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

Brown, Robert; Hoppin, F. G.; Ingram, R. H.; Saunders, N. A.; McFadden, E. R.

doi:10.1152/jappl.1978.44.3.469

Cited by 34 publications

(21 citation statements)

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“…In healthy subjects and patients with airways obstruction, the plethysmographic method typically gives values greater than the helium dilution method [30][31][32][33]. The traditional view has been that the latter underestimates lung volume because lung regions with long time constants do not reach equilibration with the rest of the lung and spirometer at the end of the test.…”

Section: Comparison Of the Helium Dilution Methods And Body Plethysmogmentioning

confidence: 99%

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Multiple breath helium dilution measurement of lung volumes in adults

Brown¹,

Leith²,

Enright³

1998

Eur Respir J

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Section: Comparison Of the Helium Dilution Methods And Body Plethysmogmentioning

confidence: 99%

“…One occurs when abdominal gas is compressed and decompressed in synchrony with thoracic gas [31]. Another is related to nonhomogeneous alveolar pressure swings during the "Boyle's law manoeuvre" [34][35][36].…”

Section: Comparison Of the Helium Dilution Methods And Body Plethysmogmentioning

confidence: 99%

Multiple breath helium dilution measurement of lung volumes in adults

Brown¹,

Leith²,

Enright³

1998

Eur Respir J

Self Cite

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“…Thoracic gas volume (TGV) is defined as the volume of intrathoracic gas at the time the airway is occluded for the plethysmographic measurement; while this is usually at FRC, in special circumstances it may not be [1,2]. Irrespective of where in the volume cycle TGV is measured, it should be adjusted to the FRC derived from plethysmography (FRCpleth) by subtracting or adding the appropriate volume correction.…”

Section: Measurement Of Lung Volumes By Plethysmographymentioning

confidence: 99%

“…(PA1-PH 2 O) × TGV1 = (PA2-PH 2 O) × TGV2 (2) where the smaller script denotes differing values of pressure and volume during the respiratory manoeuvre. PA1 and PA2 are expressed as absolute pressures, not the differences between barometric pressure (PB) and Pao.…”

Section: Theorymentioning

confidence: 99%

Measurement of lung volumes by plethysmography

Coates¹,

Peslin²,

Rodenstein³

et al. 1997

Eur Respir J

144

107

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“…The mean of at least three reproducible measurements was obtained in each subject. Calculated volumes were reduced by 130 ml in all cases to allow for abdominal gas compression (Brown et al, 1978a;Habib and Engel, 1978 scans was -0 5% of a mean chest volume of 8-71 1 (ie 45 ml), and the SD of the error was 2 2% (190 ml).…”

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confidence: 99%

Estimation of lung volumes from chest radiographs using shape information.

Pierce¹,

Brown²,

Holmes³

et al. 1979

Thorax

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The cross-sectional shapes of the chest and its contained structures have been assessed in post-mortem anatomical sections and from computerised tomographic scans in living subjects. These shapes are described by simple equations that can be used to increase the accuracy of measuring lung volumes from chest radiographs. Radiographic estimates of total lung capacity, using the equations, were compared with plethysmographic and single-breath helium dilution measurements in 35 normal subjects. The postures commonly used for taking chest radiographs were found, on average, to decrease total lung capacity (TLC) and to increase residual volume by about 200 ml when compared with the sitting positions used for the other two measurements (studies made in 18 of the subjects). After correction for this effect, the radiographic estimates of TLC, which measure the displacement volume of the lung, exceeded the plethysmographic estimates of contained gas volume by a mean of 720 ml, which was taken as the volume of tissue, blood, and water in the lungs. The single-breath dilution estimates of TLC fell short of the plethysmographic values by a mean of 480 ml, taken as the volume of contained gas that was inaccessible to helium in 10 seconds. The tomographic studies suggested that the radiographic technique of measuring lung displacement volumes has an accuracy of +210 ml. The method is rapid and simple to use and has intra-and inter-observer variabilities of <1% and <5% respectively. Barnhard et al (1960) assumed that each lung and the heart were elliptical in cross-section and considered the diaphragm as one-eighth of an ellipsoid. All these methods are dependent for their accuracy on correlations with other methods of measuring lung volume, such as plethysmography or gas dilution. The acceptability of the plethysmograph as a standard for comparison is not entirely above suspicion, especially in patients with lung disease: recent studies by Brown et al (1978b) have suggested that airways obstruction may lead to inaccurate measurement. Previous studies have also neglected the effects of postural differences on static lung volumes, and have applied a single approximate magnification factor to all radiographs.The

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

Cited by 34 publications

References 1 publication

Multiple breath helium dilution measurement of lung volumes in adults

Multiple breath helium dilution measurement of lung volumes in adults

Measurement of lung volumes by plethysmography

Estimation of lung volumes from chest radiographs using shape information.

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