the condition of the children and the BIS (bispectral index) value. The primary outcome was smooth placement rate of the first endoscope insertion. The secondary outcome was the times of additional propofol, the total amount of propofol, adverse events, recovery time, length of PACU (post anesthesia care unit) stay and endoscopist satisfaction. RESULTS: The smooth placement rate of the first endoscope insertion in Group P, Group S(0.3) and Group S(0.5) was significantly lower than that in Group S(0.7) (16.70%, 34.50%, 50.00% vs. 83.30%, respectively, P < 0.001). The times of additional propofol in Group S(0.3) (P = 0.018), Group S(0.5) (P = 0.014) and Group S(0.7) (P = 0.001) were significantly less than Group P. The total amount of propofol in Group S(0.7) was significantly less than Group P (P < 0.001). The incidence of intraoperative hypotension in Group S(0.5) and Group S(0.7) was low. Group S(0.7) had significantly higher incidence of postoperative dizziness (P = 0.003), longer PACU stay (P = 0.018) and higher endoscopist satisfaction (P = 0.001) than Group P. There was no difference in the recovery time among groups. CONCLUSION: S-ketamine (0.7 mg.kg(−1)) in combination with propofol can provide satisfactory sedative effect and reduce the dosage of propofol in school-aged children undergoing gastro-duodenoscopy, but there are higher incidence of postoperative dizziness and longer PACU stay.