Hydrostatic weighing at residual volume and functional residual capacity

1980 ◽  
Vol 49 (1) ◽  
pp. 157-159 ◽  
Author(s):  
T. R. Thomas ◽  
G. L. Etheridge
Keyword(s):  
Prone Position ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Residual Volume ◽  
Body Density ◽  
Residual Capacity ◽  
Hydrostatic Weighing ◽  
Helium Dilution ◽  
The Subject ◽  
The Difference

Hydrostatic weighing (HW) was performed at both residual volume (RV) and functional residual capacity (FRC) to determine if underwater weighing at different lung volumes affected the measurement of body density. Subjects were 43 males, 18-25 yr. Subjects were submerged in the prone position, and the lung volume was measured by helium dilution at the time of the underwater weighing. Underwater weight was first assessed at FRC followed by assessment at RV. Changes in lung volume were accurately reflected in the underwater weight. Body density (D) was not different with the use of the FRC (mean D = 1.0778) or RV (mean D = 1.0781) data. Percent fat values for the FRC and RV data were 9.3 ± 5.4 and 9.2 ± 5.1%, respectively, and were not statistically different. The results indicate that the difference between percent fat determinations by HW in the prone position at FRC and RV is negligible. Because measurement of underwater weight at FRC is more comfortable for the subject, this may be the method of choice when the lung volume can be measured during the underwater weighing.

Airway closure during anesthesia: a comparison between resident-gas and argon-bolus techniques

1979 ◽  
Vol 47 (4) ◽  
pp. 874-881 ◽  
Author(s):  
G. Hedenstierna ◽  
J. Santesson
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Healthy Subjects ◽  
Abrupt Onset ◽  
Closing Volume ◽  
Residual Volume ◽  
Airway Closure ◽  
Venous Admixture ◽  
Residual Capacity ◽  
Nitrogen Concentrations

Airway closure was measured in awake and then anesthetized supine healthy subjects with the argon-bolus and the resident-gas (nitrogen) techniques simultaneously. The preinspiratory lung volume for the closing volume maneuver was varied from residual volume to closing capacity (CC). Comparative measurements were also performed in the upright and supine positions in awake subjects. Closing volume (CV) was consistently larger with the bolus technique in supine subjects both when awake and when anesthetized (difference between methods 0.1--0.2 l, P less than 0.01), whereas no difference between the methods was noted in upright subjects. The lower “nitrogen CV” in supine subjects may be due to a shorter vertical lung height with a smaller range of nitrogen concentrations, resulting in a less abrupt onset of phase IV (taken to indicate CV). CV was not significantly affected by the preinspiratory lung volume with either technique, and CC was unchanged when anesthesia was instituted. Functional residual capacity (FRC) was reduced with anesthesia (mean reduction: 0.6 l, P less than 0.01) and FRC-CC became negative in all subjects with either technique. This implies intermittent or continuous airway closure during anesthesia and the possibility of increased venous admixture.

A fundamental problem in determining functional residual capacity or residual volume

1986 ◽  
Vol 60 (5) ◽  
pp. 1810-1813 ◽  
Author(s):  
U. Boutellier ◽  
L. E. Farhi
Keyword(s):  
Experimental Data ◽  
Functional Residual Capacity ◽  
Volume Change ◽  
Lung Volume ◽  
General Equation ◽  
Fundamental Problem ◽  
Residual Volume ◽  
Volume Changes ◽  
Final Volume ◽  
Residual Capacity

To measure a lung volume that is not directly accessible, one often follows dilution of a single-gas tracer, present initially only in the lung or in a rebreathing bag. The final volume available to the tracer is assumed to be the sum of the two initial components. Since O2 is taken up and CO2 is eliminated during the few breaths required for mixing, the total volume changes. The error in lung volume due to this volume change can exceed 10%. In this paper we 1) present theoretical and experimental data to demonstrate the effect of CO2 and O2 exchange, 2) introduce a general equation, based on N2 and Ar, which allows one to circumvent the problems created by these fluxes, and 3) show the pitfall of the back-extrapolation approach for a single tracer.

Hysteresis in the relation between diffusing capacity of the lung and lung volume

1980 ◽  
Vol 49 (4) ◽  
pp. 566-570 ◽  
Author(s):  
S. S. Cassidy ◽  
M. Ramanathan ◽  
G. L. Rose ◽  
R. L. Johnson
Keyword(s):  
Carbon Monoxide ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Total Lung Capacity ◽  
Breath Holding ◽  
Residual Volume ◽  
Diffusing Capacity ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

The diffusing capacity of the lung for carbon monoxide (DLCO) varies directly with lung volume (VA) when measured during a breath-holding interval. DLCO measured during a slow exhalation from total lung capacity (TLC) to functional residual capacity (FRC) does not vary as VA changes. Since VA is reached by inhaling during breath holding and by exhaling during the slow exhalation maneuver, we hypothesized that the variability in the relation between DLCO and VA was due to hysteresis. To test this hypothesis, breath-holding measurements of DLCO were made at three lung volumes, both when VA was reached by inhaling from residual volume (RV) and when Va was reached by exhaling from TLC. At 72% TLC, DLCO was 22% higher when VA was reached by exhalation compared to inhalation (P < 0.02). At 52% TLC, DLCO was 19% higher when VA was reached by exhalation compared to exhalation (P < 0.005). DCLO measured during a slow exhalation fell on the exhalation limb of the CLCO/VA curve. these data indicate that there is hysteresis in DLCO with respect to lung volume.

LUNG VOLUMES OF NORMAL AND ASTHMATIC CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 23 (3) ◽  
pp. 507-519
Author(s):  
John F. Andrewes ◽  
Daniel H. Simmons
Keyword(s):  
Allergic Rhinitis ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Bronchial Obstruction ◽  
Residual Volume ◽  
Normal Children ◽  
Lung Volumes ◽  
Asthmatic Children ◽  
Residual Capacity ◽  
Time Required

Measurements of the various lung volumes were carried out with 27 normal children, 21 asthmatic children and 4 with allergic rhinitis. The asthmatic children had increases in functional residual capacity and residual volume. There was a significant increase in the time required for intrapulmonary mixing of gas in the asthmatic subjects. A biphasic character to the "wash-out" curves in both normal and asthmatic subjects was shown. It was considered, though not proved, that the increases in lung volume were due to the presence of bronchial obstruction.

Lung volume effects on pharyngeal swallowing physiology

2003 ◽  
Vol 95 (6) ◽  
pp. 2211-2217 ◽  
Author(s):  
Roxann Diez Gross ◽  
Charles W. Atwood ◽  
Judith P. Grayhack ◽  
Susan Shaiman
Keyword(s):  
Functional Residual Capacity ◽  
Lung Volume ◽  
Total Lung Capacity ◽  
Regulatory Function ◽  
Residual Volume ◽  
Bolus Transit ◽  
Repeated Measures Design ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Intramuscular Electromyography

The experiment was a prospective, repeated-measures design intended to determine how the variation of lung volume affects specific measures of swallowing physiology. Swallows were recorded in 28 healthy subjects, who ranged in age from 21 to 40 yr (mean age of 29 yr), by using simultaneous videofluoroscopy, bipolar intramuscular electromyography, and respiratory inductance plethysmography. Each subject swallowed three standardized pudding-like consistency boluses at three randomized lung volumes: total lung capacity, functional residual capacity, and residual volume. The results showed that pharyngeal activity duration of deglutition for swallows produced at residual volume was significantly longer than those occurring at total lung capacity or at functional residual capacity. No significant differences were found for bolus transit time or intramuscular electromyography of the superior constrictor. The results of this experiment lend support to the hypothesis that the respiratory system may have a regulatory function related to swallowing and that positive subglottic air pressure may be important for swallowing integrity. Eventually, new treatment paradigms for oropharyngeal dysphagia that are based on respiratory physiology may be developed.

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.

LUNG VOLUME IN THE NEWBORN INFANT

PEDIATRICS ◽  
1962 ◽  
Vol 30 (1) ◽  
pp. 111-116
Author(s):  
M. Klaus ◽  
W. H. Tooley ◽  
K. H. Weaver ◽  
J. A. Clements
Keyword(s):  
Newborn Infant ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Newborn Infants ◽  
Du Bois ◽  
Residual Capacity

The plethysmographic technique of Du-Bois and associates has been modified for use in newborn infants and found suitable for the measurement of lung volume. Of 37 normal infants studied with this method, most achieved full functional residual capacity during the first few minutes of life.

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