Alterations in pulmonary diffusing capacity and pulmonary capillary blood volume with negative pressure breathing.

Steiner, Sheldon H.; Frayser, Regina; Ross, Jennifer Gunberg

doi:10.1172/jci105268

Cited by 15 publications

(4 citation statements)

References 32 publications

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“…There was no decrease in D m compared with the measurement made after 30 s of CNP suggesting that there was no induction of an interstitial oedema. Steiner et al (1965) observed an increase in V c and D m after applying high CNP for either 4 or 7 min (−26 to −52 cmH 2 O) in five subjects.…”

Section: Discussionmentioning

confidence: 82%

Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications

Glénet

Bisschop

Vargas

et al. 2007

The Journal of Physiology

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Using simultaneous nitric oxide and carbon monoxide lung transfer measurements (T LNO and T LCO ), the membrane transfer capacity (D m ) and capillary lung volume (V c ) as well as the dimensionless ratio T LNO /T LCO can be calculated. The significance of this ratio is yet unclear. Theoretically, the T LNO /T LCO ratio should be inversely related to the product of both lung alveolar capillary membrane (μ) and blood sheet thicknesses (K ). NO and CO transfers were measured in healthy subjects in various conditions likely to be associated with changes in K and/or μ. Experimentally, deflation of the lung from 7.4 to 4.8 l decreased the T LNO /T LCO ratio from 4.9 to 4.2 (n = 25) which was consistent mainly with a thickening of the blood sheet. Compared with continuous negative pressure breathing, continuous positive pressure breathing increased this ratio suggesting a thinning of the capillary sheet. It was also observed with 12 healthy subjects that slight haemodilution that may thicken the blood sheet decreased the T LNO /T LCO ratio from 4.85 to 4.52. In conclusion, the T LNO /T LCO ratio is related to the thickness of the alveolar blood barrier. This ratio provides novel information for the analysis of the diffusion properties. Diffusion of gases between the alveolar space of the lung and blood is usually described with Roughton and Forster's model (Forster et al. 1957). In this model, key factors affecting gas transfer include two components: (a) the membrane which is supposed to be homogenous and characterized by its conductance (D m ) and (b) the product of red cell conductance for a given gas (θ ) and pulmonary capillary volume (V c ). D m is considered to be an independent variable to V c .In order to calculate D m and V c the NO/CO transfer method (T LNO /T LCO ) was introduced in the lung function testing of humans in 1987 (Guénard et al. 1987). As the in vivo conductance of NO in blood is very high, the only limitation to its transfer through the barrier is the membrane. CO transfer (T LCO ) depends on D m , V c and haemoglobin concentration. T LCO also varies with pulmonary capillary oxygen tension since θ CO is inversely proportional to this pressure. The ratio of NO to CO transfer (T LNO /T LCO ) should therefore provide some insight into the relative properties of the membrane and capillaries.The surface area of the alveolar membrane and capillary are identical or closely related and by consequence, D m and V c should be directly correlated. The hypothesis of this study is based on the assumption that V c and D m are dependent parameters.Under this assumption, this study is designed to identify the significance of the T LNO /T LCO ratio through both theoretical and experimental approaches with the expectations that the new model would be relevant for physiological or clinical purposes. Specifically, we have shown that the T LNO /T LCO ratio is independent of membrane surface area and inversely proportional to the product of alveolar membrane and capillary blood layer thicknesses. Methods Theoretica...

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Section: Discussionmentioning

confidence: 82%

Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications

Glénet

Bisschop

Vargas

et al. 2007

The Journal of Physiology

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“…First, negative intrathoracic pressure can collapse the great veins and limit venous return [7]. Additionally, negative intrathoracic pressure may increase the risk of pulmonary edema or atelectasis [12–14]. Finally, it is unclear how the variety of different negative pressure techniques differs from one another.…”

Section: Introductionmentioning

confidence: 99%

Automated expiratory ventilation assistance through a small endotracheal tube can improve venous return and cardiac output

Berlin

Manoach

Oromendia

et al. 2019

ICMx

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BackgroundPositive pressure ventilation can decrease venous return and cardiac output. It is not known if expiratory ventilation assistance (EVA) through a small endotracheal tube can improve venous return and cardiac output.ResultsIn a porcine model, switching from conventional positive pressure ventilation to (EVA) with − 8 cmH20 expiratory pressure increased the venous return and cardiac output. The stroke volume increased by 27% when the subjects were switched from conventional ventilation to EVA [53.8 ± 7.7 (SD) vs. 68.1 ± 7.7 ml, p = 0.003]. After hemorrhage, subjects treated with EVA had higher median cardiac output, higher mean systemic arterial pressure, and lower central venous pressure at 40 and 60 min when compared with subjects treated with conventional ventilation with PEEP 0 cmH20. The median cardiac output was 41% higher in the EVA group than the control group at 60 min [2.70 vs. 1.59 L/min, p = 0.029].ConclusionEVA through a small endotracheal tube increased venous return, cardiac output, and mean arterial pressure compared with conventional positive pressure ventilation. The effects were most significant during hypovolemia from hemorrhage. EVA provided less effective ventilation than conventional positive pressure ventilation.

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“…Both immersion in water (124) and negative pressure breathing (125) increase DLco as a consequence of the increase thereby caused in pul monary capillary blood volume. In forward acceleration.…”

Section: Transfer Of Gases Inmentioning

confidence: 99%

Respiration

Bernstein¹

1967

Annu. Rev. Physiol.

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Limitation of space dictates that I omit several topics from this review; among these are pulmonary pathophysiology and pulmonary function testing; cell respiration; pharmacology of respiration; adaptation to long term environmental changes; and comparative physiology, either of inter species variation or of variation within the individual related to age and stage of development. These topics are included in a longer bibliography. 2 BOOKS, REVIEWS, CONFERENCESRespiration physiologists now have their own, eponymously titled jour nal (l).It has been a good year for books: Aviado's account of the pulmonary circulation (2) , that must for a long time be the definitive work in this field; Keilin's History of Cell Respiration and Cytochrome (3), completed for the press by his daughter after his death; Volume II of Section 3 (Res piration) of the American Physiological Society's Handbook of Physiology (4); Farhi's literarily and s�ientifically admirable translation into English of Dejour's chapter in Volume III of the French textbook Physiologie (C.Kayser, Ed.), now published as the book Respiration (5) ; a collection of re views (6) of recent progress in their fields, by eight active research work ers; an account of the principles, practice, and interpretation of cl inical pulmonary function tests (7); a simple exposition and discussion of the concept of inhomogeneity of distribution of ventilation and blood flow (8); a somewhat sketchy account of the comparative anatomy, histology, and physiology of respiration throughout the animal kingdom (9) ; and a gener

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Alterations in pulmonary diffusing capacity and pulmonary capillary blood volume with negative pressure breathing.

Cited by 15 publications

References 32 publications

Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications

Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications

Automated expiratory ventilation assistance through a small endotracheal tube can improve venous return and cardiac output

Respiration

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