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Ventilatory drive

Matthieu Dubois, Cécile Chenivesse, Mathieu Raux, Adrian Morales-Robles, Marie-Cécile Nierat, Gilles Garcia, Xavier Navarro-Sune, Mario Chavez, Jacques Martinerie, Thomas Similowski
: Spontaneous ventilation in mammals is driven by automatic brainstem networks that generate the respiratory rhythm and increase ventilation in the presence of increased carbon dioxide production. Hypocapnia decreases the drive to breathe and induces apnea. In humans, this occurs during sleep but not during wakefulness. We hypothesized that hypocapnic breathing would be associated with respiratory-related cortical activity similar to that observed during volitional breathing, inspiratory constraints, or in patients with defective automatic breathing (preinspiratory potentials)...
October 12, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Andrée Dionne, Mario Leone, David E Andrich, Louis Pérusse, Alain Steve Comtois
We aimed to determine the effect of aquatic cycling and different levels of immersion on respiratory responses in healthy and heart disease (HD) volunteers. Thirty-four age matched volunteers, 21 HD and 13 healthy controls (HC) took part in this study. The ventilatory pattern, phase 1VE and steady-state ventilatory responses to progressive exercise from 40 to peak rpm, were measured while participants exercised on a water stationary bike (WSB) at different levels of immersion. No effect of immersion was observed on steady-state respiratory responses in the HD group, but immersion reduced VE phase 1 by ∼79% at pedaling cadences of 40, 50 and 60rpm...
September 23, 2016: Respiratory Physiology & Neurobiology
Veronica J Cerpa, Yuanming Wu, Eduardo Bravo, Frida A Teran, Rachel S Flynn, George B Richerson
Serotonin (5-HT) neurons contribute to respiratory chemoreception in adult mice, but it is unclear whether they play a similar role in neonatal mice. We studied breathing during development in Lmx1b(f/f/p) mice, which lack 5-HT neurons. From postnatal days 1-7 (P1-P7), ventilation of Lmx1b(f/f/p) mice breathing room air was 50% of WT mice (p < 0.001). By P12, baseline ventilation increased to a level equal to WT mice. In contrast, the hypercapnic ventilatory response (HCVR) of neonatal Lmx1b(f/f/p) and WT mice were equal to each other, but were both much less than adult WT mice...
September 9, 2016: Neuroscience
Ary Serpa Neto, Matthieu Schmidt, Luciano C P Azevedo, Thomas Bein, Laurent Brochard, Gernot Beutel, Alain Combes, Eduardo L V Costa, Carol Hodgson, Christian Lindskov, Matthias Lubnow, Catherina Lueck, Andrew J Michaels, Jose-Artur Paiva, Marcelo Park, Antonio Pesenti, Tài Pham, Michael Quintel, V Marco Ranieri, Michael Ried, Roberto Roncon-Albuquerque, Arthur S Slutsky, Shinhiro Takeda, Pier Paolo Terragni, Marie Vejen, Steffen Weber-Carstens, Tobias Welte, Marcelo Gama de Abreu, Paolo Pelosi, Marcus J Schultz
PURPOSE: Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for patients with acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate associations between ventilatory settings during ECMO for refractory hypoxemia and outcome in ARDS patients. METHODS: In this individual patient data meta-analysis of observational studies in adult ARDS patients receiving ECMO for refractory hypoxemia, a time-dependent frailty model was used to determine which ventilator settings in the first 3 days of ECMO had an independent association with in-hospital mortality...
September 1, 2016: Intensive Care Medicine
A Mark Evans, Amira D Mahmoud, Javier Moral-Sanz, Sandy Hartmann
Regulation of breathing is critical to our capacity to accommodate deficits in oxygen availability and demand during, for example, sleep and ascent to altitude. It is generally accepted that a fall in arterial oxygen increases afferent discharge from the carotid bodies to the brainstem and thus delivers increased ventilatory drive, which restores oxygen supply and protects against hypoventilation and apnoea. However, the precise molecular mechanisms involved remain unclear. We recently identified as critical to this process the AMP-activated protein kinase (AMPK), which is key to the cell-autonomous regulation of metabolic homoeostasis...
September 1, 2016: Biochemical Journal
Scott A Sands, Yoseph Mebrate, Bradley A Edwards, Shamim Nemati, Charlotte H Manisty, Akshay S Desai, Andrew Wellman, Keith Willson, Darrel P Francis, James P Butler, Atul Malhotra
RATIONALE: In patients with chronic heart failure, daytime oscillatory breathing at rest is associated with high mortality risk. Experimental evidence, including exaggerated ventilatory responses to carbon dioxide (CO2) and prolonged circulation time, implicates the ventilatory control system and suggests feedback instability (loop gain>1) is responsible. However, daytime oscillatory patterns often appear remarkably irregular versus classical instability (Cheyne-Stokes respiration), suggesting our mechanistic understanding is limited...
August 25, 2016: American Journal of Respiratory and Critical Care Medicine
Rajashree Ranjita, Alex Hankey, H R Nagendra, Soubhagylaxmi Mohanty
BACKGROUND: Coal mine dust exposure causes chronic airflow limitation in coal miners resulting in dyspnea, fatigue, and eventually chronic obstructive pulmonary disease (COPD). Yoga can alleviate dyspnea in COPD by improving ventilatory mechanics, reducing central neural drive, and partially restoring neuromechanical coupling of the respiratory system. OBJECTIVES: To evaluate the effectiveness of Integrated Approach of Yoga Therapy (IAYT) in the management of dyspnea and fatigue in coal miners with COPD...
July 2016: Journal of Ayurveda and Integrative 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
Vivian Rotman, Alysson Roncally Carvalho, Rosana Souza Rodrigues, Denise Machado Medeiros, Eduardo Costa Pinto, Fernando Augusto Bozza, Carlos Roberto Ribeiro Carvalho
BACKGROUND: Ventilation with low tidal volume (VT) is well recognized as a protective approach to patients with acute respiratory distress syndrome (ARDS), but the optimal level of positive end-expiratory pressure (PEEP) remains uncertain. This study aims to evaluate two protective ventilatory strategies sequentially applied in patients with early ARDS. METHODS: In this prospective cohort study, fifteen patients were ventilated during 24 h with positive end-expiratory pressure (PEEP) adjusted according to the ARDSnet low-PEEP table (ARDSnet-24 h)...
2016: BMC Anesthesiology
Alessandro Amaddeo, Annick Frapin, Brigitte Fauroux
Use of long-term non-invasive ventilation is increasing exponentially worldwide in children of all ages. The treatment entails delivery of ventilatory assistance through a non-invasive interface. Indications for use of non-invasive ventilation include conditions that affect normal respiratory balance (eg, those associated with dysfunction of the central drive or respiratory muscles) and disorders characterised by an increase in respiratory load (eg, obstructive airway or lung diseases). The type of non-invasive ventilation used depends on the pathophysiological features of the respiratory failure...
July 13, 2016: Lancet Respiratory Medicine
Jianheng Zhang, Qun Luo, Huijin Zhang, Rongchang Chen
The inspiratory pressure is often set by tolerance of chronic obstructive pulmonary disease (COPD) patient during noninvasive pressure support ventilation (PSV). However, physiological effects of this setting remain unclear. This study was undertaken to assess the physiological effect of highest tolerated assist level on COPD patient.  The baseline inspiratory pressure (PS) was titrated by tolerance in 15 severe COPD patients with hypercapnia during acute exacerbation. In addition to the baseline PS, an additional decrease by 25% (PS- = 75% PS) or increase by 25% (PS+ = 125% PS) of PS was applied to the patients...
July 6, 2016: COPD
Rodrigo Del Rio, David C Andrade, Claudia Lucero, Paulina Arias, Rodrigo Iturriaga
Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, enhances carotid body (CB) chemosensory responses to hypoxia and produces autonomic dysfunction, cardiac arrhythmias, and hypertension. We tested whether autonomic alterations, arrhythmogenesis, and the progression of hypertension induced by CIH depend on the enhanced CB chemosensory drive, by ablation of the CB chemoreceptors. Male Sprague-Dawley rats were exposed to control (Sham) conditions for 7 days and then to CIH (5% O2, 12/h 8 h/d) for a total of 28 days...
August 2016: Hypertension
Adeline Zbrzeski, Yannick Bornat, Brian Hillen, Ricardo Siu, James Abbas, Ranu Jung, Sylvie Renaud
Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA)...
2016: Frontiers in Neuroscience
Gino S Panza, Jeffrey E Herrick, Jared M Gollie, Donal Murray, John Collins, Andrew A Guccione
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Keith R Burgess, Philip N Ainslie
The discovery of central sleep apnea (CSA) at high altitude is usually attributed to Angelo Mosso who published in 1898. It can occur in susceptible individuals at altitude above 2000 m, but at very high altitude, say above 5000 m, it will occur in most subjects. Severity is correlated with ventilatory responsiveness, particularly to hypoxia. Theoretically, it should spontaneously improve with time and acclimatization. Although the time course of resolution is not well described, it appears to persist for more than a month at 5000 m...
2016: Advances in Experimental Medicine and Biology
Thomas P Olson, Bruce D Johnson, Barry A Borlaug
OBJECTIVES: The purpose of this study was to compare measures of gas exchange at rest and during exercise in patients with heart failure and preserved ejection fraction (HFpEF) with age- and sex-matched control subjects. BACKGROUND: Patients with HFpEF display elevation in left heart pressures, but it is unclear how this affects pulmonary gas transfer or its determinants at rest and during exercise. METHODS: Patients with HFpEF (n = 20) and control subjects (n = 26) completed a recumbent cycle ergometry exercise test with simultaneous measurement of ventilation and gas exchange...
June 2016: JACC. Heart Failure
Davide Chiumello, Matteo Brioni
BACKGROUND: Acute respiratory distress syndrome (ARDS) is characterized by a noncardiogenic pulmonary edema with bilateral chest X-ray opacities and reduction in lung compliance, and the hallmark of the syndrome is hypoxemia refractory to oxygen therapy. Severe hypoxemia (PaO2/FiO2 < 100 mmHg), which defines severe ARDS, can be found in 20-30 % of the patients and is associated with the highest mortality rate. Although the standard supportive treatment remains mechanical ventilation (noninvasive and invasive), possible adjuvant therapies can be considered...
2016: Critical Care: the Official Journal of the Critical Care Forum
Camilo Toledo, David C Andrade, Claudia Lucero, Harold D Schultz, Noah Marcus, Mauricio Retamal, Carlos Madrid, Rodrigo Del Rio
Chronic Heart failure (CHF) is a major public health problem. Tonic hyper-activation of sympathetic neural outflow is commonly observed in patients with CHF. Importantly, sympatho-excitation in CHF exacerbates its progression and is strongly related to poor prognosis and high mortality risk. Increases in peripheral and central chemoreflex drive are both considered markers of the severity of CHF. The principal peripheral chemoreceptors are the carotid bodies (CBs) and alteration in their function has been described in CHF...
May 24, 2016: Journal of Physiology
Flavio F Arbex, Maria Clara Alencar, Aline Souza, Adriana Mazzuco, Priscila A Sperandio, Alcides Rocha, Daniel M Hirai, Frederico Mancuso, Danilo C Berton, Audrey Borghi-Silva, Dirceu R Almeida, Denis E O'Donnell, J Alberto Neder
Systolic heart failure is a common and disabling co-morbidity of chronic obstructive pulmonary disease (COPD) which may increase exercise ventilation due to heightened neural drive and/or impaired pulmonary gas exchange efficiency. The influence of heart failure on exercise ventilation, however, remains poorly characterized in COPD. In a prospective study, 98 patients with moderate to very severe COPD [41 with coexisting heart failure; 'overlap' (left ventricular ejection fraction < 50%)] underwent an incremental cardiopulmonary exercise test (CPET)...
May 12, 2016: COPD
Anne-Sophie Perrin-Terrin, Florine Jeton, Aurelien Pichon, Alain Frugière, Jean-Paul Richalet, Laurence Bodineau, Nicolas Voituron
Many studies seek to identify and map the brain regions involved in specific physiological regulations. The proto-oncogene c-fos, an immediate early gene, is expressed in neurons in response to various stimuli. The protein product can be readily detected with immunohistochemical techniques leading to the use of c-FOS detection to map groups of neurons that display changes in their activity. In this article, we focused on the identification of brainstem neuronal populations involved in the ventilatory adaptation to hypoxia or hypercapnia...
2016: Journal of Visualized Experiments: JoVE
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