The respiratory muscles during exercise

Although during exercise respiratory muscles are finely controlled, they can contribute to limit performance http://ow.ly/qYUc300m9uP

Wearable technology: role in respiratory health and disease

In the future, diagnostic devices will be able to monitor a patient's physiological or biochemical parameters continuously, under natural physiological conditions and in any environment through wearable biomedical sensors. Together with apps that capture and interpret data, and integrated enterprise and cloud data repositories, the networks of wearable devices and body area networks will constitute the healthcare's Internet of Things. In this review, four main areas of interest for respiratory healthcare are described: pulse oximetry, pulmonary ventilation, activity tracking and air quality assessment. Although several issues still need to be solved, smart wearable technologies will provide unique opportunities for the future or personalised respiratory medicine

Physiology of respiratory disturbances in muscular dystrophies

Muscular dystrophy is a group of inherited myopathies characterised by progressive skeletal muscle wasting, including of the respiratory muscles. Respiratory failure, i.e. when the respiratory system fails in its gas exchange functions, is a common feature in muscular dystrophy, being the main cause of death, and it is a consequence of lung failure, pump failure or a combination of the two. The former is due to recurrent aspiration, the latter to progressive weakness of respiratory muscles and an increase in the load against which they must contract. In fact, both the resistive and elastic components of the work of breathing increase due to airway obstruction and chest wall and lung stiffening, respectively. The respiratory disturbances in muscular dystrophy are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. They can be present at different rates according to the type of muscular dystrophy and its progression, leading to different onset of each symptom, prognosis and degree of respiratory involvement

Regional lung function and heterogeneity of specific gas volume in healthy and emphysematous subjects.

The aim of our study was to study regional lung function by standard computed tomography (CT) and characterise regional variations of density and specific gas volume (SVg) between different lung volumes. We studied 10 healthy and 10 severely emphysematous subjects. Corresponding CT images taken at high and low lung volumes were registered by optical flow to obtain two-dimensional maps of pixel-by-pixel differences of density (ΔHU) and SVg (ΔSVg) at slice levels near the aortic arch, carina and top diaphragm. In healthy subjects, ΔHU was higher at all levels (p<0.001) with higher variability expressed as interquartile range (p<0.001), largely due to its differences between dorsal and ventral regions. In patients, median ΔSVg values were 3.2 times lower than healthy volunteers (p<0.001), while heterogeneity of ΔSVg maps, expressed as quartile coefficient of variation, was 5.4 times higher (p<0.001). In all patients, there were areas with negative values of ΔSVg. In conclusion, ΔSVg is uniform in healthy lungs and minimally influenced by gravity. The significant ΔSVg heterogeneity observed in emphysema allows identification of areas of alveolar destruction and gas trapping and suggests that ΔSVg maps provide useful information for evaluation and planning of emerging treatments that target trapped gas for removal

From morphological heterogeneity at alveolar level to the overall mechanical lung behavior: an in vivo microscopic imaging study.

In six male anesthetized, tracheotomized, and mechanically ventilated rabbits, we imaged subpleural alveoli under microscopic view (60×) through a "pleural window" obtained by stripping the endothoracic fascia and leaving the parietal pleura intact. Three different imaging scale levels were identified for the analysis on increasing stepwise local distending pressure (P ld) up to 16.5 cmH2O: alveoli, alveolar cluster, and whole image field. Alveolar profiles were manually traced, clusters of alveoli of similar size were identified through a contiguity-constrained hierarchical agglomerative clustering analysis and alveolar surface density (ASD) was estimated as the percentage of air on the whole image field. Alveolar area distributions were remarkably right-skewed and showed an increase in median value with a large topology-independent heterogeneity on increasing P ld. Modeling of alveolar area distributions on increasing P ld led to hypothesize that absolute alveolar compliance (change in surface area over change in P ld) increases fairly linearly with increasing initial alveolar size, the corollary of this assumption being a constant specific compliance. Clusters were reciprocally interweaved due to their highly variable complex shapes. ASD was found to increase with a small coefficient of variation (CV <25\%) with increasing P ld. The CV of lung volume at each transpulmonary pressure was further decreased (about 6\%). The results of the study suggest that the considerable heterogeneity of alveolar size and of the corresponding alveolar mechanical behavior are homogenously distributed, resulting in a substantially homogenous mechanical behavior of lung units and whole organ

Assessment and management of respiratory function in patients with duchenne muscular dystrophy: Current and emerging options

Duchenne muscular dystrophy (DMD) is an X-linked myopathy resulting in progressive weakness and wasting of all the striated muscles including the respiratory muscles. The consequences are loss of ambulation before teen ages, cardiac involvement and breathing difficulties, the main cause of death. A cure for DMD is not currently available. In the last decades the survival of patients with DMD has improved because the natural history of the disease can be changed thanks to a more comprehensive therapeutic approach. This comprises interventions targeted to the manifestations and complications of the disease, particularly in the respiratory care. These include: 1) pharmacological intervention, namely corticosteroids and idebenone that significantly reduce the decline of spirometric parameters; 2) rehabilitative intervention, namely lung volume recruitment techniques that help prevent atelectasis and slows the rate of decline of pulmonary function; 3) scoliosis treatment, namely steroid therapy that is used to reduce muscle inflammation/degeneration and prolong ambulation in order to delay the onset of scoliosis, being an additional contribution to the restrictive lung pattern; 4) cough assisted devices that improve airway clearance thus reducing the risk of pulmonary infections; and 5) non-invasive mechanical ventilation that is essential to treat nocturnal hypoventilation, sleep disordered breathing, and ultimately respiratory failure. Without any intervention death occurs within the first 2 decades, however, thanks to this multidisciplinary therapeutic approach life expectancy of a newborn with DMD nowadays can be significantly prolonged up to his fourth decade. This review is aimed at providing state-of-the-art methods and techniques for the assessment and management of respiratory function in DMD patients

The effect of posture on asynchronous chest wall movement in COPD

Priori R, Aliverti A, Albuquerque AL, Quaranta M, Albert P, Calverley PM. the effect of posture on asynchronous chest wall movement in COPD. J Appl Physiol 114: 1066-1075, 2013. First published February 14, 2013; doi:10.1152/japplphysiol.00414.2012.-Chronic obstructive pulmonary disease (COPD) patients often show asynchronous movement of the lower rib cage during spontaneous quiet breathing and exercise. We speculated that varying body position from seated to supine would influence rib cage asynchrony by changing the configuration of the respiratory muscles. Twenty-three severe COPD patients (forced expiratory volume in 1 s = 32.5 +/- 7.0% predicted) and 12 healthy age-matched controls were studied. Measurements of the phase shift between upper and lower rib cage and between upper rib cage and abdomen were performed with opto-electronic plethysmography during quiet breathing in the seated and supine position. Changes in diaphragm zone of apposition were measured by ultrasounds. Control subjects showed no compartmental asynchronous movement, whether seated or supine. in 13 COPD patients, rib cage asynchrony was noticed in the seated posture. This asynchrony disappeared in the supine posture. in COPD, upper rib cage and abdomen were synchronous when seated, but a strong asynchrony was found in supine. the relationships between changes in diaphragm zone of apposition and volume variations of chest wall compartments supported these findings. Rib cage paradox was noticed in approximately one-half of the COPD patients while seated, but was not related to impaired diaphragm motion. in the supine posture, the rib cage paradox disappeared, suggesting that, in this posture, diaphragm mechanics improves. in conclusion, changing body position induces important differences in the chest wall behavior in COPD patients.Politecn Milan, Dipartimento Elettron Informaz & Bioingn, I-20133 Milan, ItalyUniversidade Federal de São Paulo, Dept Med, São Paulo, BrazilUniv Liverpool, Univ Hosp Aintree, Ctr Clin Sci, Liverpool L69 3BX, Merseyside, EnglandUniversidade Federal de São Paulo, Dept Med, São Paulo, BrazilWeb of Scienc

Limitation in tidal volume expansion partially determines the intensity of physical activity in COPD

open8In patients with Chronic Obstructive Pulmonary Disease (COPD) reduced levels of daily physical activity are associated with the degree of impairment in lung, peripheral muscle and central hemodynamic function. There is however, limited evidence as to whether limitations in tidal volume expansion also, importantly determine daily physical activity levels in COPD. Eighteen consecutive COPD patients [9 active (FEV1:1.59±0.64 liters) with an average daily movement intensity >1.88 m/sec(2) and 9 less active patients (FEV1:1.16±0.41 liters) with an average intensity <1.88 m/sec(2)] underwent a 4-min treadmill test at a constant speed corresponding to each individual patient's average movement intensity, captured by a triaxial accelerometer during a preceding 7-day period. When chest wall volumes, captured by Optoelectronic Plethysmography, were expressed relative to comparable levels of minute ventilation (ranging between 14.5±4.3 to 33.5±4.4 liters/min), active patients differed from the less active ones in terms of the lower increase in end-expiratory chest wall volume (by 0.15±0.17 versus 0.45±0.21 liters), the greater expansion in tidal volume (by 1.76±0.58 versus 1.36±0.24 liters) and the larger inspiratory reserve chest wall volume (IRVcw: by 0.81±0.25 versus 0.39±0.27 liters). IRVcw (r(2)=0.420), expiratory flow (r(2) change=0.174) and Borg dyspnoea score (r(2) change=0.123) emerged as the best contributors accounting for 71.7\% of the explained variance in daily movement intensity. COPD patients exhibiting greater ability to expand tidal volume and to maintain adequate inspiratory reserve volume tend to be more physically active. Thus, interventions aiming at mitigating restrictions on operational chest wall volumes are expected to enhance daily physical activity levels in COPD.openE. A. Kortianou;A. Aliverti;Z. Louvaris;M. Vasilopoulou;I. Nasis;A. Asimakos;S. G. Zakynthinos;I. VogiatzisE. A., Kortianou; Aliverti, Andrea; Z., Louvaris; M., Vasilopoulou; I., Nasis; A., Asimakos; S. G., Zakynthinos; I., Vogiatzi

Surgery corrects asynchrony of ribcage secondary to extra-thoracic tumor but leads to expiratory dysfunction during exercise

BACKGROUND: The effect of chest wall tumours on chest wall mechanics is uncertain even less is known about the effects of resection and reconstruction. Our aim is to study how chest wall mechanics are altered in chest wall sarcoma and to determine the effect of chest wall reconstruction on chest wall kinetics. CASE PRESENTATION: Using Optoelectronic Plethysmography (OEP), total and regional chest wall volumes were measured in a patient with unilateral extra-thoracic chest wall sarcoma, before and 5 months after resection and reconstruction, during quiet breathing and exercise using cycle ergometry. During quiet breathing the unilateral tumour was associated with reduced in motion of the lower rib cage and abdominal compartments on both sides of the chest as well as asynchronous motion of the contralateral lower rib cage. Surgery corrected these abnormalities in quiet breathing. But during exercise there was a reduction in the upper rib cage motion compared to pre-operative measures from 0.43+/−0.06 to 0.36 +/− 0.02 L postoperatively (p <0.05). This impairment was characterised by a significant increase in the end expiratory volume on the operated side of the chest 5 months after surgery by 6.5 +/− 0.6 and 5.7 +/− 0.7 % during 50 and 100 % exercise respectively (p <0.0001) a finding that was not replicated in the non-operated side. CONCLUSION: This physiological study demonstrates the negative effect of chest wall tumours on global chest wall mechanics during quiet breathing and exercise and shows that surgery reverses this abnormality, but only at rest

Telemonitoring systems for respiratory patients: technological aspects.

Abstract This review introduces the reader to the available technologies in the field of telemonitoring, with focus on respiratory patients. In the materials and methods section, a general structure of telemonitoring systems for respiratory patients is presented and the sensors of interest are illustrated, i.e., respiratory monitors (wearable and non-wearable), activity trackers, pulse oximeters, environmental monitors and other sensors of physiological variables. Afterwards, the most common communication protocols are briefly introduced. In the results section, selected clinical studies that prove the significance of the presented parameters in chronic respiratory diseases are presented. This is followed by a discussion on the main current issues in telemedicine, in particular legal aspects, data privacy and benefits both in economic and health terms