Objectives: Although targeting the effect site concentration may offer advantages over the traditional forms of administering intravenous anesthetics, it is not applicable for sufentanil in children because its plasma effect site equilibration rate constant (k e0) is not known yet. We estimated k e0 of sufentanil in children using the time to peak effect (tpeak) method. Materials and Methods: Under general anesthesia, sufentanil tpeak was measured after administration of a submaximal bolus dose by means of the decrease in heart rate, blood pressure and calculated approximate entropy (ApEn) of electroencephalogram in 105 children (age range: 3-11 years). k e0 was estimated using tpeak and known sufentanil pharmacokinetic parameters in normal children. Results: The mean tpeaks were measured as 44 ± 22 s and 227 ± 91 s by heart rate and by mean blood pressure respectively. The estimated k e0 were 5.16/min and 0.49/min by heart rate and blood pressure respectively. tpeak could not be measured using the ApEn, thus k e0 could not be calculated by ApEn in children. Conclusions: Shorter measured sufentanil tpeak by heart rate compared to blood pressure indicate that the heart rate decrease faster than decreasing of blood pressure. Moreover, the calculated sufentanil k e0 in children depends on the pharmacodynamics parameters.
- plasma effect site equilibration rate constant