Source: Annual Congress 2012 - Various issues in clinical physiology
Disease area: Airway diseases, Respiratory critical care

Abstract

Hypercapnia has been purposed among the systemic factors participating in muscle dysfunction occurring in COPD. Aim: To assess the effects of acute and chronic exposure to bouts of hypercapnia on peripheral and respiratory muscle function. Methods: Two subgroups of 8 Wistar rats each were submitted to either a hypercapnic gas mixture (FICO₂ 0.5) or room air, 2 h/d for 15 days. Maximal inspiratory pressure (MIP), lower limb dynamometry (LLD), breathing pattern, work of breathing, P0.1 and arterial blood gases were determined at the beginning and at the end of each exposure. Results: Acute exposure to hypercapnia (1^st single bout) did not involve changes in muscle function. However, chronic exposure to hypercapnic bouts resulted in a lower weight gain, and a decrease in both MIP (% ref) and LLD (% ref) in hypercapnic animals when compared with controls. Interestingly, acute exposure to hypercapnia in the last (15^th) day also involved a decrease in both MIP and LLD. Acute hypercapnia resulted in increases in respiratory rate (RR) but minute ventilation (VE) and P0.1 remained constant. Chronic exposure to hypercapnic bouts did not change breathing pattern nor ventilatory drive. Conclusions: Although a single acute exposure to hypercapnia did not induce changes in muscle function, repeated exposures resulted in both a loss in muscle strength and an increase in susceptibility to a further impairment with new hypercapnic bouts. The similar behavior of respiratory and limb muscle strength, both normalized by rat anthropometry, indicates that the loss of force is the result of hypercapnia and not a consequence of either the increase in ventilatory work or the decrease in weight gain. Supported by ERS short fellowship, SEPAR and J.Gras Grants.

Rating:

Share or cite this content

Citations should be made in the following way:
M. Sanzsarovskaya, S. Pascual, F. Sánchez-Corredera, M. Domínguez.Alvarez, C. Casadevall, E. Barreiro, J. Gea (Tomsk, Russian Federation; Barcelona, Spain). Exposure to hypercapnia and muscle function. Eur Respir J 2012; 40: Suppl. 56, 3791

Member's Comments

No comment yet.

Related content which might interest you: Progression of diaphragmatic fatigue during inspiratory muscle loading in normoxia and hypoxia Source: Annual Congress 2013 –Respiratory muscles at rest and during exercise: from physiology to clinical context Year: 2013 Aminophylline increases respiratory muscle activity during hypercapnia in humans Source: Annual Congress 2008 - Respiratory muscle pathophysiology Year: 2008 Human inspiratory muscle fatigue during resistive load under normo-, hypo- and hyperoxia Source: Annual Congress 2007 - Exercise: respiratory muscle fatigue and dynamic hyperinflation Year: 2007 Hyperoxic effects on inspiratory muscle fatigue in cycling healthy humans Source: Annual Congress 2008 - Pulmonary mechanics and gas exchange Year: 2008 Positive effects of inspiratory muscle training(IMT) on ventilatory response to progressive hypercapnia in healthy subjects Source: Annual Congress 2011 - Respiratory and skeletal muscle assessment in health and disease Year: 2011 Acute effects of normocapnic hyperpnoea exercise on intercostal and locomotor muscle oxygenation in COPD Source: International Congress 2018 – Respiratory muscles and lung function: from healthy subjects to patients Year: 2018 Hypercapnia does not affect inspiratory muscle fatigue in exercising human Source: Annual Congress 2008 - Exercise: system responses Year: 2008 Effects of progressive isocapnic hypoxia on ventilatory response and respiratory center output in animal asthma model Source: Eur Respir J 2006; 28: Suppl. 50, 503s Year: 2006 The effect of normobaric hypoxia on respiratory muscle oxygenation during incremental inspiratory threshold loading (ITL) in healthy adults Source: International Congress 2015 – Respiratory muscles and airways function: from physiology to clinical implications Year: 2015 Sustained maximal inspiratory pressure as a measure to inspiratory muscle function Source: International Congress 2015 – Respiratory physiotherapy: outcomes in disease and health Year: 2015 Acute effects of intermittent and continuous normocapnic hyperpnea on lung function and airway resistance in asthmatics Source: Annual Congress 2012 - New issues in pulmonary function Year: 2012 Relationship between ventilatory constraint and muscle fatigue during exercise in COPD Source: Eur Respir J 2009; 33: 763-770 Year: 2009 Effects of airway smooth muscle activation and unloading on short-term variability of inspiratory impedance in healthy and asthmatic subjects Source: Annual Congress 2012 - New issues in pulmonary function Year: 2012 Intrinsic tone in human airway smooth muscle increases subsequent contractile response Source: International Congress 2018 – Preclinical pharmacology: novel targets in airway inflammation, narrowing and neural control Year: 2018 Effects of sustained hypoxia on sternohyoid and diaphragm muscle during development Source: Eur Respir J 2014; 43: 1149-1158 Year: 2014 Respiratory muscle activation, breathing pattern and respiratory muscle oxygen availability during Tapered Flow Resistive Loading and Normocapnic Hyperpnea in COPD. Source: International Congress 2019 – Assessment and training of respiratory muscles Year: 2019 Determinants of breathing effort sensation in normoxia and hypobaric hypoxia Source: Annual Congress 2009 - Respiratory muscle function and pattern of breathing Year: 2009 Effect of hypoxia on proliferation and VEGF-release of human bronchial smooth muscle cells Source: Annual Congress 2013 –Novel in vitro and animal models to study lung diseases Year: 2013 The voluntary drive to breathe is not decreased in hypercapnic patients with severe COPD Source: Eur Respir J 2001; 18: 53-60 Year: 2001 Respiratory muscles training with isocapnic hyperpnoea (hy) method improves ventilatory parameters and exercise capacity Source: Annual Congress 2009 - Gas exchange and exercise in respiratory diseases Year: 2009