Oral high-dose midazolam premedication for infants and children undergoing cardiovascular surgery.

Background: The purpose of this study was to determine whether oral midazolam 1.5 mg x kg(-1) is a safe and effective alternative to standard-dose midazolam (0.5-1.0 mg x kg(-1)) premedication for infants and children with congenital heart disease.

Methods: A total of 193 infants and children (4 months to 2 years) undergoing cardiovascular surgery were studied. Each patient received 0.5, 1.0, or 1.5 mg x kg(-1) of oral midazolam. The level of sedation was assessed with a 5-point scale and vital signs were measured including blood pressure (BP), heart rate (HR) and oxyhaemoglobin saturation (SpO2) before and after the medication.

Results: Infants and children premedicated with oral midazolam 1.5 mg x kg(-1) were better sedated than those with standard-dose midazolam: 4% of infants and children given 1.5 mg x kg(-1) of midazolam became agitated compared with 14% given 1.0 mg x kg(-1) and 26% in those given 0.5 mg x kg(-1). Ninety percentage of infants and children given 1.5 mg x kg(-1) of midazolam achieved satisfactory sedation (calm, drowsy, or asleep) in 30 min, whereas 68% in those given 1.0 mg x kg(-1) and 35% in those given 0.5 mg x kg(-1). Midazolam 1.5 mg x kg(-1) did not cause any statistically significant decrease in BP, HR, or SpO2, although eight infants and children showed > or =20% drop in systolic BP and six infants and children showed >5% drop in SpO2. No 'spelling attacks', seizure-like activity, apnoea, nor laryngospasm were observed in any infants and children during and after the medication.

Conclusions: Oral midazolam 1.5 mg x kg(-1) is excellent for preanaesthetic medication for infants and children undergoing cardiovascular surgery.