Efficacy of ketamine and midazolam as co-induction agents with propofol for laryngeal mask insertion in children

Paediatr Anaesth. 2008 Jul;18(7):628-34. doi: 10.1111/j.1460-9592.2008.02563.x. Epub 2008 May 8.


Objectives: Use of midazolam and ketamine lowers the induction dose of propofol (co-induction) producing hemodynamic stability.

Background: Large doses of propofol needed for induction and laryngeal mask (LM) insertion in children may be associated with hemodynamic and respiratory effects. Co-induction has the advantage of reducing dose and therefore maintaining hemodynamic stability.

Aim: To examine the effect of co-induction on hemodynamics, LM insertion and recovery in children.

Methods/materials: A prospective, randomized, double-blind, controlled study was conducted in 60 ASA I/II children, age 1-8 years. Normal saline, ketamine 0.5 mg.kg(-1), midazolam 0.05 mg.kg(-1) were administered in groups P (propofol), PK (propofol-ketamine) and PM (propofol-midazolam), respectively, 2 min prior to the administration of the induction dose of propofol. Propofol 3.5 mg.kg(-1) (group P) or 2.5 mg.kg(-1) (groups PK and PM) was used for induction, LM inserted 30 s later and insertion conditions assessed. Heart rate and blood pressure were recorded immediately after propofol bolus, then every min till 2 min after LMA insertion. Recovery was assessed using Steward's Score.

Result: In group P, systolic blood pressure (SBP) showed a significantly greater decrease compared to group PK and group PM (P < 0.005). Only 5% of patients in groups PK and PM showed >20% fall in SBP compared to 89% in group P (P < 0.005). More children in groups PK and PM had acceptable conditions for LM insertion compared to group P (P < 0.05). The time to achieve Steward Score of 6 was longer in groups PK and PM compared to group P (P < 0.005).

Conclusion: In children, the combination of propofol with ketamine or midazolam produces stable hemodynamics and improved LM insertion conditions but is associated with delayed recovery.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Analgesics / administration & dosage
  • Analgesics / adverse effects
  • Analgesics / pharmacology
  • Anesthesia Recovery Period
  • Anesthetics, Combined / administration & dosage
  • Anesthetics, Combined / adverse effects
  • Anesthetics, Combined / pharmacology*
  • Anesthetics, Intravenous / administration & dosage
  • Anesthetics, Intravenous / adverse effects
  • Anesthetics, Intravenous / pharmacology
  • Blood Pressure / drug effects
  • Child
  • Child, Preschool
  • Double-Blind Method
  • Drug Synergism
  • Female
  • Humans
  • Infant
  • Ketamine / administration & dosage
  • Ketamine / adverse effects
  • Ketamine / pharmacology*
  • Laryngeal Masks*
  • Male
  • Midazolam / administration & dosage
  • Midazolam / adverse effects
  • Midazolam / pharmacology*
  • Propofol / administration & dosage*
  • Propofol / adverse effects
  • Prospective Studies
  • Sodium Chloride / administration & dosage
  • Treatment Outcome


  • Analgesics
  • Anesthetics, Combined
  • Anesthetics, Intravenous
  • Sodium Chloride
  • Ketamine
  • Midazolam
  • Propofol