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On one side, decompression sickness (DCS) with neurological disorders lead to a reshuffle of the fecal metabolome from rat caecum. On the other side, there is high inter-individual variability in terms of occurrence of DCS. One could wonder whether the fecal metabolome could be linked to the DCS-susceptibility. We decided to study male and female rats selected for their resistance to decompression sickness, and we hypothesize a strong impregnation concerning the fecal metabolome. The aim is to verify whether the rats resistant to the accident have a fecal metabolomic signature different from the stem generations sensitive to DCS. 39 DCS-resistant animals (21 females and 18 males), aged 14 weeks, were compared to 18 age-matched standard Wistar rats (10 females and 8 males), i.e., the same as those we used for the founding stock. Conventional and ChemRICH approaches helped the metabolomic interpretation of the 226 chemical compounds analyzed in the cecal content. Statistical analysis shows a panel of 81 compounds whose expression had changed following the selection of rats based on their resistance to DCS. 63 compounds are sex related. 39 are in common. This study shows the spectral fingerprint of the fecal metabolome from the caecum of a strain of rats resistant to decompression sickness. This study also confirms a difference linked to sex in the metabolome of non-selected rats, which disappear with selective breeding. Results suggest hormonal and energetic reshuffle, including steroids sugars or antibiotic compounds, whether in the host or in the microbial community.

Massive bubble formation after diving can lead to decompression sickness (DCS), which can result in neurological disorders. We demonstrated that hydrogen production from intestinal fermentation could exacerbate DCS in rats fed with a standard diet. The aim of this study is to identify a fecal metabolomic signature that may result from the effects of a provocative hyperbaric exposure. The fecal metabolome was studied in two groups of rats previously fed with maize or soy in order to account for diet effects. 64 animals, weighing 379.0_20.2 g on the day of the dive, were exposed to the hyperbaric protocol. The rats were separated into two groups: 32 fed with maize (Div MAIZE) and 32 fed with soy (Div SOY). Gut fermentation before the dive was estimated by measuring exhaled hydrogen. Following hyperbaric exposure, we assessed for signs of DCS. Blood was analyzed to assay inflammatory cytokines. Conventional and ChemRICH approaches helped the metabolomic interpretation of the cecal content. The effect of the diet is very marked at the metabolomic level, a little less in the blood tests, without this appearing strictly in the clinic status. Nevertheless, 37 of the 184 metabolites analyzed are linked to clinical status. 35 over-expressed compounds let suggest less intestinal absorption, possibly accompanied by an alteration of the gut microbial community, in DCS. The decrease in another metabolite suggests hepatic impairment. This spectral difference of the ceca metabolomes deserves to be studied in order to check if it corresponds to functional microbial particularities.

BACKGROUND Postoperative pulmonary complications are associated with increased morbidity. Identifying patients at higher risk for such complications may allow preemptive treatment. METHODS Patients with an American Society of Anesthesiologists (ASA) score >1 and who were scheduled for major surgery of >2 hours were enrolled in a single-center prospective study. After extubation, lung ultrasound was performed after a median time of 60 minutes by 2 certified anesthesiologists in the postanesthesia care unit after a standardized tracheal extubation. Postoperative pulmonary complications occurring within 8 postoperative days were recorded. The association between lung ultrasound findings and postoperative pulmonary complications was analyzed using logistic regression models. RESULTS Among the 327 patients included, 69 (19%) developed postoperative pulmonary complications. The lung ultrasound score was higher in the patients who developed postoperative pulmonary complications (12 [7-18] vs 8 [4-12]; P < .001). The odds ratio for pulmonary complications in patients who had a pleural effusion detected by lung ultrasound was 3.7 (95% confidence interval, 1.2-11.7). The hospital death rate was also higher in patients with pleural effusions (22% vs 1.3%; P < .001). Patients with pulmonary consolidations on lung ultrasound had a higher risk of postoperative mechanical ventilation (17% vs 5.1%; P = .001). In all patients, the area under the curve for predicting postoperative pulmonary complications was 0.64 (95% confidence interval, 0.57-0.71). CONCLUSIONS When lung ultrasound is performed precociously

Background Rapid response teams are intended to improve early diagnosis and intervention in ward patients who develop acute respiratory or circulatory failure. A management protocol including the use of a handheld ultrasound device for immediate point-of-care ultrasound (POCUS) examination at the bedside may improve team performance. The main objective of the study was to assess the impact of implementing such a POCUS-guided management on the proportion of adequate immediate diagnoses in two groups. Secondary endpoints included time to treatment and patient outcomes. Methods A prospective, observational, controlled study was conducted in a single university hospital. Two teams alternated every other day for managing in-hospital ward patients developing acute respiratory and/or circulatory failures. Only one of the team used an ultrasound device (POCUS group). Results We included 165 patients (POCUS group 83, control group 82). Proportion of adequate immediate diagnoses was 94% in the POCUS group and 80% in the control group (p = 0.009). Time to first treatment/intervention was shorter in the POCUS group (15 [10–25] min vs. 34 [15–40] min, p p = 0.007), but this difference was not confirmed in the propensity score sample (29% vs. 34%, p = 0.53). Conclusion Our study suggests that protocolized use of a handheld POCUS device at the bedside in the ward may improve the proportion of adequate diagnosis, the time to initial treatment and perhaps also survival of ward patients developing acute respiratory or circulatory failure. Clinical Trial Registration NCT02967809. Registered 18 November 2016, https://clinicaltrials.gov/ct2/show/NCT02967809.

Background An association was reported between the left ventricular longitudinal strain (LV-LS) and preload. LV-LS reflects the left cardiac function curve as it is the ratio of shortening over diastolic dimension. The aim of this study was to determine the sensitivity and specificity of LV-LS variations after a passive leg raising (PLR) maneuver to predict fluid responsiveness in intensive care unit (ICU) patients with acute circulatory failure (ACF). Methods Patients with ACF were prospectively included. Preload-dependency was defined as a velocity time integral (VTI) variation greater than 10% between baseline (T0) and PLR (T1), distinguishing the preload-dependent (PLD+) group and the preload-independent (PLD-) group. A 7-cycles, 4-chamber echocardiography loop was registered at T0 and T1, and strain analysis was performed off-line by a blind clinician. A general linear model for repeated measures was used to compare the LV-LS variation (T0 to T1) between the two groups. Results From June 2018 to August 2019, 60 patients (PLD+ = 33, PLD- = 27) were consecutively enrolled. The VTI variations after PLR were +21% (±8) in the PLD+ group and -1% (±7) in the PLD- group (pp = 0.12). LV-LS increased in the whole population after PLR +16.0% (±4.0) (p = 0.04). The LV-LS variations after PLR were +19.0% (±31) (p = 0.05) in the PLD+ group and +11.0% (±38) (p = 0.25) in the PLD- group, with no significant difference between the two groups (p = 0.08). The area under the curve for the LV-LS variations between T0 and T1 was 0.63 [0.48–0.77]. Conclusion Our study confirms that LV-LS is load-dependent; however, the variations in LV-LS after PLR is not a discriminating criterion to predict fluid responsiveness of ICU patients with ACF in this cohort.

Chest ultrasonography has proven to be useful in the diagnosis of diaphragm dysfunction. The aim of the present study was to determine the normal values of the motion of both hemidiaphragms recorded by M-mode ultrasonography. Healthy volunteers were studied while in a seated position. Diaphragmatic excursions and diaphragm profiles were measured during quiet breathing, voluntary sniffing and deep breathing. Diaphragmatic excursions were assessed by M-mode ultrasonography, using an approach perpendicular to the posterior part of the diaphragm. Anatomical M-mode was used for the recording of the complete excursion during deep breathing. The study included 270 men and 140 women. The diaphragmatic motions during quiet breathing and voluntary sniffing were successfully recorded in all of the participants. The use of anatomical M-mode was particularly suitable for measurement of the entire diaphragmatic excursion during deep breathing. The statistical analysis showed that the diaphragmatic excursions were larger in men compared to women, supporting the determination of normal values based on sex. The lower and upper limits of normal excursion were determined for men and women for both hemidiaphragms during the three manoeuvres that were investigated. The lower limits of normal diaphragmatic excursions during deep breathing should be used to detect diaphragmatic hypokinesia, i.e. 3.3 and 3.2 cm in women and 4.1 and 4.2 cm in men for the right and the left sides, respectively. The normal values of the diaphragmatic motion and the lower and upper limits of normal excursion can be used by clinicians to detect diaphragmatic dysfunction., These normal values of diaphragmatic motion, and the lower and upper limits of normal excursion, can be used by physicians to detect diaphragm hypokinesia and hyperkinesia, and thus diagnose diaphragmatic dysfunction https://bit.ly/35R9OFk

Rest hypoxemia can be attributed to alteration of lung oxygenation function inducing abnormal distribution of the ventilation perfusion ratio (VA/Q) or disorders of the alveolarcapillary diffusion...

International audience; Purpose Long static or intense dynamic apnoea-like high-altitude exposure is inducing hypoxia. Adenosine is known to participate to the adaptive response to hypoxia leading to the control of heart rate, blood pressure and vasodilation. Extracellular adenosine level is controlled through the equilibrative nucleoside transporter 1 (ENT-1) and the enzyme adenosine deaminase (ADA). The aim of this study was to determine the control of adenosine blood level (ABL) via ENT-1 and ADA during apnoea-induced hypoxia in elite freedivers was similar to high-altitude adaptation. Methods Ten freediver champions and ten controls were studied. Biological (e.g. ENT-1, ADA, ABL, PaO2, PaCO(2)and pH) and cardiovascular (e.g. heart rate, arterial pressure) parameters were measured at rest and after a submaximal dry static apnoea. Results In freedivers, ABL was higher than in control participants in basal condition and increased more in response to apnoea. Also, freedivers showed an ADA increased in response to apnoea. Finally, ENT-1 level and function were reduced for the free divers. Conclusion Our results suggest in freedivers the presence of an adaptive mechanism similar to the one observed in human exposed to chronic hypoxia induced by high-altitude environment.

International audience; Introduction: Ultrasound is a feasible and reproducible method for measuring right diaphragmatic excursion (RDE) in ED patients with acute dyspnea (AD). In AD patients, the correlation between the RDE value and the need for mechanical ventilation (MV) is not known.Materials: This was a bicentric, observational prospective study. The RDE measurement was done at admission. The need for MV was defined by the use of MV within 4 h of AD management. An optimal threshold for RDE was determined as the value that minimized the incorrect predictions of the use of MV in the first 4 h as the highest Youden index.Results: We analyzed 102 patients (79 [70; 86] years), 38 (37%) of whom had been ventilated. The RDE value was 1.7 cm [1.4; 2.0] and 2.2 cm [1.8; 2.6] in the ventilated and non-ventilated groups, respectively (p = 0.06). The AUC was 0.68 95% CI [0.57; 0.80]. With a threshold of 2 cm, the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 76% [60%; 89%], 59% [46%; 71%], 81% [67%; 91%], and 53% [39%; 66%], respectively. In the non-COPD patients, the RDE values were 1.5 cm [1.2; 1.9] and 2.2 cm [1.8; 2.6] (p < 0.01) in the ventilated and not-ventilated groups, respectively. The AUC was 0.77 95% CI [0.64; 0.90]. With a threshold of 2.18 cm, the sensitivity, specificity, NPV, and PPV were 91% [71%; 99%], 51% [36%; 66%], 92% [75%; 99%], and 54% [38%; 69%], respectively.Conclusion: The RDE values at ED admission were unable to define a prognostic threshold value associated with subsequent MV need in the AD patients. In non-COPD patients, the NPV was 92%.

This article reports the various methods used to assess diaphragmatic function by ultrasonography. The excursions of the two hemidiaphragms can be measured using two-dimensional or M-mode ultrasonography, during respiratory maneuvers such as quiet breathing, voluntary sniffing and deep inspiration. On the zone of apposition to the rib cage for both hemidiaphragms, it is possible to measure the thickness on expiration and during deep breathing to assess the percentage of thickening during inspiration. These two approaches make it possible to assess the quality of the diaphragmatic function and the diagnosis of diaphragmatic paralysis or dysfunction. These methods are particularly useful in circumstances where there is a high risk of phrenic nerve injury or in diseases affecting the contractility or the motion of the diaphragm such as neuro-muscular diseases. Recent methods such as speckle tracking imaging and ultrasound shear wave elastography should provide more detailed information for better assessment of diaphragmatic function.

International audience; BACKGROUND:Water immersion has demonstrated its effectiveness in the recovery process after exercise. This study presents for the first time the impact of water immersion on heart rate recovery after low-intensity cycle exercise.METHODS:Sixteen male volunteers were involved in the study. The experiment consisted of two cycling exercises: 1 h in ambient air and 1 h in water (temperature: 32 ± 0·2°C). The exercise intensity was individually prescribed to elicit around 35%-40% of VO2 peak for both conditions. Heart rate recovery was analysed according to recognized methods, such as the differences between heart rate at exercise completion and within the 2 min recovery period.RESULTS:Although the two exercises were performed both at same energy expenditure and heart rate, the indexes used to assess the fast and slow decay of the heart rate recovery were significantly shortened after exercise in water.CONCLUSION:The results of the present study suggest that cycling in thermoneutral water decreases the cardiac work after exercise when compared with cycling on land.

International audience; Purpose Lung ultrasound is used for the diagnosis of pneumothorax, based on lung sliding abolition which is a qualitative and operator-dependent assessment. Speckle tracking allows the quantification of structure deformation over time by analysing acoustic markers. We aimed to test the ability of speckle tracking technology to quantify lung sliding in a selected cohort of patients and to observe how the technology may help the process of pneumothorax diagnosis. Methods We performed retrospectively a pleural speckle tracking analysis on ultrasound loops from patients with pneumothorax. We compared the values measured by two observers from pneumothorax side with contralateral normal lung side. The receiver operating characteristic (ROC) curve was constructed to evaluate the performance of maximal pleural strain to detect the lung sliding abolition. Diagnosis performance and time to diagnosis between B-Mode and speckle tracking technology were compared from a third blinded observer. Results We analysed 104 ultrasound loops from 52 patients. The area under the ROC curve of the maximal pleural strain value to identify lung sliding abolition was 1.00 [95%CI 1.00; 1.00]. Specificity was 100% [95%CI 93%; 100%] and sensitivity was 100% [95%CI 93%; 100%] with the best cut-off of 4%. Over 104 ultrasound loops, the blinded observer made two errors with B-Mode and none with speckle tracking. The median diagnosis time was 3 [2–5] seconds for B-Mode versus 2 [1–2] seconds for speckle tracking (p = 0.001). Conclusion Speckle tracking technology allows lung sliding quantification and detection of lung sliding abolition in case of pneumothorax on selected ultrasound loops.

International audience; The mechanism of atrial fibrillation (AF) in patients with normal heart remains unclear. While exogenous adenosine can trigger AF, nothing is known about the behavior of endogenous adenosine plasma level (APL) at the onset of AF and during ablation procedure. Ninety-one patients (68 with paroxysmal AF: 40 males, 66 ± 16 years; 23 with persistent AF: 14 males, 69 ± 11 years) and 18 controls were included. Among paroxysmal patients: i) medical therapy alone was performed in 45 cases and ablation procedure in 23. AF was spontaneously resolutive in 6 cases; ii) 23 underwent ablation procedure and blood was collected simultaneously in a brachial vein and in the left atrium; 17 were spontaneously in sinus rhythm while 6 were in sinus rhythm after direct current cardioversion. Among persistent patients: i) in 17 patients, blood samples were collected in a brachial vein before and after direct current cardioversion; ii) in 6 patients, blood samples were collected simultaneously in a brachial vein and in left atrium before and after cardioversion during ablation procedure. CV-APL was higher in patients with persistent AF vs patients with paroxysmal AF (median [range]: 0.9[0.6-1.1] vs 0.7[0.4-1.1] μM; p < 0.001). In patients with paroxysmal AF, LA-APL increased during the AF episode (0.95[0.85-1.4] vs 2.7[1.5-7] μM; p = 0.03) and normalized in sinus rhythm after DCCV. In patients with persistent AF, LA-APL was higher than CV-APL (1.2[0.7-1.8] vs 0.9[0.6-1.1] μM; p < 0.001), and both normalized in sinus rhythm (CV-APL: 0.8[0.6-1.1] vs 0.75[0.4-1] μM; p = 0.03), (LA-APL: 1.95[1.3-3] vs 1[0.5-1.15] μM; p = 0.03). The occurrence of AF is associated with a strong increase of APL in the atrium. The cause of this increase needs further investigations.

In recent years, several works have supported the significance of ultrasonography in the assessment of diaphragmatic function [1,2].

International audience; Background M-mode ultrasonography might be useful for detecting hemidiaphragm paralysis. The objective of the present study was to describe the motion recorded by M-mode ultrasonography of both diaphragmatic leaves in patients with a pre-established diagnosis of hemidiaphragm paralysis. Methods A study was conducted in 26 patients (18 men, 8 women) with unilateral diaphragmatic paralysis. They were referred to two different rehabilitation centres after thoracic surgery in 23 cases and cardiac interventional procedures in three cases. The pulmonary function tests and the study of the diaphragmatic motion using M-mode ultrasonography were recorded. Results The pulmonary function tests showed a restrictive pattern. The M-mode ultrasonography reported either the absence of motion or a weak paradoxical (cranial) displacement (less than 0 center dot 5 cm) of the paralysed hemidiaphragm during quiet breathing. A paradoxical motion was recorded in all patients during voluntary sniffing, reaching around -1 cm. During deep breathing, a paradoxical motion at the beginning of the inspiration was observed. Thereafter, a re-establishment of the motion in the craniocaudal direction was recorded. The excursions measured on the healthy side, during quiet breathing and voluntary sniffing, were increased in patients suffering from contralateral hemidiaphragm paralysis, when compared with 170 healthy volunteers. Conclusions To detect diaphragmatic dysfunction in patients at risk, it would be useful to study diaphragmatic motion by M-mode ultrasonography during quiet breathing, voluntary sniffing and deep breathing.

International audience; Background: The COVID-19 pandemic has provided an opportunity to use low- and non-radiating chest imaging techniques on a large scale in the context of an infectious disease, which has never been done before. Previously, low-dose techniques were rarely used for infectious diseases, despite the recognised danger of ionising radiation. Method: To evaluate the role of low-dose computed tomography (LDCT) and lung ultrasound (LUS) in managing COVID-19 pneumonia, we performed a review of the literature including our cases. Results: Chest LDCT is now performed routinely when diagnosing and assessing the severity of COVID-19, allowing patients to be rapidly triaged. The extent of lung involvement assessed by LDCT is accurate in terms of predicting poor clinical outcomes in COVID-19-infected patients. Infectious disease specialists are less familiar with LUS, but this technique is also of great interest for a rapid diagnosis of patients with COVID-19 and is effective at assessing patient prognosis. Conclusions: COVID-19 is currently accelerating the transition to low-dose and “no-dose” imaging techniques to explore infectious pneumonia and their long-term consequences.

During exercise, cardiac oxygen consumption increases and the resulting low oxygen level in the myocardium triggers coronary vasodilation. This response to hypoxia is controlled notably by the vasodilator adenosine and its A2A receptor (A2AR). According to the “spare receptor” pharmacological model, a strong A2AR-mediated response can occur in the context of a large number of receptors remaining unoccupied, the activation of only a weak fraction of A2AR (evaluated using KD), which results in maximal cAMP production (evaluated using EC50), and hence in maximal coronary vasodilation. In coronary artery disease (CAD), myocardial ischemia limits adaptation to exercise, which is commonly detected using the exercise stress test (EST). We hypothesized that spare A2AR is present in CAD patients to correct ischemia. Seventeen patients with angiographically documented CAD and 17 control subjects were studied. We addressed adenosine-plasma concentration and A2AR-expression at the mononuclear cell-surface, which reflects cardiovascular expression. The presence of spare A2AR was tested using an innovative pharmacological approach based on a homemade monoclonal antibody with agonist properties. EST was positive in 82% of patients and in none of the controls. Adenosine plasma concentration increased by 60% at peak exercise in patients and in none of the controls (p < 0.01). Most patients (65%), and none of the controls, had spare A2AR (identified when EC50/KD ≤ 0.1) and a low A2AR-expression (mean: −37% versus controls; p < 0.01). All patients with spare A2AR had a positive EST whereas the subjects without spare A2AR had a negative EST (p < 0.05). Spare A2AR is therefore associated with positive EST in CAD patients and its detection may be used as a diagnostic marker.

Aeroatelectasis has developed in aircrew flying routine peacetime flights on the latest generation high-performance aircraft, when undergoing excessive oxygen supply. To single out the effects of hyperoxia and hypergravity on lung tissue compression, and on ventilation and perfusion, eight subjects were studied before and after 1 h 15 min exposure to +1 to +3.5 Gz in a human centrifuge. They performed the protocol three times, breathing air, 44.5% O2, or 100% O2 and underwent functional and topographical imaging of the whole lung by ultrasound and single-photon emission computed tomography combined with computed tomography (SPECT/CT). Ultrasound lung comets (ULC) and atelectasis both increased after exposure. The number of ULC was

International audience; This study investigated the sources of physiological stress in diving by comparing SCUBA dives (stressors: hydrostatic pressure, cold, and hyperoxia), apneic dives (hydrostatic pressure, cold, physical activity, hypoxia), and dry static apnea (hypoxia only). We hypothesized that despite the hypoxia induces by a long static apnea, it would be less stressful than SCUBA dive or apneic dives since the latter combined high pressure, physical activity, and cold exposure. Blood samples were collected from 12SCUBA and 12 apnea divers before and after dives. On a different occasion, samples were collected from the apneic group before and after a maximal static dry apnea. We measured changes in levels of the stress hormones cortisol and copeptin in each situation. To identify localized effects of the stress, we measured levels of the cardiac injury markers troponin (cTnI) and brain natriuretic peptide (BNP), the muscular stress markers myoglobin and lactate), and the hypoxemia marker ischemia-modified albumin (IMA). Copeptin, cortisol, and IMA levels increased for the apneic dive and the static dry apnea, whereas they decreased for the SCUBA dive. Troponin, BNP, and myoglobin levels increased for the apneic dive, but were unchanged for the SCUBA dive and the static dry apnea. We conclude that hypoxia induced by apnea is the dominant trigger for the release of stress hormones and cardiac injury markers, whereas cold or and hyperbaric exposures play a minor role. These results indicate that subjects should be screened carefully for pre-existing cardiac diseases before undertaking significant apneic maneuvers.

BACKGROUND: The diaphragm changes in COPD lead to functional inefficiency correlated to lung function loss. Muscle-fiber shortening follows lung hyperinflation, which results in a chronic mechanical disadvantage that impairs diaphragmatic mobility that worsens in COPD exacerbations. OBJECTIVES: To correlate the diaphragmatic mobility loss to COPD severity by using M-mode ultrasonography and to verify if the diaphragmatic mobility can improve after in-patient pulmonary rehabilitation. METHODS: We used M-mode ultrasonography to access diaphragmatic mobility during normal breathing or breathing at rest and deep inspiration in 52 subjects with moderate to very severe COPD who underwent pulmonary rehabilitation and 16 healthy subjects. Lung function test, arterial blood gas analysis, and a 6-min walk test were also performed. The measurements were performed at rehabilitation admission and discharge. RESULTS: We screened 30 subjects with severe to very severe COPD who had completed pulmonary rehabilitation. At discharge, inspiratory capacity improved, from 1.58 ± 0.5L to 1.7 ± 0.6 L (P = .04). Diaphragmatic mobility during deep inspirations increased from (mean ± SD) 4.58 ± 1.83 cm to 5.45 ± 1.56 cm (P = .05) after pulmonary rehabilitation. The diaphragmatic mobility during rest breathing was higher in the subjects with COPD (2.25 ± 0.83 cm) than in the healthy subjects (1.27 ± 0.3 cm) (P = .01). The diaphragmatic mobility for the rest breathing and deep inspirations were correlated to an FEV1 decrease (r = −0.74, P CONCLUSIONS: Our findings demonstrated diaphragmatic mobility loss in the subjects with moderate to very severe COPD. These changes were correlated with COPD severity, and diaphragmatic mobility loss improved after in-patient pulmonary rehabilitation. (ClinicalTrial.gov registration NCT02838953.)

Immersion pulmonary edema (IPE) is a serious complication of water immersion during scuba diving. Myocardial ischemia can occur during IPE that worsens outcome. Because myocardial injury impacts the therapeutic management, we aim to evaluate the profile of cardiac markers (creatine phosphokinase (CPK), brain natriuretic peptide (BNP), highly sensitive troponin T (TnT-hs) and ultrasensitive troponin I (TnI-us) of divers with IPE. Twelve male scuba divers admitted for suspected IPE were included. The collection of blood samples was performed at hospital entrance (T0) and 6 h later (T0 + 6 h). Diagnosis was confirmed by echocardiography or computed-tomography scan. Mean ± S.D. BNP (pg/ml) was 348 ± 324 at T0 and 223 ± 177 at T0 + 6 h (P

International audience; Background: Heavy backpacks are often used by soldiers and firefighters. Weight carrying could reduce the speed and efficiency in task completion by altering the foot sole sensitivity and postural control. Methods: In fifteen healthy subjects, we measured the changes in sensitivity to vibrations applied to the foot sole when standing upright or walking after load carrying (30% body weight). The participants were asked to judge different vibration amplitudes applied on the 2nd or 5th metatarsal head and the heel at two frequencies (25 and 150 Hz) to determine the vibration threshold and the global perceptual representation (psi) of the vibration amplitude (phi) given by the Stevens power function (psi = k x phi(n)). Any increase in negative k value indicated a reduction in sensitivity to the lowest loads. Pedobarographic measurements, with computation of the center of pressure (COP) and its deviations, were performed during weight carrying. Results: The 25-Hz vibration threshold significantly increased after weight carrying when standing upright or walking. After standing with the added loads, the absolute negative k value increased for the 25 Hz frequency. After walking with the added loads, the k coefficient increased for the two vibration frequencies. Weight carrying significantly increased both the CoP surface and CoP lateral deviation. Conclusions: Our data show that weight carrying reduces the sensory pathways from the foot sole and accentuates the center of pressure deviations.

The purpose of this study was to determine the substrate oxidation rate and the exercise intensity at which maximal lipid oxidation and ventilatory threshold (VT) occur in obese (BMI: 36.6 ± 6.3 kg · m(-2)) and normal-weight adolescent girls (BMI: 18.7 ± 1.6 kg · m(-2)) aged 14-18 years. Substrate oxidation rate was determined by gas exchange using an incremental field test involving walking. Body composition was assessed by bioelectrical impedance. Carbohydrate oxidation rates were significantly higher in obese than in normal-weight girls at speeds ranging from 4 to 6 km · h(-1) (P0.05), whereas no significant differences were observed between groups regarding lipid oxidation rates. The crossover point of substrate utilisation and the VT were significantly lower in obese than in normal-weight adolescents (P0.05). Maximal lipid oxidation rate was observed at 46 ± 15 and 53 ± 15 %EVO2max in obese and normal-weight adolescents, respectively. At these intensities, the Lipox(max) was significantly lower in obese than in normal-weight girls (6.7 ± 2.3 versus 8.9 ± 3.5 mg · min(-1) · kg(-1) FFM, P0.05, 95% CI: -3.7 to -0.7, d = -0.74). The present results have implications in designing interventions to promote lipid oxidation and energy expenditure during walking in severely obese adolescent girls.

Background In some sports such as rugby, a large body size is an advantage, and the desire to gain weight can bring young players to become overweight or obese. The aim of this study was to evaluate the prevalence of overweight and obesity and the contribution of body fat mass index (BFMI) and fat-free mass index (FFMI) to body mass index (BMI) changes among young male rugby players (15-a-side rugby). Methods The criteria of the International Obesity Task Force were used to define overweight and obesity from BMI. The method of skinfold thickness was used to assess percentage of body fat (%BF), BFMI, and FFMI. Excess body fat was defined by using BFMI and %BF above the 75th percentile. Data were grouped according to the age categories of the French Rugby Federation (U11, under 11 years; U13, under 13 years; U15, under 15 years) and to BMI status (NW normal-weight versus OW/OB overweight/obese). Results Overall, 32.8% of the young players were overweight, and 13.8% were obese. However, 53% of young players classified as obese and overweight by BMI had an excess body fat by using BFMI above the 75th percentile. FFMI increased significantly between U11 and U13 in both groups, without significant change in BMI and BFMI. Both groups had similar significant gains in BMI and FFMI between U13 and U15, while BFMI only increased significantly in OW/OB (+ 18.5%). The strong correlations between BMI and %BF were systematically lower than those between BMI and BFMI. FFMI was strongly or moderately associated with BFMI. Conclusions Chart analysis of BFMI and FFMI could be used to distinguish changes in body composition across age categories in young male rugby players classified as normal-weight, overweight, and obese by BMI.

International audience; Background: The risk factors of pulmonary edema induced by diving in healthy subjects are not well known. The aim of the present study was to assess the parameters contributing to the increase in extravascular lung water after diving.Methods: This study was carried out in a professional diving institute. All divers participating in the teaching program from June 2012 to June 2014 were included in the study. Extravascular lung water was assessed using the detection of ultrasound lung comets (ULC) by chest ultrasonography. Clinical parameters and dive profiles were recorded using a questionnaire and a dive computer.Results: One-hundred six divers were investigated after 263 dives. They used an open-circuit umbilical supplying compressed gas diving apparatus in 202 cases and a self-contained underwater breathing apparatus in 61 cases. A generalized linear mixed model analysis was performed which demonstrated that the dive induced a significant increase in ULC score (incidence rate ratio: 3.16). It also identified that the predictive variable of increased extravascular lung water after the dive was the exercise intensity at depth (z = 3.99, p < 0.0001). The other parameters studied such as the water temperature, dive profile, hyperoxic exposure, or anthropometric data were not associated with the increase in extravascular lung water after the dive.Conclusions: In this study, the exercise intensity was the main contributor to the increase in extravascular lung water in healthy divers. To improve the prevention of immersion pulmonary edema, the exercise intensity experienced during the dive should thus be adapted to the aerobic fitness level of the divers.

Objective The glossopharyngeal insufflation maneuver (lung packing) is largely performed by competitive breath-hold divers to improve their performance, despite observational evidence of fainting and loss of consciousness in the first seconds of apnea. Methods We describe here the time course of hemodynamic changes, induced by breath-holding with and without lung packing, in 2 world-class apnea competitors. Results When compared with apnea performed after a deep breath (100% vital capacity), lung packing leads to a decrease in cardiac output, blood pressure, and cerebral blood flow during the first seconds after the beginning of apnea. The major hemodynamic disorders were observed in diver 1, who exhibited the greater increase in pulmonary volume after lung packing (+22% for diver 1 vs +10% for diver 2). After the initial drop in both cardiac output and blood pressure, the time course of hemodynamic alterations became quite similar between the two apneas. Conclusions Some recommendations, such as limiting the number of maneuvers and performing lung packing in the supine position, should be expressed to avoid injuries secondary to the use of glossopharyngeal insufflation.

Immersion in thermoneutral water increases cardiac output and peripheral blood flow and reduces systemic vascular resistance. This study examined the effects of head-out water immersion on vascular function. Twelve healthy middle-aged males were immersed during 60 min in the seated position, with water at the level of xiphoid. Local and central vascular tone regulating systems were studied during that time. Brachial artery diameter and blood flow were recorded using ultrasonography and Doppler. Endothelial function was assessed with flow-mediated dilation. Results were compared with the same investigations performed under reference conditions in ambient air. During water immersion, brachial artery diameter increased (3.7 ± 0.2 mm in ambient air vs. 4 ± 0.2 mm in water immersion; p < 0.05). Endothelium-mediated dilation was significantly lower in water immersion than in ambient air (10% vs. 15%; p = 0.01). Nevertheless, the difference disappeared when the percentage vasodilatation of the brachial artery was normalized to the shear stimulus. Smooth muscle-mediated dilation was similar in the 2 conditions. Spectral analysis of systolic blood pressure variability indicated a decrease in sympathetic vascular activity. Plasma levels of nitric oxide metabolites remained unchanged, whereas levels of natriuretic peptides were significantly elevated. An increase in brachial blood flow, a decrease in sympathetic activity, a warming of the skin, and an increase in natriuretic peptides might be involved in the increase in reference diameter observed during water immersion. Endothelial cell reactivity and smooth muscle function did not appear to be altered.