| [Objective] After profound development of a few decades, propofol has been widely used for induction and maintenance of anesthesia. It also serves as the first-line alternative for the sedation therapy in the Intensive Care Unit. With its common administrations in clinical settings, however, some inherent deficiencies associated with propofol, including injection pain, nosomical infection, and hyperlipidemia, were clearly exposed. Most of them have been proved to be due to lipid components in the propofol emulsion. As a result, much attentions have been focused on the propofol revolution targeting on the propofol emulsion modifications. MCT-LCT propofol is a new type of propofol emulsion with medium-chain triglyceride in place of long-chain triglyceride in traditional propofol emulsion. Our research aimed at comparison of clinical pharmacodynamics and pharmacokinetics between such modified propofol emulsion and traditional propofol emulsion.[Methods] We designed this research in two parts, which were performed in two common clinical settings.In the first part of this trial,90 ASA grade 1-2 patients receiving elective orthopedic surgery under the regional anesthesia were divided into 3 groups equally and randomly. After obtaining successful regional anesthesia, they were administered 1% LCT propofol,1% MCT-LCT propofol, and 2% MCT-LCT propofol. They were all given propofol 2 mg/kg over 60 seconds with the assistance of infusion pump. We recorded induction time and emergency time, assessed pain induced by injection of propofol on basis of VAS, and observed the changes in BP,HR,SpO2 and entropy. For the other part of our research,20 ASA grade 1-2 patients receiving orthopedic surgery under general anesthesia were divided into two groups at random. They were given 1% LCT propofol 2 mg/kg and 2% MCT-LCT propofol 2mg/kg respectively for induction of anesthesia, with appropriate fentanyl and cis-atrcurium administered to facilitate tracheal intubation and mechanical ventilation. During the whole of operation, the balanced anesthesia with sevoflurane and fentanyl were adopted for maintenance of anesthesia. Blood were sampled from contralateral radial artery before and 1,2,3,5,10,15,30,60,90,120,180 minutes after drug administration. Propofol concentration in plasma were determined with HPLC technique. All of them were used for analysis and caculation of pharmacokinetic parameters of propofol in the end.[Results] In the first part of this trial, there were no significant differences between any groups as for the induction time, emergency time, orientation recovery time, as well as the minimum EEG-derived entropy values during whole of procedure (P>0.05). In the LCT-1 group, MCT-LCT-1 group and MCT-LCT-2 group, the number of patients as to the occurrence of hypotension were 6,6 and 8 patients, respectively, while the number of patients for occurrence of apnea were 6,3 and 5 patients,respectively. No significant differences could be seen between any groups (P>0.05). In the meanwhile, the VAS scale assessment of pain induced by injection of propofol in MCT-LCT-1 group was significantly lower than that in LCT-1 (2.7±2.1 vs 5.2±2.2, P<0.001), MCT-LCT-2 group, however, was comparable to LCT-1 in terms of propofol injection pain (4.6±2.3 vs 5.2±2.2, P=0.1532). In the second part, either of LCT propofol emulsion or MCT-LCT propofol emulsion at trial demonstrated typical profile of "three-compartment" modal,with t1/2a of 4.1±1.6 min and 5.0±2.9 min, ti/2βof 61.0±20.6 min and 67.6±16.3 min, ti/2y of 623.8±171.7 min and 541.0±203.6 min, CL of 30.7±5.9ml/kg/min and 26.9±7.1ml/kg/min, Vd of 3.01±1.01L/kg and 3.75±1.53L/kg, respectively. No significant differences could be found between two groups in terms of all these paremeters (P>0.05)[Conclusion] Our research suggested that neither modification of lipid component of emulsion nor elevation of concentration of proprofol in emulsion could change the pharmacokinetic profile of propofol, and affect the anesthesia/sedation profile of propofol. However, administration of MCT-LCT propofol could lessen the injection pain compared to traditional LCT propofol, but elevation of concentration of propofol in such emulsion would lead this advantage nonexistant. Moreover, either for new type emulsion or traditional emulstion, bolus injection of propofol at dose of common clinical administration could incur a decrease in arterial blood pressure and life-threatening hypoxemia. All of them deserve our alertness with rigorous monitor of patients guaranteeing their safety during administration of propfol. |
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