scholarly journals Reduced Phrenic Motoneuron Recruitment during Sustained Inspiratory Threshold Loading Compared to Single-Breath Loading: A Twitch Interpolation Study

2016 ◽  
Vol 7 ◽  
Author(s):  
Mathieu Raux ◽  
Alexandre Demoule ◽  
Stefania Redolfi ◽  
Capucine Morelot-Panzini ◽  
Thomas Similowski
Keyword(s):  
Single Breath ◽  
Twitch Interpolation ◽  
Phrenic Motoneuron

Thoracic reflexes stabilizing loaded ventilation in normal and cord-injured man

1977 ◽  
Vol 43 (2) ◽  
pp. 339-346 ◽  
Author(s):  
K. Axen ◽  
E. H. Bergofsky
Keyword(s):  
Tidal Volume ◽  
Normal Subjects ◽  
Cervical Cord ◽  
Subjective Perception ◽  
Volume Stability ◽  
Single Breath ◽  
Phrenic Motoneuron ◽  
Spontaneously Breathing ◽  
Injured Patients ◽  
Load Conditions

The ability to regulate tidal volume was quantified in 24 cervical cord-injured patients by comparing the “effective” elastance (E′rs) observed during single-breath elastic loads to the passive respiratory elastance (Ers) measured separately with relaxed muscles. Thirteen patients, the majority of whom had an abnormal subjective perception of loading, usually failed to demonstrate any tidal volume compensation under load conditions (i.e. E′rs less than or equal to Ers). This impaired tidal volume defense, which could not be attributed either to diaphragmatic paralysis or rib cage instability, was accompanied by a markedly shortened inspiratory duration and, hence, a prematurely terminated phrenic motoneuron output. Conversely, those patients who developed a larger then previously reported “effective” elastance (i.e., E′rs greater than or equal to 2Ers) described loading as an inspiratory obstruction, as did all our normal subjects, and usually prolonged loaded inspiratory duration, probably by a consciously mediated mechanism. These findings are consistent with the hypothesis that, in spontaneously breathing intact man, thoracic sensory receptors normally maintain phrenic motoneuron output under load conditions and thereby promote tidal volume stability.

Vergleichende Bestimmung des Transferfaktors für Kohlenmonoxyd mit der Single-breath- und der Steady-state-Methode

Respiration ◽  
1974 ◽  
Vol 31 (6) ◽  
pp. 503-514
Author(s):  
H. Löllgen ◽  
U. Smidt ◽  
G. von Nieding ◽  
H. Krekeler
Keyword(s):  
Steady State ◽  
Single Breath

The effect of conductive ventilation heterogeneity on diffusing capacity measurement

2008 ◽  
Vol 104 (4) ◽  
pp. 1094-1100 ◽  
Author(s):  
Sylvia Verbanck ◽  
Daniel Schuermans ◽  
Sophie Van Malderen ◽  
Walter Vincken ◽  
Bruce Thompson
Keyword(s):  
Carbon Monoxide ◽  
Vital Capacity ◽  
Experimental Situation ◽  
Normal Subjects ◽  
Diffusing Capacity ◽  
Capacity Measurement ◽  
Alveolar Volume ◽  
Estimation Errors ◽  
Single Breath ◽  
Ventilation Heterogeneity

It has long been assumed that the ventilation heterogeneity associated with lung disease could, in itself, affect the measurement of carbon monoxide transfer factor. The aim of this study was to investigate the potential estimation errors of carbon monoxide diffusing capacity (DlCO) measurement that are specifically due to conductive ventilation heterogeneity, i.e., due to a combination of ventilation heterogeneity and flow asynchrony between lung units larger than acini. We induced conductive airway ventilation heterogeneity in 35 never-smoker normal subjects by histamine provocation and related the resulting changes in conductive ventilation heterogeneity (derived from the multiple-breath washout test) to corresponding changes in diffusing capacity, alveolar volume, and inspired vital capacity (derived from the single-breath DlCO method). Average conductive ventilation heterogeneity doubled ( P < 0.001), whereas DlCO decreased by 6% ( P < 0.001), with no correlation between individual data ( P > 0.1). Average inspired vital capacity and alveolar volume both decreased significantly by, respectively, 6 and 3%, and the individual changes in alveolar volume and in conductive ventilation heterogeneity were correlated ( r = −0.46; P = 0.006). These findings can be brought in agreement with recent modeling work, where specific ventilation heterogeneity resulting from different distributions of either inspired volume or end-expiratory lung volume have been shown to affect DlCO estimation errors in opposite ways. Even in the presence of flow asynchrony, these errors appear to largely cancel out in our experimental situation of histamine-induced conductive ventilation heterogeneity. Finally, we also predicted which alternative combination of specific ventilation heterogeneity and flow asynchrony could affect DlCO estimate in a more substantial fashion in diseased lungs, irrespective of any diffusion-dependent effects.

Assessment of cardiorespiratory function using oscillating inert gas forcing signals

1994 ◽  
Vol 76 (5) ◽  
pp. 2130-2139 ◽  
Author(s):  
E. M. Williams ◽  
J. B. Aspel ◽  
S. M. Burrough ◽  
W. A. Ryder ◽  
M. C. Sainsbury ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Dead Space ◽  
Confidence Limit ◽  
Pulmonary Blood Flow ◽  
Mean Difference ◽  
Alveolar Volume ◽  
Single Breath ◽  
Cardiorespiratory Function ◽  
Airway Dead Space

A theoretical model (Hahn et al. J. Appl. Physiol. 75: 1863–1876, 1993) predicts that the amplitudes of the argon and nitrous oxide inspired, end-expired, and mixed expired sinusoids at forcing periods in the range of 2–3 min (frequency 0.3–0.5 min-1) can be used directly to measure airway dead space, lung alveolar volume, and pulmonary blood flow. We tested the ability of this procedure to measure these parameters continuously by feeding monosinusoidal argon and nitrous oxide forcing signals (6 +/- 4% vol/vol) into the inspired airstream of nine anesthetized ventilated dogs. Close agreement was found between single-breath and sinusoid airway dead space measurements (mean difference 15 +/- 6%, 95% confidence limit), N2 washout and sinusoid alveolar volume (mean difference 4 +/- 6%, 95% confidence limit), and thermal dilution and sinusoid pulmonary blood flow (mean difference 12 +/- 11%, 95% confidence limit). The application of 1 kPa positive end-expiratory pressure increased airway dead space by 12% and alveolar volume from 0.8 to 1.1 liters but did not alter pulmonary blood flow, as measured by both the sinusoid and comparator techniques. Our findings show that the noninvasive sinusoid technique can be used to measure cardiorespiratory lung function and allows changes in function to be resolved in 2 min.

Estimation of the VA/(Q+VTIS) distribution from single-breath alkane uptake

2001 ◽  
Vol 48 (7) ◽  
pp. 772-786 ◽  
Author(s):  
J.G. van den Aardweg ◽  
S. Kezic ◽  
J.A. Bosch ◽  
A.C. Monster
Keyword(s):  
Single Breath

Single-breath-hold venous or arterial flow-suppressed pulmonary vascular MR imaging with phased-array coils

1993 ◽  
Vol 3 (4) ◽  
pp. 611-616 ◽  
Author(s):  
Thomas K. F. Foo ◽  
James R. Macfall ◽  
H. Dirk Sostman ◽  
Cecil E. Hayes
Keyword(s):  
Mr Imaging ◽  
Phased Array ◽  
Arterial Flow ◽  
Breath Hold ◽  
Single Breath ◽  
Single Breath Hold ◽  
Phased Array Coils ◽  
Array Coils

Seroflurane Versus Isoflurane in Single-Breath Induction

1996 ◽  
Vol 83 (3) ◽  
pp. 662
Author(s):  
Mark H. Sloan ◽  
Peter K. Karsunky ◽  
Pattilyn F. Conard ◽  
Jeffrey B. Gross
Keyword(s):  
Single Breath
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