Relationships between regional ventilation and vascular and extravascular volume in supine humans

Brudin, Lars; Rhodes, C. G.; Valind, Sven; Jones, T.S.; Jonson, B; Hughes, J. M. B.

doi:10.1152/jappl.1994.76.3.1195

Cited by 27 publications

(31 citation statements)

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“…As SD of V/Q profile was significantly correlated with A-aDO2 in our patients, this parameter may be a good parameter to evaluate the severity of the lung gas-exchange impairment in these patients. The finding of fairly uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls is in agreement with previous studies [27,28]. This finding reflects minimal physiologic lung V-Q imbalance for effective alveolar gas exchange.…”

Section: Discussionsupporting

confidence: 92%

Lung ventilation–perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT

Suga¹,

Kawakami²,

Koike

et al. 2010

Ann Nucl Med

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Section: Discussionsupporting

confidence: 92%

Lung ventilation–perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT

Suga¹,

Kawakami²,

Koike

et al. 2010

Ann Nucl Med

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“…Alveolar recruitment accounts for the decrease in Est,L following sustained hyperinflation in conscious seated subjects and has been attributed to changes in pulmonary blood volume [15,28] or airway smooth muscle tone [21]. Thus, decreases in Est,L and Edyn,L (by about 30%) observed just above the diaphragm in the supine posture when lung volume increases from ERV to 60% VC can be explained similarly.…”

Section: Lung Mechanicsmentioning

confidence: 95%

Measurement of lung mechanics at different lung volumes and esophageal levels in normal subjects: Effect of posture change

Baydur

Sassoon

Carlson

2004

Lung

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Lung elastance and resistance increase in the supine posture. To evaluate the effects of change in posture on regional lung mechanics at different lung volumes, lung elastance and resistance were measured at graded volume subdivisions and three esophageal levels at seated and supine body positions, using the esophageal balloon technique. Volumes were adjusted to be the same in both postures. In general, lung elastance (both static and dynamic) tended to be higher in supine posture and uniform at all lung volumes, except at 80% vital capacity, where it increased sharply. The ratio of dynamic to static lung elastance was slightly higher at the cephalad esophageal level, where regional flow rates and relative volume expansion are lower. Lung resistance varied inversely with lung volume but was higher at corresponding volume subdivisions in the supine posture. It decreased at more cephalad esophageal levels, where volume expansion and flow are less. Thus, the increase in regional flow at low volume subdivisions (most marked in the supine position) also contributed to higher lung resistance at these volumes. These findings are explained on the basis of a combination of Newtonian physics as well as nonlinear viscoelastic properties of the lung as applied to regional flow and volume expansion.

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“…This scan was used to demarcate the lung field and to calculate gas fraction (23)(24)(25)(26) of the lung (FG L ) and of six horizontal regions of interest (ROIs) of equal height (FG i , i 5 1-6, in the ventral-to-dorsal direction). Relative lung volume was calculated as the ratio of the number of voxels within an ROI (n i ) to that in the lung field (n L ).…”

Section: Pet Imagingmentioning

confidence: 99%

Relation between Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

Musch¹,

Bellani²,

Melo³

et al. 2008

Am J Respir Crit Care Med

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Rationale: In a pulmonary process characterized by spatially heterogeneous loss of aeration, the impairment of gas exchange is expected to depend on the regional distribution of perfusion relative to that of aeration. Objectives: To investigate how regional aeration, shunt, and perfusion are interrelated at different levels of end-expiratory pressure and how their interplay relates to global shunt fraction in acute lung injury. Methods: Regional shunt and perfusion were assessed by imaging with positron emission tomography the pulmonary kinetics of [ 13 N]nitrogen infused in saline solution in five sheep after lung lavage. The lung field was divided in six horizontal regions. Measurements and Main Results: Each animal showed an inverse relation between regional shunt (FS) and gas (FG) fractions: FS 5 2m Á FG 1 FS 0 . This relation was similar among animals (m 5 1.25 6 0.14, FS 0 5 0.75 6 0.15) and invariant with end-expiratory pressure, despite lack of correlation between global shunt and gas fractions and large interanimal variability in global shunt fraction. When this relation was used to estimate global shunt fraction as a perfusion-weighted average of the estimates of regional shunt fraction derived from regional gas fraction, 72% of the interanimal variability in global shunt fraction could be explained. Conclusions: Despite large interanimal variability in global shunt fraction, there was a consistent inverse relation between regional shunt and gas fractions, independent of end-expiratory pressure. Most of the interanimal variability in global shunt fraction could be explained by the combined effect of this relation and the distribution of perfusion on regional shunt, rather than by differences in global aeration.

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Relationships between regional ventilation and vascular and extravascular volume in supine humans

Cited by 27 publications

References 0 publications

Lung ventilation–perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT

Lung ventilation–perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT

Measurement of lung mechanics at different lung volumes and esophageal levels in normal subjects: Effect of posture change

Relation between Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

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