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C Hervás

Publications and source records attributed to C Hervás.

16 recordsLinked to original sources
PubMed2002

[The creation of the first anesthesiology service in Spain (Hospital de la Santa Cruz y San Pablo, Barcelona 1941)].

On the sixtieth anniversary of the founding of the first Spanish anesthesia department, we review factors that led to its creation and its early development. Hospital de la Santa Cruz y San Pablo in Barcelona was the place where the service was established for several reasons. The first was the growing need for anesthesia to be administered by specialized physicians able to handle problems developing during and after surgery. The second was the presence of a prestigious surgeon, Dr. Juan Soler Juliá, who perceived the need, alongside the only physician in Spain who was completely dedicated to anesthesiology, Dr. José Miguel Martínez. Finally, the fact that professional anesthesiology allowed a physician to earn a decent income triggered interest in the specialty among physicians.

Anesthesia Department, Hospital↗
PubMed2000

[Centenary of spinal anesthesia in Spain: first steps (1899-1904)].

With the aim of commemorating the centennial of the first spinal anesthesia in Spain, we review the process followed during the early phase of application of the technique, the period associated with spinal injection of cocaine, which was the only anesthetic agent used. We describe the first trials, the influence of the Paris Congress of 1900 in spreading interest in the technique, the varied degree of acceptance by Spanish authors, and the gradual uneasiness with the procedure that arose as a result of accidents. A look at reports by Pi Sunyer and Raventós concerning possible toxic effects on the central nervous system close this overview of the earliest times of spinal anesthesia in Spain.

Anesthesia, Spinal↗
PubMed1997

[On the 150th anniversary of the introduction of anesthesia in Spain: the role of dentists].

We first discuss the circumstances that were influential in the role played by dentists during the early stages of anesthesia. We then study the positions of several Spanish dentists on the new technique for eliminating pain. Two opposing groups are found: on the one hand physician-dentists were cautions and prudent, and on the other, professionals with lesser qualifications such as surgeon-dentists, healers and bloodletters were clearly and boldly in favor of the new technique.

Anesthesia↗
PubMed1995

Multicomponent kinetic determinations using artificial neural networks.

Neural networks were successfully used for multicomponent kinetic determinations of species with rate constant ratios approaching unity without the aid of spectral discrimination. The ensuing method relies on two inputs describing the profile of the kinetic curve for each mixture, which is obtained by preprocessing kinetic data using nonlinear least-squares regression. A straightforward network architecture (2:4s:21) was used to resolve mixtures of 2- and 3-chlorophenol; the trained network estimated the concentrations of both components in the mixture with a relative standard error of prediction of approximately 5%, which is much lower than that obtained with Kalman filtering. The effect of some variables such as the rate constant and analyte concentration ratios on the proposed multicomponent determination is discussed.

Chlorophenols↗
PubMedDate not supplied

Use of pruned computational neural networks for processing the response of oscillating chemical reactions with a view to analyzing nonlinear multicomponent mixtures.

The suitability of pruned computational neural networks (CNNs) for resolving nonlinear multicomponent systems involving synergistic effects by use of oscillating chemical reaction-based methods implemented using the analyte pulse perturbation technique is demonstrated. The CNN input data used for this purpose are estimates provided by the Levenberg-Marquardt method in the form of a three-parameter Gaussian curve associated with the singular profile obtained when the oscillating system is perturbed by an analyte mixture. The performance of the proposed method was assessed by applying it to the resolution of mixtures of pyrogallol and gallic acid based on their perturbating effect on a classical oscillating chemical system, viz. the Belousov-Zhabotinskyi reaction. A straightforward network topology (3:3:2, with 18 connections after pruning) allowed the resolution of mixtures of the two analytes in concentration ratios from 1:7 to 6:2 with a standard error of prediction for the testing set of 4.01 and 8.98% for pyrogallol and gallic acid, respectively. The reduced dimensions of the selected CNN architecture allowed a mathematical transformation of the input vector into the output one that can be easily implemented via software. Finally, the suitability of response surface analysis as an alternative to CNNs was also tested. The results were poor (relative errors were high), which confirms that properly selected pruned CNNs are effective tools for solving the analytical problem addressed in this work.

Journal Article↗
PubMedDate not supplied

Correction of temperature variations in kinetic-based determinations by use of pruning computational neural networks in conjunction with genetic algorithms.

The joint use of genetic algorithms and pruning computational neural networks is shown to be an effective means for selecting the number of inputs required to correct temperature variations in kinetic-based determinations. The genetic algorithm uses a pruning procedure based on Bayesian regularization and is highly efficient as a feature selector; it provides quite good results in the generalization process without the need to use a validation set. The fitness function is defined as the sum of two subfunctions: one controls the learning ability of the network and the other its complexity. The training, pruning, and generalization processes were initially tested with simulated data in order to acquire preliminary information for the ensuing work with real data. The performance of the proposed method was assessed by applying it to the determination of the amino acid L-glycine by its classical spectrophotometric reaction with ninhydrin. A straightforward network topology including temperature as input (40+T:2:1 with 19 connections after the pruning process) was used to estimate the L-glycine concentration from kinetic curves affected by temperature variations over the range 60-75 degrees C, using kinetic data acquired up to only 1.5 half-lives. The trained network estimates this concentration with a standard error of prediction for the testing set of ca. 8%, which is much smaller than those provided by a classical parametric method such as nonlinear regression (even if kinetic data acquired at longer half-lives are used). Finally, a kinetic interpretation of the pruning process is provided in order to better demonstrate its potential for kinetic analysis.

Algorithms↗
PubMedDate not supplied

[Approach to the scientific work of Jaume Raventós (1905-1982)].

We analyze the scientific work done by Jaume Raventós (1905-1982) preceded by a brief biographic profile. The work of this Catalonian investigator has been separated into two stages: The first one, called the Barcelona period, is the training phase and comprises three moments: during the first one (1925-1927) the scientific participation of Raventós is still marginal; during the second period (1928-1933) he began to collaborate in large projects with A. Pi Sunyer and F. Doménech Alsina; and during the third period (1932-1934) he developed its own experimental line that culminated with his Doctoral Thesis. The second stage, called the British period, includes all work done during his exile at the United Kingdom. This phase can also be divided into three periods: the first one (1936-1939) took place in Edinburgh and was characterized by a continuation of the scientific line initiated in Barcelona; the second period developed in Manchester (1939-1954) and includes the studies with intravenous barbiturates; the third period (1956-1965) encompasses the last years of Raventós investigative activity which was devoted to the study of fluothane a new volatile anesthetic agent.

Anesthesiology↗
PubMedDate not supplied

[Changes in blood calcium during liver transplant in children].

We have evaluated the changes in plasma total and ionic calcium levels in twenty hepatic transplantations in pediatric patients. Direct intraoperative monitoring of ionic calcium is fundamental, because its variability is unrelated with total calcium levels; in addition, normal ionic calcium levels contribute to the hemodynamic stability of the patient. Although at the end of the operation total and ionic calcium levels were similar to the postinduction measurement, their values were dissociated in the perianhepatic period. In the anhepatic phase ionic calcium reached its lowest value (1.00 mmol/l) although total calcium increased above postinduction level from 2.13 to 2.46 mmol/l (p less than 0.05). In hepatic transplantation in pediatric patients calcium administration is indicated during the transfusion of citrated blood, being particularly necessary during the anhepatic phase to prevent ionic hypocalcemia.

Adolescent↗
PubMedDate not supplied

[Scientific communication in Spanish anesthesiology: medical congresses (1864-1936)].

This historical-medical study proposed to determine the evolution of knowledge in Spanish anesthesiology by examining conferences and presentations at medical congresses on record for the period between the first Spanish medical congress (1864) and the start of the Spanish Civil War (1936). We have found reports of 34 scientific meetings held during this period. All but two included news on anesthesiology or related matters. Ten were international meetings, while 25 were nation-wide conferences. We have been able to arrive at a good understanding of Spanish anesthesiology's evolution as a scientific discipline during this period.

Anesthesiology↗
PubMedDate not supplied

[A Spanish modification of the caudal block: S. Gil Vernet's exradural anesthesia (1917)].

This paper describes a technique for caudal epidural anesthesia proposed by S. Gil Vernet in order to achieve a high enough level of anesthesia for use in prostate surgery. The method, proposed in 1917, modified earlier work. The acceptance of the technique among other urological surgeons in Barcelona at the time is also analyzed.

Anesthesia, Caudal↗
PubMedDate not supplied

[More on amylene].

Explore the source record for details and available documents.

Anesthetics↗