A Comparison of Two Different Doses of Rectal Ketamine Added to 0.5 mg.kg^-1Midazolam and 0.02 mg.kg^-1Atropine in Infants and Young Children

Abstract

In some circumstances, a high degree of sedation that results in a child being unconscious at the time of parental separation is desirable. We set out to investigate the efficacy and safety of a rectal premedication regimen designed to produce this increased level of sedation. Sixty-seven children aged two to 24 months were randomised into two groups. Group MK received 4 mg.kg-1 ketamine, 0.5 mg.kg-1 midazolam and 0.02 mg.kg-1 atropine and group MKK received 8 mg.kg-1 ketamine, 0.5 mg.kg-1 midazolam and 0.02 mg.kg-1 atropine per rectum. The sedation score at the time of parental separation 30 minutes after drug administration and the response to intravenous cannulation were evaluated on a fourpoint scale. Respiratory rate, heart rate and arterial oxygen saturation were recorded immediately before parental separation. More patients in group MKK were asleep during separation (62 vs 35%, P <0.05). Fewer patients in group MKK cried during intravenous cannulation (37 vs 68%, P <0.05). Sedation scores were significantly increased at both time points. There was no difference between groups in vital signs at the time of parental separation and no adverse respiratory events occurred during the study period. In cases where a high degree of sedation following premedication in infants and toddlers is desired, the addition of 8 mg.kg-1 ketamine to 0.5 mg.kg-1 midazolam and 0.02 mg.kg-1 atropine administered rectally is more efficacious than 4 mg.kg-1 ketamine.

Procedural sedation : Aspects on methods, safety and effectiveness

“…This was not the case and could reflect insufficient sedation. In an earlier study, children receiving 4 mg/kg racemic ketamine compared to 8 mg/kg cried to a greater extent during IV cannulation (61). Similar results were found in Study IV where some children with the lowest dose were assessed to have more pain during the procedure.…”

“…The combination of racemic ketamine and midazolam, compared with each drug alone, is more effective regarding sedation levels and tolerance for painful intervention without increasing complications (60), and tolerance increases with higher doses of racemic ketamine combined with midazolam (61). Depending on the type of procedure and perceived pain, the dosage for rectal racemic ketamine varies widely (62)(63)(64).…”

“…A study on painful injections in children with cerebral palsy, which possibly is a less painful procedure, showed median FLACC levels of 2 (range 0-8) with high feasibility using a mean dose of 3.9 mg/kg racemic ketamine combined with a mean dose of 0.26 mg/kg midazolam (93). Increasing the dose from 4 to 8 mg/kg with the addition of midazolam has been shown to give better pain relief but also deepen the level of sedation (61). Overall, all three doses gave adequate pain relief and good procedure feasibility but could further be improved using 6 or 8 mg/kg.…”

A rectally administered combination of midazolam and ketamine was easy, effective and feasible for procedural pain in children with cerebral palsy

“…Rectally administered pain relief for paediatric cerebral palsy outpatients receiving painful injections was a viable alternative to inhalation analgesia. (7)(8)(9)(10). However, this combination has no benefits when administered intravenously (11).…”

“…There seems to be a larger therapeutic index for analgesia and sedation when ketamine is administered orally or rectally, especially when it is combined with midazolam . However, this combination has no benefits when administered intravenously .…”