Diaphragmatic fatigue in man

1977 ◽  
Vol 43 (2) ◽  
pp. 189-197 ◽  
Author(s):  
C. S. Roussos ◽  
P. T. Macklem
Keyword(s):  
Energy Consumption ◽  
Lung Diseases ◽  
Respiratory Muscles ◽  
Transdiaphragmatic Pressure ◽  
Diaphragmatic Fatigue ◽  
Residual Capacity ◽  
The Subject ◽  
Time Required ◽  
The Relationship ◽  
Experimental Runs

The time required (tlim) to produce fatigue of the diaphragm was determined in three normal seated subjects, breathing through a variety of high alinear, inspiratory resistances. During each breath in all experimental runs the subject generated a transdiaphragmatic pressure (Pdi) which was a predetermined fraction of his maximum inspiratory Pdi (Pdimax) at functional residual capacity. The breathing test was performed until the subject was unable to generate this Pdi. The relationship between Pdi/Pdimax and tlim was curvilinear so that when Pdi/Pdimax was small tlim increased markedly for little changes in Pdi/Pdimax. The value of Pdi/Pdimax that could be generated indefinitely (Pdicrit) was around 0.4. Hypoxia appeared to have no influence on Pdicrit, but probably led to a reduction in tlim at Pdi greater than Pdicrit for equal rates of energy consumption. Insofar as the behavior of the diaphragm reflects that of other respiratory muscles it appears that quite high inspiratory loads can be tolerated indefinitely. However, when the energy consumption of the respiratory muscles exceeds a critical level, fatigue should develop. This may be a mechanism of respiratory failure in a variety in a variety of lung diseases.

Bilateral phrenic stimulation: a simple technique to assess diaphragmatic fatigue in humans

1985 ◽  
Vol 58 (1) ◽  
pp. 58-64 ◽  
Author(s):  
M. Aubier ◽  
D. Murciano ◽  
Y. Lecocguic ◽  
N. Viires ◽  
R. Pariente
Keyword(s):  
Recovery Period ◽  
Transdiaphragmatic Pressure ◽  
Single Twitch ◽  
Diaphragmatic Fatigue ◽  
Before And After ◽  
Residual Capacity ◽  
Loaded Breathing ◽  
Phrenic Nerves ◽  
The Subject ◽  
Phrenic Stimulation

Transdiaphragmatic pressure (Pdi) and the rate of relaxation of the diaphragm (tau) were measured at functional residual capacity (FRC) in six normal seated subjects during single-twitch stimulation of both phrenic nerves. The latter were stimulated supramaximally with needle electrodes with square-wave impulses of 0.1-ms duration at 1 Hz before and after diaphragmatic fatigue produced by resistive loaded breathing. Constancy of chest wall configuration was achieved by monitoring the diameter of the abdomen and the rib cage with a respiratory inductive plethysmograph system. During control the peak Pdi generated during the phrenic stimulation amounted to 34.4 +/- 4.2 (SE) cmH2O and represented in each subject a fixed fraction (17%) of its maximal transdiaphragmatic pressure. After diaphragmatic fatigue the peak Pdi decreased by an average of 45%, amounting to 18.1 +/- 2.7 cmH2O 5 min after the fatigue run, and tau increased from 55.2 +/- 9 ms during control to 77 +/- 8 ms 5 min after the fatigue run. The decrease in peak Pdi and the increase in tau observed after the fatigue run persisted throughout the 30 min of the recovery period studied, the peak Pdi amounting to 18.4 +/- 2.8 and 18.9 +/- 3.3 cmH2O and tau to 81.3 +/- 5.7 and 88.7 +/- 10 ms at 15 and 30 min after the end of the fatigue run, respectively. It is concluded that diaphragmatic fatigue can be detected in man by bilateral phrenic stimulation with needle electrodes without any discomfort for the subject and that the decrease in diaphragmatic strength after fatigue is long lasting.

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.

Respiratory movements of the vocal cords

1983 ◽  
Vol 54 (5) ◽  
pp. 1269-1276 ◽  
Author(s):  
T. Brancatisano ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Lung Volume ◽  
Respiratory Control ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Tight Coupling ◽  
Tidal Breathing ◽  
Vocal Cords ◽  
Residual Capacity ◽  
The Relationship ◽  
Respiratory Movements

We examined the movements of the vocal cords during tidal breathing, panting, and large changes in lung volume in 12 normal subjects. The glottis was observed with a fiber-optic bronchoscope, and the glottic image was recorded together with flow, volume, and a time marker onto videotape. Phasic respiratory swings in glottic width (dg) and glottic area (Ag) were reproducible in all subjects but differed substantially between subjects. In the group as a whole dg and Ag increased during inspiration to 10.1 +/- 5.6 mm and 126 +/- 8 mm2 (mean +/- SE), respectively, whereas during expiration the lowest values were 5.7 +/- 0.5 mm and 70 +/- 7 mm2, respectively. These extreme dimensions corresponded closely to the midtidal volume points in the respiratory cycle. Glottic width during vital capacity (VC) expirations was nearly 30% greater at a flow of 1.2 l/s than at 0.5 l/s, but the relationship between dg and lung volume differed between subjects. When swings in dg were minimized by panting, there was no difference in dg between functional residual capacity (FRC) and a volume corresponding to midinspiratory capacity. However, tidal breathing at this lung volume was associated with a 20% decrease in dg compared with breathing at FRC. Our observations indicate a tight coupling between the pattern of glottic movement and the respiratory volume cycle. The results suggest that during voluntary respiratory maneuvers both intrinsic laryngeal and respiratory muscles are recruited, participating as effector organs in ventilatory and respiratory control.

Ventilatory response to fatiguing and nonfatiguing resistive loads in awake sheep

1985 ◽  
Vol 59 (3) ◽  
pp. 969-978 ◽  
Author(s):  
N. Sadoul ◽  
A. R. Bazzy ◽  
S. R. Akabas ◽  
G. G. Haddad
Keyword(s):  
Considerable Increase ◽  
Minute Ventilation ◽  
Respiratory Muscles ◽  
Inspiratory Flow ◽  
Transdiaphragmatic Pressure ◽  
Arterial Pco2 ◽  
Residual Capacity ◽  
Alveolar Hypoventilation ◽  
Resistive Loads ◽  
Respiratory Muscle Endurance

To study the changes in ventilation induced by inspiratory flow-resistive (IFR) loads, we applied moderate and severe IFR loads in chronically instrumented and awake sheep. We measured inspired minute ventilation (VI), ventilatory pattern [inspiratory time (TI), expiratory time (TE), respiratory cycle time (TT), tidal volume (VT), mean inspiratory flow (VT/TI), and respiratory duty cycle (TI/TT)], transdiaphragmatic pressure (Pdi), functional residual capacity (FRC), blood gas tensions, and recorded diaphragmatic electromyogram. With both moderate and severe loads, Pdi, TI, and TI/TT increased, TE, TT, VT, VT/TI, and VI decreased, and hypercapnia ensued. FRC did not change significantly with moderate loads but decreased by 30–40% with severe loads. With severe loads, arterial PCO2 (PaCO2) stabilized at approximately 60 Torr within 10–15 min and rose further to levels exceeding 80 Torr when Pdi dropped. This was associated with a lengthening in TE and a decrease in breathing frequency, VI, and TI/TT. We conclude that 1) timing and volume responses to IFR loads are not sufficient to prevent alveolar hypoventilation, 2) with severe loads the considerable increase in Pdi, TI/TT, and PaCO2 may reduce respiratory muscle endurance, and 3) the changes in ventilation associated with neuromuscular fatigue occur after the drop in Pdi. We believe that these ventilatory changes are dictated by the mechanical capability of the respiratory muscles or induced by a decrease in central neural output to these muscles or both.

Diaphragmatic function in healthy subjects during partial curarization

1980 ◽  
Vol 48 (6) ◽  
pp. 921-926 ◽  
Author(s):  
T. J. Gal ◽  
S. K. Goldberg
Keyword(s):  
Respiratory Muscles ◽  
Upper Airway ◽  
Normal Subjects ◽  
Maximum Effect ◽  
Quiet Breathing ◽  
Transdiaphragmatic Pressure ◽  
Control Value ◽  
Diaphragmatic Function ◽  
Residual Capacity ◽  
Diaphragmatic Weakness

Diaphragmatic function estimated by transdiaphragmatic pressure (Pdi) was studied in eight normal subjects during progressive partial paralysis with d-tubocurarine (dTc). Dynamic Pdi was measured during quiet tidal breathing, maximum deep inspiration, and 12-s maximum voluntary ventilation (MVV). Maximum static transdiaphragmatic pressure (Pdimax) was also measured during maximum static inspiratory efforts at four lung volumes. The maximum effect of dTc at a cumulative dose of 0.2 mg/kg abolished head-lift and handgrip ability. Pdimax at functional residual capacity was decreased to 42% of its control value indicating significant diaphragmatic weakness at this level of curarization. The weakness had no inpact on quiet breathing and a moderate effect on maximum inspiration. In either case Pdi represented an increasing fraction of Pdimax. MVV fell significantly before the Pdi during the maneuver decreased. This decreased MVV in curarized subjects reflects upper airway obstruction caused by pharyngeal muscle weakness and the diminished contribution of the other respiratory muscles that are important at high levels of ventilatory effort but more sensitive to effects of dTc.

Mechanical arrangement of costal and crural diaphragms in dogs

1984 ◽  
Vol 56 (6) ◽  
pp. 1484-1490 ◽  
Author(s):  
M. Decramer ◽  
A. De Troyer ◽  
S. Kelly ◽  
P. T. Macklem
Keyword(s):  
Lung Volume ◽  
Quiet Breathing ◽  
Transdiaphragmatic Pressure ◽  
Length Relationship ◽  
Residual Capacity ◽  
In Series ◽  
Anesthetized Dogs ◽  
The Relationship ◽  
Mechanical Arrangement ◽  
Stimulation Of

To assess the mechanical arrangement of the costal and crural parts of the diaphragm, we studied changes in diaphragmatic length with piezoelectric crystals in 17 supine anesthetized dogs. During control resting inspiration, the crural part usually shortened more and earlier than the costal part. After phrenicotomy, the crural part always lengthened during inspiration, whereas the costal part shortened or lengthened. These interanimal differences disappeared after opening of the abdomen; the costal part then always lengthened during inspiration. During stimulation of one part, the relaxed nonstimulated part always lengthened. However, when compared with the relationship between length and transdiaphragmatic pressure (Pdi) obtained during passive deflation, the lengthening of the relaxed part during stimulation of either part was small. This difference between predicted and measured Pdi-length relationship decreased in magnitude as lung volume increased above functional residual capacity (FRC) and increased as residual volume was approached. These results indicate that 1) even during quiet breathing the diaphragm in the dog is not a single functional entity; 2) at FRC the costal and crural portions of the diaphragm behave as if they were mechanically arranged partly in parallel and partly in series; and 3) they gradually move into a pure mechanical series arrangement as lung volume increases.

Electromyogram pattern of diaphragmatic fatigue

1979 ◽  
Vol 46 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. Gross ◽  
A. Grassino ◽  
W. R. Ross ◽  
P. T. Macklem
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Normal Subjects ◽  
Progressive Increase ◽  
Transdiaphragmatic Pressure ◽  
Diaphragmatic Fatigue ◽  
Inspiratory Resistance ◽  
Residual Capacity ◽  
Emg Power Spectrum ◽  
Pressure Generator

We studied the effect of breathing at various levels of transdiaphragmatic pressure (Pdi) on the EMG power spectrum of the diaphragm. The diaphragmatic EMG was measured simultaneously with a bipolar esophageal electrode (EE) and surface electrode (SE) placed on the ventral portion of the sixth and seventh intercostal spaces in five normal subjects breathing at functional residual capacity (FRC) against an inspiratory resistance. During each fatigue run the subjects generated a Pdi, with each inspiration, that was 25, 50, or 75% of maximum Pdi (Pdimax) for a period up to 15 min. During runs at 50 and 75% of the Pdimax, which are known to produce fatigue, we found for both EE and SE a progressive increase in the amplitude of the low-frequency (L = 20-46.7 Hz) and a decrease in the high-frequency (H = 150-350 Hz) component of the EMG. These changes were not seen at 25% of Pdimax. The diaphragmatic H/L ratio was independent of Pdi when the diaphragm was not fatigued. H/L fell while the diaphragm performed fatiguing work and this was more rapid at higher Pdi's. It was thus concluded that frequency spectrum analysis of the EMG can detect diaphragmatic fatigue reliably, prior to the time when the diaphragm fails as a pressure generator.

Blood flow to respiratory muscles and major organs during inspiratory flow resistive loads

1993 ◽  
Vol 74 (1) ◽  
pp. 428-434 ◽  
Author(s):  
L. M. Pang ◽  
Y. J. Kim ◽  
A. R. Bazzy
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Respiratory Muscles ◽  
Inspiratory Flow ◽  
The Other ◽  
Transdiaphragmatic Pressure ◽  
Diaphragmatic Fatigue ◽  
Microsphere Method ◽  
Loaded Breathing ◽  
Resistive Loads

To determine whether diaphragmatic fatigue in the intact animal subjected to loaded breathing is associated with a decrease in diaphragmatic blood flow, seven unanesthetized sheep were subjected to severe inspiratory flow resistive (IFR) loads that led to a decrease in transdiaphragmatic pressure (Pdi) and a rise in arterial PCO2 (PaCO2). Blood flow to the diaphragm, other respiratory muscles, limb muscles, and major organs was measured using the radionuclide-labeled microsphere method. With these loads blood flow increased to the diaphragm (621 +/- 242%) and all the other inspiratory and expiratory diaphragm (621 +/- 242%) and all the other inspiratory and expiratory muscles; there was no statistically significant change in blood flow to these muscles at the time when Pdi decreased and PaCO2 rose. Blood flow also increased to the heart (103 +/- 34%), brain (212 +/- 39%), and adrenals (76 +/- 9%), whereas pancreatic flow decreased (-66 +/- 14%). Limb muscle blood flow remained unchanged. We conclude that in unanesthetized sheep subjected to IFR loads 1) we did not demonstrate a decrease in respiratory muscle blood flow associated with diaphragmatic fatigue and ventilatory failure, and 2) there is a redistribution of blood flow among major organs.

Effects and mechanism of action of terbutaline on diaphragmatic contractility and fatigue

1984 ◽  
Vol 56 (4) ◽  
pp. 922-929 ◽  
Author(s):  
M. Aubier ◽  
N. Viires ◽  
D. Murciano ◽  
G. Medrano ◽  
Y. Lecocguic ◽  
...  
Keyword(s):  
Low Frequencies ◽  
Transdiaphragmatic Pressure ◽  
High Frequencies ◽  
Balloon Catheters ◽  
Diaphragmatic Fatigue ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Phrenic Nerves ◽  
Indirect Stimulation ◽  
Stimulation Of

We studied the effects of intravenously administered terbutaline on diaphragmatic force and fatigue during electrical stimulation of the diaphragm in 17 anesthetized dogs. The diaphragm was stimulated indirectly through the phrenic nerves with electrodes placed around the fifth roots and directly with electrodes surgically implanted in the abdominal side of each hemidiaphragm. Transdiaphragmatic pressure (Pdi) during direct or indirect supramaximal 2-s stimulation applied over a frequency range of 10–100 Hz was measured with balloon catheters during tracheal occlusion at functional residual capacity. In seven dogs the administration of terbutaline (0.5 mg) had no effect on Pdi at any stimulation frequency applied directly or indirectly. The effect of terbutaline (0.5 mg) on diaphragmatic fatigue was then tested in 10 other dogs. Diaphragmatic fatigue was produced by continuous 20-Hz electrical supramaxial stimulation of the phrenic nerves during 30 min. At the end of the fatigue procedure Pdi decreased by 50 +/- 5 and 30 +/- 8% of control values at 10 and 100 Hz, respectively, for either direct or indirect stimulation. The decrease in Pdi for low frequencies of stimulation (10 and 20 Hz) lasted 100 +/- 18 min, whereas it lasted only 40 +/- 10 min for the high frequencies (50 and 100 Hz). When terbutaline (0.5 mg) was administered after the fatiguing procedure, Pdi increased within 15 min by 20 +/- 4% at 10 Hz and by 12 +/- 3% at 100 Hz for either direct or indirect stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Bohr effect data for blood gas calculations

1983 ◽  
Vol 55 (3) ◽  
pp. 1002-1007 ◽  
Author(s):  
M. P. Hlastala ◽  
R. D. Woodson
Keyword(s):  
Relaxation Rate ◽  
Transdiaphragmatic Pressure ◽  
Relative Contribution ◽  
Exponential Decline ◽  
Gastric Pressure ◽  
Diaphragmatic Fatigue ◽  
Residual Capacity ◽  
The Mean ◽  
Rate Of Decline ◽  
Voluntary Contractions

The rate of relaxation of the diaphragm after stimulated (4 subjects) and voluntary (8 subjects) contractions was compared in normal young men. Stimulated contractions were induced by supramaximal unilateral phrenic nerve stimulation and voluntary contractions by short, sharp sniffs of varying tensions against an occluded airway. The rate of relaxation of the diaphragm was calculated from the rate of decline of transdiaphragmatic pressure (Pdi). In both conditions the maximum relaxation rate (MRR) was proportional to the peak transdiaphragmatic pressure (Pdi), whereas the time constant (tau) of the later exponential decline in Pdi was independent of Pdi. The mean +/- SE rate constant of relaxation (MRR/Pdi) was 0.0078 +/- 0.0002 ms-1 and the mean tau was 57 +/- 3.8 ms for stimulated contractions. The rate of relaxation after sniffs was not different, and it was not affected by either the lung volume at which occluded sniffs were performed (in the range of residual volume to functional residual capacity + 1 liter) or by the relative contribution gastric pressure made to Pdi. After diaphragmatic fatigue was induced by inspiring against a high alinear resistance there was a decrease in relaxation rate. In the 1st min postfatigue MRR/Pdi decreased (0.0063 +/- 0.0003 ms-1; P less than 0.005) and tau increased (83 +/- 5 ms; P less than 0.005). Both values returned to prefatigue levels within 5 min of the end of the studies. We conclude that the sniff may prove to be clinically useful in the detection of diaphragmatic fatigue.

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