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Target-controlled infusion (TCI) anesthesia using target effect-site concentration rather than plasma concentration provides less drug consumption, safer anesthesia, less undesired side effects and improved animal welfare. The aim of this study was to calculate the constant that converts propofol plasma into effect-site concentration ( ke0) in dogs, and to implement it in a TCI system and compare it with the effect on the central nervous system (CNS). All dogs were subjected to general anesthesia using propofol. Fourteen dogs were used as the pilot group to calculate ke0, using the tpeak method. Fourteen dogs were used as the test group to test and validate the model. Rugloop ii® software was used to drive the propofol syringe pump and to collect data from S/5 Datex monitor and cerebral state monitor. The calculated ke0 was incorporated in an existing pharmacokinetic model (Beths Model). The relationship between propofol effect site concentrations and anesthetic planes, and propofol plasma and effect-site concentrations was compared using Pearson’s correlation analysis. Average tpeak was 3.1 min resulting in a ke0 of 0.7230 min−1. The test group showed a positive correlation between anesthetic planes and propofol effect-site concentration ( R = 0.69; P < 0.0001). This study proposes a ke0 for propofol with results that demonstrated a good adequacy for the pharmacokinetic model and the measured effect. The use of this ke0 will allow an easier propofol titration according to the anesthetic depth, which may lead to a reduction in propofol consumption and less undesired side effects usually associated to high propofol concentrations in dogs. [ABSTRACT FROM AUTHOR]

A factorial experiment was designed to test under different feeding levels the effects of the surgical deprivation of sensory afferences (deafferentation) arising from the gastrointestinal tract, including the intestinal chemosensitivity, on the jejunectomised pig used as a model. Within 28 days, the limited jejunectomy failed to affect the pancreas and the enzyme activities were not affected by the feeding level (within the limit of 70% of ad libitum). It was shown that the deafferentation induced significant reductions in the pancreatic tissue mass and in the various enzyme activities, thus suggesting the possible importance of intestinal sensibility for the pancreas. [ABSTRACT FROM PUBLISHER]

Hypnotic drug administration causes alterations in the electroencephalogram (EEG) in a dose-dependent manner. These changes cannot be identified easily in the raw EEG, therefore EEG based indices were adopted for assessing depth of anaesthesia (DoA). This study examines several indices for estimat-ing dogs' DoA. Data (EEG, clinical end-points) were collected from 8 dogs anaesthetized with propofol. EEG was initially collected without propofol. Then, 100 ml h-1 (1000 mg h-1) of propofol 1% infusion rate was administered until a deep anaesthetic stage was reached. The infusion rate was temporarily in-creased to 200 ml h-1 (2000 mg h-1) to achieve 80% of burst suppression. The index performance was accessed by correlation coefficient with the propofol concentrations, and prediction probability with the anaesthetic clinical end-points. The temporal entropy and the averaged instantaneous frequency were the best indices because they exhibit: (a) strong correlations with propofol concentrations, (b) high probabilities of predicting anaesthesia clinical end-points. [ABSTRACT FROM AUTHOR]

The well-known Cerebral State Index (CSI) quantities depth of anesthesia and is traditionally modeled with Hill equation and propofol effect-site concentration (Ce). This work brings out two novelties: introduction of electromyogram (EMG) and use of fuzzy logic models with ANFIS optimized parameters. The data were collected from dogs (n = 27) during routine surgery considering two propofol administration protocols: constant infusion (G1, n = 14) and bolus (G2, n = 13). The median modeling error of the fuzzy logic model with Ce and EMG was lower or similar than that of the Hill with Ce (p = 0.012-G1, p = 0.522-G2). Furthermore, there was no significant performance impact due to model structure alter- ation (p = 0.288-G1, p = 0.330-G2) and EMG introduction increased or maintained the performance (p = 0.036-G1, p = 0.798-G2). Therefore, the new model can achieve higher performance than Hill model, mostly due to EMG information and not due to changes in the model structure. In conclusion, the fuzzy models adequately describe CSI data with advantages over traditional Hill models. [ABSTRACT FROM AUTHOR]