Lung volumes in man immersed to the neck: dilution and plethysmographic techniques

1978 ◽  
Vol 44 (5) ◽  
pp. 679-682 ◽  
Author(s):  
C. H. Robertson ◽  
C. M. Engle ◽  
M. E. Bradley
Keyword(s):  
Inert Gas ◽  
Closing Volume ◽  
Residual Volume ◽  
Dilution Technique ◽  
Lung Volumes ◽  
Vascular Congestion ◽  
Hydrostatic Force ◽  
Gas Trapping ◽  
Gas Dilution ◽  
Boyle’S Law

Previous studies of lung volumes during immersion have utilized dilution techniques for residual volume. We have compared lung volumes obtained by the use of a dual inert gas dilution technique with those determined by the Boyle's law technique in a plethysmograph designed to allow measurements in air and submersed to the neck in water. Both techniques gave similar results dry, but during immersion the dilution residual volume (RV) was 0.200 liter (16%) lower than the plethysmographic value (P greater than 0.001), which suggests that there is a significant amount of gas trapping during immersion due to breathing at low lung volumes and the central shift of blood. The unchanged RV due to hydrostatic force on the chest wall is balanced by the tendency to increase RV due to vascular congestion, which increases closing volume and stiffens the lung to compression.

Airway closure and closing volume

1979 ◽  
Vol 46 (1) ◽  
pp. 24-30 ◽  
Author(s):  
L. Forkert ◽  
S. Dhingra ◽  
N. R. Anthonisen
Keyword(s):  
Blood Flow ◽  
Lung Volume ◽  
Regional Perfusion ◽  
Phase Iii ◽  
Breath Hold ◽  
Closing Volume ◽  
Residual Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Phase Iv

Using boluses of radioactive Xe we compared regional N2O uptake with regional perfusion distribution during open glottis breath hold in five seated men. Measurements were made near residual volume, at closing volume (CV), above CV and when possible, between CV and residual volume (RV). At low lung volumes basal N2O uptake was small whereas basal blood flow was not. This discrepancy was interpreted as evidence of airway closure and was quantitated. All subjects showed extensive basal closure near RV. At closing volume four of five subjects demonstrated closure and some closure was evident in these subjects at volumes in excess of CV. The increase in airway closure with decreasing lung volume was much greater below CV than above it. Conventional CV tracings were obtained using helium boluses; the height of phase IV was positively correlated with the change in airway closure between CV and RV as assessed by the N2O technique. The slope of phase III did not correlate with the amount of airway closure measured at CV. We concluded that the conventionally measured CV is not the volume at which airway closure begins but that the onset of phase IV reflects an increase in basal airway closure and the height of phase IV reflects the amount of basal closure between CV and RV.

Lung recoil and gas trapping during oxygen breathing at low lung volumes

1977 ◽  
Vol 43 (1) ◽  
pp. 138-143 ◽  
Author(s):  
J. R. Rodarte ◽  
L. W. Burgher ◽  
R. E. Hyatt ◽  
K. Rehder
Keyword(s):  
Inspiratory Pressure ◽  
Closing Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Recoil Pressure ◽  
Normal Volunteers ◽  
Oxygen Breathing ◽  
Gas Trapping ◽  
Low Volume

If airways are closed at lung volumes less than the closing volume (CV), there should be correlations among 1) the volume of trapped N2 (VTN) during N2-washout performed below CV, 2) the increase in static lung recoil pressure (delta P) while breathing below CV after denitrogenation compared with breathing air (due to absorption atelectasis distal to closed airways), and 3) the CV. Static inspiratory pressure-volume (PV) curves and CV were measured in 18 seated normal volunteers (ages 24–48 yr). Subjects then breathed air for 30 s and O2 for 2.5 min at RV + 0.6 liter (LVB-air), and an inspiratory PV curve and VTN were determined. While still breathing O2, the subjects repeated the 3 min of low-volume breathing (LVB-O2). There was a significant (P less than 0.001) delta P with LVB but no difference between delta P (LVB-air) and delta P (LVB-O2). CV was not related to VTN or to either delta P. VTN was not related to delta P (LVB-O2)--delta P (LVB-air) nor to delta P (LVB-air), but was related to delta P (LVB-O2). Evidence of airway closure could not be demonstrated in all subjects by LVB and when present showed no correlation with CV.

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.

Lung volume specificity of inspiratory muscle training

1994 ◽  
Vol 77 (2) ◽  
pp. 789-794 ◽  
Author(s):  
G. E. Tzelepis ◽  
D. L. Vega ◽  
M. E. Cohen ◽  
F. D. McCool
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Inspiratory Muscle ◽  
Control Group ◽  
Residual Volume ◽  
Maximal Inspiratory Pressure ◽  
Muscle Training ◽  
Inspiratory Capacity ◽  
Lung Volumes ◽  
Before And After

We examined the extent to which training-related increases of inspiratory muscle (IM) strength are limited to the lung volume (VL) at which the training occurs. IM strength training consisted of performing repeated static maximum inspiratory maneuvers. Three groups of normal volunteers performed these maneuvers at one of three lung volumes: residual volume (RV), relaxation volume (Vrel), or Vrel plus one-half of inspiratory capacity (Vrel + 1/2IC). A control group did not train. We constructed maximal inspiratory pressure-VL curves before and after a 6-wk training period. For each group, we found that the greatest improvements in strength occurred at the volume at which the subjects trained and were significantly greater for those who trained at low (36% for RV and 26% for Vrel) than at high volumes (13% for Vrel + 1/2IC). Smaller increments in strength were noted at volumes adjacent to the training volume. The range of vital capacity (VC) over which strength was increased was greater for those who trained at low (70% of VC) than at high VL (20% of VC). We conclude that the greatest improvements in IM strength are specific to the VL at which training occurs. However, the increase in strength, as well as the range of volume over which strength is increased, is greater for those who trained at the lower VL.

Regional intrapulmonary gas distribution in awake and anesthetized-paralyzed prone man

1978 ◽  
Vol 45 (4) ◽  
pp. 528-535 ◽  
Author(s):  
K. Rehder ◽  
T. J. Knopp ◽  
A. D. Sessler
Keyword(s):  
Mechanical Ventilation ◽  
Vertical Distribution ◽  
Vertical Gradient ◽  
Phase Iii ◽  
Residual Volume ◽  
Gas Distribution ◽  
Lung Volumes ◽  
Regional Lung ◽  
Residual Capacity ◽  
The Vertical Distribution

The intrapulmonary distribution of inspired gas (ventilation/unit lung volume, VI), functional residual capacity (FRC), closing capacity (CC), and the slope of phase III were determined in five awake and five anesthetized-paralyzed volunteers who were in the prone position with the abdomen unsupported. After induction of anesthesia-paralysis, FRC was less in four of five subjects and CC was consistently less. At FRC there was no difference in the vertical gradient of regional lung volumes between the awake and anesthetized-paralyzed prone subjects. Also, there was no difference in VI between the two states. The normalized slope of phase III decreased consistently with induction of anesthesia-paralysis, but the vertical distribution of a 133Xe bolus inhaled from residual volume was not different between the two states. The data of the study are compatible with 1) a pattern of expansion of the respiratory system during anesthesia-paralysis and mechanical ventilation different than that during spontaneous breathing and 2) a more uniform intraregional distribution of inspired gas and/or a different sequence of emptying during anesthesia-paralysis.

Inflection point on transpulmonary pressure-volume curves and closing volume

1975 ◽  
Vol 38 (2) ◽  
pp. 228-235 ◽  
Author(s):  
M. Demedts ◽  
J. Clement ◽  
D. C. Stanescu ◽  
K. P. van de Woestijne
Keyword(s):  
Inflection Point ◽  
Vital Capacity ◽  
Transpulmonary Pressure ◽  
Bronchial Obstruction ◽  
Closing Volume ◽  
Lung Volumes ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Space Effect ◽  
Washout Curves

In 20 healthy subjects and 18 patients with bronchial obstruction, closing volume (CV) on single-breath nitrogen washout curves and inflection point (IP) on transpulmonary pressure-volume curves were recorded simultaneously during slow expiratory vital capacity maneuvers. IP and CV did not occur at identical lung volumes, IP being systematically larger than CV for small CV values. This discrepancy could not be attributed to an esophageal or mediastinal artifact. It is suggested that, though CV and IP both express “airway closure,” their sensitivity to closure may differ: CV underestimates closure because of a dead space effect; the latter may vary individually. On the other hand, IP may not reflect the true beginning of closure, particularly when it occurs at higher lung volumes.

Respiratory physiology teaching: determination of residual volume by applying the indicator-dilution technique.

1998 ◽  
Vol 274 (6) ◽  
pp. S53
Author(s):  
H Heller ◽  
K Granitza ◽  
B Eixmann
Keyword(s):  
Indicator Dilution ◽  
Respiratory Physiology ◽  
Successful Outcome ◽  
Residual Volume ◽  
Dilution Technique ◽  
Laboratory Courses ◽  
Single Breath ◽  
Indicator Dilution Technique ◽  
Single Breath Method

Apart from the current teaching of spirometric methods in laboratory courses on respiratory physiology, we have included an experiment in which medical students determine their own residual volume by applying the indicator-dilution technique. For hygienic reasons we used a bag-in-the-box system to dilute helium within alveolar space by performing the single-breath method. Although each participant independently underwent only one single-breath maneuver, we gained a reliable relationship between residual volume and subjects' height and body weight in 68 female (r = 0.6, P < 0.0001) and 99 male (r = 0.42, P < 0.0001) students. From this successful outcome and with the opportunity to discuss the limitations of the single-breath method as well, we inferred that this experiment affords a transparent and instructive approach to interpreting the determination of lung volumes on the basis of the indicator-dilution technique.

Effect of central vascular engorgement and immersion on various lung volumes

1983 ◽  
Vol 54 (4) ◽  
pp. 1094-1096 ◽  
Author(s):  
M. J. Buono
Keyword(s):  
Hydrostatic Pressure ◽  
Vital Capacity ◽  
Residual Volume ◽  
Lung Volumes ◽  
Control Value ◽  
Relative Contribution ◽  
Male Volunteers

The purpose of this study was to determine the relative contribution of central vascular engorgement (CVE) and increased hydrostatic pressure on various lung volumes during head-out immersion in water. Residual volume (RV) and vital capacity (VC) were determined on 12 male volunteers under three randomly assigned conditions: control, CVE, and immersion. CVE was produced via G-suit inflation. There were significant (P less than 0.01) mean decreases, compared with the control value, of 4.9% (280 ml) and 5.9% (340 ml) in VC during CVE and immersion, respectively. RV was not significantly changed across the three conditions. It was concluded that more than 80% of the decrease in VC during immersion can be attributed to CVE. However, the mechanism by which CVE decreased VC is still unclear. In addition, these data suggest that RV is relatively insensitive to the increase in CVE normally associated with immersion. Therefore, during immersion, RV is not simply the result of the balance of these opposing forces (i.e., CVE and hydrostatic pressure), as previously suggested.

Effect of previous volume history on airway closure

1983 ◽  
Vol 55 (2) ◽  
pp. 294-299
Author(s):  
H. W. Greville ◽  
L. J. Slykerman ◽  
P. A. Easton ◽  
N. R. Anthonisen
Keyword(s):  
Regional Distribution ◽  
Lung Parenchyma ◽  
Breath Hold ◽  
Closing Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Normal Humans ◽  
Volume History ◽  
Previous Volume

We studied the effect of volume history on airway closure in six healthy males ranging from 32 to 67 yr of age. The method used was to compare the regional distribution of 133Xe boluses distributed according to N2O uptake during open-glottis breath-hold maneuvers with the regional distribution of boluses of intravenously injected 133Xe. Measurements were made at two lung volumes, one close to residual volume (RV) and the other just below closing volume. The required volume was reached either by expiring from total lung capacity or by inspiring from RV. Although there was considerable airway closure in the basal regions of the lungs at both lung volumes studied, the degree of airway closure was not dependent on the previous volume history. We conclude that the airways concerned with closure have a volume-pressure hysteresis similar to that of the lung parenchyma. Furthermore in normal humans the volume-pressure hysteresis of the lung is not secondary to airway closure.

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