Determination of optimal combined doses of oral midazolam and intranasal dexmedetomidine for use in pediatric magnetic resonance imaging.

BACKGROUND

Sedation is often required for infant and preschool children to obtain clear magnetic resonance imaging (MRI). This study was designed to determine the 95% effective dose (ED) of oral midazolam (MID) and intranasal dexmedetomidine (DEX) in combination for sedation in pediatric MRI.

METHODS

We have used a biased coin design up-and-down sequential methodology. Initially, 144 patients were split into two groups. A total of 72 patients were randomly assigned to determine the ED of DEX in combination with a fixed dose of 0.5 mg/kg MID, and 72 were given various doses of MID combined with a fixed dose of DEX at 1 µg/kg to determine the ED of MID. ED was calculated using isotonic regression. At last, the plan was to include 225 cases to test the sedation success rate of DEX combined with MID ED dose. Adverse events were recorded.

RESULTS

The ED of DEX was 0.89 µg/kg (95% confidence interval (CI) 0.68 to 0.95) combined with a fixed dose of MID at 0.5 mg/kg. The ED of MID was 0.47 mg/kg (95% CI 0.30 to 0.50) combined with a fixed intranasal dose of 1 µg/kg DEX. Using 1 µg/kg DEX combined with 0.5 mg/kg MID, the sedation success rate was 95.1% in a verification group of 225 children.

CONCLUSIONS

This study reports relatively low ED doses of intranasal DEX and oral MID when DEX is determined with a fixed dose of MID and MID determined with a fixed dose of DEX. The combination provides efficient and safe sedation for young children for MRI scanning. Further validation is required.

TRIAL REGISTRATION NUMBER

ChiCTR2300068611.