Objective: To determine the influence of midazolam on the function of the lower urinary tract when used to sedate the patient.
Patients and methods: Urodynamic studies were performed on 20 patients (seven boys and 13 girls, mean age 4.04 years, range 1 day to 10 years) before and after the intranasal administration of 0.5 mg/kg of midazolam. The patients' heart rate, respiratory rate and oxygen saturation were monitored and the level of sedation recorded by an anaesthesiologist and a surgeon during the study.
Results: Heart rate and respiratory rate did not change and the percentage oxygen saturation remained stable throughout the study period. The childrens' behaviour began to change 3-5 min after the intranasal administration of midazolam. The sedation lasted 2 h and the full co-operation of the patient was assured. The difference between the initial and post-midazolam evaluation of maximal cystometric capacity, contractility, compliance, intravesical pressure, maximum flow rate, intravesical pressure at maximum flow and the amount of residual urine were statistically insignificant (P > 0.05). Electromyographic characteristics showed no significant change with the use of midazolam (P > 0.05).
Conclusion: Despite the suggestion that benzodiazepines, especially diazepam, are useful for the relaxation of pelvic floor striated musculature in voiding dysfunctions, there was no effect on urodynamic variables when midazolam was used in a single dose intranasally. The anxiolytic and sedative effects allowed children to undergo urodynamic studies in comfort.