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Introduction et but de l’etude La sarcopenie se definit par l’association d’une perte importante de masse et de fonctionnalite musculaire (force et/ou performance physique) lors du vieillissement [1] . Notre objectif etait d’etudier l’apport de l’echographie d’un muscle du quadriceps (rectus femoris) dans le diagnostic du vieillissement musculaire, dans une population adulte en bonne sante, issue du projet EIT Health CHRONOS. Materiel et methodes Des volontaires sains (sans pathologies neurologiques, endocriniennes, musculaires et sans medicament affectant le muscle) et actifs physiquement (categories 2 et 3 au questionnaire International Physical Activity Questionnaire version longue [2] ) repartis equitablement entre sexes et decades de 25 a 75 ans ont beneficie d’une mesure de force de prehension par dynamometre manuel (Jamar®), d’une evaluation de performance physique grâce au Short Physical Performance Battery (SPPB), d’une mesure de distance de marche de 6 minutes et d’une evaluation nutritionnelle par releve alimentaire de 3 jours. Leur composition corporelle a ete evaluee par absorptiometrie biphotonique a rayons X (DEXA) et par echographie au niveau du muscle rectus femoris. Resultats et analyse statistique Les 82 volontaires actifs physiquement presentaient en moyenne un âge de 49 ± 14 ans et un indice de masse corporelle (IMC) de 23,7 ± 2,7 kg/m2. Leur IMC, leur niveau d’activite physique, leurs apports alimentaires (en kilocalories/kg/jour et proteines/kg/jour) et leur niveau de comorbidite (score de Charlson) ne differaient pas entre les 5 decades. Leur index de masse musculaire squelettique estime par DEXA, leur force de prehension et leur distance de marche n’etaient pas differents selon les classes d’âge. L’epaisseur musculaire du rectus femoris mesure par echographie diminuait avec l’âge passant de 20,0 ± 2,4 mm entre 25–34 ans a 15,9 ± 1,1 mm entre 65–75 ans (p Conclusion L’echographie musculaire du quadriceps serait un outil non invasif d’evaluation du vieillissement musculaire, potentiellement plus sensible que la DEXA ou les autres criteres classiques de sarcopenie.

International audience; Classical signal averaging is an important operation in signal processing applications but is meaningless if shape or time variability is present among the signals being averaged. Structural Average Estimation (SAE) and Integral Shape Averaging (ISA) are recent methods that deal with these types of variability by providing a "structural average" for SAE and a "mean shape signal" for ISA that can act as a complement to the classical average in signal analysis. In this paper, these two techniques are regarded from the perspective of the time warping problem. We approach ISA using a new formalism that emphasizes the theoretical connections between the two techniques. A simulation study is then carried out to compare the two methods in three kinds of time fluctuation. Two SAE algorithms are employed, namely, Dynamic Time Warping (DTW) and Self-Modeling Registration (SMR). The discussion of the results obtained in this comparison offers specific guidelines for the application-dependent use of each approach.

To determine the pharmacokinetics of long-term infusion of sufentanil in ICU patients. Open-label study in a surgical intensive care unit. Ten consecutive patients without renal or hepatic failure requiring mechanical ventilation for at least 6 days. Patients received sufentanil (initial bolus 0.5 µg/kg and continuous infusion rate of 0.5 µg/kg per hour) and midazolam (initial bolus 0.08 mg/kg and continuous infusion 0.05 mg/kg per hour). Sedation was adjusted according to the Ramsay scale (score >3). Blood samples were taken during and up to 72 h after the infusion, and plasma concentrations were measured using a sensitive radioimmunoassay method. Plasma concentration-time profiles of sufentanil and pharmacokinetic parameters such as initial postinfusion half-life (t 1/2α), elimination half-life (t 1/2β), total clearance (Cl), volume of distribution (Vdβ), and time required to obtain a 50% decrease in plasma concentration (tcp 0/2). The mean duration of sedation was 12±7 days. The initial half-life t 1/2α was 1.33±1.15 h. The observed prolonged elimination half-life (t 1/2β=25.5±9.4 h) was related to the large volume of distribution (Vdβ=22.6±9.4 l/kg). The mean total clearance was 13.4±7.0 ml/kg per minute. The mean time required to obtain a 50% decrease in plasma concentration was short (tcp 0/2=4.7±3.7 h). The pharmacokinetic analysis of sufentanil for ICU sedation revealed increased volume of distribution and elimination half-life. Nevertheless the rapid distribution and elimination processes suggest that the rapid reversibility of sedation with sufentanil is maintained after long duration of infusion. Further studies should be carried out to evaluate the clinical relevance of these results.

The surface detected motor unit action potential (MUAP) morphology depends on many physiological and anatomical characteristics of the contracting muscle that are not directly accessible to measurement. In this paper, a neural network based approach is proposed to estimate the motor unit (MU) parameters from a simulated single surface MUAP. We have developed an estimation system that is composed of the following stages: conduction velocity estimation, signal dimension reduction, MU parameters estimation, and number of MU fibres estimation. The parameter estimation stage employs four multilayer neural networks trained on simulated MUAPs corresponding to various ranges of MU parameters. In the estimation mode, this module produces four MU parameters sets. The selected set of the five muscle characteristics is that which minimises an error criterion on a signal reconstructed from the estimated parameters. The proposed system is tested with several simulated MUAPs signals with additive white noise in order to evaluate its performance. It is shown that the technique performs well when the signal to noise ratio is greater than 20 dB.

Esophageal replacement after esophagogastric injury caused by ingestion of lye may require the interposition of a retrosternal ileocolic graft. In this new anatomic situation, the mesenteric circulation supplying the graft is subjected to the intrathoracic pressure surrounding the graft. Thus, mesenteric blood flow supplying the graft may be impaired when intrathoracic pressure is increased during mechanical ventilation. This study was designed to evaluate the effect of increasing intrathoracic pressure by application of a positive end-expiratory pressure on mesenteric blood flow supplying esophageal ileocolic grafts. Eight cases were studied in the immediate postoperative period. Miniaturized implantable Doppler microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Two sets of measurements were successively performed with zero end-expiratory pressure ventilation and after application of a 15 cm water positive end-expiratory pressure. Positive end-expiratory pressure induces mean arterial pressure (-12%); p p p

Regional ischemia may induce cervical anastomosis leakage or stenosis or graft necrosis after esophageal reconstruction by retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the relationship between immediate postoperative arterial blood supply to the graft, arterial patency monitored by angiography, and clinical outcome. Eight patients (mean age 30 ± 4 years; standard deviation) were studied. Miniaturized Doppler implantable microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Systemic hemodynamic parameters and mesenteric hemodynamic data were collected 3 hours after the end of the surgical procedure. These data were compared with the angiogram of the right superior colic artery supplying the graft, systematically performed on the fifteenth postoperative day, and with the clinical course of follow-up for 3 months. Five patients (group 1) had excellent clinical and angiographic results. Mean mesenteric blood flow in these patients was 51 ± 49 ml · min-1 (± standard deviation, ranging from 9 to 122). Three patients (group 2) had a poor clinical outcome. One had early complete graft necrosis and the two others had leakage of the cervical anastomosis with poor distal arterial vascularization of the graft on the angiogram. Mean mesenteric blood flow was nul in the first patient and, respectively, 24 and 28 ml · min-1 in the two others. Cardiac output and mean arterial pressure were in the same range for all patients. Phasic velocity shape analysis revealed that the three group 2 patients had an end-systolic or end-diastolic reverse flow pattern that was not observed in the five group 1 patients, which suggested a submaximal increase in downstream vascular resistance. This reverse flow pattern seems to be a good predictor of ischemia-related complications. We conclude that perioperative pulsed Doppler blood flow monitoring in an ileocolic graft may be useful for the diagnosis and prevention of ischemic complications. (J T horac C ardiovasc S urg 1992;104:385-90)

Regional ischemia may induce anastomotic leakage or stenosis after esophageal reconstruction using retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the influence of inhalational anesthetic agents on the intestinal circulation supplying these ileocolic grafts. Seven patients (age 30 +/- 5 yr, mean +/- standard deviation [SD]) were studied in the immediate postlaparotomy period. Miniaturized Doppler implantable microprobes were sutured to the single artery supplying the graft and connected to an 8-MHz pulsed Doppler flowmeter. Continuous fentanyl infusion (300 micrograms.h-1) was maintained throughout the study. Measurements were performed at the end of four 30-min periods, which were, successively: first control; isoflurane or halothane anesthesia; second control; and isoflurane or halothane anesthesia. Isoflurane and halothane were administered in cross sequence with end-tidal concentration of 0.8% and 0.5%, respectively, to induce equipotent anesthesia. Both anesthetics induced similar decreases in mean systemic arterial pressure (MAP), cardiac output (CO), and systemic vascular resistance. During isoflurane, mean mesenteric blood flow (MBFm) supplying the graft was increased (+38%; P less than 0.05), and the mesenteric vascular resistance index (MVRI; -44%; P less than 0.05) was decreased, leading to an increase in the MBFm/CO ratio (P less than 0.05). Halothane changed neither the MBFm nor the MBFm/CO ratio, despite a mild decrease in MVRI (-14%; P less than 0.05). Diastolic blood flow velocity increased significantly (2.3 +/- 0.9 vs. 0.8 +/- 0.3 cm.s-1, P less than 0.05) only with isoflurane, suggesting a local vasodilation not observed with halothane.(ABSTRACT TRUNCATED AT 250 WORDS)

Studying the firing strategies of Motor Units (MU) from Surface Electromygram (sEMG) is of particular interest. The objective of this study is to explore the possible relationship between MU firing law shapes, given as a sEMG model input, with the shape of the evolution of spectral moments, obtained from the simulated EMG, in order to follow up the recruitment strategies of the MUs. For this purpose, a shape analysis is done by using the Distribution Function Method (DFM) to track similarities between two signals. The method is applied for analyzing the shape of the time evolution of spectral moment parameters computed on the PSD of the simulated EMG during isometric effort. We computed, using a recent sEMG model, 36 muscle configurations and generated sEMG sequences by MU time recruitment with an increasing firing rate followed by a decreasing part. Three patterns of firing variations are tested, 12 signals for each pattern, giving thus three classes of simulated sEMG. The (DFM) criterion is then used to quantify the shape dispersion among classes and between them, according to the firing pattern. In addition, the Integral Shape Averaging (ISA) approach has been used to get the class centroids. The obtained results are discussed with emphasis on the relevant ability for the spectral moments, coupled to shape analysis, to detect electrophysiological changes into muscles.

International audience; In this paper, we propose a method for detecting alterations in the Ensemble Spontaneous Activity (ESA), a random signal representing the composite spontaneous contribution of the auditory nerve recorded on the round window. The proposed method is based on shape analysis of the ESA amplitude histogram. For this task, we use a recent approach, the Corrected Integral Shape Averaging (CISA). Using this approach, a shape clustering algorithm is proposed to classify healthy and pathological ESA signals generated by a recent ESA model. This model allows a precise simulation of neural mechanisms occurring in the auditory nerve. The obtained results demonstrate that this shape analysis is very sensitive for detecting a small number of fibers with correlated firing, supposed to occur during a particular type of tinnitus. In comparison, the classical spectral index fails in this detection.

Providing sample shape statistics for time warped signals or more generally for heterogeneous shape signals can be useful in many signal processing applications. In fact, the classical mean and the L distance are inadequate in describing and quantifying the time or shape variability among such signals. Specific methods derived from the curve registration (CR) theory were developed to deal with this warping or shape problem. More recently, two approaches seem similar in many points. Functional convex averaging (FCA) and integral shape averaging (ISA) proposed an alternative to CR methods in averaging and comparing time warped signals. Both methods estimate a sample mean without requiring that observed signals are well structured and consider the warping as a stochastic process. The objective of the study is to compare ISA and FCA methods with respect to shape equality condition. For this purpose, shape equality is defined and the used methods are recalled with an emphasis on the similarities. After, a corrected ISA (CISA) approach providing a mean and a distance is proposed and compared to the FCA approach. This comparison with simulations shows that the CISA approach is more suitable for quantifying shape variability than FCA one since it respects shape equality condition

Plasma cystatin C, a new marker of glomerular filtration rate (GFR), was prospectively evaluated in surgical intensive care. Cystatin C was measured (immunonephelometry, Dade-Behring) in 10 patients selected to cover a full range of GFR (phase I) and in 28 unselected consecutive patients followed for 5 days post-admission (phase II). Results were compared with (51)Cr-EDTA clearance (phase I only), plasma creatinine (kinetic Jaffe, Roche), 24-h or estimated by Cockcroft and Gault (CG) creatinine clearance (CrCl), and modified diet in renal disease (MDRD)-estimated GFR. In phase I, the highest correlation with(51)Cr-EDTA clearance (22-198 mL/min) was noted for CG CrCl (r(2): 0.883, p

Increased intrathoracic pressure with positive pressure breathing (PPB) induces renal hypoperfusion and excretion function impairment the mechanism of which may be partially related to reflex sympathetic nerve activation. The consequences of renal denervation on PPB-induced renal impairment are unknown. This study was conducted to evaluate the effects of increasing intrathoracic pressure with positive end-expiratory pressure (PEEP) on renal blood flow (RBF, pulsed Doppler implantable microprobes) and function in 12 kidney transplantation recipients during the immediate post-transplantation period. Three sets of measurements were performed during successively zero end-expiratory pressure (ZEEP), 15 cm H2O PEEP, and back to ZEEP. PEEP ventilation was associated with mean arterial pressure (MAP) and cardiac output (CO) decrease (-12%, p < 0.01; -26%, p < 0.01, respectively). RBF remained constant in the three protocol conditions. PEEP ventilation was associated with a decrease in urinary output (8.5 +/- 5.6 versus 12.9 +/- 8.6 ml/min; p < 0.01), urinary sodium concentration (115 +/- 14 versus 121 +/- 12 mmol/L; p < 0.01) sodium excretion rate (1 +/- 0.7 versus 1.6 +/- 1.1 mmol/min; p < 0.01), and creatinine clearance (17.1 +/- 10 versus 23.2 +/- 13.6 ml/min; p < 0.01). PEEP-induced urinary output decrease was correlated to renal perfusion pressure decrease (r = 0.7, p = 0.016). These results suggest that despite denervation and renal blood flow stability, renal handling of water and salt is perfusion pressure-dependent during PEEP in human renal allograft recipients.

Esophageal replacement after esophagogastric injury caused by ingestion of lye may require the interposition of a retrosternal ileocolic graft. In this new anatomic situation, the mesenteric circulation supplying the graft is subjected to the intrathoracic pressure surrounding the graft. Thus, mesenteric blood flow supplying the graft may be impaired when intrathoracic pressure is increased during mechanical ventilation. This study was designed to evaluate the effect of increasing intrathoracic pressure by application of a positive end-expiratory pressure on mesenteric blood flow supplying esophageal ileocolic grafts. Eight cases were studied in the immediate postoperative period. Miniaturized implantable Doppler microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Two sets of measurements were successively performed with zero end-expiratory pressure ventilation and after application of a 15 cm water positive end-expiratory pressure. Positive end-expiratory pressure induces mean arterial pressure (-12%); p0.05) and cardiac output (-17%; p0.05) decrease. Mesenteric blood flow also decreases (-38%; p0.05) as did the mesenteric blood flow/cardiac output ratio, suggesting a potential mesenteric vasoconstriction assessed by mesenteric vascular resistance increase and mesenteric diastolic blood flow velocity decrease. These results suggest that, in the particular anatomic situation of the graft, increased intrathoracic pressure induces mesenteric blood flow decrease in relation to systemic hemodynamic alterations associated with perivisceral pressure increase. This change may be deleterious to graft perfusion.

Accidental intra-arterial injection of a colouring agent (Bonney's blue) in a 28-year-old male patient induced acute ischaemia of the lower limb, resistant to standard therapy. Its successful treatment was finally obtained by intra-arterial infusion of nicardipine.

Regional ischemia may induce cervical anastomosis leakage or stenosis or graft necrosis after esophageal reconstruction by retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the relationship between immediate postoperative arterial blood supply to the graft, arterial patency monitored by angiography, and clinical outcome. Eight patients (mean age 30 +/- 4 years; standard deviation) were studied. Miniaturized Doppler implantable microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Systemic hemodynamic parameters and mesenteric hemodynamic data were collected 3 hours after the end of the surgical procedure. These data were compared with the angiogram of the right superior colic artery supplying the graft, systematically performed on the fifteenth postoperative day, and with the clinical course of follow-up for 3 months. Five patients (group 1) had excellent clinical and angiographic results. Mean mesenteric blood flow in these patients was 51 +/- 49 ml.min-1 (+/- standard deviation, ranging from 9 to 122). Three patients (group 2) had a poor clinical outcome. One had early complete graft necrosis and the two others had leakage of the cervical anastomosis with poor distal arterial vascularization of the graft on the angiogram. Mean mesenteric blood flow was nul in the first patient and, respectively, 24 and 28 ml.min-1 in the two others. Cardiac output and mean arterial pressure were in the same range for all patients. Phasic velocity shape analysis revealed that the three group 2 patients had an end-systolic or end-diastolic reverse flow pattern that was not observed in the five group 1 patients, which suggested a submaximal increase in downstream vascular resistance. This reverse flow pattern seems to be a good predictor of ischemia-related complications. We conclude that perioperative pulsed Doppler blood flow monitoring in an ileocolic graft may be useful for the diagnosis and prevention of ischemic complications.

A prospective study was designed to evaluate coagulation abnormalities induced by early abortion (before ten weeks of pregnancy). Fifty-two women underwent suction abortion, under diazepam-fentanyl anaesthesia with spontaneous ventilation; they were screened for coagulation parameters before and after surgery. Eight tests were carried out: prothrombin time, activated partial thromboplastin time (APTT), thrombin time platelet count, fibrinogen levels, fibrin split products, fibrin soluble complexes and euglobulin lysis time. Results were consistent with activation. Consequences were limited and one general test (APTT) was not significantly modified. Suction abortion, even performed in early pregnancy, exposed to biological disseminated intravascular coagulation with a general risk of venous thrombosis.

A prospective study was designed to evaluate coagulation abnormalities induced by early abortion (before ten weeks of pregnancy). Fifty-two women underwent suction abortion, under diazepam-fentanyl anaesthesia with spontaneous ventilation; they were screened for coagulation parameters before and after surgery. Eight tests were carried out: prothrombin time, activated partial thromboplastin time (APTT), thrombin time platelet count, fibrinogen levels, fibrin split products, fibrin soluble complexes and euglobulin lysis time. Results were consistent with activation. Consequences were limited and one general test (APTT) was not significantly modified. Suction abortion, even performed in early pregnancy, exposed to biological disseminated intravascular coagulation with a general risk of venous thrombosis.A prospective study was designed to evaluate coagulation abnormalities induced by early abortion (before 10 weeks of pregnancy). 52 women underwent suction abortion, under diazepam--fentanyl anesthesia with spontaneous ventilation; they were screened for coagulation parameters before and after surgery. 8 tests were carried out: prothrombin time, activated partial thromboplastin time (APTT), thrombin time platelet count, fibrinogen levels, fibrin split products, fibrin soluble complexes and euglobulin lysis time. Results were consistent with activation. Consequences were limited and 1 general test (APTT) was not significantly modified. Suction abortion, even performed in early pregnancy, exposed the patient to biologically disseminated intravascular coagulation with a general risk of venous thrombosis. (author's modified)

International audience; OBJECTIVE: To determine the concomitant incidence, molecular diversity, management and outcome of nosocomial candidemia and candiduria in intensive care unit (ICU) patients in France. DESIGN: A 1-year prospective observational study in 24 adult ICUs. PATIENTS: Two hundred and sixty-two patients with nosocomial candidemia and/or candiduria. MEASUREMENTS AND RESULTS: Blood and urine samples were collected when signs of sepsis were present. Antifungal susceptibility of Candida strains was determined; in addition, all blood and 72% of urine C. albicans isolates were analyzed by using multi-locus sequence type (MLST). The mean incidences of candidemia and candiduria were 6.7 and 27.4/1000 admissions, respectively. Eight percent of candiduric patients developed candidemia with the same species. The mean interval between ICU admission and candidemia was 19.0[Symbol: see text]+/-[Symbol: see text]2.9 days, and 17.2[Symbol: see text]+/-[Symbol: see text]1.1 days for candiduria. C. albicans and C. glabrata were isolated in 54.2% and 17% of blood and 66.5% and 21.6% of urine Candida-positive cultures, respectively. Fluconazole was the most frequently prescribed agent. In all candidemic patients, the prescribed curative antifungal agent was active in vitro against the responsible identified strain. Crude ICU mortality was 61.8% for candidemic and 31.3% for candiduric patients. Seventy-five percent of the patients were infected with a unique C. albicans strain; cross-transmission between seven patients was suggested in one hospital. CONCLUSIONS: Candidemia is late-onset ICU-acquired infection associated with high mortality. No difference in susceptibility and genetic background were found between blood and urine strains of Candida species.