S(+)-ketamine for rectal premedication in children

Our purpose for this prospective, randomized, and double-blinded study was to evaluate the anesthetic efficacy of S(+)-ketamine, an enantiomer of race mic ketamine, compared with a combination of S(+)-ketamine and midazolam, a nd plain midazolam for rectal premedication in pediatric anesthesia. Sixty- two children, ASA physical status I and II, scheduled for minor surgery, we re randomly assigned to be given rectally one of the following: 1.5 mg/kg p reservative-free S(+)ketamine, a combination of 0.75 mg/kg preservative-fre e S(+)-ketamine and 0.75 mg/kg midazolam, or 0.75 mg/kg midazolam. Preopera tive anesthetic efficacy was graded during a period of 20 min by using a fi ve-point scale from 1 = awake to 5 = asleep. Tolerance during anesthesia in duction via face mask was graded by using a four-point scale from 1 = very good to 4 = bad. A sufficient anesthetic level (greater than or equal to3) after rectal premedication was reached in 86% in midazolam/S(+)-ketamine pr emedicated children, in 75% in midazolam premedicated children, but only in 30% in S(+)ketamine premedicated children (P < 0.05 S(+)ketamine versus mi dazolam/S(+)-ketamine and midazolam groups). The incidence of side effects after rectal premedication was rare. Whereas the mask acceptance score was comparable in the three study groups, a 25% rate of complications during an esthesia induction via face was observed in the S(+)ketamine study group (P < 0.05 versus other study groups). Our conclusions are that S(+)-ketamine for rectal premedication in the dose we chose shows a poor anesthetic effec t and a frequent incidence of side effects during induction of anesthesia v ia face mask compared with the combination of midazolam/S(+)ketamine and pl ain midazolam. Dose-response studies of S(+)-ketamine for rectal premedicat ion in pediatric anesthesia may be warranted.