[Show abstract][Hide abstract] ABSTRACT: Sepsis is involved in the decrease of membrane excitability of skeletal muscle, leading to polyneuromyopathy. This effect is mediated by alterations of the properties of voltage-gated sodium channels (Na(V)), but the exact mechanism is still unknown. The aim of the present study was to check whether tumor necrosis factor (TNF-α), a cytokine released during sepsis, exerts a rapid effect on Na(V). Sodium current (I(Na)) was recorded by macropatch clamp in skeletal muscle fibers isolated from rat peroneus longus muscle, in control conditions and after TNF-α addition. Analyses of dose-effect and time-effect relationships were carried out. Effect of chelerythrine, a PKC inhibitor, was also studied to determine the way of action of TNF-α. TNF-α induced a reversible dose- and time-dependent inhibition of I(Na). A maximum inhibition of 75% of the control current was observed. A shift toward more negative potentials of activation and inactivation curves of I(Na) was also noticed. These effects were prevented by chelerythrine pretreatment. TNF-α is a cytokine released in the early stages of sepsis. Besides a possible transcriptional role, i.e., modification of the channel type and/or number, we demonstrated the existence of a rapid, posttranscriptional inhibition of Na(V) by TNF-α. The downregulation of the sodium current could be mediated by a PKC-induced phosphorylation of the sodium channel, thus leading to a significant decrease in muscle excitability.
[Show abstract][Hide abstract] ABSTRACT: Our aim was to investigate the effect of TNFα on muscle resting potential (RP) and then in muscle excitability and to demonstrate another mechanism implicated in intensive care units (ICU) acquired polyneuromyopathy.
Experiments were carried out on adult female Wistar rats. After isolation of muscle fibres from peroneus longus, influence of TNFα was tested on RP by using intracellular microelectrodes. Digoxin and chelerythrin were used to determine the mechanism of TNFα action.
First, we found that TNFα induced a concentration dependent increase of muscle RP and that this mechanism, which was blocked by digoxin, was due to an effect on the Na/K ATPase. As it was also blocked by chelerythrin it was concluded that this effect was mediated by PKC activation of the Na/K ATPase.
We demonstrated that TNFα leads to a PKC mediated increase in muscle RP. Depolarization needed to reach the threshold voltage for muscle action potential should then be higher and this could be involved in the decrease in muscle excitability observed in acquired polyneuromyopathy.
[Show abstract][Hide abstract] ABSTRACT: We report the case of a healthy 21-year-old woman who performed iterative breath-hold dives in relatively cold water, not exceeding depths of 5 meters but with "empty lungs." At the end of a dive, after experiencing an intense involuntary diaphragmatic contraction underwater, she presented hemoptysis followed by chest pain and cough. Chest radiography and computed tomography were performed 24 hours later, confirming the diagnosis of pneumomediastinum. The clinical course was benign: However, chest pain and effort dyspnea lasted for a few weeks. The pathophysiology of this accident may be explained by a combination of mechanisms involved in several clinical entities, namely pulmonary edema of immersion, pulmonary barotrauma and spontaneous pneumomediastinum.
No preview · Article · May 2011 · Undersea & hyperbaric medicine: journal of the Undersea and Hyperbaric Medical Society, Inc
[Show abstract][Hide abstract] ABSTRACT: Acute kidney injury (AKI) is defined as an abrupt and sustained decrease in kidneyfunction. There are a lot of definitions in the literature, which explain the large variationsin the reported incidence. It is well recognized for its impact on the outcome of patients,as it increases morbidity and mortality. Diagnosis of AKI is always difficult, particularlyin the early stage of the disease. Numerous definitions and parameters have been used butthe gold standard in clinical practice remains the creatinine clearance. Recently, in orderto develop early biomarkers, cystatin C (CysC) was proposed. CysC is a proteaseinhibitor produced in a constant manner by nucleated cells. This molecule is passivelyfiltrated by the glomerule and quite completely catabolized in the proximal tubules. It hasthe advantage of not being influenced by age, sex, race or muscular mass. Its excretionincreases after reversible and mild dysfunction and may not necessarily be associatedwith persistent or irreversible damage. However, it is primilarly a sensitive marker ofreduction in glomerular filtration rate but it cannot differentiate between different typesof AKI. Some studies demonstrated the superiority of CysC over plasma creatinine whileother studies did not, depending on the population. On the other hand, urinary CysCseems superior to conventional and new plasma markers, but its main disadvantage is itsinstability in the urine samples. In conclusion, we can use CysC like an additionalargument of renal failure but it does not seem to be superior to plasma creatinine in theearly diagnosis of AKI in all situations.
[Show abstract][Hide abstract] ABSTRACT: Objective
To compare the PaCO2 with the ETCO2 obtained with the Smart Capnoline™ in the postoperative setting of cardiac surgery during ventilation and after extubation
No preview · Article · Jan 2011 · Annales Françaises d Anesthésie et de Réanimation
[Show abstract][Hide abstract] ABSTRACT: Objective
To test a high-frequency jet ventilator, the Monsoon™ (Acutronic laboratory) on a lung model with regard to delivered tidal volume and tracheal pressure measured through the injector.
No preview · Article · Nov 2010 · Annales Françaises d Anesthésie et de Réanimation
[Show abstract][Hide abstract] ABSTRACT: Many devices are available to assess cardiac output (CO) in critically ill patients and in the operating room. Classical CO monitoring via a pulmonary artery catheter involves continuous cardiac output (CCO) measurement. The second generation of Flotrac/Vigileo monitors propose an analysis of peripheral arterial pulse waves to calculate CO (APCO) without calibration. The aim of our study was to compare the CO between the Swan Ganz catheter and the VigileoT. In this observational study, nine patients undergoing coronary artery bypass grafting were prospectively included. APCO, mean (CCO) and instantaneous CO (ICO) were measured. Perioperative and postoperative assessments were performed up to 24 hours post-surgery. Measurements were recorded every minute, resulting in the collection of 6492 data pairs. Comparison of APCO and ICO showed a limited bias of -0.1 l/min but an important percentage error of 48%. Corresponding values were -0.1 l/min and 46% for the APCO versus CCO comparison, and 0 and 17% for ICO versus CCO comparison. Large inter-individual variability does exist. During cardiac surgery and after leaving the operating room, Vigileo is not clinically equivalent to continuous thermodilution by pulmonary artery catheter Nevertheless, the connection between CCO and ICO relates the difference between APCO and CCO more to the different algorithms used. Further efforts should be concentrated on assessing the ability of this device to track changes in cardiac output.
No preview · Article · Mar 2010 · Anaesthesia and intensive care
[Show abstract][Hide abstract] ABSTRACT: Les complications liées à l’immobilité, à l’alitement et aux gestes plus ou moins invasifs en réanimation font l’objet d’une
prévention reposant sur des procédures écrites enseignées à tous les soignants. En effet, leur survenue prolonge souvent le
séjour, augmente la charge en soins, induit des coûts supplémentaires et met parfois en jeu le pronostic vital.
[Show abstract][Hide abstract] ABSTRACT: Les techniques d’épuration extrarénales se sont progressivement améliorées tant en ce qui concerne leur efficacité que leur
facilité d’utilisation. Le personnel infirmier joue un rôle central dans la mise en œuvre et la gestion de ces techniques.
Il n’en demeure pas moins que l’insuffisance rénale reste une affection grave qui comporte un risque vital propre.
[Show abstract][Hide abstract] ABSTRACT: L’insuffisance rénale est de survenue fréquente en réanimation périopératoire où les causes se trouvent rassemblées pour produire
une atteinte rénale multifactorielle. Les techniques d’épuration extrarénale se sont progressivement améliorées tant en ce
qui concerne leur efficacité que leur facilité d’utilisation; il n’en demeure pas moins que l’insuffisance rénale reste une
affection grave qui comporte un risque vital propre. Par ailleurs, les suites opératoires en urologie se sont trouvées simplifiées
par l’avènement de techniques chirurgicales moins invasives, limitant les complications hémorragiques notamment. Le TURP syndrome
voit également sa fréquence diminuer par l’utilisation d’une irrigation avec du sérum physiologique, et non de l’eau glycocollée,
rendue possible par l’emploi de la résection par laser.
[Show abstract][Hide abstract] ABSTRACT: L’indication de pose d’un cathéter veineux profond implique l’emploi d’un équipement adapté, une technique appropriée de pose
et des conditions d’asepsie chirurgicale. Tout aussi importants que la technique d’insertion, les soins apportés à l’accès
veineux après sa pose conditionnent la durée de vie du cathéter permettant ainsi d’épargner le capital veineux du patient
et surtout de prévenir toute complication septique pouvant mettre en danger la vie du patient.