Effects of expiratory resistive loading on the sensation of dyspnea

To determine whether an increase in expiratory motor output accentuates the sensation of dyspnea (difficulty in breathing), the following experiments were undertaken. Ten normal subjects, in a series of 2-min trials, breathed freely (level I) or maintained a target tidal volume equal to (level II) or twice the control (level III) at a breathing frequency of 15/min (similar to the control frequency) with an inspiratory load, an expiratory load, and without loads under hyperoxic normocapnia. In tests at levels II and III, end-expiratory lung volume was maintained at functional residual capacity. A linear resistance of 25 cmH2O.1(-1).s was used for both inspiratory and expiratory loading; peak mouth pressure (Pm) was measured, and the intensity of dyspnea (psi) was assessed with a visual analog scale. The sensation of dyspnea increased significantly with the magnitude of expiratory Pm during expiratory loading (level II: Pm = 9.4 +/- 1.5 (SE) cmH2O, psi = 1.26 +/- 0.35; level III: Pm = 20.3 +/- 2.8 cmH2O, psi = 2.22 +/- 0.48) and with inspiratory Pm during inspiratory loading (level II: Pm = 9.7 +/- 1.2 cmH2O, psi = 1.35 +/- 0.38; level III: Pm = 23.9 +/- 3.0 cmH2O, psi = 2.69 +/- 0.60). However, at each level of breathing, neither the intensity of dyspnea nor the magnitude of peak Pm during loading was different between inspiratory and expiratory loading. The augmentation of dyspnea during expiratory loading was not explained simply by increases in inspiratory activity. The results indicate that heightened expiratory as well as inspiratory motor output causes comparable increases in the sensation of difficulty in breathing.

Download Full-text

Phasic vagal influence on inspiratory motor output in anesthetized human subjects

Journal of Applied Physiology ◽

10.1152/jappl.1980.49.4.609 ◽

1980 ◽

Vol 49 (4) ◽

pp. 609-619 ◽

Cited By ~ 37

Author(s):

J. Polacheck ◽

R. Strong ◽

J. Arens ◽

C. Davies ◽

I. Metcalf ◽

...

Keyword(s):

Tidal Volume ◽

Human Subjects ◽

Normal Subjects ◽

Airway Disease ◽

Apparent Volume ◽

Motor Output ◽

Restrictive Lung Disease ◽

Tracheal Pressure ◽

Inspiratory Motor ◽

Vagal Influence

Vagal influence on inspiratory motor output was assessed in 20 normal subjects and in 12 patients with respiratory disorders under enflurane anethesia using the method of airway occlusion. The change in inspiratory duration during occlusion (delta TI) was measured from mechanical parameters (respiratory flow and tracheal pressure). In eight of the subjects, however, the effect of occlusion and augmentation of tidal volume was further evaluated from diaphragmatic electromyogram. In normal subjects delta TI (mechanical) averaged 0.15 s (range -0.1 to +0.77 s) and correlated with the duration of inspiration during occlusion. Electromyographic observations indicated that the change in neural TI exceeds the change in mechanical TI by approximately 0.2 s and that augmentation of tidal volume shortens TI with no apparent volume threshold. There was a tendency for vagal influence to be higher with restrictive lung disease and lower with obstructive airway disease. These observations indicate that a majority of humans display a significant vagal influence on TI in the spontaneous tidal volume range under anesthesia.

Download Full-text

Research on Simulation Technology for Supervisory Control Software in NPP DCS

Volume 1: Operations and Maintenance, Engineering, Modifications, Life Extension, Life Cycle and Balance of Plant; I&C, Digital Controls, and Influence of Human Factors ◽

10.1115/icone25-66064 ◽

2017 ◽

Author(s):

Hanjun Gao ◽

Ming Qu ◽

CaiKe Zhang ◽

Kui Xu ◽

PeiBang Liu ◽

...

Keyword(s):

Supervisory Control ◽

Control Level ◽

Configuration Software ◽

High Fidelity ◽

Operator Training ◽

Level Ii ◽

Crucial Component ◽

Level I ◽

License Examination ◽

High Degree

The DCS simulator is a crucial component of FSS which is used for operator training and license examination. It is always divided into process control level (short for Level I) and supervisory control level (short for Level II). Among these, the Level II directly faces to operators and engineers. Therefore it requires a high degree of fidelity, reliability and good user experience. Be aimed at the requirement of the Level II, a high-fidelity simulation system based on MVC mode is constructed. And multiple technologies of self-dependent innovation and custom-built software are designed and developed, such as the data middleware, the configuration software, and the SimBase et al. The successful application in the HAINAN’s NPP proves that the DCS Level II’s simulator has a high fidelity, reliability, and accumulates valuable experiences for the development of our own DCS Level II as well.

Download Full-text

Dissociation between respiratory effort and dyspnoea in a subset of patients with stroke

Clinical Science ◽

10.1042/cs1030467 ◽

2002 ◽

Vol 103 (5) ◽

pp. 467-473 ◽

Cited By ~ 6

Author(s):

Barbara LANINI ◽

Francesco GIGLIOTTI ◽

Claudia COLI ◽

Roberto BIANCHI ◽

Assunta PIZZI ◽

...

Keyword(s):

Carbon Dioxide ◽

Tidal Volume ◽

Normal Subjects ◽

Carbon Dioxide Tension ◽

Motor Output ◽

Control Group ◽

Quiet Breathing ◽

Oesophageal Pressure ◽

Inspiratory Motor ◽

Tomography Scanning

Dyspnoea is not a prominent complaint of resting patients with recent hemispheric stroke (RHS). We hypothesized that, in patients with RHS presenting abnormalities in respiratory mechanics, increased respiratory motor output could translate into an increased perception of dyspnoea. We studied eight wheelchair-bound patients with RHS (mean age 62.4 years), previously evaluated by computerized tomography scanning, and a control group of normal subjects, matched for age and sex. We assessed routine spirometry, inspiratory and expiratory muscle pressures, breathing pattern and dyspnoea using a modified Borg scale. In six patients, we also measured oesophageal pressure during the maximal sniff manoeuvre and tidal inspiratory swing, and mechanical characteristics of the lung in terms of dynamic elastance during both quiet breathing and a hypercapnic/hyperoxic rebreathing test. During room air breathing, ventilation and tidal volume were similar in patients and controls, while tidal inspiratory swings of oesophageal pressure, an index of inspiratory motor output, were greater in patients (P = 0.005). Patients also exhibited a greater dynamic elastance (P = 0.013). During rebreathing, dynamic elastance remained higher (P = 0.01) and a greater than normal inspiratory motor output was found (P = 0.03). Responses of ventilation and tidal volume to carbon dioxide tension were normal, and in all patients but one a lower Borg score for the unit change in carbon dioxide tension and ventilation was found. In conclusion, a higher than normal inspiratory motor output was unexpectedly associated with a blunted perception of dyspnoea in this subset of RHS patients. This is likely to be due to the modulation of the integration process of respiratory sensation.

Download Full-text

Español a Lo Vivo, Level I, Hansen, Terrence L., Wilkins, Ernest J,, New York: Blaisdell Publishing Company, 1964Español a lo Vivo, Level I, Hansen, Terrence L., Wilkins, Ernest J,, New York: Blaisdell Publishing Company, 1964. xxiii + 387 pp. $7.50. Level II (Preliminary edition), 1963. viii + 408 pp. Mimeograph. Tapes.

Canadian Modern Language Review/ La Revue canadienne des langues vivantes ◽

10.3138/cmlr.22.1.74a ◽

1965 ◽

Vol 22 (1) ◽

pp. 74a-76

Author(s):

Richard F. Allen

Keyword(s):

New York ◽

Publishing Company ◽

Level Ii ◽

Level I

Download Full-text

CLINICAL FEATURES, INDICATIONS AND RESULT OF TRACHEOTOMY

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2017.3.7 ◽

2017 ◽

pp. 50-55

Author(s):

Duc Luu Ngo ◽

Tu The Nguyen ◽

Manh Hung Ho ◽

Thanh Thai Le

Keyword(s):

Clinical Features ◽

University Hospital ◽

Female Ratio ◽

Tube Obstruction ◽

Level Ii ◽

Study Results ◽

Male Female Ratio ◽

Hospital Patients ◽

Level I

Background: This study aims to survey some clinical features, indications and results of tracheotomy at Hue Central Hospital and Hue University Hospital. Patients and method: Studying on 77 patients who underwent tracheotomy at all of departments and designed as an prospective, descriptive and interventional study. Results: Male-female ratio was 4/1. Mean age was 49 years. Career: farmer 44.2%, worker 27.2%, officials 14.3%, student 7.8%, other jobs 6.5%. Respiratory condition before tracheotomy: underwent intubation 62.3%, didn’t undergo intubation 37.7%. Period of stay of endotracheal tube: 1-5 days 29.2%, 6-14 days 52.1%, >14 days 18.7%. Levels of dyspnea before tracheotomy: level I 41.4%, level II 48.3%, level III 0%, 10.3% of cases didn’t have dyspnea. Twenty cases (26%) were performed as an emergency while fifty seven (74%) as elective produces. Classic indications (37.7%) and modern indications (62.3%). On the bases of the site, we divided tracheostomy into three groups: high (0%), mid (25.3%) and low (74.7%). During follow-up, 44 complications occurred in 29 patients (37.7%). Tracheobronchitis 14.3%, tube obstruction 13%, subcutaneous empysema 10.4%, hemorrhage 5%, diffcult decannulation 5.2%, tube displacement 3.9%, canule watery past 2.6%, wound infection 1.3%. The final result after tracheotomy 3 months: there are 33 patients (42.9%) were successfully decannulated. In the 33 patients who were successfully decannulated: the duration of tracheotomy ranged from 1 day to 90 days, beautiful scar (51.5%), medium scar (36.4%), bad scar (12.1%). Conclusions: In tracheotomy male were more than female, adult were more than children. The main indication was morden indication. Tracheobronchitis and tube obstruction were more common than other complications. Key words: Tracheotomy

Download Full-text

Secondary prevention medication persistence and prognosis of acute ischaemic stroke or transient ischaemic attack

Stroke and Vascular Neurology ◽

10.1136/svn-2020-000471 ◽

2021 ◽

pp. svn-2020-000471

Author(s):

Lei Zhang ◽

Junfeng Shi ◽

Yuesong Pan ◽

Zixiao Li ◽

Hongyi Yan ◽

...

Keyword(s):

Secondary Prevention ◽

Ischaemic Stroke ◽

Acute Ischaemic Stroke ◽

Transient Ischaemic Attack ◽

Recurrent Stroke ◽

Medication Persistence ◽

Level Ii ◽

Composite Events ◽

Ischaemic Attack ◽

Level I

IntroductionThe risk of disability and mortality is high among recurrent stroke, which highlights the importance of secondary prevention measures. We aim to evaluate medication persistence for secondary prevention and the prognosis of acute ischaemic stroke or transient ischaemic attack (TIA) in China.MethodsPatients with acute ischaemic stroke or TIA from the China National Stroke Registry II were divided into 3 groups based on the percentage of persistence in secondary prevention medication classes from discharge to 3 months after onset (level I: persistence=0%, level II: 0%<persistence<100%, level III: persistence=100%). The primary outcome was recurrent stroke. The secondary outcomes included composite events (stroke, myocardial infarction or death from cardiovascular cause), all-cause death and disability (modified Rankin Scale score=3–5) from 3 months to 1 year after onset. Recurrent stroke, composite events and all-cause death were performed using Cox regression model, and disability was identified through logistic regression model using the generalised estimating equation method.Results18 344 patients with acute ischaemic stroke or TIA were included, 315 (1.7%) of whom experienced recurrent strokes. Compared with level I, the adjusted HR of recurrent stroke for level II was 0.41 (95% CI 0.31 to 0.54) and level III 0.37 (0.28 to 0.48); composite events for level II 0.41 (0.32 to 0.53) and level III 0.38 (0.30 to 0.49); all-cause death for level II 0.28 (0.23 to 0.35) and level III 0.20 (0.16–0.24). Compared with level I, the adjusted OR of disability for level II was 0.89 (0.77 to 1.03) and level III 0.82 (0.72 to 0.93).ConclusionsPersistence in secondary prevention medications, especially in all classes of medications prescribed by the physician, was associated with lower hazard of recurrent stroke, composite events, all-cause death and lower odds of disability in patients with acute ischaemic stroke or TIA.

Download Full-text

Source depth estimation using multi-station waveform data

Bulletin of the Seismological Society of America ◽

10.1785/bssa0740051623 ◽

1984 ◽

Vol 74 (5) ◽

pp. 1623-1643

Author(s):

Falguni Roy

Keyword(s):

Depth Estimation ◽

The United States ◽

Digital Data ◽

United States Geological Survey ◽

Travel Times ◽

Source Depth ◽

Time Data ◽

Waveform Data ◽

Level Ii ◽

Level I

Abstract A depth estimation procedure has been described which essentially attempts to identify depth phases by analyzing multi-station waveform data (hereafter called level II data) in various ways including deconvolution, prediction error filtering, and spectral analysis of the signals. In the absence of such observable phases, other methods based on S-P, ScS-P, and SKS-P travel times are tried to get an estimate of the source depth. The procedure was applied to waveform data collected from 31 globally distributed stations for the period between 1 and 15 October 1980. The digital data were analyzed at the temporary data center facilities of the National Defense Research Institute, Stockholm, Sweden. During this period, a total number of 162 events in the magnitude range 3.5 to 6.2 were defined by analyzing first arrival time data (hereafter called level I data) alone. For 120 of these events, it was possible to estimate depths using the present procedure. The applicability of the procedure was found to be 100 per cent for the events with mb > 4.8 and 88 per cent for the events with mb > 4. A comparison of level I depths and level II depths (the depths as obtained from level I and level II data, respectively) with that of the United States Geological Survey estimates indicated that it will be necessary to have at least one local station (Δ < 10°) among the level I data to obtain reasonable depth estimates from such data alone. Further, it has been shown that S wave travel times could be successfully utilized for the estimation of source depth.

Download Full-text

Triangularis sterni muscle use in supine humans

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.3.919 ◽

1987 ◽

Vol 62 (3) ◽

pp. 919-925 ◽

Cited By ~ 30

Author(s):

A. De Troyer ◽

V. Ninane ◽

J. J. Gilmartin ◽

C. Lemerre ◽

M. Estenne

Keyword(s):

Normal Subjects ◽

Abdominal Muscle ◽

Abdominal Muscles ◽

Neural Activation ◽

Trained Subjects ◽

Rib Cage ◽

Residual Capacity ◽

External Oblique ◽

Head Flexion ◽

Static Head

The electrical activity of the triangularis sterni (transversus thoracis) muscle was studied in supine humans during resting breathing and a variety of respiratory and nonrespiratory maneuvers known to bring the abdominal muscles into action. Twelve normal subjects, of whom seven were uninformed and untrained, were investigated. The electromyogram of the triangularis sterni was recorded using a concentric needle electrode, and it was compared with the electromyograms of the abdominal (external oblique and rectus abdominis) muscles. The triangularis sterni was usually silent during resting breathing. In contrast, the muscle was invariably activated during expiration from functional residual capacity, expulsive maneuvers, “belly-in” isovolume maneuvers, static head flexion and trunk rotation, and spontaneous events such as speech, coughing, and laughter. When three trained subjects expired voluntarily with considerable recruitment of the triangularis sterni and no abdominal muscle activity, rib cage volume decreased and abdominal volume increased. These results indicate that unlike in the dog, spontaneous quiet expiration in supine humans is essentially a passive process; the human triangularis sterni, however, is a primary muscle of expiration; and its neural activation is largely coupled with that of the abdominals. The triangularis sterni probably contributes to the deflation of the rib cage during active expiration.

Download Full-text

Inspiratory muscles during exercise: a problem of supply and demand

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.6.2482 ◽

1988 ◽

Vol 64 (6) ◽

pp. 2482-2489 ◽

Cited By ~ 57

Author(s):

P. Leblanc ◽

E. Summers ◽

M. D. Inman ◽

N. L. Jones ◽

E. J. Campbell ◽

...

Keyword(s):

Lung Volume ◽

Static Pressure ◽

Total Lung Capacity ◽

Supply And Demand ◽

Normal Subjects ◽

Esophageal Pressure ◽

Maximum Exercise ◽

Lung Capacity ◽

Inspiratory Muscles ◽

Residual Capacity

The capacity of inspiratory muscles to generate esophageal pressure at several lung volumes from functional residual capacity (FRC) to total lung capacity (TLC) and several flow rates from zero to maximal flow was measured in five normal subjects. Static capacity was 126 +/- 14.6 cmH2O at FRC, remained unchanged between 30 and 55% TLC, and decreased to 40 +/- 6.8 cmH2O at TLC. Dynamic capacity declined by a further 5.0 +/- 0.35% from the static pressure at any given lung volume for every liter per second increase in inspiratory flow. The subjects underwent progressive incremental exercise to maximum power and achieved 1,800 +/- 45 kpm/min and maximum O2 uptake of 3,518 +/- 222 ml/min. During exercise peak esophageal pressure increased from 9.4 +/- 1.81 to 38.2 +/- 5.70 cmH2O and end-inspiratory esophageal pressure increased from 7.8 +/- 0.52 to 22.5 +/- 2.03 cmH2O from rest to maximum exercise. Because the estimated capacity available to meet these demands is critically dependent on end-inspiratory lung volume, the changes in lung volume during exercise were measured in three of the subjects using He dilution. End-expiratory volume was 52.3 +/- 2.42% TLC at rest and 38.5 +/- 0.79% TLC at maximum exercise.

Download Full-text