The uterine electrohysterogram (EHG) has been recorded on the abdomen of pregnant women, from 19 to 37 weeks of gestation (WG), and processed in order to defect preterm delivery. The EHG being corrupted by different electromagnetic noises, we have developed specific algorithms, based on wavelet decomposition, for the denoising of the EHG. Classical parameters, extracted from the spectral and temporal representations and from the instantaneous frequency of the EHG, have permitted us to follow the evolution of the evolution of the signals during pregnancy. Furthermore, a discriminant analysis permitted us to evidence a difference between contractions leading to term or preterm deliveries, as soon as 30 WG. Non-stationary parameters have then been computed from EHG signals, in order to follow the two electrical waves that are known on animal recordings to be related to contraction efficiency. The extraction and characterization of these waves are made by extracting the ridges of the scalogram, computed from the continuous wavelet transform. The instrumental part development has started with the analysis of maternal movement artifacts and with the comparison of different kinds of electrodes, suitable for 24 hours recording. A first portable recorder prototype is presently under development.
To evaluate the thermal performance of a radiant warmer with a heated mattress, a thermal manikin which represents the complex geometrical forms of a newborn has been designed. Each segment can act independently from the others to simulate regional skin temperature heterogeneity. The radiation intensity received by the manikin depends on the distance between the heater module and the mattress. In horizontal position the manikin received more radiation intensity to keep constant the set-point temperature of the different segments. In inclined position the lower limbs received less heat than the other segments. The radiant heat power was reduced by 4.7 to 7.6% when the temperature surface of the mattress was set over 33°C. This small reduction represents the conductive heat exchange between the manikin and the mattress. In conclusion, the regional skin temperatures of a newborn are strongly influenced by the mattress position as regards to the radiant heat source. In inclining position, the lower limbs received less heat than the remaining body segments. A heated mattress seems to be of low efficiency to rewarm newborn nursed under radiant warmer.
CT-guided biopsies are widely accepted. This technique improves with the use of fluoro-CT. We report our experience in the use of this technology in two different series: pulmonary nodules and abdominal nodes. Fluoro-CT allows faster and safer biopsies with fewer complications. This technique helps to aspirate smaller targets. Patient radiation is equivalent in both techniques; operator radiation is higher, and it is mandatory to use the usual protection systems, including a tool to manipulate the biopsy needle.
Anesthetical properties of isoflurane such modulating effect, arteriolar vasodilatation or potential protective cerebral effect enhance this use during ECC. Nevertheless isoflurane induced failure oxygenators have been reported (plastic cracks of the top of oxygenator accidently exposed to liquid form) when administered via vaporizer into the oxygen line. Components of hollow fiber oxygenator are directly exposed to vaporized form when isoflurane is administered through it. Thus the aim of this study was to search potential physicochemical modification of exposed components. Design of the study. For materials potentially exposed to isoflurane (polycarbonate plastic, polyurethane and silicone joints, polypropylene fibers) were analysed with vapour phase chromatography, optical and electronic microscopy. Materials were sampled on the same model of oxygenator used in various conditions with and without isoflurane. Results and discussion. After exposition to vaporized form, material chromatographic examinations showed that isoflurane was adsorbed on all material, but did not react with it. Any other compound than isoflurane was obviously observed in the liquid phase. Microscopic optical examination showed longitudinal striae on polypropylene fibers of oxygenators used with and without isoflurane. Electronic microscopical examination of the polypropylene fibers surface did not evidence any significative structural defect.
In order to study physical adaptation of children with insulin dependent diabete mellitus (DID), two kinds of test were proposed: an isometric test as a force maintain (50% of voluntary maximal force) in leg extension and an linear incremental test on ergocycle (from 20% to 100% of the maximal aerobic power during 8 min). For each test, electromyographic signal (EMG) of quadriceps muscle was characterised in the spectral domain by calculating total energy (ET) and mean power frequency (FM). During incremental test, cardio-respiratory, CO production) and metabolic variables (glycemia, lactatemia, and kaliemia) were measured. According to a healthy children group (SNS), DID showed in isometric condition a fatigability more important. In dynamic condition, changes in cardio-respiratory variables were similar while metabolic variables were differently modified. Changes in ET and FM were illustrated by specific profiles for children with respect to adolescent children (quasi-linear increase for ET, relative stability for FM). Using a discriminant analysis, SNS and DID children may be differenced. Thus, EMG signal reflects metabolic changes during incremental test and may be used to characterized DID physical aptitude.
A specific ergometer was conceived in order to analyse the mechanical properties of the musculo-articular system in prepubertal children. The ergometer consists in two main modulus, a 'table modulus' and a 'motor modulus' which are presented in this paper as well as the different functionalities of the ergometric apparatus: isometric testing, iso-kinetic testing, quick-release testing and sinusoidal perturbation testing. These different tests represent a good tool to characterise the elastic properties of the musculo-tendinous and of the musculo-articular units. Preliminary results were obtained from 8 children in order to validate the functionalities of the ergometer. These results confirm that children develop lower maximal ankle plantar flexion torques than adult subjects. They also indicate a lower musculo-tendinous and musculo-articular stiffness of the ankle. This has to be confirmed on a large number of children. The ergometer, now located in the department of muscular readaptation of an hospital center, will be also used to quantify motor deficit and to follow the effects of a period of muscle reinforcement.
The prevention of infant death is a constant preoccupation of the pediatric team. Many abnormal events are due to neurovegetative imbalance. The aim of the article is to present different clinical studies concerning the relation between clinical events and the sympathetic-parasympathetic imbalance and the differents tests used to check this neurovegetative system.
The three-dimensional reconstruction of the heart provides complementary informations to cardiac malformations diagnostic aids. The magnetic resonance imaging is a non-invasive and painless exploration that acquires parallel and slightly separate slices with high resolution. A cardiac protocol exploration is adapted for 3D cardiac reconstruction based in a double scan of the heart from the apex to the base and inversely. The images are analyzed according to an optimized extraction of the edges for an accurate reprinting of the cardiac cavities. The segmented images are pile up according to the acquire ordure, to the image dimension and the slice gap and thickness for a three dimensional extrapolation based on a linear interpolation of the pixels in the adjacent slices. This points are posted in a direct-graph called Voronoi's graph in the goal to execute a Delauny's triangulation process that fix together the slice vertex with two of the adjacent slice. An algorithm selects the paths in the graph that join the extremities and an optimized processing based on the tuile area minimization designates the best choice. The procedure set is implemented in a Silicon Graphics workstation to organize a multifunctional platform that fated to acquire, visualize and segment all analog and digital images format.
Evaporative water losses are very important during the first weeks after birth in premature newborns. Humidity levels recommended in the literature are located between 65 and 90% of relative humidity. In most of the commercialised incubators, humidity is regulated in relative humidity although the evaporative water losses are inversely proportional to the gradient of water vapour partial pressure between the skin and the environment. In our study, in order to precise physiological effects of humidity, we have used an active humidification system, controlling the water vapour partial pressure. By using our servocontrolled skin derivative heating device, the incubator air temperature level is specific to neonate's thermal needs allowing to maintain body temperature constant independently of humidity level. With this system we have tested the effects of humidity level on sleep, heart rate and respiratory frequency in 9 neonates without inducing modifications of their thermal balance. A high humidity level of 4000 Pa (80% at 32°C) did not induce any disruption of sleep or cardiac and respiratory frequencies if thermal equilibrium of the neonate is maintained. This is observed when an increase of the humidity level is accompanied by a decrease of incubator air temperature of 0.35°C-kPa .
The knowledge of the neonate's sound environment in incubators has the aim to better define the ways to protect neonates of noise effects and to improve their acoustic comfort. The present study, realized in 9 hospitals, constitutes a sound database of 216 hours of recording inside and outside of neonate's compartments, allowing valid statistical analysis and characterisation. The statistical index analysis of sound data shows that continuous noises are generally higher inside of incubators (50 ± 3 dBA) than outside (42 ± 8 dBA). Their origins are mainly the incubator itself and the external medical devices sometimes used. On the contrary, impulsive noises are far more frequent and intense outside of the incubator than inside. Most of these noises come from the hospital activity for 88% of the time and are essentially produced by medical staff and nurses. Furthermore, 25 incubators without neonate are evaluated with respect to the NF EN 60601- 2-19 standard. Among these incubators, one is out of standard for the internal level, an other is also out of standard for the internal alarm sound, while all tested incubators are out of standard for alarm sound perceived outside. The protection of neonates and the improvement of their acoustic comfort can be achieved by instrumental, human and architectural proposals.
Isoflurane, sevoflurane and desflurane during cardiopulmonary bypass are not used routinely in France. Two factors affect the solubility of inhaled anesthetics in blood during CPB; lower temperature and haemodilution. Monitoring of washin and washout is necessary to control administration and elimination of volatile anesthetics. Operatory ventilation and scavenger evacuation rate could be use to prevent toxicity of gas leakage. Narcosis and vasodilatation are good indications to perform on inhaled anesthetics during CPB.
The limits and constraints of using current antithrombotic treatments have led researchers to settle on and experiment with new molecules raising the antithrombotic efficacy without increasing the risks of hemorrhage. Among these new molecules, several seem to fit the objectives, and are classed in different families according to their mode of action: thrombin inhibitors (direct or indirect), Xa inhibitors (direct or indirect), and physiological coagulation inhibitors. Some of these new molecules already have a clinical application in the context of continuous hemofiltration and cardiopulmonary bypass.