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Jose Fernando Valencia

Jose Fernando Valencia
Universidad de San Buenaventura, Cali, Colombia · Department of Electronic Engineering

Ph.D

About

50
Publications
9,419
Reads
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591
Citations
Additional affiliations
February 2013 - present
San Buenaventura University
Position
  • Professor (Full)
January 2013 - present
Universidad de San Buenaventura, Cali, Colombia
Position
  • Professor (Full)
January 2013 - present
Universidad de San Buenaventura, Cali, Colombia
Position
  • Professor (Full)
Education
December 2005 - December 2010
Universitat Politècnica de Catalunya
Field of study
  • Biomedical Engineering
July 1989 - March 1995
Universidad del Valle (Colombia)
Field of study
  • Electrical Engineering

Publications

Publications (50)
Article
Full-text available
Intraoperative targeting of the analgesic effect still lacks an optimal solution. Opioids are currently the main drug used to achieve anti‐nociception, and while underdosing can lead to an increased stress response, overdose can also lead to undesirable side‐effects. To better understand how to achieve the optimal analgesic effect of opioids, we st...
Article
Background: The aim of this observational study was to determine whether bilateral bispectral index (BIS) monitoring can detect seizures in epileptic patients. Methods: Four-channel frontal BIS monitoring and standard 40-channel electroencephalography monitoring were conducted in epileptic patients undergoing evaluation for epilepsy surgery. The...
Article
Poincare plot is a non-linear method which allows analyzing the variability of a signal by plotting the signal against itself after a delay time. Although this method has been used to analyze the electroencephalogram (EEG) in order to assess general anesthesia, its application on light sedation has not been addressed in depth yet. In this work, sev...
Article
Full-text available
It has been suggested that a viable strategy to improve complexity estimation based on the assessment of pattern similarity is to increase the pattern matching rate without enlarging the series length. We tested this hypothesis over short simulations of nonlinear deterministic and linear stochastic dynamics affected by various noise amounts. Severa...
Article
Full-text available
The refined multiscale entropy (RMSE) approach is commonly applied to assess complexity as a function of the time scale. RMSE is normally based on the computation of sample entropy (SampEn) estimating complexity as conditional entropy. However, SampEn is dependent on the length and standard deviation of the data. Recently, fuzzy entropy (FuzEn) has...
Conference Paper
Monitoring the levels of sedation-analgesia may be helpful for managing patient stress on minimally invasive medical procedures. Monitors based on EEG analysis and designed to assess general anesthesia cannot distinguish reliably between a light and deep sedation. In this work, the Poincaré plot is used as a nonlinear technique applied to EEG signa...
Article
The analysis of heart rate variability (HRV) by nonlinear methods has been gaining increasing interest due to their ability to quantify the complexity of cardiovascular regulation. In this study, multiscale entropy (MSE) and refined MSE (RMSE) were applied to track the complexity of HRV as a function of time scale in three pathological conscious an...
Article
The analysis of heart rate variability (HRV) by nonlinear methods has been gaining increasing interest due to their ability to quantify the complexity of cardiovascular regulation. In this study, multiscale entropy (MSE) and refined MSE (RMSE) were applied to track the complexity of HRV as a function of time scale in three pathological conscious an...
Article
Full-text available
The level of sedation in patients undergoing medical procedures is decided to assure unconsciousness and prevent pain. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additional information about the state of the patient. However, the...
Article
Background: Respiratory depression is a common adverse effect of propofol and remifentanil. We aimed to develop a model for respiratory depressant effects of propofol with remifentanil in patients undergoing endoscopy with sedation. Methods: Data were available for 136 patients undergoing endoscopy with sedation. Participants randomly received i...
Article
Full-text available
The level of sedation in patients undergoing medical procedures evolves continuously, affected by the interaction between the effect of the anesthetic and analgesic agents and the pain stimuli. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to...
Article
The purpose of this study was to identify optimal target propofol and remifentanil concentrations to avoid a gag reflex in response to insertion of an upper gastrointestinal endoscope. Patients presenting for endoscopy received target-controlled infusions (TCI) of both propofol and remifentanil for sedation-analgesia. Patients were randomized to 4...
Article
Full-text available
Myocardial ischaemia is hypothesized to stimulate the cardiac sympathetic excitatory afferents and, therefore, the spontaneous changes of heart period (approximated as the RR interval), and the QT interval in ischaemic dilated cardiomyopathy (IDC) patients might reflect this sympathetic activation. Symbolic analysis is a nonlinear and powerful tool...
Article
The aim of the present study was to investigate the suitability of the Phase-Rectified Signal Averaging (PRSA) method for improved risk prediction in cardiac patients. Moreover, this technique, which separately evaluates acceleration and deceleration processes of cardiac rhythm, allows the effect of sympathetic and vagal modulations of beat-to-beat...
Poster
qNOX is a measure of peroperative nociception. However it responds to hypnotic effects evoked by propofol. This poster presents an adaptation of the qNOX algorithm to decrease the influence of propofol on qNOX
Article
La segmentación del iris es una de las etapas más importantes en los sistemas de reconocimiento del iris. En este trabajo se aplican algoritmos de preprocesamiento de la imagen con el objetivo de evaluar su impacto en los porcentajes de segmentación exitosa del iris. Los algoritmos utilizados se basan en el ajuste del histograma, filtros Gaussianos...
Article
The level of sedation in patients undergoing medical procedures is affected by the interaction between the effect of the anesthetic and analgesic agents and the pain stimuli. The presence of the A118G single nucleotide polymorphism (SNP) in the OPRM1 gene affects the requirements of opioids for patients undergoing sedation-analgesia. The purpose of...
Article
Background: The objective of the present study was to validate the qCON index of hypnotic effect and the qNOX index of nociception. Both indices are derived from the frontal electroencephalogram (EEG) and implemented in the qCON 2000 monitor (Quantium Medical, Barcelona, Spain). Methods: The study was approved by the local ethics committee, incl...
Article
Segmentation is one of the most important stages in iris recognition systems. In this paper, image preprocessing algorithms are applied in order to evaluate their impact on successful iris segmentation. The preprocessing algorithms are based on histogram adjustment, Gaussian filters and suppression of specular reflections in human eye images. The s...
Conference Paper
The level of sedation in patients undergoing medical procedures evolves continuously since the effect of the anesthetic and analgesic agents is counteracted by noxious stimuli. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additiona...
Article
Full-text available
The study assesses complexity of the cardiac control directed to the sinus node and to ventricles in long QT syndrome type 1 (LQT1) patients with KCNQ1-A341V mutation. Complexity was assessed via refined multiscale entropy (RMSE) computed over the beat-to-beat variability series of heart period (HP) and QT interval. HP and QT interval were approxim...
Article
The level of sedation in patients undergoing medical procedures evolves continuously, such as the effect of the anesthetic and analgesic agents is counteracted by pain stimuli. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additiona...
Article
The level of sedation in patients undergoing medical procedures evolves continuously, such as the effect of the anesthetic and analgesic agents is counteracted by pain stimuli. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additiona...
Article
This study assesses complexity of cardiovascular control in patients affected by type-1 variant of long QT (LQT1) syndrome. Complexity was assessed by refined multiscale entropy of heart period (HP) and QT interval variabilities. HP was taken as the time distance between two consecutive R peaks (RR) and QT interval was approximated as the time dist...
Article
Background: The presence of the A118G single nucleotide polymorphism in the OPRM1 gene as well as noxious stimulation might affect the requirements of remifentanil for patients undergoing ultrasonographic endoscopy under sedation-analgesia with propofol and remifentanil. Bispectral index (BIS) was used as a surrogate measure of effect. Method: A...
Article
Full-text available
In this work, a univariate and multivariate statistical analysis of indexes derived from heart rate variability (HRV) was conducted to stratify patients with ischemic dilated cardiomyopathy (IDC) in cardiac risk groups. Indexes conditional entropy, refined multiscale entropy (RMSE), detrended fluctuation analysis, time and frequency analysis, were...
Article
Full-text available
The increasing demand for anesthetic procedures in the gastrointestinal endoscopy area has not been followed by a similar increase in the methods to provide and control sedation and analgesia for these patients. In this study, we evaluated different combinations of propofol and remifentanil, administered through a target-controlled infusion system,...
Conference Paper
Full-text available
In this work, Refined Multiscale Entropy (RMSE) was applied to characterize risk of cardiac death in ischemic cardiomyopathy patients, analyzing heart rate variability (HRV) by means of RR series during daytime and nighttime. RMSE approach measures an entropy rate in different time scales of a series, giving a multiscale characterization of complex...
Article
Full-text available
This work has proposed a methodology based on the concept of entropy rates to study the complexity of the short-term heart-rate variability (HRV) for improving risk stratification to predict sudden cardiac death (SCD) of patients with established ischemic-dilated cardiomyopathy (IDC). The short-term HRV was analyzed during daytime and nighttime by...
Conference Paper
Full-text available
Detrended fluctuation analysis (DFA) has been shown to be a useful tool for diagnosis of patients with cardiac diseases. The scaling exponents obtained with DFA are an indicator of power-law correlations in signal fluctuation, independently of signal amplitude and external trends. In this work, an approach based on DFA was proposed for analyzing he...
Article
Full-text available
Multiscale entropy (MSE) was proposed to characterize complexity as a function of the time-scale factor tau. Despite its broad use, this technique suffers from two limitations: (1) the artificial MSE reduction due to the coarse graining procedure and (2) the introduction of spurious MSE oscillations due to the suboptimal procedure for the eliminati...
Article
In the present document the multiscale entropy (MSE) methodology has been applied to analyze the complex behavior of the heart rate variability (HRV), in patients with aortic stenosis (AS). A set of healthy voluntaries have been used as a control group. MSE analysis calculates an entropy rate over different time scales to assess the complexity of t...
Conference Paper
Full-text available
The purpose of this study was to provide a methodology in order to characterize autonomous nervous system (ANS) changes before, during and after percutaneous transluminal coronary angioplasty (PTCA). This methodology, based on a multiscale information analysis (MIA) of the heart rate variability, has taken into account entropy rates. The study grou...
Article
Full-text available
Subjects with ischemic dilated cardiomiopathy tend to suffer episodes of sudden cardiac death, thus risk stratification is essential to establish an adequate therapy for the patients. In this work, a new methodology was proposed for the study of the heart rate variability by using a multiscale analysis based on the concept of entropy rates, for imp...
Article
Full-text available
El presente artículo es una propuesta metodológica de trabajo en el laboratorio para la formación de ingenieros electrónicos. En él se plantea la importancia de potenciar las habilidades prácticas y la creatividad de los estudiantes de ingeniería a través dinámicos e interactivos trabajos de laboratorio, que privilegien el razonamiento y el análisi...

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