A novel factor influencing perioperative midazolam administration: The effect of presentation dose on administration dose

BACKGROUND AND AIMS: Determinants of pharmaceutical unit presentations are not well understood and often appear indiscriminate. However, the dose administered may play a key role in the patient's anesthetic course. A recent change in a pharmaceutical vendor at our institution resulted in a change in midazolam presentation. In this study, we sought to determine whether the dose in which midazolam was dispensed to anesthesiologists was associated with the quantity of midazolam administered perioperatively. MATERIAL AND METHODS: In this retrospective, observational study, we examined 310 adult patients who underwent general anesthesia at a single site, tertiary care, university hospital before and after a change in midazolam presentation from 2 mg to 3 mg. The primary outcome was the quantity of midazolam administered during the anesthetic. Additional clinical variables measured included patient age, weight, gender, and American Society of Anesthesiology (ASA) classification. RESULTS: The mean dose of midazolam administered to the 3 mg presentation cohort was 2.67 mg compared to 1.99 mg to the 2 mg presentation cohort (mean difference: 0.68 mg, 95% CI: 0.46–0.9 mg; P value <0.001). According to a logistic regression model, the odds of receiving a dose of 3 mg or greater in the 3 mg presentation cohort was 22 times greater than the odds of receiving such a dose in the 2 mg presentation cohort (OR: 22.3; 95% CI: 10.6–47.0; P < 0.001). This effect of presentation dose on administration dose was not observed in patients greater than or equal to 65 years of age. CONCLUSIONS: Midazolam presentation dose influences the administration dose.