Effect of abdominal compression on maximum transdiaphragmatic pressure

1990 ◽  
Vol 68 (6) ◽  
pp. 2296-2304 ◽  
Author(s):  
D. R. Hillman ◽  
J. Markos ◽  
K. E. Finucane
Keyword(s):  
Applied Pressure ◽  
Abdominal Muscle ◽  
Inspiratory Effort ◽  
Neural Activation ◽  
Abdominal Compression ◽  
External Compression ◽  
Transdiaphragmatic Pressure ◽  
Trained Subjects ◽  
Maximum Effort ◽  
Residual Capacity

Transdiaphragmatic pressure (Pdi) is lower during maximum inspiratory effort with the diaphragm alone than when maximum inspiratory and expulsive efforts are combined. The increase in Pdi with expulsive effort has been attributed to increased neural activation of the diaphragm. Alternatively, the increase could be due to stretching of the contracted diaphragm. If this were so, Pdi measured during a combined maximum effort would overestimate the capacity of the diaphragm to generate inspiratory force. This study determined the likely contribution of stretching of the contracted diaphragm to estimates of maximum Pdi (Pdimax) obtained during combined inspiratory and expulsive effort. Three healthy trained subjects were studied standing. Diaphragmatic Mueller maneuvers were performed at functional residual capacity and sustained during subsequent abdominal compression by either abdominal muscle expulsive effort or externally applied pressure. Measurements were made of changes in abdominal (Pab) and pleural (Ppl) pressure, Pdi, rib cage and abdominal dimensions and respiratory electromyograms. Three reproducible performances of each maneuver from each subject were analyzed. When expulsive effort was added to maximum diaphragmatic inspiratory effort, Pdimax increased from 86 +/- 12 to 148 +/- 14 (SD) cmH2O within the 1st s and was 128 +/- 14 cmH2O 2 s later. When external compression was added to maximum diaphragmatic inspiratory effort, Pdimax increased from 87 +/- 16 to 171 +/- 19 cmH2O within the 1st s and was 152 +/- 16 cmH2O 2 s later.(ABSTRACT TRUNCATED AT 250 WORDS)

Triangularis sterni muscle use in supine humans

1987 ◽  
Vol 62 (3) ◽  
pp. 919-925 ◽  
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.

Effects of fenoterol on inspiratory effort sensation and fatigue during inspiratory threshold loading

1996 ◽  
Vol 80 (3) ◽  
pp. 727-733 ◽  
Author(s):  
J. Suzuki ◽  
S. Suzuki ◽  
T. Okubo
Keyword(s):  
Low Frequency ◽  
Normal Subjects ◽  
Motor Command ◽  
Inspiratory Effort ◽  
Double Blind ◽  
Endurance Time ◽  
Transdiaphragmatic Pressure ◽  
Mouth Pressure ◽  
Residual Capacity ◽  
Low Frequency Power

We studied the effects of a single dose of fenoterol on the relationship between inspiratory effort sensation (IES) and inspiratory muscle fatigue induced by inspiratory threshold loading in healthy subjects. The magnitude of the threshold was 60% of maximal static inspiratory mouth pressure (PI,mmax) at functional residual capacity, and the duty cycle was 0.5. Subjects continued the threshold loaded breathing until the target mouth pressure could no longer be maintained (endurance time). The intensity of the IES was scored with a modified Borg scale. Either fenoterol (5 mg) or a placebo was given orally 2 h before loading in a randomized double-blind crossover protocol. The endurance time with fenoterol (34.4 +/- 8.6 min) was longer than that with the placebo (22.2 +/- 7.1 min; P < 0.05). The ratio of high- to low-frequency power of the diaphragmatic electromyogram (EMGdi) decreased during loading; the decrease was less with fenoterol (P < 0.05). The EMGdi also decreased with loading; the decrease was greater on fenoterol treatment (P < 0.01). The PI,mmax and maximal transdiaphragmatic pressure (Pdi) were similarly decreased after loading on either treatment. The intensity of the IES rose with time during loading in both groups but was lower with fenoterol than with the placebo (P < 0.05). The ratio of Pdi to integrated activity of the EMGdi increased with fenoterol (P < 0.05). Fenoterol treatment increased both superimposed Pdi twitch and Pdi twitch of relaxed diaphragm and decreased the value of (1-superimposed Pdi twitch/Pdi twitch of relaxed diaphragm). Thus we conclude that in normal subjects fenoterol reduces diaphragmatic fatigue and decreases the motor command to the diaphragm, resulting in a decrease in IES during inspiratory threshold loading and a prolongation of endurance.

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.

Relationships among pressure, tension, and shape of the diaphragm

1983 ◽  
Vol 55 (6) ◽  
pp. 1899-1905 ◽  
Author(s):  
W. A. Whitelaw ◽  
L. E. Hajdo ◽  
J. A. Wallace
Keyword(s):  
Cross Section ◽  
Radius Of Curvature ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
Residual Capacity ◽  
Best Fitting ◽  
Pressure Generator ◽  
Free Membrane ◽  
Relationship Of ◽  
Shape Changes

The shape of the diaphragm dome was calculated from transdiaphragmatic pressure and tension in the diaphragm. It was assumed that the muscle acts as a free membrane, attached at its edges to the inside of a vertical rib cage circular in cross section, that the attachments are inferior to the point at which the dome makes contract with the rib cage, and that the abdomen is filled with fluid with a hydrostatic gradient in pressure. The shape is different from a section of a sphere, with a radius of curvature substantially greater at the apex of the dome than at the sides. Observed shapes of human hemidiaphragm domes at functional residual capacity are not spherical but closely match the calculated shapes. Best-fitting shapes correspond to transdiaphragmatic pressures of about 3 cmH2O transdiaphragmatic pressure, suggesting that such a pressure and corresponding tension are present in the human diaphragm when it is at rest in an erect subject. In this model; as lung volume increases and the diaphragm shortens, its shape changes in such a way that the ratio between transdiaphragmatic pressure and tension in the diaphragm remains nearly constant, rather than increasing with volume. Such a model can explain the observation that the length-tension relationship of the muscle is much more important than curvature in determining the effectiveness of the diaphragm as a pressure generator.

Effects of digoxin on diaphragmatic strength generation

1986 ◽  
Vol 61 (5) ◽  
pp. 1767-1774 ◽  
Author(s):  
M. Aubier ◽  
N. Viires ◽  
D. Murciano ◽  
J. P. Seta ◽  
R. Pariente
Keyword(s):  
Cardiac Output ◽  
Sartorius Muscle ◽  
Transdiaphragmatic Pressure ◽  
Balloon Catheters ◽  
Hindlimb Muscle ◽  
Intramuscular Electrodes ◽  
Plasmatic Level ◽  
Residual Capacity ◽  
Group A ◽  
Group B

Contrary to hindlimb muscle, extracellular calcium plays an important role in diaphragmatic strength generation (J. Appl. Physiol. 58: 2054–61, 1985). Since the inotropic effect of digitalis appears to be related to cell membrane transport of calcium, we studied the effect of digoxin on diaphragmatic contractility in 20 anesthetized dogs. The diaphragm was electrically stimulated with intramuscular electrodes. The transdiaphragmatic pressure (Pdi) during supramaximal (50 V) 2-s stimulations applied over a frequency range of 10–100 Hz was measured with balloon catheters at functional residual capacity. Cardiac output was measured with a Swan-Ganz catheter and diaphragmatic blood flow (Qdi) by timed volume collections of left inferior venous effluent. The force generated by the sartorius muscle during electrical stimulations was studied concomitantly to Pdi. In 10 dogs (group A) 0.04 mg/kg of digoxin was infused in 10 min. In 10 other dogs (group B) 0.2 mg/kg was administered. All measurements were performed during control and 30, 60, 90, and 120 min after digoxin administration. In group A, digoxin plasmatic level at 60 min reached a therapeutic range in all dogs (1.8 +/- 0.3 ng/ml), whereas in group B, digoxin plasmatic level was higher (8 +/- 1.3 ng/ml). No significant change in cardiac output and Qdi was noted after administration of digoxin, either in the dogs of group A or those of group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinematics and mechanics of midcostal diaphragm of dog

1997 ◽  
Vol 83 (4) ◽  
pp. 1068-1075 ◽  
Author(s):  
Aladin M. Boriek ◽  
Joseph R. Rodarte ◽  
Theodore A. Wilson
Keyword(s):  
Functional Residual Capacity ◽  
Spontaneous Breathing ◽  
Total Lung Capacity ◽  
Radius Of Curvature ◽  
Transdiaphragmatic Pressure ◽  
Lung Capacity ◽  
Circular Arcs ◽  
Residual Capacity ◽  
Three Bundles ◽  
Marker Location

Boriek, Aladin M., Joseph R. Rodarte, and Theodore A. Wilson. Kinematics and mechanics of midcostal diaphragm of dog. J. Appl. Physiol. 83(4): 1068–1075, 1997.—Radiopaque markers were attached to the peritoneal surface of three neighboring muscle bundles in the midcostal diaphragm of four dogs, and the locations of the markers were tracked by biplanar video fluoroscopy during quiet spontaneous breathing and during inspiratory efforts against an occluded airway at three lung volumes from functional residual capacity to total lung capacity in both the prone and supine postures. Length and curvature of the muscle bundles were determined from the data on marker location. Muscle lengths for the inspiratory states, as a fraction of length at functional residual capacity, ranged from 0.89 ± 0.04 at end inspiration during spontaneous breathing down to 0.68 ± 0.07 during inspiratory efforts at total lung capacity. The muscle bundles were found to have the shape of circular arcs, with the three bundles forming a section of a right circular cylinder. With increasing lung volume and diaphragm displacement, the circular arcs rotate around the line of insertion on the chest wall, the arcs shorten, but the radius of curvature remains nearly constant. Maximal transdiaphragmatic pressure was calculated from muscle curvature and maximal tension-length data from the literature. The calculated maximal transdiaphragmatic pressure-length curve agrees well with the data of Road et al. ( J. Appl. Physiol. 60: 63–67, 1986).

Effect of digitalis on the diaphragm in anesthetized dogs

1987 ◽  
Vol 63 (1) ◽  
pp. 277-284 ◽  
Author(s):  
Y. Kikuchi ◽  
W. Hida ◽  
C. Shindoh ◽  
T. Chonan ◽  
H. Miki ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Stimulus Frequency ◽  
Dependent Manner ◽  
Phrenic Nerve Stimulation ◽  
Transdiaphragmatic Pressure ◽  
Mechanically Ventilated ◽  
Before And After ◽  
Residual Capacity ◽  
Anesthetized Dogs

We examined the effect of digitalis on diaphragmatic contractility and fatigability in 19 anesthetized mechanically ventilated dogs. The diaphragmatic force was assessed from transdiaphragmatic pressure (Pdi) developed at functional residual capacity against an occluded airway during cervical phrenic nerve stimulation. In a first group of five dogs, Pdi-stimulus frequency relationships were compared before and after administration of ouabain in doses of 0.01, 0.02, and 0.04 mg/kg. In a second group, diaphragmatic fatigue was produced by bilateral phrenic nerve stimulation at 30 Hz. Ten seconds of stimulation and 15 s of mechanical ventilation were repeated for 30 min. The rates of decrease in Pdi were compared between two groups, one of 0.05 mg/kg deslanoside-treated dogs (n = 7) and one of nontreated dogs (n = 7). After ouabain administration Pdi was significantly greater at each frequency in a dose-dependent manner. On the other hand, the rate of decrease in Pdi in the deslanoside group was significantly smaller than that in the nontreated group, whereas deslanoside did not greatly change the Pdi-frequency curves in fresh diaphragm. We conclude that ouabain improves contractility of the fresh diaphragm and that deslanoside has a protective effect against fatigability.

Assessment of transdiaphragmatic pressure in humans

1985 ◽  
Vol 58 (5) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Laporta ◽  
A. Grassino
Keyword(s):  
Pulmonary Disease ◽  
Visual Feedback ◽  
Random Order ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Disease Group ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Residual Capacity ◽  
Group 1

Maximal force developed by the diaphragm at functional residual capacity is a useful index to establish muscle weakness; however, great disparity in its reproducibility can be observed among reports in the literature. We evaluated five maneuvers to measure maximal transdiaphragmatic pressure (Pdimax) in order to establish best reproducibility and value. Thirty-five naive subjects, including 10 normal subjects (group 1), 12 patients with chronic obstructive pulmonary disease (group 2), and 13 patients with restrictive pulmonary disease (group 3), were studied. Each subject performed five separate maneuvers in random order that were repeated until reproducible values were obtained. The maneuvers were Mueller with (A) and without mouthpiece (B), abdominal expulsive effort with open glottis (C), two-step (maneuver C combined with Mueller effort) (D), and feedback [two-step with visual feedback of pleural (Ppl) and abdominal (Pab) pressure] (E). The greatest reproducible Pdimax values were obtained with maneuver E (P less than 0.01) (group 1: 180 +/- 14 cmH2O). The second best maneuvers were A, B, and D (group 1: 154 +/- 25 cmH2O). Maneuver C produced the lowest values. For all maneuvers, group 1 produced higher values than groups 2 and 3 (P less than 0.001), which were similar. The Ppl to Pdi ratio was 0.6 in maneuvers A and B, 0.4 in D and E, and 0.2 in C. We conclude that visual feedback of Ppl and Pab helped the subjects to elicit maximal diaphragmatic effort in a reproducible fashion. It is likely that the great variability of values in Pdimax previously reported are the result of inadequate techniques.

Effect of body position on regional diaphragm function in dogs

1990 ◽  
Vol 69 (6) ◽  
pp. 2296-2302 ◽  
Author(s):  
J. Sprung ◽  
C. Deschamps ◽  
S. S. Margulies ◽  
R. D. Hubmayr ◽  
J. R. Rodarte
Keyword(s):  
Prone Position ◽  
Regional Differences ◽  
Body Position ◽  
Vertical Gradient ◽  
Transdiaphragmatic Pressure ◽  
Lung Capacity ◽  
Volume Relationship ◽  
Residual Capacity ◽  
Fractional Shortening

The in situ lengths of muscle bundles of the crural and three regions of the costal diaphragm between origin and insertion were determined with a video roentgenographic technique in dogs. At total lung capacity (TLC) in both the prone and supine positions, the length of the diaphragm is not significantly different from the unstressed excised length, suggesting that the diaphragm is not under tension at TLC and that there is a hydrostatic gradient of pleural pressure on the diaphragmatic surface. Except for the ventral region of the costal diaphragm, which does not change length at lung volumes greater than 70% TLC, all other regions are stretched during passive deflations from TLC. Therefore below TLC the diaphragm is under passive tension and supports a transdiaphragmatic pressure (Pdi). The length of the diaphragm relative to its unstressed length is not uniform at functional residual capacity (FRC) and does not follow a strict vertical gradient that reverses when the animal is changed from the supine to the prone position. By inference, the length of muscle bundles is determined by factors other than the vertical gradient of Pdi. During mechanical ventilation, regional shortening is identical to the passive deflation length-volume relationship near FRC. Prone and supine FRC is the same, but the diaphragm is slightly shorter in the prone position. In both positions, during spontaneous ventilation there are no consistent differences in regional fractional shortening, despite regional differences in initial length relative to unstressed length.

Phrenic afferent contribution to reflexes elicited by changes in diaphragm length

1990 ◽  
Vol 69 (2) ◽  
pp. 640-647 ◽  
Author(s):  
M. Cheeseman ◽  
W. R. Revelette
Keyword(s):  
Muscle Activation ◽  
Motor Drive ◽  
Inspiratory Time ◽  
Abdominal Compression ◽  
Dorsal Rhizotomy ◽  
Residual Capacity ◽  
Bilateral Vagotomy ◽  
Spinal Section ◽  
Length Changes ◽  
Crural Diaphragm

Recent evidence from several laboratories suggests that activation of afferents in the diaphragm can reflexly affect inspiratory muscle activation. This study determined whether afferents in the diaphragm contribute to compensatory changes in phrenic motor drive when the operating length of the diaphragm is suddenly increased. Experiments were performed in six closed-chest pentothal-anesthetized cats. Length changes were measured using a pair of piezoelectric crystals implanted in the left crural diaphragm. The crural electromyogram (EMGdi) was measured by electrodes fixed to each crystal. The animal was suspended in a spinal frame, and a Plexiglas tube was fitted around the cat's abdomen. A balloon placed inside the tube was inflated during the expiratory phase to produce a mean increase of 17% in diaphragm length at functional residual capacity. Ten trials were performed in succession under the following conditions: intact, after bilateral vagotomy, after spinal section at C7, and after cervical dorsal rhizotomy. Peak integrated EMGdi (integral of EMGdi) and neural inspiratory time (nTI) were measured for the last control inspiration and the first after inflation. There was a significant reduction in the peak integral of EMGdi when the length of the diaphragm was increased for all conditions except after rhizotomy. Although not measured, it is likely that the tension developed by the diaphragm was also increased during abdominal compression. Results suggest that afferents sensitive to changes in the operating length and/or tension in the diaphragm contribute to compensatory alterations in phrenic motor drive.

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