Pharmacokinetics of propofol during conscious sedation using target-controlled infusion in anxious patients undergoing dental treatment.

Infusion of propofol by a target-controlled infusion (TCI) system is effective in achieving conscious sedation for anxious patients presenting for dental surgery. It is a common clinical observation that anxious patients require more anaesthetic drugs than non-anxious individuals. In study 1 we have defined blood propofol concentrations necessary for conscious sedation in both anxious (n = 23) and non-anxious (n = 18) patients. The pump performance of the TCI system, using Gepts' pharmacokinetic model, was evaluated in these two patient groups. Subsequently, clearance of propofol was compared in the two groups. Mean measured venous serum propofol concentrations obtained between 20 and 35 min after the optimal sedation level was reached were 1.6 (SD 0.2) micrograms ml-1 in the anxious patients compared with 1.7 (0.3) micrograms ml-1 in the control group (study 1) and 1.4 (0.27) micrograms ml-1 in study 2. The pump systematically overpredicted measured propofol concentrations in both groups (study 1). There was no significant difference in propofol clearance between the two groups. In study 2, an optimized set of microconstants was derived which should more accurately predict the pharmacokinetic profile of the anxious population and this set was tested prospectively in another group of 12 anxious dental patients. Bias and precision with the optimized kinetic set were significantly less than the values obtained in study 1. We conclude that there was no significant pharmacokinetic differences between anxious and non-anxious subjects receiving subanaesthetic doses of propofol for conscious sedation.

Patient-controlled versus anesthesiologist-controlled conscious sedation with propofol for dental treatment in anxious patients.

UNLABELLED: In a randomized, cross-over study, we prospectively compared the efficacy and quality of two methods to achieve conscious sedation with propofol in 11 unpremedicated, anxious dental patients. Each patient underwent two dental procedures, one that was conducted under target-controlled infusion (TCI) by the anesthesiologist (ACS), and the other that used patient-controlled sedation (PCS). The initial target concentration in the ACS mode was 2.5 microg/mL, which was manipulated in both directions until the desired clinical end point was achieved. In the PCS mode, a 4-mg bolus of propofol (10 mg/mL) was delivered at each activation of the machine, infused over 7 s without a lockout interval. The anxious dental patients could induce and maintain conscious sedation with the PCS settings. The mean (range) venous blood propofol concentrations were not significantly different with either mode: ACS 1.8 (0.8-2.7) microg/mL and PCS 1.2 (0.2-2.5) microg/mL. The level of patient satisfaction, quality of sedation, and treatability were not different for either mode of sedation. The intensity of amnesia for intraoperative events was related to the blood concentrations achieved. In the ACS mode, one patient became unresponsive (sedation level 4) immediately after the start of sedation. No adverse cardiorespiratory effects resulted from either mode of propofol sedation. Five patients expressed a strong preference for PCS, and three would prefer ACS in the future. The results of the present study suggest that with these PCS settings, a satisfactory level of conscious sedation and a high level of patient satisfaction was achieved. IMPLICATIONS: In a randomized, cross-over study, the blood propofol concentrations necessary to achieve conscious sedation in anxious dental patients using a target-controlled infusion conducted by the anesthesiologist versus patient-controlled sedation were not different. With the patient-controlled sedation settings, a satisfactory level of conscious sedation and a high level of patient satisfaction were achieved.

Computer controlled infusion of propofol for conscious sedation in dental treatment.

OBJECTIVE: To assess a drug delivery system that can rapidly achieve and maintain a constant blood concentration of Propofol (2,6 di-isopropyl phenol) which, in subanaesthetic doses, is an effective intravenous sedative for treating anxious or handicapped patients in dentistry. DESIGN: The clinical use of a computer controlled infusion system to induce and maintain conscious sedation with propofol was prospectively studied. Based on a 3-compartment pharmacokinetic model, the system calculates the initial bolus dose and infusion rates to achieve a user-selected target blood concentration. SETTING: Amsterdam Center for Special Dental Care. SUBJECTS: 89 patients attending for dental treatment. RESULTS: Treatment could be performed within 2 minutes after the onset of the infusion. The median therapeutic target blood propofol concentration was 2.5 micrograms/ml and the median recovery time was 9 minutes. Transient oversedation (38 procedures) could easily be treated by decreasing the target concentration. No adverse cardiorespiratory effects resulted from propofol sedation. Venous blood propofol concentrations were measured in 25 anxious patients. The kinetic data set used in this study underestimated the distribution and elimination of propofol in our patients. CONCLUSIONS: Computer controlled infusion of propofol can provide satisfactory and safe conscious sedation in dental patients.