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Thomas Similowski - One of the best experts on this subject based on the ideXlab platform.
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Diaphragm shear modulus reflects transDiaphragmatic Pressure Diaphragm shear modulus reflects transDiaphragmatic Pressure 1 during isovolumetric inspiratory efforts and ventilation against 2 inspiratory loading 3
Journal of Applied Physiology, 2019Co-Authors: Damien Bachasson, Martin Dres, Marie-cecile Nierat, Jean-luc Gennisson, Jean-yves Hogrel, Jonne Doorduin, Thomas SimilowskiAbstract:The reference method for the assessment of Diaphragm function relies on the measurement of transDiaphragmatic Pressure (Pdi). Local muscle stiffness measured using ultrafast shear wave elastography (SWE) provides reliable estimates of muscle force in locomotor muscles. This study aimed at investigating whether SWE could be used as a surrogate of Pdi to evaluate Diaphragm function. Fifteen healthy volunteers underwent a randomized stepwise inspiratory loading protocol of 0-60% of maximal isovolumetric inspiratory Pressure during closed-airways maneuvers and 0-50% during ventilation against an external inspiratory threshold load. During all tasks, Pdi was measured and SWE was used to assess shear modulus of the right hemiDiaphragm (SMdi) at the zone of apposition. Pearson correlation coefficients ( r) and repeated-measures correlation coefficients ( R) were computed to determine within-individual and overall relationships between Pdi and SMdi, respectively. During closed-airways maneuvers, mean Pdi correlated to mean SMdi in all participants [ r ranged from 0.77 to 0.96, all P < 0.01; R = 0.82, 95% confidence intervals (0.76, 0.86), P < 0.01]. During ventilation against inspiratory threshold loading, Pdi swing correlated to maximal SMdi in all participants [ r ranged from 0.40 to 0.90, all P < 0.01; R = 0.70, 95% confidence intervals (0.66, 0.73), P < 0.001]. Changes in Diaphragm stiffness as assessed by SWE reflect changes in transDiaphragmatic Pressure. SWE provides a new opportunity for direct and noninvasive assessment of Diaphragm function. NEW & NOTEWORTHY Accurate and specific estimation of Diaphragm effort is critical for evaluating and monitoring Diaphragm dysfunction. The measurement of transDiaphragmatic Pressure requires the use of invasive gastric and esophageal probes. In the present work, we demonstrate that changes in Diaphragm stiffness assessed with ultrasound shear wave elastography reflect changes in transDiaphragmatic Pressure, therefore offering a new noninvasive method for gauging Diaphragm effort.
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Diaphragm dysfunction on admission to the intensive care unit. Prevalence, risk factors, and prognostic impact-a prospective study.
American journal of respiratory and critical care medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr,stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr,stim less than 11 cm H2O. Independent predictors of low Ptr,stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr,stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr,stim were similar. A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis. Clinical trial registered with www.clinicaltrials.gov (NCT 00786526).
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Diaphragm Dysfunction on Admission to the Intensive Care Unit. Prevalence, Risk Factors, and Prognostic Impact—A Prospective Study
American Journal of Respiratory and Critical Care Medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Rationale: Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. Objectives: To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Methods: Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Measurements and Main Results: Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr, stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr, stim less than 11 cm H2O. Independent predictors of low Ptr, stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr, stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr, stim were similar. Conclusions: A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis.
Samir Jaber - One of the best experts on this subject based on the ideXlab platform.
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Diaphragm dysfunction on admission to the intensive care unit. Prevalence, risk factors, and prognostic impact-a prospective study.
American journal of respiratory and critical care medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr,stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr,stim less than 11 cm H2O. Independent predictors of low Ptr,stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr,stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr,stim were similar. A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis. Clinical trial registered with www.clinicaltrials.gov (NCT 00786526).
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Diaphragm Dysfunction on Admission to the Intensive Care Unit. Prevalence, Risk Factors, and Prognostic Impact—A Prospective Study
American Journal of Respiratory and Critical Care Medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Rationale: Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. Objectives: To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Methods: Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Measurements and Main Results: Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr, stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr, stim less than 11 cm H2O. Independent predictors of low Ptr, stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr, stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr, stim were similar. Conclusions: A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis.
Alexandre Demoule - One of the best experts on this subject based on the ideXlab platform.
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Diaphragm dysfunction on admission to the intensive care unit. Prevalence, risk factors, and prognostic impact-a prospective study.
American journal of respiratory and critical care medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr,stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr,stim less than 11 cm H2O. Independent predictors of low Ptr,stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr,stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr,stim were similar. A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis. Clinical trial registered with www.clinicaltrials.gov (NCT 00786526).
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Diaphragm Dysfunction on Admission to the Intensive Care Unit. Prevalence, Risk Factors, and Prognostic Impact—A Prospective Study
American Journal of Respiratory and Critical Care Medicine, 2013Co-Authors: Alexandre Demoule, Thomas Similowski, Boris Jung, Hélène Prodanovic, Nicolas Molinari, Gerald Chanques, Catherine Coirault, Stefan Matecki, Alexandre Duguet, Samir JaberAbstract:Rationale: Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, Diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. Objectives: To determine the incidence, risk factors, and prognostic impact of Diaphragmatic impairment on ICU admission. Methods: Prospective, 6-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours after intubation (Day 1) and 48 hours later (Day 3). Seventeen anesthetized intubated control anesthesia patients were also studied. The Diaphragm was assessed by twitch tracheal Pressure in response to bilateral anterior magnetic phrenic nerve stimulation (Ptr,stim). Measurements and Main Results: Eighty-five consecutive patients aged 62 (54-75) (median [interquartile range]) were evaluated (medical admission, 79%; Simplified Acute Physiology Score II, 54 [44-68]). On Day 1, Ptr, stim was 8.2 (5.9-12.3) cm H2O and 64% of patients had Ptr, stim less than 11 cm H2O. Independent predictors of low Ptr, stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; P = 0.002) and Simplified Acute Physiology Score II (linear regression coefficient, -0.07; standard error, 1.69; P = 0.03). Compared with nonsurvivors, ICU survivors had higher Ptr, stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cm H2O; P = 0.004). This was also true for hospital survivors versus nonsurvivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cm H2O; P = 0.004). Day 1 and Day 3 Ptr, stim were similar. Conclusions: A reduced capacity of the Diaphragm to produce inspiratory Pressure (Diaphragm dysfunction) is frequent on ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis.
Armele Dornelas - One of the best experts on this subject based on the ideXlab platform.
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Effects of Inspiratory Muscle Training in Elderly Women on Respiratory Muscle Strength, Diaphragm Thickness and Mobility
The journals of gerontology. Series A Biological sciences and medical sciences, 2014Co-Authors: Helga Cecília Muniz De Souza, Taciano Rocha, Maíra Pessoa, Catarina Rattes, Daniella Cunha Brandão, Guilherme Fregonezi, Shirley Lima Campos, Andrea Aliverti, Armele DornelasAbstract:BACKGROUND Aging results in a decline in the function of the respiratory muscles. Inspiratory muscle training is emerging as a possible intervention to attenuate the decline of respiratory muscles in the elderly. The aim of this study was to evaluate the efficacy of inspiratory muscle training on respiratory strength, Diaphragm thickness, and Diaphragmatic mobility in elderly women. METHODS This was a controlled, randomized, and double-blind clinical trial, performed on 22 elderly women distributed in two groups, training (TG) and control (CG). Over an 8-week period a moderate intensity inspiratory muscle training protocol was followed in the TG, while CG followed a sham protocol. In addition maximum expiratory and inspiratory Pressure, mobility of the Diaphragm and Diaphragmatic thickness were evaluated by ultrasound. RESULTS After training, in TG maximal inspiratory Pressure, maximal expiratory Pressure, Diaphragm thickness, and mobility increased by 37%, 13%, 11%, and 9% respectively, and their values were significantly higher than CG (p < .005, p = .013, p = .001, and p = .001). CONCLUSION Inspiratory muscle training of moderate intensity improves respiratory muscle strength, Diaphragm thickness, and Diaphragm mobility in elderly women and it should be considered to minimize changes associated with senescence.
Jonne Doorduin - One of the best experts on this subject based on the ideXlab platform.
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Diaphragm shear modulus reflects transDiaphragmatic Pressure Diaphragm shear modulus reflects transDiaphragmatic Pressure 1 during isovolumetric inspiratory efforts and ventilation against 2 inspiratory loading 3
Journal of Applied Physiology, 2019Co-Authors: Damien Bachasson, Martin Dres, Marie-cecile Nierat, Jean-luc Gennisson, Jean-yves Hogrel, Jonne Doorduin, Thomas SimilowskiAbstract:The reference method for the assessment of Diaphragm function relies on the measurement of transDiaphragmatic Pressure (Pdi). Local muscle stiffness measured using ultrafast shear wave elastography (SWE) provides reliable estimates of muscle force in locomotor muscles. This study aimed at investigating whether SWE could be used as a surrogate of Pdi to evaluate Diaphragm function. Fifteen healthy volunteers underwent a randomized stepwise inspiratory loading protocol of 0-60% of maximal isovolumetric inspiratory Pressure during closed-airways maneuvers and 0-50% during ventilation against an external inspiratory threshold load. During all tasks, Pdi was measured and SWE was used to assess shear modulus of the right hemiDiaphragm (SMdi) at the zone of apposition. Pearson correlation coefficients ( r) and repeated-measures correlation coefficients ( R) were computed to determine within-individual and overall relationships between Pdi and SMdi, respectively. During closed-airways maneuvers, mean Pdi correlated to mean SMdi in all participants [ r ranged from 0.77 to 0.96, all P < 0.01; R = 0.82, 95% confidence intervals (0.76, 0.86), P < 0.01]. During ventilation against inspiratory threshold loading, Pdi swing correlated to maximal SMdi in all participants [ r ranged from 0.40 to 0.90, all P < 0.01; R = 0.70, 95% confidence intervals (0.66, 0.73), P < 0.001]. Changes in Diaphragm stiffness as assessed by SWE reflect changes in transDiaphragmatic Pressure. SWE provides a new opportunity for direct and noninvasive assessment of Diaphragm function. NEW & NOTEWORTHY Accurate and specific estimation of Diaphragm effort is critical for evaluating and monitoring Diaphragm dysfunction. The measurement of transDiaphragmatic Pressure requires the use of invasive gastric and esophageal probes. In the present work, we demonstrate that changes in Diaphragm stiffness assessed with ultrasound shear wave elastography reflect changes in transDiaphragmatic Pressure, therefore offering a new noninvasive method for gauging Diaphragm effort.
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The Calcium Sensitizer Levosimendan Improves Human Diaphragm Function
American journal of respiratory and critical care medicine, 2012Co-Authors: Jonne Doorduin, Christer Sinderby, Jennifer Beck, Dick F. Stegeman, Hieronymus W. H. Van Hees, Johannes G. Van Der Hoeven, Leo M. A. HeunksAbstract:Acquired Diaphragm muscle weakness is a key feature in several chronic conditions, including chronic obstructive pulmonary disease, congestive heart failure, and difficult weaning from mechanical ventilation. No drugs are available to improve respiratory muscle function in these patients. Recently, we have shown that the calcium sensitizer levosimendan enhances the force-generating capacity of isolated Diaphragm fibers. To investigate the effects of the calcium sensitizer levosimendan on in vivo human Diaphragm function. In a double-blind, randomized, crossover design, 30 healthy subjects performed two identical inspiratory loading tasks. After the first loading task, subjects received levosimendan (40 μg/kg bolus followed by 0.1/0.2 μg/kg/min continuous infusion) or placebo. TransDiaphragmatic Pressure, Diaphragm electrical activity, and their relationship (neuromechanical efficiency) were measured during loading. Magnetic phrenic nerve stimulation was performed before the first loading task and after bolus administration to assess twitch contractility. Center frequency of Diaphragm electrical activity was evaluated to study the effects of levosimendan on muscle fiber conduction velocity. The placebo group showed a 9% (P=0.01) loss of twitch contractility after loaded breathing, whereas no loss in contractility was observed in the levosimendan group. Neuro-mechanical efficiency of the Diaphragm during loading improved by 21% (P<0.05) in the levosimendan group. Baseline center frequency of Diaphragm electrical activity was reduced after levosimendan administration (P<0.05). The calcium sensitizer levosimendan improves neuromechanical efficiency and contractile function of the human Diaphragm. Our findings suggest a new therapeutic approach to improve respiratory muscle function in patients with respiratory failure.