Analysis of forced expiratory maneuvers from raised lung volumes in preterm infants

1998 ◽  
Vol 85 (5) ◽  
pp. 1989-1997 ◽  
Author(s):  
Matthias Henschen ◽  
Janet Stocks ◽  
Ah-Fong Hoo ◽  
Paul Dixon
Keyword(s):  
Preterm Infants ◽  
Lung Volume ◽  
Elastic Equilibrium ◽  
Forced Expiration ◽  
Compression Technique ◽  
Lung Volumes ◽  
Conventional Analysis ◽  
Airway Function ◽  
Fixed Times ◽  
Made In

During recent years it has been suggested that forced expiratory measurements, derived from a lung volume set by a standardized inflation pressure, are more reproducible than those attained during tidal breathing when the rapid thoracoabdominal compression technique is used in infants. The aim of this study was to evaluate the feasibility of obtaining measurements from raised lung volumes in unsedated preterm infants. Measurements were made in 18 infants (gestational age 26–35 wk, postnatal age 1–10 wk, test weight 1.4–3.5 kg). Several inflations [1.5–2.5 kPa (15–25 cmH2O)] were used to briefly inhibit respiratory effort before the rapid thoracoabdominal compression was performed. Conventional analysis of flows and volumes at fixed times and percentages of the forced expiration resulted in a relatively high variability in this population. However, by using the elastic equilibrium point (i.e., the passively determined lung volume, derived from passive expirations before the forced expiration) as a volume landmark, it was feasible to achieve reproducible results in unsedated preterm infants, despite their strong respiratory reflexes and rapid respiratory rates. Because this approach is independent of changes in expiratory time, expired volume, or applied pressures, it may facilitate investigation of the effects of growth, development, and disease on airway function in infants, particularly during the first weeks of life, when conventional analysis of forced expirations may be inappropriate.

Effect of lung volume on forced expiratory flows during rapid thoracoabdominal compression in infants

1995 ◽  
Vol 78 (5) ◽  
pp. 1993-1997 ◽  
Author(s):  
J. Hammer ◽  
C. J. Newth
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Forced Expiration ◽  
Flow Volume ◽  
Older Children ◽  
Lung Volumes ◽  
Volume Segment ◽  
Forced Expiratory Flow ◽  
Residual Capacity ◽  
End Tidal

The rapid thoracoabdominal compression (RTC) technique is commonly used in pulmonary function laboratories to assess flow-volume relationships in infants unable to produce a voluntary forced expiration maneuver. This technique produces forced expiratory flows over only a small lung volume segment (i.e., tidal volume). It has been argued that the RTC technique should be modified to measure flow-volume relationships over a larger portion of the vital capacity range to imitate the voluntary maximal forced expiratory maneuver obtained in older children and adults. We examined the effect of volume history on forced expiratory flows by generating forced expiratory flow-volume curves by RTC from well-defined inspiratory volumes delineated by inspiratory pressures of 10, 20, 30, and 40 cmH2O down to residual volume (i.e., the reference volume) in seven intubated and anesthetized infants with normal lungs [age 8.0 +/- 2.0 (SE) mo, weight 6.7 +/- 0.6 kg]. We compared maximal expiratory flows at isovolume points (25 and 10% of forced vital capacity) and found no significant differences in maximal isovolume flow rates measured from the different lung volumes. We conclude that there is no obvious need to initiate RTC from higher lung volumes if the technique is used for flow comparisons. However, compared with measurements of maximal flows at functional residual capacity by RTC from end-tidal inspiration, the initiation of RTC from a defined and reproducible inspiratory level appears to decrease the intrasubject variability of the maximal expiratory flows at low lung volumes.

Flow limitation in normal infants: a new method for forced expiratory maneuvers from raised lung volumes

1996 ◽  
Vol 80 (6) ◽  
pp. 2019-2025 ◽  
Author(s):  
A. Feher ◽  
R. Castile ◽  
J. Kisling ◽  
C. Angelicchio ◽  
D. Filbrun ◽  
...  
Keyword(s):  
Lung Volume ◽  
Transpulmonary Pressure ◽  
Forced Expiration ◽  
Flow Limitation ◽  
Residual Volume ◽  
Flow Curves ◽  
Lung Volumes ◽  
Pressure Flow ◽  
Healthy Infants ◽  
Pressure Transmission

Forced expiratory maneuvers generated by rapid thoracic compression have been used to assess airway function in infants. It remains unclear whether flow limitation can be achieved in healthy infants because low pressure transmission across the chest wall and inspiratory effort may limit the maximum transpulmonary pressure developed during the maneuver. We have found that several rapid inflations to a lung volume set at an airway pressure of 30 cmH2O (V80) briefly inhibit respiratory effort and allow forced expiration to proceed from V80 to residual volume. We used a water-filled esophageal catheter to measure isovolume pressure-flow curves in seven healthy infants (3-88 mo). Forced vital capacity (FVC) was defined as the volume between V80 and residual volume. Pressure transmission between the compression jacket and the esophagus decreased with decreasing lung volume and averaged 60 and 37% at 50 and 75% of expired FVC, respectively. Subjects demonstrated plateaus in their isovolume pressure-flow curves at 50% of expired FVC and lower lung volumes. We conclude that this new methodology enables forced expiratory maneuvers to achieve flow limitation in healthy infants over at least the lower portion of their lung volume.

Retinoic acid-induced alveolar cellular growth does not improve function after right pneumonectomy

2004 ◽  
Vol 96 (3) ◽  
pp. 1090-1096 ◽  
Author(s):  
D. Merrill Dane ◽  
Xiao Yan ◽  
Rahul M. Tamhane ◽  
Robert L. Johnson ◽  
Aaron S. Estrera ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Retinoic Acid ◽  
Lung Volume ◽  
Transpulmonary Pressure ◽  
Cellular Growth ◽  
Lung Volumes ◽  
Airway Function ◽  
All Trans Retinoic Acid ◽  
Lower Lung

To determine whether all- trans retinoic acid (RA) treatment enhances lung function during compensatory lung growth in fully mature animals, adult male dogs ( n = 4) received 2 mg·kg-1·day-1 po RA 4 days/wk beginning the day after right pneumonectomy (R-PNX, 55-58% resection). Litter-matched male R-PNX controls ( n = 4) received placebo. After 3 mo, transpulmonary pressure (TPP)-lung volume relationship, diffusing capacities for carbon monoxide and nitric oxide, cardiac output, and septal volume (Vtiss-RB) were measured under anesthesia by a rebreathing technique at two lung volumes. Lung air and tissue volumes (Vair-CT and Vtiss-CT) were also measured from high-resolution computerized tomographic (CT) scans at a constant TPP. In RA-treated dogs compared with controls, TPP-lung volume relationships were similar. Diffusing capacities for carbon monoxide and nitric oxide were significantly impaired at a lower lung volume but similar at a high lung volume. Whereas Vtiss-RB was significantly lower at both lung volumes in RA-treated animals, Vair-CT and Vtiss-CT were not different between groups; results suggest uneven distribution of ventilation consistent with distortion of alveolar geometry and/or altered small airway function induced by RA. We conclude that RA does not improve resting pulmonary function during the early months after R-PNX despite histological evidence of its action in enhancing alveolar cellular growth in the remaining lung.

Tube law for the intrapulmonary airway

1988 ◽  
Vol 65 (1) ◽  
pp. 7-13 ◽  
Author(s):  
D. Elad ◽  
R. D. Kamm ◽  
A. H. Shapiro
Keyword(s):  
Experimental Data ◽  
Lung Volume ◽  
Elastic Behavior ◽  
Semiempirical Model ◽  
Forced Expiration ◽  
Lung Volumes ◽  
Wall Stiffness ◽  
Pressure Area ◽  
Nonlinear Elastic ◽  
Similarity Law

A semiempirical model of a pressure-area relationship for the bronchial airways is developed. It is described by a single similarity law consistent in form with the nonlinear elastic behavior of biological tissue. The tethering effect of the parenchyma is lumped into the wall properties of the bronchi and is included in an effective wall stiffness. The model, which is fitted to the experimental data of Takishima and his associates (J. Appl. Physiol. 38: 875-881, 1975), is lung-volume dependent and is therefore suitable for the analyses of airflow at different lung volumes, especially for modeling of forced expiration.

Methacholine-induced bronchoconstriction in dogs: effects of lung volume and O3 exposure

1988 ◽  
Vol 65 (6) ◽  
pp. 2679-2686 ◽  
Author(s):  
S. T. Kariya ◽  
S. A. Shore ◽  
W. A. Skornik ◽  
K. Anderson ◽  
R. H. Ingram ◽  
...  
Keyword(s):  
Lung Volume ◽  
Maximal Response ◽  
Maximal Effect ◽  
Response Curves ◽  
Lung Volumes ◽  
Before And After ◽  
Residual Capacity ◽  
Induced Changes ◽  
Conducting Airways ◽  
Concentration Response Curve

The maximal effect induced by methacholine (MCh) aerosols on pulmonary resistance (RL), and the effects of altering lung volume and O3 exposure on these induced changes in RL, was studied in five anesthetized and paralyzed dogs. RL was measured at functional residual capacity (FRC), and lung volumes above and below FRC, after exposure to MCh aerosols generated from solutions of 0.1-300 mg MCh/ml. The relative site of response was examined by magnifying parenchymal [RL with large tidal volume (VT) at fast frequency (RLLS)] or airway effects [RL with small VT at fast frequency (RLSF)]. Measurements were performed on dogs before and after 2 h of exposure to 3 ppm O3. MCh concentration-response curves for both RLLS and RLSF were sigmoid shaped. Alterations in mean lung volume did not alter RLLS; however, RLSF was larger below FRC than at higher lung volumes. Although O3 exposure resulted in small leftward shifts of the concentration-response curve for RLLS, the airway dominated index of RL (RLSF) was not altered by O3 exposure, nor was the maximal response using either index of RL. These data suggest O3 exposure does not affect MCh responses in conducting airways; rather, it affects responses of peripheral contractile elements to MCh, without changing their maximal response.

Breathing at low lung volumes and chest strapping: a comparison of lung mechanics

1981 ◽  
Vol 50 (3) ◽  
pp. 650-657 ◽  
Author(s):  
N. J. Douglas ◽  
G. B. Drummond ◽  
M. F. Sudlow
Keyword(s):  
Lung Volume ◽  
Maximum Flow ◽  
Normal Subjects ◽  
Lung Mechanics ◽  
Lung Volumes ◽  
Flow Rates ◽  
Recoil Pressure ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
Expiratory Flow Rates

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.

scholarly journals Crackle Pitch Rises Progressively during Inspiration in Pneumonia, CHF, and IPF Patients

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Andrey Vyshedskiy ◽  
Raymond Murphy
Keyword(s):  
Heart Failure ◽  
Lung Volume ◽  
Interstitial Fibrosis ◽  
Lung Sounds ◽  
Lung Sound ◽  
Lung Volumes ◽  
Alternate Explanation ◽  
40 Hz

Objective. It is generally accepted that crackles are due to sudden opening of airways and that larger airways produce crackles of lower pitch than smaller airways do. As larger airways are likely to open earlier in inspiration than smaller airways and the reverse is likely to be true in expiration, we studied crackle pitch as a function of crackle timing in inspiration and expiration. Our goal was to see if the measurement of crackle pitch was consistent with this theory.Methods. Patients with a significant number of crackles were examined using a multichannel lung sound analyzer. These patients included 34 with pneumonia, 38 with heart failure, and 28 with interstitial fibrosis.Results. Crackle pitch progressively increased during inspirations in 79% of all patients. In these patients crackle pitch increased by approximately 40 Hz from the early to midinspiration and by another 40 Hz from mid to late-inspiration. In 10% of patients, crackle pitch did not change and in 11% of patients crackle pitch decreased. During expiration crackle pitch progressively decreased in 72% of patients and did not change in 28% of patients.Conclusion. In the majority of patients, we observed progressive crackle pitch increase during inspiration and decrease during expiration. Increased crackle pitch at larger lung volumes is likely a result of recruitment of smaller diameter airways. An alternate explanation is that crackle pitch may be influenced by airway tension that increases at greater lung volume. In any case improved understanding of the mechanism of production of these common lung sounds may help improve our understanding of pathophysiology of these disorders.

scholarly journals THE LUNG VOLUME IN HEART DISEASE

1923 ◽  
Vol 38 (4) ◽  
pp. 445-476 ◽  
Author(s):  
Carl A. L. Binger
Keyword(s):  
Heart Disease ◽  
Lung Volume ◽  
Vital Capacity ◽  
Lung Volumes ◽  
Total Lung Volume ◽  
Surface Areas ◽  
Normal Individuals ◽  
The Absolute ◽  
Total Capacity ◽  
Residual Air

The lung volumes in a group of individuals suffering from chronic cardiac disease have been studied by a method which is applicable to patients suffering from dyspnea. In a number of instances the same patients were investigated during various stages of decompensation and compensation. The values found have been compared with those determined in a group of normal subjects. Lung volumes have been considered from three points of view: (1) relative lung volumes or subdivisions of total lung volume expressed as percentage of total lung volume; (2) the absolute lung volumes of patients with heart disease have been compared with lung volumes calculated for normal individuals having similar surface areas or chest measurements; and (3) in individual cases absolute lung volumes have been measured in various stages of compensation and decompensation. (1) In patients with heart disease it has been observed that the vital capacity forms a portion of the total lung volume relatively smaller than in normal individuals, and that the mid-capacity and residual air form relatively larger portions. When the patient progresses from the compensated to the decompensated state these changes become more pronounced. (2) When the absolute lung volumes determined for patients are compared with volumes of the same sort, as calculated for normal individuals of the same surface areas and chest measurements, the following differences are found. The vital capacities are always smaller in the patients and the volumes of residual air are always larger. There is a tendency for middle capacity and total capacity to be smaller, though, when the patients are in a compensated state, these volumes may approximate normal. (3) When decompensation occurs the absolute lung volumes undergo changes as follows: (a) vital capacity, mid-capacity, and total capacity decrease in volume; and (b) the residual air may either increase or decrease according to the severity of the state of decompensation. The significance of these changes has been discussed and an explanation offered for the occurrence of a residual air of normal volume in patients with heart disease. It results from a combination of two tendencies working in opposite directions: one to increase the residual air—stiffness of the lungs (Lungenstarre); the other to decrease it—distended capillaries (Lungenschwellung), edema, round cell infiltration.

Flow-Volume Curves in Infants with Lung Disease

PEDIATRICS ◽  
1983 ◽  
Vol 72 (4) ◽  
pp. 517-522
Author(s):  
S. Godfrey ◽  
E. Bar-Yishay ◽  
I. Arad ◽  
L. I. Landau ◽  
L. M. Taussig
Keyword(s):  
Lung Disease ◽  
Airway Obstruction ◽  
Lung Volume ◽  
Airway Resistance ◽  
Whole Body ◽  
Small Airways ◽  
Forced Expiration ◽  
Flow Volume ◽  
Complete Evaluation ◽  
Expiratory Flow

Partial expiratory flow-volume maneuvers have been performed on nine occasions on six infants with a variety of pulmonary problems using a new tech nique for thoracic compression. The infants were placed within an inflatable bag that was, itself, within a canvas bag. By sudden controlled inflation of the inner bag at end inspiration, partial expiratory flow-volume curves were generated and recorded by means of a face mask and pneumotachograph. By comparing these flow results with those airway resistance and lung volume measurements obtained from the infants in whole body plethysmography and by noting the effect of inhaling a helium/oxygen gas mixture, it was possible to partition the airway obstruction between large and small airways. The presence of small airway obstruction was noted in the absence of changes in airway resistance or lung volume in several instances. A complete evaluation of airway function should include this test of forced expiration for greater understanding and treatment of lung disease in infancy.

scholarly journals Assessment of the influence of lung inflation state on the quantitative parameters derived from hyperpolarized gas lung ventilation MRI in healthy volunteers

2019 ◽  
Vol 126 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Paul J. C. Hughes ◽  
Laurie Smith ◽  
Ho-Fung Chan ◽  
Bilal A. Tahir ◽  
Graham Norquay ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Lung Volume ◽  
Lung Ventilation ◽  
Lung Volumes ◽  
Lung Inflation ◽  
Longitudinal Measurements ◽  
Anatomical Images ◽  
Lower Lung ◽  
Ventilation Heterogeneity ◽  
Residual Capacity

In this study, the effect of lung volume on quantitative measures of lung ventilation was investigated using MRI with hyperpolarized 3He and 129Xe. Six volunteers were imaged with hyperpolarized 3He at five different lung volumes [residual volume (RV), RV + 1 liter (1L), functional residual capacity (FRC), FRC + 1L, and total lung capacity (TLC)], and three were also imaged with hyperpolarized 129Xe. Imaging at each of the lung volumes was repeated twice on the same day with corresponding 1H lung anatomical images. Percent lung ventilated volume (%VV) and variation of signal intensity [heterogeneity score (Hscore)] were evaluated. Increased ventilation heterogeneity, quantified by reduced %VV and increased Hscore, was observed at lower lung volumes with the least ventilation heterogeneity observed at TLC. For 3He MRI data, the coefficient of variation of %VV was <1.5% and <5.5% for Hscore at all lung volumes, while for 129Xe data the values were 4 and 10%, respectively. Generally, %VV generated from 129Xe images was lower than that seen from 3He images. The good repeatability of 3He %VV found here supports prior publications showing that percent lung-ventilated volume is a robust method for assessing global lung ventilation. The greater ventilation heterogeneity observed at lower lung volumes indicates that there may be partial airway closure in healthy lungs and that lung volume should be carefully considered for reliable longitudinal measurements of %VV and Hscore. The results suggest that imaging patients at different lung volumes may help to elucidate obstructive disease pathophysiology and progression. NEW & NOTEWORTHY We present repeatability data of quantitative metrics of lung function derived from hyperpolarized helium-3, xenon-129, and proton anatomical images acquired at five lung volumes in volunteers. Increased regional ventilation heterogeneity at lower lung inflation levels was observed in the lungs of healthy volunteers.

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