RESUMEN
BACKGROUND: Propofol formulated with medium- and long-chain triglycerides (MCT/LCT propofol) has rapidly replaced propofol formulated with long-chain triglycerides (LCT propofol). Despite this shift, the modified Marsh and Schnider pharmacokinetic models developed using LCT propofol are still widely used for target-controlled infusion (TCI) of propofol. This study aimed to validate the external applicability of these models by evaluating their predictive performance during TCI of MCT/LCT propofol in general anesthesia. METHODS: Adult patients (n = 48) undergoing elective surgery received MCT/LCT propofol via a TCI system using either the modified Marsh or Schnider models. Blood samples were collected at various target propofol concentrations and at specific time points, including the loss of consciousness and the recovery of consciousness (13 samples per patient). The actual plasma concentration of propofol was determined using high-performance liquid chromatography. The predictive performance of each pharmacokinetic model was assessed by calculating four parameters: inaccuracy, bias, divergence, and wobble. RESULTS: Both the modified Marsh and Schnider models demonstrated predictive performances within clinically acceptable ranges for MCT/LCT propofol. The inaccuracy values were 24.4% for the modified Marsh model and 26.9% for the Schnider model. Both models showed an overall positive bias, 16.4% for the modified Marsh model and 16.6% for the Schnider model. The predictive performance of MCT/LCT propofol was comparable to that of LCT propofol, suggesting formulation changes might exert only a minor impact on the reliability of the TCI system during general anesthesia. Additionally, both models exhibited higher bias and inaccuracy at target concentrations ranging from 3.5 ~ 5 ug/ml than at concentrations between 2 ~ 3 ug/ml. CONCLUSIONS: The modified Marsh and Schnider models, initially developed for LCT propofol, remain clinically acceptable for TCI with MCT/LCT propofol. TRIAL REGISTRATION: This study was registered at the Clinical Research Information Service of the Korean National Institute of Health ( https://cris.nih.go.kr ; registration number: KCT0002191; 06/01/2017).
Asunto(s)
Propofol , Adulto , Humanos , Propofol/farmacocinética , Anestésicos Intravenosos/farmacocinética , Reproducibilidad de los Resultados , Humedales , Infusiones Intravenosas , Anestesia General/métodos , TriglicéridosRESUMEN
BACKGROUND: We investigated effect-site concentrations of propofol, changes in blood pressure and heart rate, time to loss of consciousness, time to loss of eyelid reflex and awakening time during anesthesia using effect-site target-controlled infusion, to compare the differences between Schnider and modified Marsh model. METHODS: Forty American Society of Anesthesiologists (ASA) physical status I or II patients between the ages of 18 and 55 years old and who were scheduled for elective surgery under general anesthesia were enrolled in this study. The patients were randomized into two groups: one group using modified Marsh model (Group 1) and the other group using Schnider model (Group 2). Effect-site concentrations of propofol, blood pressure, heart rate and BIS at each anesthetic stage were recorded. Time to loss of consciousness, time to loss of eyelid reflex and awakening time were measured. RESULTS: Group 1 showed shorter time to loss of consciousness and eyelid reflex at the lower effect-site concentration of propofol than Group 2 (P < 0.05). The effect-site concentrations of Group 1 were higher than those of Group 2 at eye opening and extubation (P < 0.05). CONCLUSIONS: Induction of anesthesia is achieved at lower effect-site concentration of propofol and more rapidly in the modified Marsh model than in the Schnider model. However the effect-site concentrations of propofol for awakening are higher in the modified Marsh model than in the Schnider model.