Serial determination of lung volume in small animals by nitrogen washout

1985 ◽  
Vol 59 (1) ◽  
pp. 205-210 ◽  
Author(s):  
T. A. Standaert ◽  
W. A. LaFramboise ◽  
R. E. Tuck ◽  
D. E. Woodrum
Keyword(s):  
Lung Volume ◽  
Small Animals ◽  
Calibration Data ◽  
Water Displacement ◽  
Lung Capacity ◽  
Serial Determination ◽  
Residual Capacity ◽  
Volume Measurements

This report describes the design of an apparatus and the procedures used to serially measure the total lung capacity and the functional residual capacity of small animals utilizing the N2-washout technique. The calibration data indicate that the technique is accurate to within 1 ml and has a variance of less than 5%. The in vivo lung volume measurements of rats were validated by comparing them with values obtained with a water-displacement technique; the means were within 0.3 ml. Examples of the precision and changes in lung volume of animals during studies are included to demonstrate the reliability and usefulness of the technique.

Static lung mechanics of intact and excised rhesus monkey lungs and lobes

1978 ◽  
Vol 44 (4) ◽  
pp. 547-552 ◽  
Author(s):  
P. D. Pare ◽  
R. Boucher ◽  
M. C. Michoud ◽  
J. C. Hogg
Keyword(s):  
Lung Volume ◽  
Transpulmonary Pressure ◽  
Lung Mechanics ◽  
Unit Weight ◽  
Water Displacement ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Boyle’S Law

Subdivisions of lung volume and pressure-volume (PV) curves of the lung and chest wall (CW) were measured in 12 rhesus monkeys (Macacca mulatta) under pentobarbital anesthesia. In addition, volumes and PV curves were obtained on the excised lungs and lobes of 12 cynomolgus monkeys (M. fasicularis). Boyle's law was used to determine functional residual capacity (FRC) in the intact animals and water displacement to determine minimal volume (MV) in the excised lungs. Total lung capacity (TLC = lung volume at a transpulmonary pressure of 30 cmH2O) was similar in vivo and in vitro (90 + 83 ml/kg) but residual volume (RV = volume at airway pressure of -50 cmH2O) and MV differed markedly (16.5 + 5.9 ml/kg). In the intact animals a very stiff CW appeared to determine RV, whereas airway closure determined MV in excised lungs. PV curves of upper and lower lobes were not different when expressed as %TLC but when expressed as milliliters of gas per gram of lung, the upper lobes contained significantly more gas per unit weight.

Inspiratory muscles during exercise: a problem of supply and demand

1988 ◽  
Vol 64 (6) ◽  
pp. 2482-2489 ◽  
Author(s):  
P. Leblanc ◽  
E. Summers ◽  
M. D. Inman ◽  
N. L. Jones ◽  
E. J. Campbell ◽  
...  
Keyword(s):  
Lung Volume ◽  
Static Pressure ◽  
Total Lung Capacity ◽  
Supply And Demand ◽  
Normal Subjects ◽  
Esophageal Pressure ◽  
Maximum Exercise ◽  
Lung Capacity ◽  
Inspiratory Muscles ◽  
Residual Capacity

The capacity of inspiratory muscles to generate esophageal pressure at several lung volumes from functional residual capacity (FRC) to total lung capacity (TLC) and several flow rates from zero to maximal flow was measured in five normal subjects. Static capacity was 126 +/- 14.6 cmH2O at FRC, remained unchanged between 30 and 55% TLC, and decreased to 40 +/- 6.8 cmH2O at TLC. Dynamic capacity declined by a further 5.0 +/- 0.35% from the static pressure at any given lung volume for every liter per second increase in inspiratory flow. The subjects underwent progressive incremental exercise to maximum power and achieved 1,800 +/- 45 kpm/min and maximum O2 uptake of 3,518 +/- 222 ml/min. During exercise peak esophageal pressure increased from 9.4 +/- 1.81 to 38.2 +/- 5.70 cmH2O and end-inspiratory esophageal pressure increased from 7.8 +/- 0.52 to 22.5 +/- 2.03 cmH2O from rest to maximum exercise. Because the estimated capacity available to meet these demands is critically dependent on end-inspiratory lung volume, the changes in lung volume during exercise were measured in three of the subjects using He dilution. End-expiratory volume was 52.3 +/- 2.42% TLC at rest and 38.5 +/- 0.79% TLC at maximum exercise.

scholarly journals The Strain on Airway Smooth Muscle During a Deep Inspiration to Total Lung Capacity

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ynuk Bossé
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Total Lung Capacity ◽  
In Vitro Studies ◽  
Deep Inspiration ◽  
Bronchodilator Effect ◽  
Lung Capacity ◽  
Residual Capacity

The deep inspiration (DI) maneuver entices a great deal of interest because of its ability to temporarily ease the flow of air into the lungs. This salutary effect of a DI is proposed to be mediated, at least partially, by momentarily increasing the operating length of airway smooth muscle (ASM). Concerningly, this premise is largely derived from a growing body of in vitro studies investigating the effect of stretching ASM by different magnitudes on its contractility. The relevance of these in vitro findings remains uncertain, as the real range of strains ASM undergoes in vivo during a DI is somewhat elusive. In order to understand the regulation of ASM contractility by a DI and to infer on its putative contribution to the bronchodilator effect of a DI, it is imperative that in vitro studies incorporate levels of strains that are physiologically relevant. This review summarizes the methods that may be used in vivo in humans to estimate the strain experienced by ASM during a DI from functional residual capacity (FRC) to total lung capacity (TLC). The strengths and limitations of each method, as well as the potential confounders, are also discussed. A rough estimated range of ASM strains is provided for the purpose of guiding future in vitro studies that aim at quantifying the regulatory effect of DI on ASM contractility. However, it is emphasized that, owing to the many limitations and confounders, more studies will be needed to reach conclusive statements.

Comparison of postnatal lung growth and development between C3H/HeJ and C57BL/6J mice

2006 ◽  
Vol 100 (5) ◽  
pp. 1577-1583 ◽  
Author(s):  
Shawn E. Soutiere ◽  
Wayne Mitzner
Keyword(s):  
Lung Volume ◽  
Lung Development ◽  
Inbred Mice ◽  
Left Lung ◽  
Transpulmonary Pressure ◽  
Mean Linear Intercept ◽  
Old Mice

Previous work by our group has demonstrated substantial differences in lung volume and morphometric parameters between inbred mice. Specifically, adult C3H/HeJ (C3) have a 50% larger lung volume and 30% greater mean linear intercept than C57BL/6J (B6) mice. Although much of lung development occurs postnatally in rodents, it is uncertain at what age the differences between these strains become manifest. In this study, we performed quasi-static pressure-volume curves and morphometric analysis on neonatal mice. Lungs from anesthetized mice were degassed in vivo using absorption of 100% O2. Pressure-volume curves were then recorded in situ. The lungs were then fixed by instillation of Zenker’s solution at a constant transpulmonary pressure. The left lung from each animal was used for morphometric determination of mean air space chord length ( Lma). We found that the lung volume of C3 mice was substantially greater than that of B6 mice at all ages. In contrast, there was no difference in Lma (62.7 μm in C3 and 58.5 μm in B6) of 3-day-old mice. With increasing age (8 days), there was a progressive decrease in the Lma of both strains, with the magnitude of the decrease in B6 Lma mice exceeding that of C3. C3 lung volume remained 50% larger. The combination of parenchymal architectural similarity with lung air volume differences and different rates of alveolar septation support the hypothesis that lung volume and alveolar dimensions are independently regulated.

Effects of body position and lung volume on in situ operating length of canine diaphragm

1990 ◽  
Vol 69 (5) ◽  
pp. 1702-1708 ◽  
Author(s):  
S. S. Margulies ◽  
G. A. Farkas ◽  
J. R. Rodarte
Keyword(s):  
Lung Volume ◽  
Body Position ◽  
Vertical Gradient ◽  
Postoperative Recovery ◽  
Optimal Force ◽  
Residual Capacity ◽  
Crural Diaphragm

The performance of the diaphragm is influenced by its in situ length relative to its optimal force-generating length (Lo). Lead markers were sutured to the abdominal surface of the diaphragm along bundles of the left ventral, middle, and dorsal regions of the costal diaphragm and the left crural diaphragm of six beagle dogs. After 2-3 wk postoperative recovery, the dogs were anesthetized, paralyzed, and scanned prone and supine in the Dynamic Spatial Reconstructor (DSR) at a total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV). The location of each marker was digitized from the reconstructed DSR images, and in situ lengths were determined. After an overdose of anesthetic had been administered to the dogs, each marked diaphragm bundle was removed, mounted in a 37 degrees C in vitro chamber, and adjusted to Lo (maximum tetanic force). The operating length of the diaphragm, or in situ length expressed as percent Lo, varied from region to region at the lung volumes studied; variability was least at RV and increased with increasing lung volume. At FRC, all regions of the diaphragm was shorter in the prone posture compared with the supine, but there was no clear gravity-dependent vertical gradient of in situ length in either posture. Because in vitro length-tension characteristics were similar for all diaphragm regions, regional in vivo length differences indicate that the diaphragm's potential to generate maximal force is nonuniform.

Effects of lung volume on collateral and airways resistance in man

1979 ◽  
Vol 46 (1) ◽  
pp. 67-73 ◽  
Author(s):  
C. R. Inners ◽  
P. B. Terry ◽  
R. J. Traystman ◽  
H. A. Menkes
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Total Lung Capacity ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Collateral Pathways ◽  
Flow Through ◽  
Airways Resistance ◽  
Young Subjects ◽  
The Relationship

The effects of changing lung volume (VL) on collateral resistance (Rcoll) and total airways resistance (Raw) were compared in six young volunteers. At functional residual capacity (FRC) = 55% total lung capacity (TLC), mean Rcoll was 4,664 +/- 1,518 (SE) cmH2O/(l/s) and mean Raw was 1.57 +/- 0.11 (SE) cmH2O/l/s). When VL increased to 80% TLC, Rcoll decreased by 63.3 +/- 7.8%, and Raw decreased by 50.3 +/- 4.2 (SE) %. The decrease in Rcoll with increasing lung volume was not statistically different from that of Raw (P less than 0.05). If the airways obstructed for measurements of Rcoll served between 2 and 5% of the lungs, then Rcoll was approximately 50 times as great as the resistance to flow through airways serving the same volume of lung at FRC. The relationship did not change significantly when VL increased by 25% TLC. If changes in Raw reflect changes in airways supplying sublobar portions of lung, these results indicate that there is no tendency for the redistribution of ventilation through airways and collateral pathways with changes in VL in young subjects.

Lung volume and pleural pressure in the anesthetized hamster

1979 ◽  
Vol 46 (5) ◽  
pp. 927-931 ◽  
Author(s):  
Y. L. Lai
Keyword(s):  
Lung Volume ◽  
Esophageal Pressure ◽  
Lung Compliance ◽  
Pleural Pressure ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Residual Capacity ◽  
Wall Compliance

Lung volumes and respiratory pressures were measured in anesthetized male hamsters weighing an average 117 g. In 16 supine animals functional residual capacity (FRC) determined by body plethysmograph was 1.12 +/- 0.23 (SD) ml (about 20% total lung capacity, TLC) slightly and significantly larger than the FRC measured by saline displacement, 1.01 +/- 0.15 ml. Similar results were found in six prone animals. Paralysis did not significantly alter supine FRC. Contrary to published reports, pleural pressure (Ppl) estimated from esophageal pressure was negative at FRC. The fact that lung volume decreased by 0.2 ml (about 4% TLC) when the chest was opened at FRC provided additional evidence of negative Ppl at FRC. No consistent changes in the lung pressure-volume curve were found after the chest was opened. Deflation chest wall compliance just above FRC was about twice lung compliance. The vital capacity and reserve volumes in this study agreed with values reported in the literature. However, absolute lung volumes (TLC, FRC, and residual volume) were lower by about 1.4 ml, possibly because of earlier overestimates of box FRC.

Influence of abdominal gas on the Boyle's law determination of thoracic gas volume

1978 ◽  
Vol 44 (3) ◽  
pp. 469-473 ◽  
Author(s):  
R. Brown ◽  
F. G. Hoppin ◽  
R. H. Ingram ◽  
N. A. Saunders ◽  
E. R. McFadden
Keyword(s):  
Vital Capacity ◽  
Relative Magnitude ◽  
Lung Capacity ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
Almost All ◽  
Gas Volume ◽  
Boyle’S Law ◽  
Different Levels

In a body plethysmograph we have demonstrated differences in total lung capacity (TLC) derived from panting maneuvers performed at different levels in the vital capacity. In almost all cases, the discrepancies were due to the magnitude of the abdominal gas volume (AGV) and the relative magnitude of abdominal and thoracic pressure swings during the panting mandeuver. When panting was performed at functional residual capacity (FRC), the effect of AGV compression on the determination of thoracid gas volume (TGV) was small. Of 11 individuals studied 2 were known to have mild asthma. Compression and decompression of AGV appeared to be an insufficient explanation for discrepancies in derived TLC's in these two, suggesting that other as yet unidentified factors may influence the plethysmographic determination of TGV.

Respiratory mechanics of a small carnivore: the ferret

1982 ◽  
Vol 52 (4) ◽  
pp. 832-837 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
P. C. Kosch
Keyword(s):  
Total Lung Capacity ◽  
Lung Compliance ◽  
Pulmonary Resistance ◽  
Mustela Putorius ◽  
Tidal Breathing ◽  
Lung Capacity ◽  
Maximum Expiratory Flow ◽  
Residual Capacity ◽  
Dynamic Lung Compliance

The ferret, Mustela putorius furo, is a small relatively inexpensive carnivore with minimal housing requirements. Measurements were made from anesthetized tracheotomized supine males. Values obtained during tidal breathing for six animals (576 +/- 12 g) were as follows: tidal volume, 6.06 +/- 0.30 ml; respiratory frequency, 26.7 +/- 3.9 breaths min-1; dynamic lung compliance, 2.48 +/- 0.21 ml cmH2O-1; pulmonary resistance, 22.56 +/- 1.61 cmH2O . l–1 . s. Pressure-volume curves from nine ferrets revealed almost infinitely compliant chest walls so that lung and total respiratory system curves were essentially the same. Total lung capacity (TLC, 89 +/- 5 ml) and functional residual capacity (17.8 +/- 2.0 ml) were determined by gas freeing the lungs in vivo. The TLC of these ferrets is about the same as in 2.5-kg rabbits. Maximum expiratory flow-volume curves showed peak flows of 10.1 vital capacities (VC) . s-1 at 75% VC and flows of 8.4 and 5.4 VC . s-1 at 50 and 25% VC.

The bimodal quasi-static and dynamic elastance of the murine lung

2008 ◽  
Vol 105 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Graeme R. Zosky ◽  
Tibor Z. Janosi ◽  
Ágnes Adamicza ◽  
Elizabeth M. Bozanich ◽  
Vincenzo Cannizzaro ◽  
...  
Keyword(s):  
Lung Volume ◽  
Lung Mechanics ◽  
Mouse Lung ◽  
Forced Oscillation Technique ◽  
Mechanically Ventilated ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
Gas Volume ◽  
Tissue Elastance

The double sigmoidal nature of the mouse pressure-volume (PV) curve is well recognized but largely ignored. This study systematically examined the effect of inflating the mouse lung to 40 cm H2O transrespiratory pressure (Prs) in vivo. Adult BALB/c mice were anesthetized, tracheostomized, and mechanically ventilated. Thoracic gas volume was calculated using plethysmography and electrical stimulation of the intercostal muscles. Lung mechanics were tracked during inflation-deflation maneuvers using a modification of the forced oscillation technique. Inflation beyond 20 cm H2O caused a shift in subsequent PV curves with an increase in slope of the inflation limb and an increase in lung volume at 20 cm H2O. There was an overall decrease in tissue elastance and a fundamental change in its volume dependence. This apparent “softening” of the lung could be recovered by partial degassing of the lung or applying a negative transrespiratory pressure such that lung volume decreased below functional residual capacity. Allowing the lung to spontaneously recover revealed that the lung required ∼1 h of mechanical ventilation to return to the original state. We propose a number of possible mechanisms for these observations and suggest that they are most likely explained by the unfolding of alveolar septa and the subsequent redistribution of the fluid lining the alveoli at high transrespiratory pressure.

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