A new route, jet injection for anesthetic induction in children. IV. Midazolam plasma levels.

The jet injector route for midazolam was used in 40 children 1 - 6 years of age undergoing various short duration surgical procedures. A randomly selected dose of 100, 150, and 200 microg/kg was given by a jet injector and compared to 80 microg/kg by conventional i.m. injection with syringe and needle to induce sedation/anesthesia. Because of clinical limitations, plasma midazolam levels were measured for only up to 32 min post-injection. Peak levels were 70.4, 105.8, 157.3, and 135.5 ng/ml in the corresponding groups. Plasma levels reached their peak faster after 200 microg/kg jet injection than after 80microg/kg i.m. midazolam. Furthermore, midazolam plasma levels were sustained longer after 200 microg/kg by jet injection. Larger doses of midazolam are required by jet injection than by i.m. injection. Individual subjects showed considerable variability in plasma levels of midazolam by both methods of administration, although jet injection was more convenient and less traumatic.