Pulmonary compliance and nonelastic resistance during treadmill exercise

1965 ◽  
Vol 20 (6) ◽  
pp. 1194-1198 ◽  
Author(s):  
S. T. Chiang ◽  
Neal H. Steigbigel ◽  
Harold A. Lyons
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Treadmill Exercise ◽  
Normal Subjects ◽  
Lung Compliance ◽  
Respiratory Frequency ◽  
Respiratory Flow ◽  
Pulmonary Compliance ◽  
Exercise Effect ◽  
Residual Capacity

Trans-pulmonary pressure, respiratory flow, and tidal volume of seven normal subjects were measured at rest and during treadmill exercise on the level at a speed of 1.5 mph. Pulmonary compliance remained unchanged during exercise. Nonelastic resistance showed an insignificant increase (0.9—1.4 cm H2O per liter per sec). Examination of other parameters which may affect compliance were made. Functional residual capacity decreased 120—200 ml during exercise, tidal volume doubled, and respiratory frequency increased 43.5%, yet none of these factors affected the lung compliance. The phenomenon of “second wind” was experienced by four of the subjects, and nothing was observed to explain its occurrence during exercise. exercise second wind; change in functional residual capacity during exercise; effect of functional residual capacity on compliance; effect of tidal volume on compliance during exercise; effect of respiratory frequency on compliance Submitted on January 15, 1965

Estimation of pulmonary ventilation with nitrogen and helium, using the mass spectrometer

1959 ◽  
Vol 14 (4) ◽  
pp. 499-506 ◽  
Author(s):  
K. Tokuyasu ◽  
A. Coblentz ◽  
H. R. Bierman
Keyword(s):  
Tidal Volume ◽  
Mass Spectrometer ◽  
Functional Residual Capacity ◽  
Pulmonary Ventilation ◽  
Normal Subjects ◽  
Alveolar Ventilation ◽  
Pulmonary Lesions ◽  
Normal Subject ◽  
Residual Capacity ◽  
Uneven Ventilation

Estimation of pulmonary ventilation was attempted by measuring the elimination of nitrogen and helium with the mass spectrometer. Exhalatory concentrations of nitrogen and helium were continuously recorded in each of 12 normal subjects and 10 patients with pulmonary enphysema or space-occupying pulmonary lesions. Uniform values for both slow and rapid uneven ventilation were found in all normal subjects but always less than in emphysematous states. Ratios of effective tidal volume (Vt) and alveolar ventilation volume (f·Vt) to functional residual capacity P = Vt/Vr and Q = f·Vt/Vr were one half or less than those in the normal subject. Smaller values of uneven ventilation were found for helium than nitrogen. Data computed by the theory of 'periodic' ventilation gave greater values for uneven ventilation (Q) and more accurately represented the physiologic conditions than derived by ‘continuous’ ventilation. Submitted on August 7, 1958

Ventilatory compensation for changes in functional residual capacity during sleep

1987 ◽  
Vol 62 (3) ◽  
pp. 1299-1306 ◽  
Author(s):  
R. L. Begle ◽  
J. B. Skatrud ◽  
J. A. Dempsey
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Minute Ventilation ◽  
Muscle Length ◽  
Normal Subjects ◽  
Conscious State ◽  
Inspiratory Muscle ◽  
Compensatory Response ◽  
Inspiratory Muscles ◽  
Residual Capacity

The role of conscious factors in the ventilatory compensation for shortened inspiratory muscle length and the potency of this compensatory response were studied in five normal subjects during non-rapid-eye-movement sleep. To shorten inspiratory muscles, functional residual capacity (FRC) was increased and maintained for 2–3 min at a constant level (range of increase 160–1,880 ml) by creating negative pressure within a tank respirator in which the subjects slept. Minute ventilation was maintained in all subjects over the entire range of increased FRC (mean change +/- SE = -3 +/- 1%) through preservation of tidal volume (-2 +/- 2%) despite slightly decreased breathing frequency (-6 +/- 2%). The decrease in frequency (-13 +/- 2%) was due to a prolongation in expiratory time. Inspiratory time shortened (-10 +/- 1%). Mean inspiratory flow increased 15 +/- 3% coincident with an increase in the slope of the moving time average of the integrated surface diaphragmatic electromyogram (67 +/- 21%). End-tidal CO2 did not rise. In two subjects, control tidal volume was increased 35–50% with CO2 breathing. This augmented tidal volume was still preserved when FRC was increased. We concluded that the compensatory response to inspiratory muscle shortening did not require factors associated with the conscious state. In addition, the potency of this response was demonstrated by preservation of tidal volume despite extreme shortening of the inspiratory muscles and increase in control tidal volumes caused by CO2 breathing. Finally, the timing changes we observed may be due to reflexes following shortening of inspiratory muscle length, increase in abdominal muscle length, or cardiovascular changes.

Dynamic mechanisms determine functional residual capacity in mice, Mus musculus

1979 ◽  
Vol 46 (5) ◽  
pp. 867-871 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
D. E. Leith
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Flow Volume ◽  
Linear Portion ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
The Difference ◽  
Pentobarbital Sodium Anesthesia

Awake mice (22.6--32.6 g) were anesthetized intravenously during head-out body plethysmography. One minute after pentobarbital sodium anesthesia, tidal volume had fallen from 0.28 +/- 0.04 to 0.14 +/- 0.02 ml and frequency from 181 +/- 20 to 142 +/- 8. Functional residual capacity (FRC) decreased by 0.10 +/- 0.02 ml. Expiratory flow-volume curves were linear, highly repeatable, and submaximal over substantial portions of expiration in awake and anesthetized mice; and expiration was interrupted at substantial flows that abruptly fell to and crossed zero as inspiration interrupted relaxed expiration. FRC is maintained at a higher level in awake mice due to a higher tidal volume and frequency coupled with expiratory braking (persistent inspiratory muscle activity or increased glottal resistance). In anesthetized mice, the absence of braking, coupled with reductions in tidal volume and frequency and a prolonged expiratory period, leads to FRCs that approach relaxation volume (Vr). An equation in derived to express the difference between FRC and Vr in terms of the portion of tidal volume expired without braking, the slope of the linear portion of the expiratory flow-volume curve expressed as V/V, the time fraction of one respiratory cycle spent in unbraked expiration, and respiratory frequency.

STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Compliance ◽  
Respiratory Physiology ◽  
Residual Volume ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

Relation between anatomic respiratory dead space and body size and lung volume

1963 ◽  
Vol 18 (3) ◽  
pp. 519-522 ◽  
Author(s):  
M. C. Hart ◽  
M. M. Orzalesi ◽  
C. D. Cook
Keyword(s):  
Surface Area ◽  
Functional Residual Capacity ◽  
Dead Space ◽  
Technical Assistance ◽  
Newborn Infants ◽  
Early Period ◽  
Somatic Growth ◽  
Normal Subjects ◽  
Significant Difference ◽  
Residual Capacity

The respiratory anatomic dead space has been measured by the single breath nitrogen washout method of Fowler in 73 normal subjects ranging from 4 to 42 years of age. The volume of the anatomic dead space correlated closely with height (Vd (ml) = 7.585 x Ht (cm)2.363 x 10-4·ɣ = .917), but also with body weight, surface area, and functional residual capacity. When compared on the basis of any of these parameters there was no significant difference between the anatomic dead space values for males and females. Comparisons with available data for newborn infants suggest that the value of the anatomic dead space has a relatively constant relation to height from birth to adulthood. Dead space appears to increase more rapidly than weight, surface area, and functional residual capacity during, at least, the early period of somatic growth. Note: (With the Technical Assistance of J. H. Shaw) Submitted on October 25, 1962

scholarly journals Lung elastic recoil during breathing at increased lung volume

1999 ◽  
Vol 87 (4) ◽  
pp. 1491-1495 ◽  
Author(s):  
Joseph R. Rodarte ◽  
Gassan Noredin ◽  
Charles Miller ◽  
Vito Brusasco ◽  
Riccardo Pellegrino ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Tidal Volume ◽  
Lung Volume ◽  
Normal Subjects ◽  
Dynamic Hyperinflation ◽  
Airway Closure ◽  
Elastic Recoil ◽  
Volume Increase ◽  
Before And After ◽  
Residual Capacity

During dynamic hyperinflation with induced bronchoconstriction, there is a reduction in lung elastic recoil at constant lung volume (R. Pellegrino, O. Wilson, G. Jenouri, and J. R. Rodarte. J. Appl. Physiol. 81: 964–975, 1996). In the present study, lung elastic recoil at control end inspiration was measured in normal subjects in a volume displacement plethysmograph before and after voluntary increases in mean lung volume, which were achieved by one tidal volume increase in functional residual capacity (FRC) with constant tidal volume and by doubling tidal volume with constant FRC. Lung elastic recoil at control end inspiration was significantly decreased by ∼10% within four breaths of increasing FRC. When tidal volume was doubled, the decrease in computed lung recoil at control end inspiration was not significant. Because voluntary increases of lung volume should not produce airway closure, we conclude that stress relaxation was responsible for the decrease in lung recoil.

Effects of vagal denervation on cardiorespiratory and behavioral responses in the newborn lamb

2001 ◽  
Vol 91 (5) ◽  
pp. 2301-2313 ◽  
Author(s):  
Salim Lalani ◽  
John E. Remmers ◽  
Francis H. Green ◽  
Ashfaq Bukhari ◽  
Gordon T. Ford ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Functional Residual Capacity ◽  
Neonatal Period ◽  
Minute Ventilation ◽  
Lung Compliance ◽  
Early Postoperative Period ◽  
Breathing Patterns ◽  
Normal Breathing ◽  
Residual Capacity ◽  
New Evidence

Recently, Wong et al. (Wong KA, Bano A, Rigaux A, Wang B, Bharadwaj B, Schurch S, Green F, Remmers JE, and Hasan SU, J Appl Physiol 85: 849–859, 1998) demonstrated that fetal lambs that have undergone vagal denervation prenatally do not establish adequate alveolar ventilation shortly after birth. In their study, however, vagal denervation was performed prenatally and the deleterious effects of vagal denervation on breathing patterns and gas exchange could have resulted from the prenatal actions of the neurotomy. To quantify the relative roles of pre- vs. postnatal vagal denervation on control of breathing, we studied 14 newborn lambs; 6 were sham operated, and 8 were vagally denervated below the origin of the recurrent laryngeal nerve. Postoperatively, all denervated animals became hypoxemic and seven of eight succumbed to respiratory failure. In vagally denervated lambs, expiratory time increased, whereas respiratory rate, minute ventilation, and lung compliance decreased compared with the sham-operated animals. In the early postoperative period, the frequency of augmented breaths was lower but gradually increased over time in the denervated vs. sham-operated group. The dynamic functional residual capacity was significantly higher than the passive functional residual capacity among the sham-operated group compared with the denervated group. No significant differences were observed in the prevalence of various sleep states and in the amount of total phospholipids or large- and small-aggregate surfactants between the two groups. We provide new evidence indicating that intrauterine actions of denervation are not required to explain the effects of vagal denervation on postnatal survival. Our data suggest that vagal input is critical in the maintenance of normal breathing patterns, end-expiratory lung volume, and gas exchange during the early neonatal period.

Characteristics of an inspiration-augmenting reflex in anesthetized cats

1962 ◽  
Vol 17 (4) ◽  
pp. 683-688 ◽  
Author(s):  
Leslie B. Reynolds
Keyword(s):  
Mechanical Properties ◽  
Functional Residual Capacity ◽  
Lung Compliance ◽  
Respiratory Cycle ◽  
Effective Stimulus ◽  
Deep Breath ◽  
Residual Capacity

Overinflation or release from deflation of the lungs in anesthetized cats induced a vagally mediated, inspiration-augmenting reflex, characterized by a sudden phrenic motor discharge and an increase in rate and depth of inspiration. It resulted in an increase in end-expiratory volume and lung compliance. In a series of sinusoidal inflations, the reflex could exhibit summation to occur on any single inflation, but having occurred, was temporarily refractory to further inflations. The spontaneous deep breath was shown to be the same reflex, being vagally mediated, and similarly related to changes in mechanical properties of the lungs. The effective stimulus was shown to be a function of velocity and duration of inflation, while the refractoriness shown by the reflex was related to the accompanying increase in end-expiratory volume. The inspiration-augmenting reflex, by increasing functional residual capacity and compliance, was presumed to open alveolar units. It may interact with the Hering-Breuer inspiration-limiting reflex in controlling the respiratory cycle. Submitted on January 8, 1962

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