scholarly journals Ultrasonographic assessment of diaphragmatic contraction and relaxation properties: correlations of diaphragmatic displacement with oesophageal and transdiaphragmatic pressure

2021 ◽  
Vol 8 (1) ◽  
pp. e001006
Author(s):  
Entela Koco ◽  
Eleni Soilemezi ◽  
Panagiota Sotiriou ◽  
Savvoula Savvidou ◽  
Matthew Tsagourias ◽  
...  
Keyword(s):  
Displacement Curve ◽  
Respiratory Drive ◽  
Transdiaphragmatic Pressure ◽  
Non Invasive ◽  
Normal Breathing ◽  
Weaning Failure ◽  
Diaphragmatic Fatigue ◽  
Contraction And Relaxation ◽  
Ultrasonographic Assessment ◽  
Insight Into

Transdiaphragmatic (Pdi) and oesophageal pressures (Pes) are useful in understanding the pathophysiology of the respiratory system. They provide insight into respiratory drive, intrinsic positive end-expiratory pressure, diaphragmatic fatigue and weaning failure.BackgroundThe use of Pdi and Pes in clinical practice is restricted due to the invasiveness of the technique and the cumbersome equipment needed. On the other hand, diaphragmatic displacement is non-invasively and easily assessed with M-mode ultrasound.PurposeWe observed striking similarities in shape and magnitude between M-mode diaphragmatic displacement, Pes and Pdi pressures. The study aimed to evaluate if the information provided by these two pressures could be obtained non-invasively from the diaphragmatic displacement curve.Material and methodsIn 14 consecutive intubated patients undergoing a weaning trial, simultaneous recordings of Pes and Pdi pressures and the diaphragmatic displacement were assessed while breathing spontaneously and during a sniff-like manoeuvre. Moreover, the slope of the diaphragmatic displacement curve during relaxation was compared with the maximal relaxation rate (MRR) obtained from the Pdi curve.ResultsMore than 200 breaths were analysed in pairs. Diaphragmatic displacement significantly correlated with Pdi (R2=0.33, p<0.001) and Pes (R2=0.44, p<0.001), and this correlation further improved during sniff (R2=0.47, p<0.001) and (R2=0.64, p<0.001), respectively. Additionally, a significant correlation was found between the relaxation slope derived from the diaphragmatic displacement curve and the MRR derived from the Pdi curve, both in normal breathing (R2=0.379, p<0.001) and during the sniff manoeuvre (R2=0.71, p<0.001).ConclusionsM-mode diaphragmatic displacement parameters correlate well with the ones obtained from oesophageal pressure and Pdi, particularly during sniffing. Diaphragmatic displacement assessment possibly offers an alternative non-invasive solution for understanding and clinically monitoring the diaphragmatic contractile properties and weaning failure due to diaphragmatic fatigue.

scholarly journals Cardiorespiratory failure in rat induced by severe inspiratory resistive loading

2007 ◽  
Vol 102 (4) ◽  
pp. 1556-1564 ◽  
Author(s):  
Jeremy A. Simpson ◽  
Steve Iscoe
Keyword(s):  
Respiratory Failure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Respiratory Pattern ◽  
Respiratory Drive ◽  
Resistive Load ◽  
Endurance Time ◽  
Transdiaphragmatic Pressure ◽  
Tracheal Pressure ◽  
Diaphragmatic Fatigue

The mechanisms underlying acute respiratory failure induced by respiratory loads are unclear. We hypothesized that, in contrast to a moderate inspiratory resistive load, a severe one would elicit central respiratory failure (decreased respiratory drive) before diaphragmatic injury and fatigue. We also wished to elucidate the factors that predict endurance time and peak tracheal pressure generation. Anesthetized rats breathed air against a severe load (∼75% of the peak tracheal pressure generated during a 30-s occlusion) until pump failure (fall in tracheal pressure to half; mean 38 min). Hypercapnia and hypoxemia developed rapidly (∼4 min), coincident with diaphragmatic fatigue (decreased ratio of transdiaphragmatic pressure to peak integrated phrenic activity) and the detection in blood of the fast isoform of skeletal troponin I (muscle injury). At ∼23 min, respiratory frequency and then blood pressure fell, followed immediately by secondary diaphragmatic fatigue. Blood taken after termination of loading contained cardiac troponin T (myocardial injury). Contrary to our hypothesis, diaphragmatic fatigue and injury occurred early in loading before central failure, evident only as a change in the timing but not the drive component of the central respiratory pattern generator. Stepwise multiple regression analysis selected changes in mean arterial pressure and arterial Pco2 during loading as the principal contributing factors in load endurance time, and changes in mean arterial pressure as the principal contributing factor in peak tracheal pressure generation. In conclusion, the temporal development of respiratory failure is not stereotyped but depends on load magnitude; moreover respiratory loads induce cardiorespiratory, not just respiratory, failure.

scholarly journals Oxygen administration for patients with ARDS

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Shinichiro Ohshimo
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Positive Pressure ◽  
Respiratory Drive ◽  
Severe Hypoxemia ◽  
Airway Occlusion ◽  
Non Invasive ◽  
Oxygen Administration ◽  
Essential Interventions ◽  
Invasive Techniques

AbstractAcute respiratory distress syndrome (ARDS) is a fatal condition with insufficiently clarified etiology. Supportive care for severe hypoxemia remains the mainstay of essential interventions for ARDS. In recent years, adequate ventilation to prevent ventilator-induced lung injury (VILI) and patient self-inflicted lung injury (P-SILI) as well as lung-protective mechanical ventilation has an increasing attention in ARDS.Ventilation-perfusion mismatch may augment severe hypoxemia and inspiratory drive and consequently induce P-SILI. Respiratory drive and effort must also be carefully monitored to prevent P-SILI. Airway occlusion pressure (P0.1) and airway pressure deflection during an end-expiratory airway occlusion (Pocc) could be easy indicators to evaluate the respiratory drive and effort. Patient-ventilator dyssynchrony is a time mismatching between patient’s effort and ventilator drive. Although it is frequently unrecognized, dyssynchrony can be associated with poor clinical outcomes. Dyssynchrony includes trigger asynchrony, cycling asynchrony, and flow delivery mismatch. Ventilator-induced diaphragm dysfunction (VIDD) is a form of iatrogenic injury from inadequate use of mechanical ventilation. Excessive spontaneous breathing can lead to P-SILI, while excessive rest can lead to VIDD. Optimal balance between these two manifestations is probably associated with the etiology and severity of the underlying pulmonary disease.High-flow nasal cannula (HFNC) and non-invasive positive pressure ventilation (NPPV) are non-invasive techniques for supporting hypoxemia. While they are beneficial as respiratory supports in mild ARDS, there can be a risk of delaying needed intubation. Mechanical ventilation and ECMO are applied for more severe ARDS. However, as with HFNC/NPPV, inappropriate assessment of breathing workload potentially has a risk of delaying the timing of shifting from ventilator to ECMO. Various methods of oxygen administration in ARDS are important. However, it is also important to evaluate whether they adequately reduce the breathing workload and help to improve ARDS.

Detection of diaphragmatic fatigue in man by phrenic stimulation

1981 ◽  
Vol 50 (3) ◽  
pp. 538-544 ◽  
Author(s):  
M. Aubier ◽  
G. Farkas ◽  
A. De Troyer ◽  
R. Mozes ◽  
C. Roussos
Keyword(s):  
Phrenic Nerve ◽  
Chronic Obstructive Lung Disease ◽  
Chronic Obstructive ◽  
Low Frequencies ◽  
Transdiaphragmatic Pressure ◽  
Control Value ◽  
Transcutaneous Stimulation ◽  
Diaphragmatic Fatigue ◽  
Residual Capacity ◽  
Stimulation Of

Transdiaphragmatic pressure (Pdi) was measured at functional residual capacity (FRC) in four normal seated subjects during supramaximal, supraclavicular transcutaneous stimulation of one phrenic nerve (10, 20, 50, and 100 Hz--0.1 ms duration) before and after diaphragmatic fatigue, produced by breathing through a high alinear inspiratory resistance. Constancy of chest wall configuration was achieved by placing a cast around the abdomen and the lower one-fourth of the rib cage. Pdi increased with frequency of stimulation, so that at 10, 20, and 50 Hz, the Pdi generated was 32 +/- 4 (SE), 70 +/- 3, and 98 +/- 2% of Pdi at 100 Hz, respectively. After diaphragmatic fatigue, Pdi was less than control at all frequencies of stimulation. Recovery for high stimulation frequencies was complete at 10 min, but at low stimulation frequencies recovery was slow: after 30 min of recovery, Pdi at 20 Hz was 31 +/- 7% of the control value. It is concluded that diaphragmatic fatigue can be detected in man by transcutaneous stimulation of the phrenic nerve and that diaphragmatic strength after fatigue recovers faster at high than at low frequencies of stimulation. Furthermore, it is suggested that this long-lasting element of fatigue might occur in patients with chronic obstructive lung disease, predisposing them to respiratory failure.

Fertilization state ofAscaris suumdetermined by electrorotation

2006 ◽  
Vol 80 (1) ◽  
pp. 25-31 ◽  
Author(s):  
C. Dalton ◽  
A.D. Goater ◽  
H.V. Smith
Keyword(s):  
Dielectric Properties ◽  
Physicochemical Properties ◽  
Parasitic Nematode ◽  
Invasive Technique ◽  
Non Invasive ◽  
Egg Morphology ◽  
Parasite Biology ◽  
Response Modelling ◽  
Non Destructive ◽  
Insight Into

AbstractElectrorotation is a non-invasive technique that is capable of detecting changes in the morphology and physicochemical properties of microorganisms. The first detailed electrorotation study of the egg (ovum) of a parasitic nematode, namelyAscaris suumis described to show that electrorotation can rapidly differentiate between fertilized and non-fertilized eggs. Support for this conclusion is by optical microscopy of egg morphology, and also from modelling of the electrorotational response. Modelling was used to determine differences in the dielectric properties of the unfertilized and fertilized eggs, and also to investigate specific differences in the spectra of fertilized eggs only, potentially reflecting embryogenesis. The potential of electrorotation as an investigative tool is shown, as undamaged eggs can be subjected to further non-destructive and destructive techniques, which could provide further insight into parasite biology and epidemiology.

scholarly journals Dislocation–grain boundary interactions: recent advances on the underlying mechanisms studied via nanoindentation testing

2021 ◽  
Author(s):  
Farhan Javaid ◽  
Habib Pouriayevali ◽  
Karsten Durst
Keyword(s):  
Grain Boundary ◽  
Mechanical Response ◽  
Displacement Curve ◽  
Ambient Conditions ◽  
Recent Advances ◽  
Slip Transfer ◽  
Depth Analysis ◽  
Dislocation Interactions ◽  
Underlying Mechanisms ◽  
Insight Into

Abstract To comprehend the mechanical behavior of a polycrystalline material, an in-depth analysis of individual grain boundary (GB) and dislocation interactions is of prime importance. In the past decade, nanoindentation emerged as a powerful tool to study the local mechanical response in the vicinity of the GB. The improved instrumentation and test protocols allow to capture various GB–dislocation interactions during the nanoindentation in the form of strain bursts on the load–displacement curve. Moreover, the interaction of the plastic zone with the GB provides important insight into the dislocation transmission effects of distinct grain boundaries. Of great importance for the analysis and interpretation of the observed effects are microstructural investigations and computational approaches. This review paper focused on recent advances in the dislocation–GB interactions and underlying mechanisms studied via nanoindentation, which includes GB pop-in phenomenon, localized grain movement under ambient conditions, and an analysis of the slip transfer mechanism using theoretical treatments and simulations. Graphical abstract

scholarly journals Mechanisms of exercise intolerance in Global Initiative for Chronic Obstructive Lung Disease grade 1 COPD

2014 ◽  
Vol 44 (5) ◽  
pp. 1177-1187 ◽  
Author(s):  
Jordan A. Guenette ◽  
Roberto C. Chin ◽  
Sicheng Cheng ◽  
Paolo B. Dominelli ◽  
Natya Raghavan ◽  
...  
Keyword(s):  
Work Of Breathing ◽  
Pressure Ratio ◽  
Chronic Obstructive Lung Disease ◽  
Exercise Intolerance ◽  
Chronic Obstructive ◽  
Respiratory Drive ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Generating Capacity ◽  
Neuromuscular Abnormalities

The purpose of this study was to determine if a dissociation existed between respiratory drive, as estimated by diaphragmatic electromyography (EMGdi), and its pressure-generating capacity during exercise in mild chronic obstructive pulmonary disease (COPD) and whether this, if present, had negative sensory consequences.Subjects meeting spirometric criteria for mild COPD (n=16) and age and sex-matched controls (n=16) underwent detailed pulmonary function testing and a symptom limited cycle test while detailed ventilatory, sensory and respiratory mechanical responses were measured.Compared with controls, subjects with mild COPD had greater ventilatory requirements throughout submaximal exercise. At the highest equivalent work rate of 60 W, they had a significantly higher: total work of breathing (32±17 versus 16±7 J·min−1; p<0.01); EMGdi (37.3±17.3 versus 17.9±11.7% of maximum; p<0.001); and EMGdi to transdiaphragmatic pressure ratio (0.87±0.38 versus 0.52±0.27; p<0.01). Dyspnoea–ventilation slopes were significantly higher in mild COPD than controls (0.17±0.12 versus 0.10±0.05; p<0.05). However, absolute dyspnoea ratings reached significant levels only at high levels of ventilation.Increased respiratory effort and work of breathing, and a wider dissociation between diaphragmatic activation and pressure-generating capacity were found at standardised work rates in subjects with mild COPD compared with controls. Despite these mechanical and neuromuscular abnormalities, significant dyspnoea was only experienced at higher work rates.

Non-Invasive Data Acquisition and Measurement in Bio-Medical Technology

2016 ◽  
pp. 27-45 ◽  
Author(s):  
H. G. Sandeep Patil ◽  
Ajit N. Babu ◽  
P. S. Ramkumar
Keyword(s):  
Health Care ◽  
Infectious Diseases ◽  
Medical Devices ◽  
Care Delivery ◽  
Non Invasive ◽  
Technological Advances ◽  
Mathematical Techniques ◽  
The One ◽  
Insight Into ◽  
Technology Trends

Non-invasive medical measurements have expanded into several types of diagnostic and monitoring activities in health care delivery. They are being used in handling a number of non-infectious diseases such as diabetes, asthma, hypertension, congestive heart failure, cardiac arrhythmia, etc., as well as infectious diseases such as cholera, malaria, etc.. Non-Invasive Medical Devices (NIMDs) are naturally preferred over invasive methods considering patient convenience, reduced patient risk, increased speed, and operational simplicity. However non-invasive methods are often perceived to be less accurate than their invasive counterparts. Over the last decade, technological advances and mathematical techniques have improved significantly, challenging this perception across the board. The chapter will discuss this important transformation in health care diagnostics and monitoring. The chapter will also provide further insight into some of the currently available non-invasive measurement products and explore how futuristic techniques and technology trends which have great potential to transform healthcare into a significantly different paradigm than the one we experience today.

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