Dynamic Lung Compliance and the Effect of Oxygen Breathing in Patients with Chronic Bronchitis

1970 ◽  
Vol 39 (4) ◽  
pp. 497-503
Author(s):  
T. W. Astin
Keyword(s):  
Tidal Volume ◽  
Chronic Bronchitis ◽  
Lung Compliance ◽  
Minute Volume ◽  
Physiological Dead Space ◽  
Oxygen Breathing ◽  
Airways Resistance ◽  
Effect Of Oxygen ◽  
Dynamic Lung Compliance ◽  
Ventilation Of The Lungs

1. Simultaneous measurements of the tidal volume and the intra-oesophageal pressure were made in fifteen hypoxaemic patients with chronic bronchitis during periods of air breathing and 30% oxygen breathing; values of dynamic lung compliance were obtained. 2. During the period of oxygen breathing, the dynamic lung compliance increased in fourteen of the patients (the mean increase was 28%). 3. The increase in dynamic lung compliance could not be accounted for by a change in the frequency of breathing, tidal volume or minute volume. 4. It is concluded that the increase in dynamic lung compliance reflected a reduction in airways resistance during oxygen breathing. It is suggested that this could lead to a change in the physiological dead space in the absence of any change in the overall ventilation of the lungs.

Development of stability of the respiratory system in preterm infants

1988 ◽  
Vol 65 (1) ◽  
pp. 441-444 ◽  
Author(s):  
G. P. Heldt
Keyword(s):  
Chest Wall ◽  
Preterm Infants ◽  
Pulmonary Ventilation ◽  
Lung Compliance ◽  
Minute Volume ◽  
Lung Mechanics ◽  
Diaphragmatic Function ◽  
Postconceptional Age ◽  
Intraesophageal Pressure ◽  
Dynamic Lung Compliance

Chest wall distortion leads to increased minute volume displacement of the diaphragm (MVDD) and diaphragmatic work (DW) in preterm infants. Lung mechanics, MVDD, and DW were measured at weekly intervals in six preterm infants between 29 and 36 wk postconceptional age. Over the period of study, MVDD and DW decreased significantly, whereas dynamic lung compliance consistently increased. There was no consistent change in the pulmonary ventilation, total pulmonary resistance, the work performed on the lungs, or the change in intraesophageal pressure with tidal breathing. The improvement in the stability of the chest wall, as indicated by the change in these dynamic measurements of diaphragmatic function, parallels the decrease in static chest wall compliance and the clinical course of the resolution of apnea of prematurity.

Rapidly adapting receptors monitor lung compliance in spontaneously breathing dogs

1990 ◽  
Vol 68 (5) ◽  
pp. 1997-2005 ◽  
Author(s):  
T. E. Pisarri ◽  
A. Jonzon ◽  
J. C. Coleridge ◽  
H. M. Coleridge
Keyword(s):  
Tidal Volume ◽  
Spontaneous Breathing ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Vagus Nerves ◽  
Concomitant Increase ◽  
Inflatable Cuff ◽  
Lung Expansion ◽  
Dynamic Lung Compliance ◽  
Spontaneously Breathing

We examined the ability of rapidly adapting receptors (RARs) to monitor changes in dynamic lung compliance (Cdyn) in anesthetized spontaneously breathing dogs by recording RAR impulses from the vagus nerves. We decreased Cdyn in steps through the physiological range by briefly restricting lung expansion with an inflatable cuff around the chest and recording the response after deflating the cuff; we restored Cdyn to control by hyperinflating the lungs. Of 45 RARs, 34 were stimulated by a 40 +/- 2% reduction in Cdyn, their inspiratory discharge increasing on average more than threefold. Two-thirds of responsive RARs were stimulated by less than or equal to 20% reductions in Cdyn; in most, firing increased proportionately with lung stiffness (1/Cdyn) as Cdyn was decreased further. Stimulation by reduced Cdyn was not simply a function of the concomitant increase in transpulmonary pressure, because similar increases in pressure produced by increasing tidal volume produced smaller increases in firing. RAR stimulation was unaffected by atropine and, hence, was not dependent on neurally mediated changes in bronchomotor tone. Our results indicate that during spontaneous breathing RARs provide a signal inversely proportional to Cdyn.

Using Conventional Infant Ventilators at Unconventional Rates

PEDIATRICS ◽  
1984 ◽  
Vol 74 (4) ◽  
pp. 487-492 ◽  
Author(s):  
Stephen J. Boros ◽  
Dennis R. Bing ◽  
Mark C. Mammel ◽  
Erik Hagen ◽  
Margaret J. Gordon
Keyword(s):  
Tidal Volume ◽  
Airway Pressure ◽  
Important Determinant ◽  
Peak Inspiratory Pressure ◽  
Lung Compliance ◽  
Minute Volume ◽  
Inspiratory Pressure ◽  
Positive End Expiratory Pressure ◽  
Inspiratory Time ◽  
Pressure Monitor

The effect of progressive increases in ventilator rate on delivered tidal and minute volumes, and the effect of changing peak inspiratory pressure (Pmax), positive end-expiratory pressure (PEEP), and inspiration to expiration (I:E) ratio at different ventilator rates were examined. Five different continuous-flow, time-cycled, pressure-preset infant ventilators were studied using a pneumotachograph, an airway pressure monitor, and a lung simulator. As rates increased from 10 to 150 breaths per minute, tidal volume stayed constant until 25 to 30 breaths per minute; then progessively decreased. In all, tidal volume began to decrease when proximal airway pressure waves lost inspiratory pressure plateaus. As rates increased, minute volume increased until 75 breaths per minute, then leveled off, then decreased. Substituting helium for O2 increased the ventilator rate at which this minute volume plateau effect occurred. Increasing peak inspiratory pressure consistently increased tidal volume. Increasing positive end-expiratory pressure decreased tidal volume. At rates less than 75 breaths per minute, inspiratory time (inspiration to expiration ratio) had little effect on delivered volume. At rates greater than 75 breaths per minute, inspiratory time became an important determinant of minute volume. For any given combination of lung compliance and airway resistance: (1) there is a maximum ventilator rate beyond which tidal volume progressively decreases and another maximum ventilator rate beyond which minute volume progressively decreases; (2) at slower rates, delivered volumes are determined primarily by changes in proximal airway pressures; (3) at very rapid rates, inspiratory time becomes a key determinant of delivered volume.

Effect of lowering serum cholesterol on the composition of surfactant in adult rat lung

1997 ◽  
Vol 272 (1) ◽  
pp. L106-L114 ◽  
Author(s):  
K. G. Davidson ◽  
S. M. Acton ◽  
H. A. Barr ◽  
T. E. Nicholas
Keyword(s):  
Tidal Volume ◽  
Serum Cholesterol ◽  
Protein A ◽  
Lamellar Body ◽  
Principal Component ◽  
Surfactant Protein ◽  
Lung Compliance ◽  
Adult Rat ◽  
Alveolar Surfactant ◽  
Dynamic Lung Compliance

Treatment of rats with 10 mg.kg body wt-1 day-1 4-aminopyrazolo[3,4-d]pyrimidine (APP) for 2 days markedly reduced serum cholesterol and phospholipids. This was associated with large decreases in the principal component of alveolar surfactant, the disaturated phospholipids (DSP), in the lamellar body and in the tubular myelin-rich and -poor alveolar fractions, but with no concomitant change in cholesterol or surfactant protein A. These decreases in DSP were associated with a decrease in the synthesis of surfactant phospholipids. Despite these large changes in composition of alveolar surfactant, we could detect no change in either static or dynamic lung compliance. However, the treatment markedly increased both the minimum and maximum surface tension of the lipid extract of the tubular myelin-rich fraction, as measured by bubble surfactometry. Whereas these changes appeared unimportant in the isolated perfused lung at resting tidal volume, they were associated with edema after an increase in tidal volume. The ability of APP to inhibit phospholipid synthesis selectively makes it a useful tool in investigating the surfactant system.

Contribution of vagal afferents to respiratory reflexes evoked by acute inhalation of ozone in dogs

1993 ◽  
Vol 74 (5) ◽  
pp. 2338-2344 ◽  
Author(s):  
E. S. Schelegle ◽  
M. L. Carl ◽  
H. M. Coleridge ◽  
J. C. Coleridge ◽  
J. F. Green
Keyword(s):  
Muscle Tension ◽  
Lung Compliance ◽  
Minute Volume ◽  
Vagal Afferents ◽  
C Fibers ◽  
Shallow Breathing ◽  
Lower Trachea ◽  
Afferent Vagal ◽  
Lower Airways ◽  
Dynamic Lung Compliance

Acute inhalation of ozone induces vagally mediated rapid shallow breathing and bronchoconstriction. In spontaneously breathing anesthetized dogs, we attempted to determine whether afferent vagal C-fibers in the lower airways contributed to these responses. Dogs inhaled 3 ppm ozone for 40–70 min into the lower trachea while cervical vagal temperature was maintained successively at 37, 7, and 0 degrees C. At 37 degrees C, addition of ozone to the inspired air decreased tidal volume and dynamic lung compliance and increased breathing frequency, total lung resistance, and tracheal smooth muscle tension. Ozone still evoked significant effects when conduction in myelinated vagal axons was blocked selectively by cooling the nerves to 7 degrees C. Ozone-induced effects were largely abolished when nonmyelinated vagal axons were blocked by cooling to 0 degree C, breathing during ozone inhalation at 0 degree C being generally similar to that during air breathing at 0 degree C, except that minute volume and inspiratory flow were higher. We conclude that afferent vagal C-fibers in the lower airways make a major contribution to the acute respiratory effects of ozone and that nonvagal afferents contribute to the effects that survive vagal blockade.

LUNG FUNCTION AND PATHOLOGY IN A PREMATURE INFANT WITH CHRONIC PULMONARY INSUFFICIENCY (WILSON-MIKITY SYNDROME)

PEDIATRICS ◽  
1967 ◽  
Vol 40 (6) ◽  
pp. 962-974
Author(s):  
W. A. Aherne ◽  
K. W. Cross ◽  
E. N. Hey ◽  
Sheila R. Lewis
Keyword(s):  
Lung Function ◽  
Premature Infant ◽  
Lung Biopsy ◽  
Signs And Symptoms ◽  
Lung Compliance ◽  
Alveolar Ventilation ◽  
Pulmonary Insufficiency ◽  
Normal Limits ◽  
Dynamic Lung Compliance ◽  
Symptoms And Signs

Detailed lung function studies at the age of 8 months and 1 year are reported for an infant who weighed 992 gm at birth and who developed chronic progressive pulmonary insufficiency 2 weeks after birth. The symptoms and signs were similar to those described by Wilson and Mikity in 1960. A confirmatory lung biopsy was obtained when the child was 11 months old. Dynamic lung "compliance" was very significantly reduced while a static estimate of lung compliance was within normal limits. These and other lung function findings are interpreted as indicating that uneven alveolar ventilation was the probable functional basis for all the signs and symptoms observed.

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.

MECHANICAL VENTILATION OF THE LUNGS WITH A TARGETED TIDAL VOLUME IN NEWBORNS AND INFANTS WITH VARIOUS LUNG DISEASES

2021 ◽  
Vol 100 (5) ◽  
pp. 76-82
Author(s):  
A.V. Mostovoy ◽  
◽  
S.S. Mezhinsky ◽  
A.L. Karpova ◽  
A.N. Nikolishin ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Lung Diseases ◽  
Lung Ventilation ◽  
First Year ◽  
Lung Pathology ◽  
Pathological Conditions ◽  
Artificial Lung Ventilation ◽  
First Year Of Life ◽  
Ventilation Of The Lungs ◽  
Selection Of

The review presents and systematizes the current provisions on artificial lung ventilation (ALV) with a guaranteed or target tidal volume as the most effective and safe mode of ALV in neonatal practice. The application of this method of respiratory support is described. The authors present the main provisions on the optimal selection of the target tidal volume in various pathological conditions. The use of various modes of ALV in combination with a guaranteed tidal volume makes it possible to prevent or reduce the harmful impact of ALV in patients with acute and chronic lung pathology, in newborns and children in the first year of life.

Ventilation standards for small mammals

1964 ◽  
Vol 19 (2) ◽  
pp. 360-362 ◽  
Author(s):  
Leonard I. Kleinman ◽  
Edward P. Radford
Keyword(s):  
Body Weight ◽  
Tidal Volume ◽  
Small Mammals ◽  
Artificial Respiration ◽  
Alveolar Ventilation ◽  
Breathing Frequency ◽  
Slide Rule ◽  
Physiological Dead Space ◽  
The Relationship ◽  
Tidal Volume Breathing

Ventilation standards for small mammals have been prepared on the basis of the relationship between alveolar ventilation and metabolism. On the assumptions of an average respiratory quotient of 0.85 and physiological dead space directly proportional to tidal volume, the relationship between tidal volume, breathing frequency, and body weight has been derived. The standards are presented in a graphic form and as a slide rule. animal ventilation; artificial respiration; tidal volume, breathing frequency and body weight relationship Submitted on August 15, 1963

Dynamic lung compliance in newborn and adult cats

1986 ◽  
Vol 60 (3) ◽  
pp. 743-750 ◽  
Author(s):  
K. J. Sullivan ◽  
J. P. Mortola
Keyword(s):  
Stress Relaxation ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Theoretical Treatment ◽  
The Difference ◽  
Adult Cats ◽  
Isolated Lungs ◽  
Dynamic Lung Compliance ◽  
Volume History ◽  
Lung Stress

Static (Cstat) and dynamic (Cdyn) lung compliance and lung stress relaxation were examined in isolated lungs of newborn kittens and adult cats. Cstat was determined by increasing volume in increments and recording the corresponding change in pressure; Cdyn was calculated as the ratio of the changes in volume to transpulmonary pressure between points of zero flow at ventilation frequencies between 10 and 110 cycles/min. Lung volume history, end-inflation volume, and end-deflation pressure were maintained constant. At the lowest frequency of ventilation, Cdyn was less than Cstat, the difference being greater in newborns. Between 20 and 100 cycles/min, Cdyn of the newborn lung remained constant, whereas Cdyn of the adult lung decreased after 60 cycles/min. At all frequencies, the rate of stress relaxation, measured as the decay in transpulmonary pressure during maintained inflation, was greater in newborns than in adults. The frequency response of Cdyn in kittens, together with the relatively greater rate of stress relaxation, suggests that viscoelasticity contributes more to the dynamic stiffening of the lung in newborns than in adults. A theoretical treatment of the data based on a linear model of viscoelasticity supports this conclusion.

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