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Transdiaphragmatic pressure

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
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
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
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
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
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
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
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
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
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
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
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
Henri Meric, Line Falaize, Didier Pradon, David Orlikowski, Hélène Prigent, Frédéric Lofaso
Late-onset Pompe disease, for which enzyme replacement therapy is available, induces progressive diaphragmatic weakness. Monitoring diaphragmatic function is therefore crucial but is hindered by the need to insert esophageal and gastric probes. Vital capacity (VC), inspiratory capacity, maximal inspiratory pressure, and sniff nasal pressure are noninvasive measurements but reflect only global inspiratory-muscle function. Diaphragmatic function may be assessable noninvasively based on abdominal contribution to breathing and abdominal volume change during the VC maneuver (AVC-VC), obtained by 3-dimensional chest-wall analysis...
February 2016: Neuromuscular Disorders: NMD
Barbara K Smith, Manuela Corti, A Daniel Martin, David D Fuller, Barry J Byrne
Pompe disease is an inherited neuromuscular disorder that affects respiratory function and leads to dependence on external ventilatory support. We studied the activation of the diaphragm using bilateral phrenic magnetic stimulation and hypothesized that diaphragm compound muscle action potential (CMAP) amplitude and evoked transdiaphragmatic pressure (Twitch PDI) would correlate to disease severity. Eight patients with late onset Pompe disease (LOPD, aged 14-48 years) and four healthy control subjects completed the tests...
February 1, 2016: Respiratory Physiology & Neurobiology
Taishin Ito, Fumiyo Yasuma, Yousuke Toyonaga, Yoko Kobayashi, Aki Shinohara, Mika Furuya, Yuka Shiga, Yasuhiro Maehara
Pseudomyxoma peritonei (PMP) is a condition characterized by production of a large amount of mucopolysaccharides by neoplastic epithelium, with intraabdominal cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) known to be viable treatment options. Pleural extension from an PMP is unusual and thought to be related to diaphragmatic perforation during surgery or transdiaphragmatic spreading of the disease through the lymphatic lacunae. Here, we report a patient with PMP with pleural extension of a mucinous tumor for whom CRS was performed twice...
June 2015: Masui. the Japanese Journal of Anesthesiology
Leonardo M Del Grande, Fernando A M Herbella, Amilcar M Bigatao, Henrique Abrao, Jose R Jardim, Marco G Patti
No abstract text is available yet for this article.
January 2016: Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract
Prashanth Bhat, Olie Chowdhury, Sandeep Shetty, Simon Hannam, Gerrard F Rafferty, Janet Peacock, Anne Greenough
UNLABELLED: Our aims were to determine whether volume-targeted ventilation (VTV) or pressure-limited ventilation (PLV) reduced the time to successful extubation and if any difference was explained by a lower work of breathing (WOB), better respiratory muscle strength or less thoracoabdominal asynchrony (TAA) and associated with fewer hypocarbic episodes. Infants born at ≥34 weeks of gestational age were randomised to VTV or PLV. The WOB was assessed by the transdiaphragmatic pressure time product, respiratory muscle strength by the maximum inflation (Pimax) and expiratory (Pemax) pressures and TAA assessed using uncalibrated respiratory inductance plethysmography...
January 2016: European Journal of Pediatrics
Jonne Doorduin, Jenneke Leentjens, Matthijs Kox, Hieronymus W H van Hees, Johannes G van der Hoeven, Peter Pickkers, Leo M A Heunks
INTRODUCTION: Systemic inflammation is a well-known risk factor for respiratory muscle weakness. Studies using animal models of inflammation have shown that endotoxin administration induces diaphragm dysfunction. However, the effects of in vivo endotoxin administration on diaphragm function in humans have not been studied. Our aim was to evaluate diaphragm function in a model of systemic inflammation in healthy subjects. METHODS: Two groups of 12 male volunteers received an intravenous bolus of 2 ng/kg of Escherichia coli lipopolysaccharide (LPS) and were monitored until 8 h after LPS administration...
October 2015: Shock
Anna L Hudson, Fabrice Joulia, Annie A Butler, Richard C Fitzpatrick, Simon C Gandevia, Jane E Butler
During quiet breathing, activation of obligatory inspiratory muscles differs in timing and magnitude. To test the hypothesis that this coordinated activation can be modified, we determined the effect of the upside-down posture compared with standing and lying supine. Subjects (n=14) breathed through a pneumotachometer with calibrated inductance bands around the chest wall and abdomen. Surface electromyographic activity (EMG) was recorded from the scalene muscles. Crural diaphragmatic EMG and oesophageal and gastric pressures were measured in a subset of six subjects...
June 2016: Respiratory Physiology & Neurobiology
Juan S Medina-Martínez, Sarah M Greising, Gary C Sieck, Carlos B Mantilla
We developed and tested a semi-automated algorithm to generate large data sets of ventilatory information (amplitude, premotor drive and timing) across a range of motor behaviors. Adult spontaneously breathing, anesthetized mice (n = 27) underwent measurements of transdiaphragmatic pressure (Pdi) during eupnea, hypoxia-hypercapnia, and tracheal occlusion with values ranging from 8 ± 1 to 9 ± 2 to 44 ± 3 cmH2O, respectively. Premotor drive to phrenic motor neurons (estimated by the rate of rise during initial 60 ms) was ∼ 5-fold greater during tracheal occlusion compared to other behaviors...
August 15, 2015: Respiratory Physiology & Neurobiology
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