Patients with dental phobia frequently require intravenous sedation to complete dental treatment. We encountered a case of a patient who received frequent sedation by propofol, which required escalation in the dosage of propofol required. The patient was a healthy young female with severe dental phobia, and the dental procedures were initiated under intravenous sedation. Intravenous sedation was administered to the patient more than 100 times over 9 years, and the dosages were analyzed. The mean dosage of propofol administered per hour was 6.9 ± 2.4 mg/kg/h, and the dosage tended to increase with frequency (0.06–0.1 mg/kg/h in each administration). Increased dosage was needed with a shorter interval between sedations after 30 episodes of sedation. Regarding the mean dosage of propofol per hour, the step-down method exhibited the highest increase in dosage rate of 0.18 mg/kg/h per administration followed by target-controlled infusion at 0.07 mg/kg/h per administration and combination sedation at 0.06 mg/kg/h per administration. We discuss factors that may be associated with acute tolerance to propofol when frequent propofol sedations are provided.
Changes in mean infusion rate of propofol. Graphs show the correlation between the frequency of intravenous sedation and mean dosage of propofol. In the upper graph, the dosage tended to increase with increasing frequency, particularly after the 30th and the 60th episode of intravenous sedation. In the lower graph, as the administration interval decreased, a tendency of a considerable increase in propofol dosage was observed.
Regression and correlation analysis between the mean infusion rate of propofol and frequency (total number of cases, only propofol, propofol, and other sedative drugs). A significant positive correlation was observed between the frequency of intravenous sedation and the dosage of propofol. A tendency for a slower increase in propofol dosage was seen when combined with other drugs such as midazolam ± butorphanol, as the slope of the regression line is decreased.
Regression and correlation analysis between the mean infusion rate of propofol and frequency (total number of cases, target-controlled infusion, and step-down method). A significant positive correlation was observed between the frequency of intravenous sedation and the dosage of propofol in each situation. The step-down method exhibited the higher increase in rate of propofol infusion at 0.18 mg/kg/h per administration versus TCI at 0.07 mg/kg/h per administration.
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