Effect Of Volume History Research Articles

Time dependence of maximum flow as an index of nonuniform emptying.

Nonhomogeneous lungs are predicted to exhibit time dependence of maximal expiratory flow (Vmax): faster regions would contribute more flow early in the expiration, whatever the initial volume, resulting in different Vmax at a given total lung volume, depending on how long flow limitation has been operating. To test this concept a new technique was developed that permits accurate superimposition of Vmax data over small volume intervals. When quick-release interrupted partial curves with similar volume history but different volume of initiation were compared over their late common-volume segments, the volume-history effects could be differentiated from time dependence of the Vmax. Such time dependence was found in 7 of 7 bronchitics, 3 of 5 smokers, and 0 of 14 nonsmokers tested. We conclude that the emptying during the forced expirations is not uniform even in mild disease states and the time dependence of Vmax is a sensitive test of lung inhomogeneity.

Effect of volume history on successive partial expiratory flow-volume maneuvers.

In normal subjects, the second of two successive partial expiratory flow-volume (PEFV 2) curves often had higher isovolume maximal expiratory flow rates (Vmax) than the first (PEFV 1) (mean increase 30.2 +/- 13%). The higher Vmax on PEFV 2 was present only when there was a greater lung elastic recoil pressure (Pst(L)). In eight subjects the Pst(L) derived from sequential partial quasi-static pressure-volume curves, from interruption of the flow-volume maneuvers and at the start of the PEFV curves showed that isovolume upstream resistance increased although Vmax also increased after going to residual volume (RV). In four subjects the RV volume history did not change the pressure flow relationship across the upstream airways. If airways dimensions were the sole determinant of Vmax, then Vmax on PEFV 2 would be the same or smaller than on PEFV 1. That the opposite was observed in our study indicates that the increase in Pst(L), which results from parenchymal hysteresis, offsets any dimensional decrease in upstream airways due to airways hysteresis.

The effect of volume history on shunt flow in excised dog lungs

Excised dog lungs were distended with oxygen and perfused with the venous blood of donor dogs. The anatomical shunt flow through the lungs was measured by the oxygen content method. Large shunt flows ranging from 9 to 28 per cent of the total flow were found. The pulmonary arterial pressure for perfusion of the lungs at a constant flow and low venous pressure was significantly lower after inflation from a smaller volume than after deflation from a larger volume to the same alveolar pressure. At an alveolar pressure of 10 cm H 2O the mean shunt was 18 per cent greater after inflation than after deflation. However, at alveolar pressures of 20 cm H 2O and above, shunt flow was not significantly affected by volume history. The results suggest that the lower pulmonary arterial pressure necessary for perfusion of the excised lung after inflation is not due to shunt channels through areas of atelectasis which can be abolished by a hyperinflation.

Pulmonary blood flow and the incorporation of palmitate-I-C14 by dog lung in vivo.

ArticlePulmonary blood flow and the incorporation of palmitate-I-C14 by dog lung in vivo.A NaimarkA NaimarkPublished Online:01 Jul 1966https://doi.org/10.1152/jappl.1966.21.4.1292MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByIs the lung scan alive and well? Facts and controversies in defining the role of lung scintigraphy for the diagnosis of pulmonary embolism in the era of MDCT27 January 2009 | European Journal of Nuclear Medicine and Molecular Imaging, Vol. 36, No. 3Chronic Thromboembolic Occlusion of Main Pulmonary Artery Does Not Reduce the Lung Clearance of 99m Tc-DTPAAmerican Review of Respiratory Disease, Vol. 139, No. 6Regulation of fetal lung disaturated phosphatidylcholine synthesis by de novo palmitate supplyBiochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, Vol. 958, No. 1Effects of lobar pulmonary blood flow on the evolution of oleic acid lung injury in dogsJournal of Surgical Research, Vol. 41, No. 4Lipid Synthesis and Surfactant Turnover in the Lungs1 January 2011General Enzymology of the LungLung Maturity and Pulmonary Phospholipid MetabolismLungenstoffwechsel bei SchocklungeVital Capacity and Congestive Heart FailureCirculation, Vol. 49, No. 6Pyruvate metabolism by rat lung in vitroLipids, Vol. 8, No. 6The physiologic factors affecting regional ventilation and perfusionSeminars in Nuclear Medicine, Vol. 1, No. 2The causes of progressive pulmonary insufficiency in surgical patientsJournal of Surgical Research, Vol. 9, No. 12The effect of volume history on shunt flow in excised dog lungsRespiration Physiology, Vol. 7, No. 1The Lung as a Metabolic OrganNew England Journal of Medicine, Vol. 279, No. 24Insulin and the lungDiabetologia, Vol. 4, No. 4Bronchiolar and Large Alveolar Cell in Pulmonary Phospholipid MetabolismScience, Vol. 158, No. 3806Effects of hypoxemia, hypercarbia, acidosis, and reduced pulmonary blood flow on the surfactant of fetal lamb lungThe Journal of Pediatrics, Vol. 71, No. 3 More from this issue > Volume 21Issue 4July 1966Pages 1292-8 https://doi.org/10.1152/jappl.1966.21.4.1292PubMed5916665History Published online 1 July 1966 Published in print 1 July 1966 Metrics