Respiratory muscle function in the critically ill

2016 ◽  
Author(s):  
Theodoros Vassilakopoulos ◽  
Charis Roussos
Keyword(s):  
Muscle Function ◽  
Respiratory Muscle ◽  
Magnetic Stimulation ◽  
Abdominal Muscles ◽  
Energy Demands ◽  
Inspiratory Muscles ◽  
Respiratory Muscle Function ◽  
Generating Capacity ◽  
Over Time ◽  
Stimulation Of

The inspiratory muscles are the diaphragm, external intercostals and parasternal internal intercostal muscles. The internal intercostals and abdominal muscles are expiratory. The ability of a subject to take one breath depends on the balance between the load faced by the inspiratory muscles and their neuromuscular competence. The ability of a subject to sustain the respiratory load over time (endurance) depends on the balance between energy supplied to the inspiratory muscles and their energy demands. Hyperinflation puts the diaphragm at a great mechanical disadvantage, decreasing its force-generating capacity. In response to acute increases in load the inspiratory muscles become fatigued and inflammed. In response to reduction in load by the use of mechanical ventilation they develop atrophy and dysfunction. Global respiratory muscle function can be tested using maximum static inspiratory and expiratory mouth pressures, and sniff pressure. Diaphragm function can be tested by measuring the transdiaphragmatic and twitch pressures developed upon electrical or magnetic stimulation of the phrenic nerve.

Airway resistance and respiratory muscle function in snorers during NREM sleep

1985 ◽  
Vol 59 (2) ◽  
pp. 328-335 ◽  
Author(s):  
J. B. Skatrud ◽  
J. A. Dempsey
Keyword(s):  
Tidal Volume ◽  
Muscle Function ◽  
Respiratory Muscle ◽  
Dynamic Compression ◽  
Nrem Sleep ◽  
Abdominal Muscles ◽  
Resistive Load ◽  
Rib Cage ◽  
Inspiratory Muscles ◽  
Respiratory Muscle Function

The effect of non-rapid-eye-movement (NREM) sleep on total pulmonary resistance (RL) and respiratory muscle function was determined in four snorers and four nonsnorers. RL at peak flow increased progressively from wakefulness through the stages of NREM sleep in all snorers (3.7 +/- 0.4 vs. 13.0 +/- 4.0 cmH2O X 0.1(-1) X s) and nonsnorers (4.8 +/- 0.4 vs. 7.5 +/- 1.1 cmH2O X 1(-1) X s). Snorers developed inspiratory flow limitation and progressive increase in RL within a breath. The increased RL placed an increased resistive load on the inspiratory muscles, increasing the pressure-time product for the diaphragm between wakefulness and NREM sleep. Tidal volume and minute ventilation decreased in all subjects. The three snorers who showed the greatest increase in within-breath RL demonstrated an increase in the contribution of the lateral rib cage to tidal volume, a contraction of the abdominal muscles during a substantial part of expiration, and an abrupt relaxation of abdominal muscles at the onset of inspiration. We concluded that the magnitude of increase in RL leads to dynamic compression of the upper airway during inspiration, marked distortion of the rib cage, recruitment of the intercostal muscles, and an increased contribution of expiratory muscles to inspiration. This increased RL acts as an internal resistive load that probably contributes to hypoventilation and CO2 retention in NREM sleep.

scholarly journals The Effect of Habitual Exercise on Respiratory-Muscle Function in Older Adults

2005 ◽  
Vol 13 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Mark L. Watsford ◽  
Aron J. Murphy ◽  
Matthew J. Pine ◽  
Aaron J. Coutts
Keyword(s):  
Older Adults ◽  
Muscle Strength ◽  
Muscle Function ◽  
Respiratory Muscle ◽  
Endurance Capacity ◽  
Respiratory Muscle Strength ◽  
Exercise Participation ◽  
Inspiratory Muscles ◽  
Respiratory Muscle Function ◽  
Habitual Exercise

Older adults’ participation in habitual exercise might be affected by alterations to respiratory mechanics such as decreased respiratory-muscle strength. This reduction can cause a decrease in efficiency of the ventilatory pump, potentially compromising exercise participation. This research examined the role of habitual exercise in respiratory-muscle function and the associated implications for exercise performance. Seventy-two healthy older adults (36 men, 64.9 ± 8.6 years, 177.2 ± 8.4 cm, 82.5 ± 11.9 kg; 36 women, 64.9 ± 9.5 years, 161.7 ± 6.4 cm, 61.6 ± 9.2 kg) undertook respiratory-function and walking-performance tests. Active men and women achieved higher scores than their inactive counterparts for all tests except spirometry, where no differences were evident. The results indicate that a significant amount of the elevated fitness level might be accounted for by increased endurance capacity of the inspiratory muscles. Inactive older individuals might be at risk for inadequate respiratory-muscle strength, so interventions should be considered.

Multifocal Noninvasive Magnetic Stimulation of the Primary Motor Cortex in Type 1 Myotonic Dystrophy –A Proof of Concept Pilot Study

2021 ◽  
pp. 1-10
Author(s):  
Ericka Greene ◽  
Jason Thonhoff ◽  
Blessy S. John ◽  
David B. Rosenfield ◽  
Santosh A. Helekar
Keyword(s):  
Motor Cortex ◽  
Myotonic Dystrophy ◽  
Muscle Function ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Compound Muscle Action Potential ◽  
Sham Stimulation ◽  
Stimulation Of

Background: Repeated neuromuscular electrical stimulation in type 1 Myotonic Dystrophy (DM1) has previously been shown to cause an increase in strength and a decrease in hyperexcitability of the tibialis anterior muscle. Objective: In this proof-of-principle study our objective was to test the hypothesis that noninvasive repetitive transcranial magnetic stimulation of the primary motor cortex (M1) with a new portable wearable multifocal stimulator causes improvement in muscle function in DM1 patients. Methods: We performed repetitive stimulation of M1, localized by magnetic resonance imaging, with a newly developed Transcranial Rotating Permanent Magnet Stimulator (TRPMS). Using a randomized within-patient placebo-controlled double-blind TRPMS protocol, we performed unilateral active stimulation along with contralateral sham stimulation every weekday for two weeks in 6 adults. Methods for evaluation of muscle function involved electromyography (EMG), hand dynamometry and clinical assessment using the Medical Research Council scale. Results: All participants tolerated the treatment well. While there were no significant changes clinically, EMG showed significant improvement in nerve stimulus-evoked compound muscle action potential amplitude of the first dorsal interosseous muscle and a similar but non-significant trend in the trapezius muscle, after a short exercise test, with active but not sham stimulation. Conclusions: We conclude that two-week repeated multifocal cortical stimulation with a new wearable transcranial magnetic stimulator can be safely conducted in DM1 patients to investigate potential improvement of muscle strength and activity. The results obtained, if confirmed and extended by future safety and efficacy trials with larger patient samples, could offer a potential supportive TRPMS treatment in DM1.

scholarly journals Respiratory muscle function in the newborn: a narrative review

2021 ◽  
Author(s):  
Theodore Dassios ◽  
Aggeliki Vervenioti ◽  
Gabriel Dimitriou
Keyword(s):  
Congenital Anomalies ◽  
Muscle Function ◽  
Respiratory Muscle ◽  
Work Of Breathing ◽  
Respiratory Muscles ◽  
Current Evidence ◽  
Muscle Fibres ◽  
List Type ◽  
Respiratory Muscle Function ◽  
Neurally Adjusted Ventilator Assist

Abstract Our aim was to summarise the current evidence and methods used to assess respiratory muscle function in the newborn, focusing on current and future potential clinical applications. The respiratory muscles undertake the work of breathing and consist mainly of the diaphragm, which in the newborn is prone to dysfunction due to lower muscle mass, flattened shape and decreased content of fatigue-resistant muscle fibres. Premature infants are prone to diaphragmatic dysfunction due to limited reserves and limited capacity to generate force and avoid fatigue. Methods to assess the respiratory muscles in the newborn include electromyography, maximal respiratory pressures, assessment for thoraco-abdominal asynchrony and composite indices, such as the pressure–time product and the tension time index. Recently, there has been significant interest and a growing body of research in assessing respiratory muscle function using bedside ultrasonography. Neurally adjusted ventilator assist is a novel ventilation mode, where the level of the respiratory support is determined by the diaphragmatic electrical activity. Prolonged mechanical ventilation, hypercapnia and hypoxia, congenital anomalies and systemic or respiratory infection can negatively impact respiratory muscle function in the newborn, while caffeine and synchronised or volume-targeted ventilation have a positive effect on respiratory muscle function compared to conventional, non-triggered or pressure-limited ventilation, respectively. Impact Respiratory muscle function is impaired in prematurely born neonates and infants with congenital anomalies, such as congenital diaphragmatic hernia. Respiratory muscle function is negatively affected by prolonged ventilation and infection and positively affected by caffeine and synchronised compared to non-synchronised ventilation modes. Point-of-care diaphragmatic ultrasound and neurally adjusted ventilator assist are recent diagnostic and therapeutic technological developments with significant clinical applicability.

scholarly journals A review of respiratory manifestations and their management in Ehlers-Danlos syndromes and hypermobility spectrum disorders

2021 ◽  
Vol 18 ◽  
pp. 147997312110253
Author(s):  
Karan Chohan ◽  
Nimish Mittal ◽  
Laura McGillis ◽  
Laura Lopez-Hernandez ◽  
Encarna Camacho ◽  
...  
Keyword(s):  
Sleep Apnea ◽  
Muscle Function ◽  
Respiratory Muscle ◽  
Respiratory Symptoms ◽  
Management Strategies ◽  
Narrative Review ◽  
Respiratory Muscle Function ◽  
Respiratory Management ◽  
Spectrum Disorders ◽  
Continuous Positive Pressure

Background: Ehlers-Danlos Syndromes (EDS) and Hypermobility Spectrum Disorders (HSD) are a heterogeneous group of heritable genetic connective tissue disorders with multiple characteristics including joint hypermobility, tissue fragility, and multiple organ dysfunction. Respiratory manifestations have been described in EDS patients, but have not been systematically characterized. A narrative review was undertaken to describe the respiratory presentations and management strategies of individuals with EDS and HSD. Methods: A broad literature search of Medline, Embase, Cochrane Database of Systematic Reviews, and Cochrane CENTRAL was undertaken from inception to November 2020 of all study types, evaluating EDS/ HSD and pulmonary conditions. This narrative review was limited to adult patients and publications in English. Results: Respiratory manifestations have generally been described in hypermobile EDS (hEDS), classical and vascular EDS subtypes. Depending on EDS subtype, they may include but are not limited to dyspnea, dysphonia, asthma, sleep apnea, and reduced respiratory muscle function, with hemothorax and pneumothorax often observed with vascular EDS. Respiratory manifestations in HSD have been less frequently characterized in the literature, but exertional dyspnea is the more common symptom described. Respiratory symptoms in EDS can have an adverse impact on quality of life. The respiratory management of EDS patients has followed standard approaches with thoracotomy tubes and pleurodesis for pleural manifestations, vocal cord strengthening exercises, continuous positive pressure support for sleep apnea, and exercise training. Reduced respiratory muscle function in hEDS patients responds to inspiratory muscle training. Conclusion: Respiratory symptoms and manifestations are described in EDS and HSD, and have generally been managed using conservative non-surgical strategies. Research into the prevalence, incidence and specific respiratory management strategies in EDS and HSD is needed to mitigate some of the associated morbidity.

scholarly journals Pulmonary and respiratory muscle function in response to 10 marathons in 10 days

2018 ◽  
Vol 119 (2) ◽  
pp. 509-518 ◽  
Author(s):  
Nicholas B. Tiller ◽  
Louise A. Turner ◽  
Bryan J. Taylor
Keyword(s):  
Muscle Function ◽  
Respiratory Muscle ◽  
Respiratory Muscle Function
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