Abstract
In the last decades propofol became established as an intravenous agent for the induction and maintenance of both sedation and general anesthesia procedures. In order to achieve the desired clinical effects appropriate infusion rate strategies must be designed. Moreover, it is important to avoid or minimize side effects which may be associated with adverse cardiorespiratory effects and delayed recovery. Nowadays, to attain these purposes the continuous propofol delivery is usually performed through target-controlled infusion (TCI) systems whose algorithms rely on pharmacokinetic and pharmacodynamic models (Schraag, 2001). This work presents statistical models to estimate both the infusion rate and the bolus administration. The modeling strategy relies on multivariate linear models for panel data (Wooldridge, 2002), based on patient characteristics such as age, height, weight and gender along with the desired target concentration. A clinical database collected with a RugLoopII device on 84 patients undergoing ultrasonographic endoscopy under sedation-analgesia with propofol and remifentanil, (Gambús et al., 2011), is used to estimate the models (training set with 74 cases) and assess their performance (test set with 10 cases). The results obtained in the test set comprising a broad range of characteristics are satisfactory since the models are able to predict bolus and infusion rates comparable to those of TCI. © 2012 IFAC.

Abstract
The development of automated individualized drug dosage regimens, namely in general anaesthesia environment, has been a subject of interest in the last decades. The use of continuous intravenous drug administration aims at, accurately, maintaining the system at a desired target effect concentration level. Different methods have been proposed for the design of individualized dosage regimens. In this study individual drug dose design is achieved through the characterization of transient initial response induced by a bolus administration of drug. This approach is based on the statistical analysis of the data using Walsh-Fourier spectral analysis which provides information about patient dynamics, allowing the on-line drug dose design using multiple linear least squares and quantile regression technics. The proposed methodology is illustrated in the case where the effect measured on the patient corresponds to the neuromuscular blockade (NMB) level and the drug to the muscle relaxant atracurium.

Abstract
The BRS can be quantified as the slope between SBP and RR values identified in baroreflex events, estimated by ordinary least squares (OLS) minimization. Quantile regression (QR) is a more robust procedure than OLS and allows a more complete characterization of the data, by estimating conditional functions for different quantiles of interest. In this work, OLS and QR for BRS estimation are compared regarding slope estimates and dispersion. The EuroBaVar results indicate that OLS slope and QR slopes at different quantiles do not exhibit significant differences. Also, OLS and QR slopes require similar number of beats to achieve a given BRS precision in stationary recordings. Finally, BRS estimated with OLS exhibit relative dispersion lower than 10% and 5% when computed from stationary recordings of approximately 3 and 9 minutes length, respectively.

Abstract

Abstract
Heart Period (H) results from the activity of several coexisting control mechanisms, involving Systolic Arterial Pressure (S) and Respiration (R), which operate across multiple time scales encompassing not only short-term dynamics but also long-range correlations. In this work, multiscale representation of Transfer Entropy (TE) and of its decomposition in the network of these three interacting processes is obtained by extending the multivariate approach based on linear parametric VAR models to the Vector AutoRegressive Fractionally Integrated (VARFI) framework for Gaussian processes. This approach allows to dissect the different contributions to cardiac dynamics accounting for the simultaneous presence of short and long term dynamics. The proposed method is first tested on simulations of a benchmark VARFI model and then applied to experimental data consisting of H, S and R time series measured in healthy subjects monitored at rest and during mental and postural stress. The results reveal that the proposed method can highlight the dependence of the information transfer on the balance between short-term and long-range correlations in coupled dynamical systems.

Abstract