Preanesthetic Medication of Children with Midazolam Using the Biojector Jet Injector

BACKGROUND: A rapid, dependable, and economical technique to atraumatically sedate children before anesthesia that does not prolong postanesthesia care unit time remains elusive. The Biojector jet injection system uses carbon dioxide rather than a needle to deliver an intramuscular injection. The dose-response relationship when midazolam is administered was studied using this jet injector. METHODS: Forty children (2.3 +/- 1.3 yr old) undergoing elective myringotomy and tube placement were randomly assigned to receive 0.05, 0.1, 0.15, 0.2, or 0.3 mg.kg-1 midazolam injected intramuscularly using the Biojector disposable syringe (0.006-inch orifice). Assessment of each child before, during, and 10 min after injection, on application of the anesthesia face mask, and every 15 min for 1 h after arrival to the postanesthesia care unit was made by an observer blinded to drug dosage. RESULTS: Face mask tolerance using doses > or = 0.1 mg.kg-1 midazolam was acceptable and statistically different from 0.05 mg/kg. Crying on injection tended to increase with increasing dose. All children were awake and arousable, meeting discharge criteria, after 30 min from arrival in the postanesthesia care unit. CONCLUSIONS: Midazolam (0.1-0.15 mg.kg-1) administered using jet injection effectively and rapidly produces sedation, in a manner acceptable to parents, without delaying postanesthesia care unit discharge.