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Bench-to-bedside review: Weaning failure – should we rest the respiratory muscles with controlled mechanical ventilation?
Theodoros Vassilakopoulos, Spyros Zakynthinos, Charis Roussos
Critical Care , 2005, DOI: 10.1186/cc3917
Abstract: Controlled mechanical ventilation (CMV) is a mode of ventilator support in which each breath is triggered by the ventilator's timer using a respiratory rate set by the clinician. The characteristics of the breath are also set by the clinician, i.e. pressure or flow controlled, volume, flow or time cycled. Because the respiratory muscles are not contracting, the minute ventilation is fully controlled by the ventilator, which takes full responsibility for inflating the respiratory system.CMV is traditionally used in severely ill patients who cannot tolerate partial ventilatory support (e.g., acute respiratory distress syndrome, septic shock, multiple organ failure), in cases of overt patient-ventilator dysynchrony, and in the immediate postoperative period. CMV is also used when weaning fails (especially T-piece weaning) to rest the respiratory muscle before the next weaning attempt. This review will summarize recent evidence concerning the deleterious effects of CMV on respiratory muscle function and discuss the use of CMV during weaning failure.Animal models have been used to unravel the effects of CMV that are beneficial for the respiratory muscles: reversal of respiratory muscle fatigue [1], prevention of muscle fiber injury during a short-term (four hours) model of sepsis [2], and restoration of perfusion to vital organs in shock states when blood flow is 'stolen' by the intensely working respiratory muscles [1,3].Accumulating experimental evidence suggests, however, that CMV can also induce dysfunction of the diaphragm, resulting in decreased diaphragmatic force generating capacity, diaphragmatic atrophy, and diaphragmatic injury, also called ventilator-induced diaphragmatic dysfunction (VIDD) [4].In the intact diaphragm of various animal species (including primates) studied in vivo after a period of CMV, transdiaphragmatic pressure generation caused by phrenic nerve stimulation declines at both submaximal and maximal stimulation frequencies (20 to 100 Hz) in a
Endurance training of respiratory muscles improves cycling performance in fit young cyclists
Paige Holm, Angela Sattler, Ralph F Fregosi
BMC Physiology , 2004, DOI: 10.1186/1472-6793-4-9
Abstract: After training, the experimental group increased their respiratory muscle endurance capacity by 12 %. Performance on a bicycle time trial test designed to last about 40 min improved by 4.7 % (9 of 10 subjects showed improvement). There were no test-re-test improvements in either respiratory muscle or bicycle exercise endurance performance in the placebo group, nor in the control group. After training, the experimental group had significantly higher ventilatory output and VO2, and lower PCO2, during constant work-rate exercise; the placebo and control groups did not show these changes. The perceived respiratory effort was unchanged in spite of the higher ventilation rate after training.The results suggest that respiratory muscle endurance training improves cycling performance in fit, experienced cyclists. The relative hyperventilation with no change in respiratory effort sensations suggest that respiratory muscle training allows subjects to tolerate the higher exercise ventilatory response without more dyspnea. Whether or not this can explain the enhanced performance is unknown.Understanding the effects of respiratory muscle training on endurance exercise performance (e.g., large muscle mass dynamic exercise, such as running, cycling and rowing) is an important issue in human performance physiology because such supplemental training has the potential to improve performance even in endurance athletes [1]. This is also important from a clinical standpoint, because respiratory muscle training is often used as one component of the therapy plan in patients with obstructive lung diseases. Several recent studies in healthy subjects have shown that specific training of the respiratory muscles is associated with enhanced endurance exercise performance, at least when the exercise tests require the subjects to work at about 70–80 % of their maximal capacity or less [2-8]. Others have examined the effects of respiratory muscle training on the ability to perform very intense endu
Entrenamiento de los músculos respiratorios Training of the respiratory muscles
Tania Bravo Acosta,Pablo Lino Alonso Díaz,Orlando del Valle Alonso,Alfredo Jané Lara
Revista Cubana de Medicina Militar , 2005,
Abstract: El incremento del hábito de fumar, el efecto nocivo de su adicción, la alta incidencia de las afecciones con compromiso respiratorio en la población, así como la evolución a la cronicidad en muchas de estas enfermedades motivó a realizar una revisión actualizada sobre el entrenamiento de los músculos respiratorios con vistas a conocer cómo se puede mejorar la capacidad funcional, la tolerancia al ejercicio, la autonomía e independencia para las actividades de la vida diaria en este grupo de pacientes, lo que representa una mejor calidad de vida de la población cubana. The increase of the smoking habit, the harmful effect of its addiction, the high incidence of affections with respiratory compromise in the population, as well as the evolution towards chronicity in many of these diseases motivated us to make an updated review of the training of the respiratory muscles in order to know how we can improve the functional capacity, the tolerance to exercise, and the autonomy and independence for the daily activities in this group of patients, resulting in a better quality of life of the Cuban population.
Anaerobic capacity of upper extremity muscles of male and female swimmers
Anna Ogonowska, M.S. , El bieta Hübner-Wo niak, Professor , Andrzej Kosmol, Professor , Wilhelm Gromisz, M.S.
Biomedical Human Kinetics , 2009, DOI: 10.2478/v10101-009-0020-z
Abstract: Study aim: To assess the anaerobic capacity of upper extremity muscles of male and female swimmers by applying two exercise tests. Material and methods: Male and female swimmers (n = 9 and 6, respectively), aged 19 - 23 years and having training experience of over 10 years, were subjected to two tests: 30-s Wingate for upper extremities and semitethered swimming test. The following variables were determined: body fat content (from 4 skinfolds), maximum power output, heart rate (HR) and lactate (LA) concentration in blood. Results: Relative power outputs in the Wingate test and swimming force in semi-tethered swimming test (maximum and mean) were significantly (p<0.001) higher in male than in the female swimmers. Maximum LA concentrations were higher in male than in female swimmers, but maximum LA values related to relative power output were in both genders alike. Maximum force produced in the semi-tethered swimming test was strongly (r = 0.765; p<0.001) correlated with maximum relative power output in the Wingate test. Conclusions: Both tests may be interchangeably applied to determine the anaerobic capacity of upper extremity muscles in swimmers.
Exercise capacity, respiratory mechanics and posture in mouth breathers
Okuro, Renata Tiemi;Morcillo, André Moreno;Sakano, Eulália;Schivinski, Camila Isabel Santos;Ribeiro, Maria ?ngela Gon?alves Oliveira;Ribeiro, José Dirceu;
Brazilian Journal of Otorhinolaryngology , 2011, DOI: 10.1590/S1808-86942011000500020
Abstract: chronic and persistent mouth or oral breathing (ob) has been associated with postural changes. although posture changes in ob causes decreased respiratory muscle strength, reduced chest expansion and impaired pulmonary ventilation with consequences in the exercise capacity, few studies have verified all these assumptions. objective: to evaluate exercise tolerance, respiratory muscle strength and body posture in oral breathing (ob) compared with nasal breathing (nb) children. material and method: a cross-sectional contemporary cohort study that included ob and nb children aged 8-11 years old. children with obesity, asthma, chronic respiratory diseases, neurological and orthopedic disorders, and cardiac conditions were excluded. all participants underwent a postural assessment, maximal inspiratory pressure (mip), maximal expiratory pressure (mep), the six-minute walk test (6mwt), and otorhinolaryngologic evaluation. results: there were 107 children (45 ob and 62 nb). there was an association between abnormal cervical posture and breathing pattern: 36 (80.0%) ob and 30 (48.4%) nb presented abnormal head posture (or=4.27 [95% ci: 1.63-11,42], p<0.001). the mean mip and mep were lower in ob (p=0.003 and p=0.004). conclusion: ob children had cervical spine postural changes and decreased respiratory muscle strength compared with nb.
Respiratory pathophysiology: sleep-related breathing disorders
Sch?fer, Thorsten
GMS Current Topics in Otorhinolaryngology, Head and Neck Surgery , 2006,
Abstract: A widespread network of respiratory-related neurons within the brainstem controls the regular respiratory cycle, which is dependent upon unspecific and specific drives like hypoxia or hypercapnia. This respiratory network and its respiratory drives are subjects to typical changes during the transition from wakefulness to sleep and within the various sleep states, which favor a destabilization of breathing during sleep. There is also a respiratory-related innervation of the dilating and stiffening pharyngeal muscles as well as a local reflex control of the basic tone of upper airway muscles, both of which are influenced by the different states of wakefulness and sleep. These sleep-related changes cause an increase in upper airway resistance during sleep. In healthy subjects, however, these features during sleep are almost completely compensated and the gas exchange is hardly hindered. However, in the case of illness, severe disordered breathing, disturbed gas exchange and interrupted sleep may occur. The central hypoventilation syndrome, central apnea-hypopnea syndromes, as well as the obstructive sleep apnea syndrome belong to these diseases. Because of the intense research, we have a detailed picture of the pathophysiological mechanisms of the origin and the maintenance of sleep-related breathing disorders.
Reduced exercise capacity in persons with Down syndrome: cause, effect, and management
Goncalo V Mendonca, Fernando D Pereira1 Bo Fernhall
Therapeutics and Clinical Risk Management , 2010, DOI: http://dx.doi.org/10.2147/TCRM.S10235
Abstract: uced exercise capacity in persons with Down syndrome: cause, effect, and management Review (5022) Total Article Views Authors: Goncalo V Mendonca, Fernando D Pereira1 Bo Fernhall Published Date December 2010 Volume 2010:6 Pages 601 - 610 DOI: http://dx.doi.org/10.2147/TCRM.S10235 Goncalo V Mendonca1, Fernando D Pereira1, Bo Fernhall2 1Center of Human Performance (CIPER), Faculty of Human Kinetics, Technical University of Lisbon, Lisbon, Portugal; 2Kinesiology and Community Health, University of Illinois at Urbana Champaign, Champaign, IL, USA Abstract: Persons with Down syndrome (DS) have reduced peak and submaximal exercise capacity. Because ambulation is one predictor of survival among adults with DS, a review of the current knowledge of the causes, effects, and management of reduced exercise capacity in these individuals would be important. Available data suggest that reduced exercise capacity in persons with DS results from an interaction between low peak oxygen uptake (VO2peak) and poor exercise economy. Of several possible explanations, chronotropic incompetence has been shown to be the primary cause of low VO2peak in DS. In contrast, poor exercise economy is apparently dependent on disturbed gait kinetics and kinematics resulting from joint laxity and muscle hypotonia. Importantly, there is enough evidence to suggest that such low levels of physical fitness (reduced exercise capacity and muscle strength) limit the ability of adults with DS to perform functional tasks of daily living. Consequently, clinical management of reduced exercise capacity in DS seems important to ensure that these individuals remain productive and healthy throughout their lives. However, few prospective studies have examined the effects of structured exercise training in this population. Existent data suggest that exercise training is beneficial for improving exercise capacity and physiological function in persons with DS. This article reviews the current knowledge of the causes, effects, and management of reduced exercise capacity in DS. This review is limited to the acute and chronic responses to submaximal and peak exercise intensities because data on supramaximal exercise capacity of persons with DS have been shown to be unreliable.
Local interleukin-10 production during respiratory syncytial virus bronchiolitis is associated with post-bronchiolitis wheeze
Annemieke Schuurhof, Riny Janssen, Hanneke de Groot, Hennie M Hodemaekers, Arja de Klerk, Jan LL Kimpen, Louis Bont
Respiratory Research , 2011, DOI: 10.1186/1465-9921-12-121
Abstract: This study aimed to determine the in vivo role of IL-10 in RSV pathogenesis and recurrent wheeze in a new cohort of 235 infants hospitalized for RSV bronchiolitis. IL-10 levels in nasopharyngeal aspirates (NPAs) were measured at the time of hospitalization and the IL10 SNP rs1800872 genotype was determined. Follow-up data were available for 185 children (79%).Local IL-10 levels during RSV infection turned out to be higher in infants that later developed physician diagnosed PBW as compared to infants without PBW in the first year after RSV infection (958 vs 692 pg/ml, p = 0.02). The IL10 promoter SNP rs1800872 was not associated with IL-10 concentration in NPAs.The relationship between high local IL-10 levels during the initial RSV infection and physician diagnosed PBW provides further evidence of the importance of the IL-10 response during RSV bronchiolitis.Respiratory syncytial virus (RSV) is a negative-sense, single-stranded RNA virus and a member of the Paramyxoviridae, subfamily Pneumovirinae. RSV causes a wide range of clinical symptoms, varying from mild upper respiratory tract infection to severe bronchiolitis and pneumonia [1,2]. It is the most common cause of severe lower respiratory tract infection in children aged less than 1 year, and approximately 1-3% require hospitalization [3,4]. High-risk groups for severe RSV infection include infants with preterm birth, chronic lung disease of prematurity, congenital heart disease, cystic fibrosis, immunodeficiency disorders, and Down's syndrome [5,6]. Besides infants, specific adult populations are also at risk to develop severe RSV infection [7-10]. However, most infants hospitalized for RSV infection are previously healthy infants and do not fit the profile of a high risk patient [11]. RSV bronchiolitis is often followed by recurrent episodes of wheeze, in about 50% of cases, also referred to as post-bronchiolitis wheeze (PBW) [12-16]. PBW causes significant healthcare costs, and influences quality of life [17,
Morgagni hernia with Down syndrome: a rare association -- case report and review of literature.  [cached]
Parmar R,Tullu M,Bavdekar S,Borwankar S
Journal of Postgraduate Medicine , 2001,
Abstract: Morgagni hernia is a rare diaphragmatic hernia accounting for only 2% of the congenital diaphragmatic defects. A case of Morgagni hernia was diagnosed radiologically in a 12-months-old male with Down syndrome, with recurrent respiratory distress and chest deformity. The 2-dimensional echocardiography was normal. The diagnosis of Morgagni hernia was confirmed by barium studies. The patient underwent a corrective surgery at 18 months of age following which his symptoms subsided. Literature review revealed only 18 cases of Morgagni hernia with Down syndrome reported till date, with age of presentation varying from neonatal age group to 12 years of age. The mode of presentations varied from asymptomatic detection to severe respiratory distress. The possible mechanism of association and its clinical implication has been discussed. The case emphasises a need for diaphragmatic hernia to be looked for as a possible cause of respiratory distress in Down syndrome.
Identification of serum proteomic biomarkers for early porcine reproductive and respiratory syndrome (PRRS) infection
Genini Sem,Paternoster Thomas,Costa Alessia,Botti Sara
Proteome Science , 2012, DOI: 10.1186/1477-5956-10-48
Abstract: Background Porcine reproductive and respiratory syndrome (PRRS) is one of the most significant swine diseases worldwide. Despite its relevance, serum biomarkers associated with early-onset viral infection, when clinical signs are not detectable and the disease is characterized by a weak anti-viral response and persistent infection, have not yet been identified. Surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) is a reproducible, accurate, and simple method for the identification of biomarker proteins related to disease in serum. This work describes the SELDI-TOF MS analyses of sera of 60 PRRSV-positive and 60 PRRSV-negative, as measured by PCR, asymptomatic Large White piglets at weaning. Sera with comparable and low content of hemoglobin (< 4.52 μg/mL) were fractionated in 6 different fractions by anion-exchange chromatography and protein profiles in the mass range 1–200 kDa were obtained with the CM10, IMAC30, and H50 surfaces. Results A total of 200 significant peaks (p < 0.05) were identified in the initial discovery phase of the study and 47 of them were confirmed in the validation phase. The majority of peaks (42) were up-regulated in PRRSV-positive piglets, while 5 were down-regulated. A panel of 14 discriminatory peaks identified in fraction 1 (pH = 9), on the surface CM10, and acquired at low focus mass provided a serum protein profile diagnostic pattern that enabled to discriminate between PRRSV-positive and -negative piglets with a sensitivity and specificity of 77% and 73%, respectively. Conclusions SELDI-TOF MS profiling of sera from PRRSV-positive and PRRSV-negative asymptomatic piglets provided a proteomic signature with large scale diagnostic potential for early identification of PRRSV infection in weaning piglets. Furthermore, SELDI-TOF protein markers represent a refined phenotype of PRRSV infection that might be useful for whole genome association studies.
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