Combination of oral ketamine and midazolam versus midazolam alone as a premedication in children undergoing tonsillectomy

ABSTRACT

Premedication with oral midazolam is a common practice in paediatric anaesthesia. Combining oral ketamine to midazolam has been tried with different dosing regimens and proved to give good results. The aim of this study was to compare the combination of oral ketamine and midazolam to oral midazolam alone as regard sedation and postoperative pain relief. A prospective randomized double-blind study was carried out in 60 children who were randomly allocated into two groups. Group M received 0.5 mg.kg-1 oral midazolam and group MK received 0.25 mg.kg-1 oral midazolam with 4 mg.kg-1 oral ketamine as a premedication 20 minutes preoperatively. A five points-sedation score [1 asleep to 5 agitated] on arrival to the operating room and a three points-acceptance score of separation from the parents and a three points-mask cooperation score at induction of anesthesia [1 easy to 3 markedly resistant] were used. The time to recovery from anesthesia and to achieve satisfactory Aldrete score was recorded. Time to supplementary analgesia defined as achieving a pain score of 4 or more was used to compare the two groups. At 30 min, 1, 2, and q4h postoperative, pain score was recorded by a blinded observer. Pain was treated with morphine 25 ug.kg-1 intravenously for pain score more than 4, and cumulative morphine consumption in 24hrs was used to compare postoperative analgesic requirements in both groups. Acceptable sedation scores were seen in both groups, without any serious side effects. However, the combination of Ketamine and Midazolam offered significantly more children in an awake, calm and quiet state, who were easily separated from their parents. The separation and cooperation scores were comparable between the groups. The time to recovery from anaesthesia and time to achieve satisfactory Aldrete score were also comparable between the two groups. Time to supplementary analgesia was significantly prolonged in the KM group than in the M group. Total morphine consumption was significantly less in the KM group than in the M group. Adding oral Ketamine to midazolam as a premedication in children provides good quality of sedation and decreases post operative analgesic requirements after tonsillectomy