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Background and Objective: studies have shown that rate of propofol infusion may influence the predicted propofol concentration at the effect site (Es). The aim of this study was to evaluate the Es predicted by the Marsh pharmacokinetic model (ke0 0.26min(-1)) in loss of consciousness during fast or slow induction., Method: the study included 28 patients randomly divided into two equal groups. In slow induction group (S), target-controlled infusion (TCI) of propofol with plasma, Marsh pharmacokinetic model (ke0 0.26min(-1)) with target concentration (Tc) at 2.0-μg.mL(-1) were administered. When the predicted propofol concentration at the effect site (Es) reached half of Es value, Es was increased to previous Es + 1μg.mL(-1), successively, until loss of consciousness. In rapid induction group (R), patients were induced with TCI of propofol with plasma (6.0μg.ml(-1)) at Es, and waited until loss of consciousness., Results: in rapid induction group, Tc for loss of consciousness was significantly lower compared to slow induction group (1.67±0.76 and 2.50±0.56μg.mL(-1), respectively, p=0.004)., Conclusion: the predicted propofol concentration at the effect site for loss of consciousness is different for rapid induction and slow induction, even with the same pharmacokinetic model of propofol and the same balance constant between plasma and effect site., (Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.)

Background and Objective: The constant equilibrium between the plasma and effect site (ke0) is used by pharmacokinetic models to calculate a drug concentration in its site of action (Ce). It would be interesting if Ce of propofol was similar at loss and recovery of consciousness. The objective of this study was to evaluate the clinical performance of two different ke0 (fast = 1.21 min(-1), and slow = 0.26 min(-1)) in relation to Ce during loss and recovery of consciousness using Marsh pharmacokinetic model., Methods: Twenty healthy adult male volunteers participated in this study. In all volunteers propofol was administered as target-controlled infusion, Marsh pharmacokinetic model for fast ke0 and, at a different time, the same pharmacokinetic model with slow ke0 was used. Initially, propofol was infused with a serum target-controlled infusion of 3.0 μg.mL(-1). Loss of consciousness and recovery of consciousness were based on response to verbal stimulus. Ce was recorded at the moment of loss and recovery of consciousness., Results: On loss and recovery of consciousness, the Ce for fast ke0 was different (3.64 ± 0.78 and 1.47 ± 0.29 μg.mL(-1), respectively, p < 0.0001), while with slow ke0 the Ce was similar (2.20 ± 0.70 and 2.14 ± 0.43 μg.mL(-1), respectively, p = 0.5425)., Conclusions: Clinically, the slow ke0 (0.26 min(-1)) incorporated in the Marsh pharmacokinetic model showed better performance than the fast ke0 (1.21 min(-1)), since the calculated concentration of propofol at the effect site on loss and recovery of consciousness was similar., (Copyright © 2011 Elsevier Editora Ltda. All rights reserved.)

Background and Objectives: Although being considered one of the most effective drugs to control postoperative nausea and vomiting (PONV), ondansetron is unfeasible for routine use due to its high cost. This study aimed at comparing the efficacy of droperidol, metoclopramide, and dexametasone as compared to ondansetron in preventing PONV after gynecological laparoscopies., Methods: Participated in the study 100 patients submitted to gynecological laparoscopies under general intravenous and inhalational anesthesia, who were randomly distributed in five groups according to the antiemetic medication. Group GO (n = 20) received ondansetron (4 mg); Group GM (n = 20) received metoclopramide (10 mg); Group GD (n = 20) received droperidol (1.25 mg); Group GX (n = 20) received dexametasone (8 mg); and Group GC - control group (n = 20) was not medicated. The following events were recorded: incidence of postoperative nausea and/or vomiting, hemodynamic parameters, PACU stay and anesthetic length., Results: There were no statistically significant differences among groups in demographics, hemodynamic parameters, recovery and anesthetic length. There were statistical differences among groups in the incidence of nausea (GO < GD < GX < GM < GC) and vomiting (GO < GD < GX < GM < GC)., Conclusions: Ondansetron was the most effective agent in preventing nausea and vomiting, and droperidol was the closest drug to ondansetron in preventing PONV.