Building and Application of Cardiopulmonary Bypass Model in Rats

To build a cardiopulmonary bypass model in rats, and research the feasibility. Method Cardiopulmonary bypass was built in 10 adult male SD rats of clean grade through intubation in jugular vein, caudal artery, and femoral artery, and bypass was sustained for 60 min at the flow rate of 100ml/(kg•min) to monitor heart rate, blood pressure, blood gas, and electrolyte. Result Puncture succeeded in all the 20 rats, and cardiopulmonary bypass was finished under given conditions. Conclusion The model has the following advantages, economical efficiency, simplicity, minimal invasion, cardiopulmonary bypass parameter setting similar to that of clinical trail, high rate of success. Thus, it is reliable for researching pathological and physiological changes after cardiopulmonary bypass and evaluating therapeutic strategy

Pharmacodynamic response modelling of arterial blood pressure in adult volunteers during propofol anaesthesia

International audienceBackground: Concentration effect relationships are commonly described with a direct response model as for example the sigmoid Emax model with one effect compartment as site of action. In this study we investigated whether models with more than one effect site, or indirect response, or counter-regulatory response models may be more appropriate for modelling the propofol effect on arterial blood pressure.Methods: Nine young healthy volunteers received propofol as target controlled infusion with predefined increasing and decreasing plasma target concentrations. Propofol concentrations were determined from arterial blood samples. Arterial blood pressure was measured invasively at radial artery site. Pharmacokinetic/-pharmacodynamic modelling was performed by population analysis with MONOLIX, testing different direct, indirect and counter-regulatory response models.Results: Propofol plasma concentrations were well described by a three-compartment model. The propofol effect on arterial blood pressure was best described by a direct sigmoid Emax model with two effect site compartments.Conclusions: Two effect sites were needed to describe the propofol effect on arterial blood pressure. This may reflect different pathways of arterial blood pressure response to propofol

Monitoring the Depth of Anaesthesia

One of the current challenges in medicine is monitoring the patients’ depth of general anaesthesia (DGA). Accurate assessment of the depth of anaesthesia contributes to tailoring drug administration to the individual patient, thus preventing awareness or excessive anaesthetic depth and improving patients’ outcomes. In the past decade, there has been a significant increase in the number of studies on the development, comparison and validation of commercial devices that estimate the DGA by analyzing electrical activity of the brain (i.e., evoked potentials or brain waves). In this paper we review the most frequently used sensors and mathematical methods for monitoring the DGA, their validation in clinical practice and discuss the central question of whether these approaches can, compared to other conventional methods, reduce the risk of patient awareness during surgical procedures

Influence of intensive care treatment on the protein binding of sufentanil and hydromorphone during pain therapy in postoperative cardiac surgery patients

Background: Our objective was to evaluate the effect of intensive care treatment on the protein binding of sufentanil and hydromorphone in cardiac surgery patients during postoperative analgesia using a target-controlled infusion (TCI) and patient-controlled analgesia (PCA). Methods: Fifty adult patients were enrolled in this prospective randomized study; of which, 49 completed the study (age range 40–81 yr). Sufentanil was administered as an analgesic intraoperatively, and hydromorphone was dosed after operation with TCI and PCA until 8 a.m. on the first postoperative day. Arterial plasma samples were collected for drug and protein concentration measurements up to 24 h after cardiac surgery. Corresponding patient data were collected from the electronic patient data system. After explorative data analysis with principal component analysis, multivariate regression analysis and non-linear mixed effects modelling was used to study the effect of treatment on protein binding. Results: Data of 35 patients were analysed. The median protein binding of sufentanil and hydromorphone was 88.4% (IQ range 85.7–90.5%) and 11.6% (IQ range 9.5–14.3%), respectively. Free fraction of sufentanil increased towards the end of the study period, whereas hydromorphone free fraction remained nearly constant. The total sufentanil concentration and volume balance were identified as significant covariates for the protein binding of sufentanil. For the protein binding of hydromorphone, no significant covariate effects were found. Conclusions: Sufentanil protein binding was significantly dependent on changes in the total drug concentration and volume balance addressing the importance of adequate dosing and fluid-guided therapy. Hydromorphone protein binding was nearly constant throughout the study period. Clinical trial registration: EudraCT 2011-003648-31 and ClinicalTrials.gov: NCT01490268