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Transdiaphragmatic pressure

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https://www.readbyqxmd.com/read/28620310/abdominal-binding-improves-neuromuscular-efficiency-of-the-human-diaphragm-during-exercise
#1
Sara J Abdallah, David S Chan, Robin Glicksman, Cassandra T Mendonca, Yuanming Luo, Jean Bourbeau, Benjamin M Smith, Dennis Jensen
We tested the hypothesis that elastic binding of the abdomen (AB) would enhance neuromuscular efficiency of the human diaphragm during exercise. Twelve healthy non-obese men aged 24.8 ± 1.7 years (mean ± SE) completed a symptom-limited constant-load cycle endurance exercise test at 85% of their peak incremental power output with diaphragmatic electromyography (EMGdi) and respiratory pressure measurements under two randomly assigned conditions: unbound control (CTRL) and AB sufficient to increase end-expiratory gastric pressure (Pga,ee) by 5-8 cmH2O at rest...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28522757/functional-assessment-of-the-diaphragm-by-speckle-tracking-ultrasound-during-inspiratory-loading
#2
Eline Oppersma, Nima Hatam, Jonne Doorduin, Johannes G van der Hoeven, Gernot Marx, Andreas Goetzenich, Sebastian Fritsch, Leo M A Heunks, Christian S Bruells
BACKGROUND: Assessment of diaphragmatic effort is challenging especially in critically ill patients in the phase of weaning. Fractional thickening during inspiration assessed by ultrasound has been used to estimate diaphragm effort. It is unknown whether more sophisticated ultrasound techniques such as speckle tracking are superior in the quantification of inspiratory effort. This study evaluates the validity of speckle tracking ultrasound to quantify diaphragm contractility. METHODS: Thirteen healthy volunteers underwent a randomized stepwise threshold loading protocol of 0 to 50% of the maximal inspiratory pressure...
May 18, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28502520/-exploring-the-diaphragm-ultrasound-is-essential
#3
REVIEW
P Richard
The diaphragm is the muscle most implicated in breathing. Its morphological exploration usually depends on pulmonary radiography, fluoroscopy, CT-scanning and MRI. Its function is evaluated by the classical respiratory functional tests, the measurement of maximum inspiratory and expiratory pressures, the transdiaphragmatic pressure and even an electromyogram. Ultrasound is a technique still insufficiently used in respiratory medicine. It offers, however, many advantages: it is easy to implement, there is no irradiation, it is usable at the bedside, particularly when the patient is immobile or in intensive care...
May 12, 2017: Revue des Maladies Respiratoires
https://www.readbyqxmd.com/read/28358826/a-growing-animal-model-for-neonatal-repair-of-large-diaphragmatic-defects-to-evaluate-patch-function-and-outcome
#4
Mary Patrice Eastwood, Luc Joyeux, Savitree Pranpanus, Johannes Van der Merwe, Eric Verbeken, Stephanie De Vleeschauwer, Ghislaine Gayan-Ramirez, Jan Deprest
OBJECTIVES: We aimed to develop a more representative model for neonatal congenital diaphragmatic hernia repair in a large animal model, by creating a large defect in a fast-growing pup, using functional pulmonary and diaphragmatic read outs. BACKGROUND: Grafts are increasingly used to repair congenital diaphragmatic hernia with the risk of local complications. Growing animal models have been used to test novel materials. METHODS: 6-week-old rabbits underwent fiberoptic intubation, left subcostal laparotomy and hemi-diaphragmatic excision (either nearly complete (n = 13) or 3*3cm (n = 9)) and primary closure (Gore-Tex patch)...
2017: PloS One
https://www.readbyqxmd.com/read/28318818/twitch-mouth-pressure-for-detecting-respiratory-muscle-weakness-in-suspicion-of-neuromuscular-disorder
#5
Dante Brasil Santos, Gilbert Desmarais, Line Falaize, Adam Ogna, Sandrine Cognet, Bruno Louis, David Orlikowski, Hélène Prigent, Frédéric Lofaso
Twitch mouth pressure using magnetic stimulation of the phrenic nerves and an automated inspiratory trigger is a noninvasive, non-volitional assessment of diaphragmatic strength. Our aims were to validate this method in patients with suspected neuromuscular disease, to determine the best inspiratory-trigger pressure threshold, and to evaluate whether twitch mouth pressure decreased the overdiagnosis of muscle weakness frequently observed with noninvasive volitional tests. Maximal inspiratory pressure, sniff nasal pressure, and twitch mouth pressure were measured in 112 patients with restrictive disease and suspected neuromuscular disorder...
February 2, 2017: Neuromuscular Disorders: NMD
https://www.readbyqxmd.com/read/28288012/influence-of-upper-body-exercise-on-the-fatigability-of-human-respiratory-muscles
#6
Nicholas B Tiller, Ian G Campbell, Lee M Romer
PURPOSE: Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. METHODS: Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg·min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak...
July 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28280321/transdiaphragmatic-pressure-and-neural-respiratory-drive-measured-during-inspiratory-muscle-training-in-stable-patients-with-chronic-obstructive-pulmonary-disease
#7
Weiliang Wu, Xianming Zhang, Lin Lin, Yonger Ou, Xiaoying Li, Lili Guan, Bingpeng Guo, Luqian Zhou, Rongchang Chen
PURPOSE: Inspiratory muscle training (IMT) is a rehabilitation therapy for stable patients with COPD. However, its therapeutic effect remains undefined due to the unclear nature of diaphragmatic mobilization during IMT. Diaphragmatic mobilization, represented by transdiaphragmatic pressure (Pdi), and neural respiratory drive, expressed as the corrected root mean square (RMS) of the diaphragmatic electromyogram (EMGdi), both provide vital information to select the proper IMT device and loads in COPD, therefore contributing to the curative effect of IMT...
2017: International Journal of Chronic Obstructive Pulmonary Disease
https://www.readbyqxmd.com/read/28258452/pathophysiology-of-gastroesophageal-reflux-disease
#8
Mariano A Menezes, Fernando A M Herbella
Gastroesophageal reflux disease pathophysiology is multifactorial and linked to a misbalance between the aggressiveness of the refluxate into the esophagus or adjacent organs and the failure of protective mechanisms associate or not to a defective valvular mechanism at the level of the esophagogastric junction incapable of dealing with a transdiaphragmatic pressure gradient. Antireflux mechanisms include the lower esophageal sphincter and abdominal esophagus, the diaphragm, the angle of His, the Gubaroff valve, and the phrenoesophageal membrane...
July 2017: World Journal of Surgery
https://www.readbyqxmd.com/read/28066619/clinical-management-of-chronic-obstructive-pulmonary-disease-patients-with-muscle-dysfunction
#9
REVIEW
Joaquim Gea, Carme Casadevall, Sergi Pascual, Mauricio Orozco-Levi, Esther Barreiro
Muscle dysfunction is frequently observed in chronic obstructive pulmonary disease (COPD) patients, contributing to their exercise limitation and a worsening prognosis. The main factor leading to limb muscle dysfunction is deconditioning, whereas respiratory muscle dysfunction is mostly the result of pulmonary hyperinflation. However, both limb and respiratory muscles are also influenced by other negative factors, including smoking, systemic inflammation, nutritional abnormalities, exacerbations and some drugs...
November 2016: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/27891099/reduced-phrenic-motoneuron-recruitment-during-sustained-inspiratory-threshold-loading-compared-to-single-breath-loading-a-twitch-interpolation-study
#10
Mathieu Raux, Alexandre Demoule, Stefania Redolfi, Capucine Morelot-Panzini, Thomas Similowski
In humans, inspiratory constraints engage cortical networks involving the supplementary motor area. Functional magnetic resonance imaging (fMRI) shows that the spread and intensity of the corresponding respiratory-related cortical activation dramatically decrease when a discrete load becomes sustained. This has been interpreted as reflecting motor cortical reorganization and automatisation, but could proceed from sensory and/or affective habituation. To corroborate the existence of motor reorganization between single-breath and sustained inspiratory loading (namely changes in motor neurones recruitment), we conducted a diaphragm twitch interpolation study based on the hypothesis that motor reorganization should result in changes in the twitch interpolation slope...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27494149/respiratory-muscle-strength-as-a-predictive-biomarker-for-survival-in-amyotrophic-lateral-sclerosis
#11
Michael I Polkey, Rebecca A Lyall, Ke Yang, Erin Johnson, P Nigel Leigh, John Moxham
RATIONALE: Biomarkers for survival in amyotrophic lateral sclerosis (ALS) would facilitate the development of novel drugs. Although respiratory muscle weakness is a known predictor of poor prognosis, a comprehensive comparison of different tests is lacking. OBJECTIVES: To compare the predictive power of invasive and noninvasive respiratory muscle strength assessments for survival or ventilator-free survival, up to 3 years. METHODS: From a previously published report respiratory muscle strength measurements were available for 78 patients with ALS...
January 1, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/27492828/mechanisms-of-exertional-dyspnoea-in-symptomatic-smokers-without-copd
#12
Amany F Elbehairy, Jordan A Guenette, Azmy Faisal, Casey E Ciavaglia, Katherine A Webb, Dennis Jensen, Andrew H Ramsook, J Alberto Neder, Denis E O'Donnell
Dyspnoea and activity limitation can occur in smokers who do not meet spirometric criteria for chronic obstructive pulmonary disease (COPD) but the underlying mechanisms are unknown.Detailed pulmonary function tests and sensory-mechanical relationships during incremental exercise with respiratory pressure measurements and diaphragmatic electromyography (EMGdi) were compared in 20 smokers without spirometric COPD and 20 age-matched healthy controls.Smokers (mean±sd post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity 75±4%, mean±sd FEV1 104±14% predicted) had greater activity-related dyspnoea, poorer health status and lower physical activity than controls...
September 2016: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
https://www.readbyqxmd.com/read/27492181/functional-measurement-of-respiratory-muscle-motor-behaviors-using-transdiaphragmatic-pressure
#13
Sarah M Greising, Carlos B Mantilla, Gary C Sieck
The diaphragm muscle must be able to generate sufficient forces to accomplish a range of ventilatory and non-ventilatory behaviors throughout life. Measurements of transdiaphragmatic pressure (Pdi) can be conducted during eupnea, hypoxia (10 % O2)-hypercapnia (5 % CO2), chemical airway stimulation (i.e., sneezing), spontaneously occurring deep breaths (i.e., sighs), sustained airway or tracheal occlusion, and maximal efforts elicited via bilateral phrenic nerve stimulation, representing the full range of motor behaviors available by the diaphragm muscle...
2016: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27350150/inhaled-beta-agonist-bronchodilator-does-not-affect-trans-diaphragmatic-pressure-gradient-but-decreases-lower-esophageal-sphincter-retention-pressure-in-patients-with-chronic-obstructive-pulmonary-disease-copd-and-gastroesophageal-reflux-disease-gerd
#14
Leonardo M Del Grande, Fernando A M Herbella, Amilcar M Bigatao, Jose R Jardim, Marco G Patti
BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients have a high incidence of gastroesophageal reflux disease (GERD) whose pathophysiology seems to be linked to an increased trans-diaphragmatic pressure gradient and not to a defective esophagogastric barrier. Inhaled beta agonist bronchodilators are a common therapy used by patients with COPD. This drug knowingly not only leads to a decrease in the lower esophageal sphincter (LES) resting pressure, favoring GERD, but also may improve ventilatory parameters, therefore preventing GERD...
October 2016: Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract
https://www.readbyqxmd.com/read/27036885/correlation-of-maximal-inspiratory-pressure-to-transdiaphragmatic-twitch-pressure-in-intensive-care-unit-patients
#15
Gerald S Supinski, Phillip Westgate, Leigh A Callahan
BACKGROUND: Respiratory muscle weakness contributes to respiratory failure in ICU patients. Unfortunately, assessment of weakness is difficult since the most objective test, transdiaphragmatic pressure in response to phrenic nerve stimulation (PdiTw), is difficult to perform. While most clinicians utilize maximum inspiratory pressure (Pimax) to assess strength, the relationship of this index to PdiTw has not been evaluated in a large ICU population. The purpose of the present study was to assess both PdiTw and Pimax in ICU patients to determine how these indices correlate with each other, what factors influence these indices, and how well these indices predict outcomes...
March 23, 2016: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/27035251/ultrasound-in-the-assessment-of-respiration
#16
REVIEW
Andrea J Boon, Cullen OʼGorman
Electromyographers are often asked to evaluate patients presenting with dyspnea or respiratory failure, to rule out an underlying neuromuscular cause for those symptoms. Available tools for diagnosing such patients include pulmonary function tests, transdiaphragmatic pressure testing, various imaging modalities, phrenic nerve conduction studies, and diaphragm electromyography. Phrenic nerve conduction studies and diaphragm electromyography are technically challenging and can be limited by both false positive and false negative results...
April 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
https://www.readbyqxmd.com/read/26922022/-effects-of-inhaled-short-acting-bronchodilators-on-diaphragm-function-and-neural-respiratory-drive-during-maximal-isocapnic-ventilation-in-patients-with-chronic-obstructive-pulmonary-disease
#17
RANDOMIZED CONTROLLED TRIAL
Yun Li, Yin-Huan Li, Yu-Wen Luo, Rui Xiao, Jin-Lun Huang, Kai Wang, Xin Chen
OBJECTIVE: To investigate the effects of inhaled short-acting bronchodilators on diaphragm function and neural respiratory drive in patients with chronic obstructive pulmonary disease (COPD) during maximal isocapnic ventilation (MIV). METHODS: Forty-seven patient with moderate to severe COPD were randomized into 4 groups: placebo group (n=12), salbutamol group (n=13), ipratropium group (n=10), and combined group (salbutamol and ipratropium, n=12). Each subject received an initial MIV for 3 min at baseline and inhaled placebo (400 µg), salbutamol (400 µg), ipratropium (80 µg), or both salbutamol and ipratropium, followed 30 min later by another 3 min of MIV...
February 2016: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
https://www.readbyqxmd.com/read/26845453/diaphragmatic-fatigue-during-inspiratory-muscle-loading-in-normoxia-and-hypoxia
#18
RANDOMIZED CONTROLLED TRIAL
David Johannes Walker, Franziska Farquharson, Hannes Klenze, Stephan Walterspacher, Lucia Storz, Daniel Duerschmied, Kai Roecker, Hans-Joachim Kabitz
INTRODUCTION: Diaphragmatic fatigue (DF) occurs during strenuous loading of respiratory muscles (e.g., heavy-intensity whole-body exercise, normocapnic hyperpnea, inspiratory resistive breathing). DF develops early on during normoxia, without further decline toward task failure; however, its progression during inspiratory muscle loading in during hypoxia remains unclear. Therefore, the present study used volume-corrected transdiaphragmatic pressures during supramaximal magnetic phrenic nerve stimulation (Pdi,twc) to investigate the effect of hypoxia on the progression of diaphragmatic fatigue during inspiratory muscle loading...
June 15, 2016: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/26802111/prediction-of-infant-extubation-outcomes-using-the-tension-time-index
#19
Prashanth Bhat, Janet L Peacock, Gerrard F Rafferty, Simon Hannam, Anne Greenough
OBJECTIVE: The tension-time index of the diaphragm (TTdi) is a composite assessment of the load on and the capacity of the diaphragm. TTmus is a non-invasive tension-time index of the respiratory muscles. Our aim was to determine whether TTdi or TTmus predicted extubation outcome and performed better than respiratory muscle strength (Pimax, Pdimax), respiratory drive (P0.1) and work of breathing (transdiaphragmatic pressure-time product (PTPdi)) or routinely available clinical data. DESIGN: Prospective study...
September 2016: Archives of Disease in Childhood. Fetal and Neonatal Edition
https://www.readbyqxmd.com/read/26795460/diaphragm-recruitment-increases-during-a-bout-of-targeted-inspiratory-muscle-training
#20
Andrew H Ramsook, Ryan Koo, Yannick Molgat-Seon, Paolo B Dominelli, Nafeez Syed, Christopher J Ryerson, Andrew W Sheel, Jordan A Guenette
PURPOSE: The extent to which the diaphragm is targeted during a bout of inspiratory muscle training (IMT) is unknown. The purpose of this study was to characterize the relative activation patterns of the diaphragm and extradiaphragmatic inspiratory muscles during a bout of IMT and to determine whether diaphragmatic recruitment can be increased by giving subjects specific diaphragmatic breathing instructions (IMTdi). METHODS: Ten healthy men were instrumented with surface EMG electrodes on the sternocleidomastoid (EMGscm), scalenes (EMGsca), parasternal intercostals (EMGpic), and seventh intercostal space (EMG7ic)...
June 2016: Medicine and Science in Sports and Exercise
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