Effects of pursed-lips breathing and expiratory resistive loading in healthy subjects

1996 ◽  
Vol 80 (5) ◽  
pp. 1772-1784 ◽  
Author(s):  
J. A. Spahija ◽  
A. Grassino
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Healthy Subjects ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Abdominal Muscle ◽  
Breathing Frequency ◽  
Muscle Recruitment ◽  
Rib Cage ◽  
Resistive Loading

To examine the effect of pursed-lips breathing (PLB) on breathing pattern and respiratory mechanics, we studied 11 healthy subjects breathing with and without PLB at rest and during steady-state bicycle exercise. Six of these subjects took part in a second study, which compared the effects of PLB to expiratory resistive loading (ERL). PLB was found to prolong expiratory and total breath durations and to promote a slower and deeper breathing pattern. During exercise, the compensatory increase that occurred in tidal volume was not sufficient to counter the reduction in breathing frequency, causing minute ventilation to be reduced. Although ERL similarly caused minute ventilation and breathing frequency to be decreased, unlike PLB, it produced no change in tidal volume and prolonged expiratory and total breath durations to a lesser extent. PLB and ERL increased the expiratory resistance to a comparable degree, also increasing the expiratory resistive work of breathing and promoting greater expiratory rib cage and abdominal muscle recruitment in response to the expiratory loads. End-expiratory lung volume, which was determined from inspiratory capacity maneuvers, was not altered by PLB; however, with ERL it was increased by 0.20 and 0.24 liter during rest and exercise, respectively. Inspiratory muscle recruitment patterns were not altered by PLB at rest, although small increases in the relative contribution of the rib cage/accessory muscles in conjunction with abdominal muscle relaxation occurred during exercise. Similar trends were observed with ERL. We conclude that, although ERL and PLB induce comparable respiratory muscle recruitment responses, they are not equivalent with respect to breathing pattern changes and effect on end-expiratory lung volume.

Respiratory and abdominal muscle responses to expiratory threshold loading in cystic fibrosis

1992 ◽  
Vol 72 (3) ◽  
pp. 842-850 ◽  
Author(s):  
F. Cerny ◽  
L. Armitage ◽  
J. A. Hirsch ◽  
B. Bishop
Keyword(s):  
Cystic Fibrosis ◽  
Tidal Volume ◽  
Body Position ◽  
Minute Ventilation ◽  
Abdominal Muscle ◽  
Abdominal Muscles ◽  
Breathing Frequency ◽  
Control Subjects ◽  
Lung Dysfunction ◽  
Muscle Responses

We hypothesized that the hyperinflation and pulmonary dysfunction of cystic fibrosis (CF) would distort feedback and therefore alter the abdominal muscle response to graded expiratory threshold loads (ETLs). We compared the respiratory and abdominal muscle responses with graded ETLs of seven CF patients with severe lung dysfunction with those of matched healthy control subjects in the supine and 60 degrees head-up positions. Breathing frequency, tidal volume, and ventilatory timing were determined from inspiratory flow recordings. Abdominal electromyograms (EMGs) were detected with surface electrodes placed unilaterally over the external and internal oblique and the rectus abdominis muscles. Thresholds, times of onset, and durations of phasic abdominal activity were determined from raw EMGs; peak amplitudes were determined from integrated EMGs. Graded ETLs were imposed by submerging a tube from the expiratory port of the breathing valve into a column of water at depths of 0–25 cmH2O. We found that breathing frequency, tidal volume, and expired minute ventilation were higher in CF patients than in control subjects during low ETLs; a change in body position did not alter these ventilatory responses in the CF patients but did in the control subjects. All CF patients, but none of the control subjects, had tonic abdominal activity while supine. CF patients recruited abdominal muscles at lower loads, earlier in the respiratory cycle, and to a higher recruitment level in both positions than the control subjects, but burst duration of phasic activity was not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of exercise and CO2 on breathing pattern of normal man

1979 ◽  
Vol 47 (1) ◽  
pp. 192-196 ◽  
Author(s):  
J. Askanazi ◽  
J. Milic-Emili ◽  
J. R. Broell ◽  
A. I. Hyman ◽  
J. M. Kinney
Keyword(s):  
Tidal Volume ◽  
Duty Cycle ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Inspiratory Flow ◽  
Breathing Frequency ◽  
Inspiratory Time ◽  
Noninvasive Measurements ◽  
Normal Man

Ventilatory patterns during rest, CO2 inhalation (2, 3, and 4%) and three levels of exercise were analyzed in supine men using a canopy system for noninvasive measurements. Changes in tidal volume (VT) and breathing frequency (f) with equal increases in minute ventilation (VE) differed significantly during exercise and CO2 inhalation. Increases in VE during exercise was accompanied by increases in VT and f. During CO2 inhalation, the change in frequency was less than during exercise. However, when analyzed in terms of inspiratory flow (VT/TI) and inspiratory duty cycle (TI/Ttot), the response to both stimuli was similar. With increases to twice control VE both TI/Ttot and VT/VI increased. Thereafter only VTTI increased with increasing VE. At rest, inspiratory time on a breath by breath basis increased minimally with VT, while changes in inspiratory flow accounted for the variability in VT. These two respiratory stimulants appear to increase ventilation through different mechanisms when analyzed in terms of VT and f. However, changes in inspiratory flow and duty cycle are similar in both.

Effect of intravenous midazolam on breathing pattern and chest wall mechanics in human

1984 ◽  
Vol 57 (4) ◽  
pp. 1104-1110 ◽  
Author(s):  
D. R. Morel ◽  
A. Forster ◽  
M. Bachmann ◽  
P. M. Suter
Keyword(s):  
Tidal Volume ◽  
Healthy Subjects ◽  
Breathing Pattern ◽  
Tidal Breathing ◽  
Pharmacological Agents ◽  
Rib Cage ◽  
Chest Wall Mechanics ◽  
Before And After ◽  
Central Apneas ◽  
End Tidal

Breathing pattern, thoracoabdominal motion, and separate end-expiratory positions of the rib cage and abdomen were measured noninvasively in eight healthy subjects before and after intravenous administration of either placebo or midazolam, a short-acting benzodiazepine. Compared with placebo, midazolam produced a significant (P less than 0.01) decrease in mean inspiratory flow of 29% from preinjection values, resulting in a 39% reduction in tidal volume (VT). This ventilatory depression was partly compensated by a 35% decrease in expiratory time producing an increase in respiratory rate (+39%). The fall in VT was almost entirely (91%) mediated by a reduction of the abdominal contribution to tidal breathing while sparing rib cage motion. This fact contrasts with the effects of inhalational anesthetics or morphine, which preferentially depress rib cage expansion, indicating that thoracoabdominal motion may selectively be depressed by different pharmacological agents. In addition, continuous recording of end-expiratory levels showed a significant transient fall in the rib cage's end-tidal position 2 min after midazolam administration associated with the occurrence of central apneas.

Adaptations of quadriplegic men to consecutively loaded breaths

1984 ◽  
Vol 56 (4) ◽  
pp. 1099-1103 ◽  
Author(s):  
K. Axen
Keyword(s):  
Tidal Volume ◽  
Sensory Input ◽  
Minute Ventilation ◽  
Breathing Frequency ◽  
Ventilatory Responses ◽  
Group Response ◽  
Resistive Loading ◽  
Elastic Loading ◽  
Resistive Loads ◽  
Accessory Muscles

Ventilatory responses to graded elastic and resistive loads from 20 quadriplegic men were analyzed. During the 1st, 5th, and 10th consecutively loaded inspirations 1) responses from different subjects ranged from a weak tidal volume defense coupled with an increased breathing frequency to a strong tidal volume defense coupled with a decreased frequency; 2) strong tidal volume defenders generally employed longer inspirations than did weak tidal volume defenders; and 3) individual respiratory frequencies were mediated by similar changes in inspiratory and/or expiratory timing. Thus the group response was qualitatively similar on the 1st, 5th, and 10th loaded breaths. Quantitatively, however, minute ventilation increased throughout each 10-breath episode due to progressively larger tidal volumes coupled with equal breathing frequencies. These larger tidal volumes were due to progressively stronger inspirations with no changes in timing during elastic loading, whereas they were due to both stronger and longer inspirations during resistive loading. These findings, which are qualitatively the same as those found in healthy subjects, indicate that sensory input from the mouth, lung, and diaphragm, and motor output to the diaphragm and accessory muscles are sufficient, by themselves, to mediate normal patterns of ventilatory adjustments during consecutively loaded breaths.

Expiratory muscle contribution to tidal volume in head-up dogs

1989 ◽  
Vol 67 (4) ◽  
pp. 1438-1442 ◽  
Author(s):  
G. A. Farkas ◽  
M. Estenne ◽  
A. De Troyer
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Muscle Relaxation ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
S Period ◽  
Average Contribution

A change from the supine to the head-up posture in anesthetized dogs elicits increased phasic expiratory activation of the rib cage and abdominal expiratory muscles. However, when this postural change is produced over a 4- to 5-s period, there is an initial apnea during which all the muscles are silent. In the present studies, we have taken advantage of this initial silence to determine functional residual capacity (FRC) and measure the subsequent change in end-expiratory lung volume. Eight animals were studied, and in all of them end-expiratory lung volume in the head-up posture decreased relative to FRC [329 +/- 70 (SE) ml]. Because this decrease also represents the increase in lung volume as a result of expiratory muscle relaxation at the end of the expiratory pause, it can be used to determine the expiratory muscle contribution to tidal volume (VT). The average contribution was 62 +/- 6% VT. After denervation of the rib cage expiratory muscles, the reduction in end-expiratory lung volume still amounted to 273 +/- 84 ml (49 +/- 10% VT). Thus, in head-up dogs, about two-thirds of VT result from the action of the expiratory muscles, and most of it (83%) is due to the action of the abdominal rather than the rib cage expiratory muscles.

Expiratory muscle activity in the awake and sleeping human during lung inflation and hypercapnia

1992 ◽  
Vol 72 (3) ◽  
pp. 881-887 ◽  
Author(s):  
Y. Wakai ◽  
M. M. Welsh ◽  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Ventilatory Threshold ◽  
Minute Ventilation ◽  
Abdominal Muscle ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Lung Inflation ◽  
Expiratory Muscle ◽  
Intramuscular Electrodes

Expiratory muscle activity has been shown to occur in awake humans during lung inflation; however, whether this activity is dependent on consciousness is unclear. Therefore we measured abdominal muscle electromyograms (intramuscular electrodes) in 13 subjects studied in the supine position during wakefulness and non-rapid-eye-movement sleep. Lung inflation was produced by nasal continuous positive airway pressure (CPAP). CPAP at 10–15 cmH2O produced phasic expiratory activity in two subjects during wakefulness but produced no activity in any subject during sleep. During sleep, CPAP to 15 cmH2O increased lung volume by 1,260 +/- 215 (SE) ml, but there was no change in minute ventilation. The ventilatory threshold at which phasic abdominal muscle activity was first recorded during hypercapnia was 10.3 +/- 1.1 l/min while awake and 13.8 +/- 1 l/min while asleep (P less than 0.05). Higher lung volumes reduced the threshold for abdominal muscle recruitment during hypercapnia. We conclude that lung inflation alone over the range that we studied does not alter ventilation or produce recruitment of the abdominal muscles in sleeping humans. The internal oblique and transversus abdominis are activated at a lower ventilatory threshold during hypercapnia, and this activation is influenced by state and lung volume.

Human respiratory muscle actions and control during exercise

1997 ◽  
Vol 83 (4) ◽  
pp. 1256-1269 ◽  
Author(s):  
A. Aliverti ◽  
S. J. Cala ◽  
R. Duranti ◽  
G. Ferrigno ◽  
C. M. Kenyon ◽  
...  
Keyword(s):  
Lung Volume ◽  
Respiratory Muscle ◽  
Abdominal Muscle ◽  
Abdominal Pressure ◽  
Abdominal Muscles ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Velocity Of Shortening ◽  
And Control ◽  
Muscle Actions

Aliverti, A., S. J. Cala, R. Duranti, G. Ferrigno, C. M. Kenyon, A. Pedotti, G. Scano, P. Sliwinski, Peter T. Macklem, and S. Yan. Human respiratory muscle actions and control during exercise. J. Appl. Physiol. 83(4): 1256–1269, 1997.—We measured pressures and power of diaphragm, rib cage, and abdominal muscles during quiet breathing (QB) and exercise at 0, 30, 50, and 70% maximum workload (W˙max) in five men. By three-dimensional tracking of 86 chest wall markers, we calculated the volumes of lung- and diaphragm-apposed rib cage compartments (Vrc,p and Vrc,a, respectively) and the abdomen (Vab). End-inspiratory lung volume increased with percentage of W˙max as a result of an increase in Vrc,p and Vrc,a. End-expiratory lung volume decreased as a result of a decrease in Vab. ΔVrc,a/ΔVab was constant and independent ofW˙max. Thus we used ΔVab/time as an index of diaphragm velocity of shortening. From QB to 70%W˙max, diaphragmatic pressure (Pdi) increased ∼2-fold, diaphragm velocity of shortening 6.5-fold, and diaphragm workload 13-fold. Abdominal muscle pressure was ∼0 during QB but was equal to and 180° out of phase with rib cage muscle pressure at all percent W˙max. Rib cage muscle pressure and abdominal muscle pressure were greater than Pdi, but the ratios of these pressures were constant. There was a gradual inspiratory relaxation of abdominal muscles, causing abdominal pressure to fall, which minimized Pdi and decreased the expiratory action of the abdominal muscles on Vrc,a gradually, minimizing rib cage distortions. We conclude that from QB to 0% W˙max there is a switch in respiratory muscle control, with immediate recruitment of rib cage and abdominal muscles. Thereafter, a simple mechanism that increases drive equally to all three muscle groups, with drive to abdominal and rib cage muscles 180° out of phase, allows the diaphragm to contract quasi-isotonically and act as a flow generator, while rib cage and abdominal muscles develop the pressures to displace the rib cage and abdomen, respectively. This acts to equalize the pressures acting on both rib cage compartments, minimizing rib cage distortion .

Changes in respiratory muscle activity in ponies when end-expiratory lung volume is increased

1994 ◽  
Vol 76 (5) ◽  
pp. 2015-2025 ◽  
Author(s):  
B. K. Erickson ◽  
H. V. Forster ◽  
T. F. Lowry ◽  
L. G. Pan ◽  
M. J. Korducki ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Negative Pressure ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Transversus Abdominis ◽  
Vagal Afferents ◽  
Breathing Frequency ◽  
Respiratory Muscle Activity

The objective of the present study was to determine whether lung and diaphragm afferents contribute to the changes in respiratory muscle activity when end-expiratory lung volume (EELV) is changed in ponies. We studied the responses of the diaphragm and the transversus abdominis (TA) muscles to passive increases in EELV in awake intact (I), diaphragm-deafferented (DD), pulmonary vagal- (hilar nerve) denervated (HND), and DD + HND ponies. Negative pressure of -10 or -20 cmH2O applied around the ponies′ torsos [positive transrespiratory (TR) pressure] increased (P < 0.05) EELV in all ponies; the increases were more (P < 0.05) in HND and less (P < 0.05) in DD than in I ponies. In I ponies, positive TR pressure increased (P < 0.05) the rate of rise of the integrated diaphragmatic electromyogram (EMG), reflecting increased drive to the muscle. This increase was less (P < 0.05) in DD and HND than in I ponies. In DD + HND ponies, there was no significant (P > 0.10) change in drive to the diaphragm during positive TR pressure. In I ponies, positive TR pressure increased (P < 0.05) the duration and mean activity of the TA EMG. In HND and DD + HND ponies, the TA EMG was not altered by positive TR pressure. I and DD ponies decreased (P < 0.05) breathing frequency but maintained tidal volume (VT) during positive TR pressure. HND and DD+HND ponies increased breathing frequency (P < 0.05) and decreased (P < 0.05) VT during positive TR pressure. We conclude that, during positive TR pressure when the diaphragm is presumably at a mechanical disadvantage, diaphragm and vagal afferents mediate increased drive to the diaphragm to prevent VT from decreasing. In addition, during positive TR pressure, vagal afferents mediate an increase in duration of TA activity, which minimizes the increase in EELV.

Effort sensation, chemoresponsiveness, and breathing pattern during inspiratory resistive loading

1992 ◽  
Vol 73 (2) ◽  
pp. 440-445 ◽  
Author(s):  
J. E. Clague ◽  
J. Carter ◽  
M. G. Pearson ◽  
P. M. Calverley
Keyword(s):  
Tidal Volume ◽  
Breathing Pattern ◽  
Free Breathing ◽  
Normal Subjects ◽  
Inspiratory Effort ◽  
Sustained Load ◽  
Resistive Loading ◽  
End Tidal ◽  
Few Data ◽  
Normal Men

Although inspiratory resistive loading (IRL) reduces the ventilatory response to CO2 (VE/PCO2) and increases the sensation of inspiratory effort (IES), there are few data about the converse situation: whether CO2 responsiveness influences sustained load compensation and whether awareness of respiratory effort modifies this behavior. We studied 12 normal men during CO2 rebreathing while free breathing and with a 10-cmH2O.l-1.s IRL and compared these data with 5 min of resting breathing with and without the IRL. Breathing pattern, end-tidal PCO2, IES, and mouth occlusion pressure (P0.1) were recorded. Free-breathing VE/PCO2 was inversely related to an index of effort perception (IES/VE; r = -0.63, P less than 0.05), and the reduction in VE/PCO2 produced by IRL was related to the initial free-breathing VE/PCO2 (r = 0.87, P less than 0.01). IRL produced variable increases in inspiratory duration (TI), IES, and P0.1 at rest, and the change in tidal volume correlated with both VE/PCO2 (r = 0.63, P less than 0.05) and IES/VE (r = -0.69, P less than 0.05), this latter index also predicting the changes in TI with loading (r = -0.83, P less than 0.01). These data suggest that in normal subjects perception of inspiratory effort can modify free-breathing CO2 responsiveness and is as important as CO2 sensitivity in determining the response to short-term resistive loading. Individuals with good perception choose a small-tidal volume and short-TI breathing pattern during loading, possibly to minimize the discomfort of breathing.

Ventilatory adjustments during sustained mechanical loading in conscious humans

1983 ◽  
Vol 55 (4) ◽  
pp. 1211-1218 ◽  
Author(s):  
K. Axen ◽  
S. S. Haas ◽  
F. Haas ◽  
D. Gaudino ◽  
A. Haas
Keyword(s):  
Mechanical Loading ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Ventilatory Responses ◽  
Frequency Responses ◽  
Group Response ◽  
Resistive Loading ◽  
Elastic Loading ◽  
Resistive Loads ◽  
Load Size

Ventilatory responses to inspiratory elastic and resistive loads of 67 men were analyzed. During the 1st, 5th, and 10th consecutively loaded breaths 1) individual responses ranged from a rapid-shallow to a slow-deep breathing pattern; 2) strong tidal volume (VT) defenders employed longer inspirations than did weak VT defenders; and 3) individual frequency responses were mediated by changes in inspiratory and/or expiratory timing. Thus the group response was qualitatively similar on the 1st, 5th, and 10th loaded breaths. Quantitatively, however, the group's mean minute ventilation increased throughout each episode owing to progressively larger tidal volumes coupled with equal breathing frequencies. During elastic loading this amplified VT defense was achieved by stronger inspirations with no systematic changes in timing, whereas during resistive loading it was achieved both by stronger and longer inspirations. Inspiring 5% CO2 induced a degree of hypercapnia exceeding that accompanying mechanical loading and yet elicited a comparatively modest enhancement of respiratory output. These findings suggest that in conscious humans 1) repeated mechanical loading activates neural load-compensating mechanisms; 2) the range of these neural adjustments varies with both load size and type; and 3) the stimulus to initiate this behavior is largely nonchemical.

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