Effect of negative intra-alveolar pressure on pulmonary diffusing capacity

1960 ◽  
Vol 15 (3) ◽  
pp. 372-376 ◽  
Author(s):  
J. E. Cotes ◽  
D. P. Snidal ◽  
R. H. Shepard
Keyword(s):  
Carbon Monoxide ◽  
Venous Pressure ◽  
Capillary Blood ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Alveolar Pressure ◽  
Holding Period ◽  
Capillary Membrane ◽  
Capillary Blood Volume ◽  
Alveolar Capillary

In one of two subjects studied in detail, using 0.1% carbon monoxide in the test gas and a 10-second breath-holding period, the alveolar capillary blood volume (Vc) was found to increase by nearly 100% when the intra-alveolar pressure was made negative during breath holding. This was accompanied by a reduction in venous pressure in the forearm. In both subjects Vc was increased on exercise. The diffusing capacity of the alveolar capillary membrane (Dm) remained relatively constant in spite of large changes in Vc. The findings suggest that stationary blood is present in some alveolar capillaries at rest. The implications of this finding and a likely mechanism for the increase in Vc with negative pressure are discussed. xsSubmitted on September 14, 1959

Pulmonary diffusing capacity and capillary blood volume in normal and anemic dogs

1965 ◽  
Vol 20 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Denise Jouasset-Strieder ◽  
John M. Cahill ◽  
John J. Byrne ◽  
Edward A. Gaensler
Keyword(s):  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Alveolar Volume ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Capillary Membrane ◽  
Capillary Blood Volume ◽  
The Mean ◽  
Alveolar Capillary

The CO diffusing capacity (Dl) was measured by the single-breath method in eight anesthetized dogs. Pulmonary capillary blood volume (Vc) and membrane diffusing capacity (Dm) were determined in six animals by the method of Roughton and Forster. The studies were repeated after anemia had been induced by replacing whole blood with plasma. Large dogs were selected with a mean body weight of 29 kg and a mean alveolar volume of 2,020 ml (STPD) during tests. The mean arterial blood Hb decreased from 14.3 to 6.6 g/100 ml, the mean Dl from 27 to 12 ml/min mm Hg, and the mean Dm from 100 to 47 ml/min mm Hg. Vc averaged 67 ml in the control state and was not significantly changed during anemia. Reductions in Dl and Dm during anemia were proportional to the fall in blood Hb. Both Dl and Dm in all dogs, normal and anemic, were proportional to the volume of red blood cells in the lung capillaries (Vrbc). These results suggest that Vrbc might be an estimate of the useful area of the alveolar-capillary membrane while Dm/Vrbc should vary with changes in its thickness. The latter was not altered by anemia. alveolar capillary membrane; pulmonary membrane; diffusing capacity; pulmonary capillary RBC volume; pulmonary diffusion pathway; carbon monoxide Submitted on March 2, 1964

Oxygen transport during exercise in large mammals. II. Oxygen uptake by the pulmonary gas exchanger

1989 ◽  
Vol 67 (2) ◽  
pp. 871-878 ◽  
Author(s):  
M. Constantinopol ◽  
J. H. Jones ◽  
E. R. Weibel ◽  
C. R. Taylor ◽  
A. Lindholm ◽  
...  
Keyword(s):  
Transit Time ◽  
Capillary Blood ◽  
Morphometric Parameters ◽  
O2 Consumption ◽  
Diffusing Capacity ◽  
Large Mammals ◽  
O2 Uptake ◽  
Capillary Blood Volume ◽  
Standardbred Racehorses ◽  
Alveolar Capillary

Because the maximal rate of O2 consumption (VO2max) of the horse is 2.6 times larger than that of steers of equal size, we wondered whether their pulmonary gas exchanger is proportionately larger. Three Standardbred racehorses [body mass (Mb) = 447 kg] and three domestic steers (Mb = 474 kg) whose cardiovascular function at VO2max had been thoroughly studied (Jones et al. J. Appl. Physiol. 67: 862–870, 1989) were used to study their lungs by morphometry. The basic morphometric parameters were similar in both species. The nearly 2 times larger lung volumes of the horses caused the gas exchange surfaces and capillary blood volume to be 1.6 to 1.8 times larger. Morphometric pulmonary diffusing capacity was 2 times larger in the horse than in the steer; the 2.6-fold greater rate of O2 uptake thus required the alveolar-capillary PO2 difference to be 1.3 times larger in the horse than in the steer. Combining physiological and morphometric data, we calculated capillary transit time at VO2max to be 0.4–0.5 s. Bohr integration showed capillary blood to be equilibrated with alveolar air after 75 and 58% of transit time in horses and steers, respectively; horses maintain a smaller degree of redundancy in their pulmonary gas exchanger.

Gas Transfer for Carbon Monoxide in Polycythaemia Secondary to Hypoxic Lung Disease

1985 ◽  
Vol 68 (1) ◽  
pp. 57-62 ◽  
Author(s):  
J. A. Wedzicha ◽  
F. E. Cotter ◽  
P. J. W. Wallis ◽  
A. C. Newland ◽  
D. W. Empey
Keyword(s):  
Carbon Monoxide ◽  
Lung Disease ◽  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Capillary Blood Volume ◽  
The Mean

1. The transfer factor for carbon monoxide and its subdivisions, the membrane diffusing capacity (Dm) and the pulmonary capillary blood volume (Vc), were measured in 16 patients with polycythaemia secondary to chronic hypoxic lung disease and in ten hypoxic non-polycythaemic control subjects. 2. The mean pulmonary capillary blood volume was significantly lower in the polycythaemic patients (31.6 ml, sd 11.2) compared with the control group (65.2 ml, sd 22.5) (P<0.001). 3. Erythrapheresis, as a method of isovolaemic haemodilution, was performed in 15 of the polycythaemic patients. The mean packed cell volume fell from 58 (sd 5)% to 47 (sd 5)% after treatment, with significant reductions in blood viscosity at both high and lower shear rates (P<0.001). 4. The mean pulmonary capillary blood volume increased from 32.3 ml (sd 11.3) before treatment to 48.7 ml (sd 18.7) after erythrapheresis (P<0.01), with no significant change in membrane diffusing capacity. 5. The rise in pulmonary capillary blood volume is another potential physiological advantage of the reduction of packed cell volume in patients with polycythaemia secondary to hypoxic lung disease.

Effects of anemia and hemorrhagic shock on pulmonary diffusion in the dog lung

1963 ◽  
Vol 18 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Benjamin Burrows ◽  
Albert H. Niden
Keyword(s):  
Carbon Monoxide ◽  
Blood Flow ◽  
Blood Cell ◽  
Hemorrhagic Shock ◽  
Red Blood Cell ◽  
Lung Volume ◽  
Diffusing Capacity ◽  
Pulmonary Diffusing Capacity ◽  
Capillary Membrane ◽  
Alveolar Capillary

Hemorrhagic shock induced a marked fall in the pulmonary diffusing capacity for carbon monoxide in the dog (Dl) and produced marked nonuniformity of Dl/Va ratios throughout the lung as assessed by the “equilibration technique”. Difficulties in calculating over-all Dl under these conditions are discussed. Induced anemia also produced a fall in Dl, but little change in the uniformity of Dl/Va ratios was noted. In isolated perfused dog lungs where blood flow, pulmonary vascular pressures, lung volume, and ventilation were maintained constant, Dl was found to be proportional to hematocrit, suggesting either: 1) that virtually all resistance to CO diffusion is in the erythrocyte or 2) that the apparent diffusing capacity of the alveolar-capillary membrane is dependent upon hematocrit, carbon monoxide transfer being reduced across portions of membrane which are some distance from a red blood cell. Submitted on January 12, 1962

scholarly journals Calculating alveolar capillary conductance and pulmonary capillary blood volume: comparing the multiple- and single-inspired oxygen tension methods

2010 ◽  
Vol 109 (3) ◽  
pp. 643-653 ◽  
Author(s):  
Maile L. Ceridon ◽  
Kenneth C. Beck ◽  
Thomas P. Olson ◽  
Jordan A. Bilezikian ◽  
Bruce D. Johnson
Keyword(s):  
Carbon Monoxide ◽  
Blood Volume ◽  
Membrane Conductance ◽  
Capillary Blood ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
Pulmonary Capillary Blood ◽  
Pulmonary Capillary Blood Volume ◽  
Predicted Values ◽  
Alveolar Capillary

Key elements for determining alveolar-capillary membrane conductance (Dm) and pulmonary capillary blood volume (Vc) from the lung diffusing capacity (Dl) for carbon monoxide (DlCO) or for nitric oxide (DlNO) are the reaction rate of carbon monoxide with hemoglobin (θCO) and the DmCO/DlNO relationship (α-ratio). Although a range of values have been reported, currently there is no consensus regarding these parameters. The study purpose was to define optimal parameters (θCO, α-ratio) that would experimentally substantiate calculations of Dm and Vc from the single-inspired O2 tension [inspired fraction of O2 (FiO2)] method relative to the multiple-FiO2 method. Eight healthy men were studied at rest and during moderate exercise (80-W cycle). Dm and Vc were determined by the multiple-FiO2 and single-FiO2 methods (rebreathe technique) and were tabulated by applying previously reported θCO equations (both methods) and by varying the α-ratio (single-FiO2 method) from 1.90 to 2.50. Values were then compared between methods throughout the examined α-ratios. Dm and Vc were critically dependent on the applied θCO equation. For the multiple-FiO2 method, Dm was highly variable between θCO equations (rest and exercise); the range of Vc was less widespread. For the single-FiO2 method, the θCO equation by Reeves and Park (1992) combined with an α-ratio between 2.08 and 2.26 gave values for Dm and Vc that most closely matched those from the multiple-FiO2 method and were also physiologically plausible compared with predicted values. We conclude that the parameters used to calculate Dm and Vc values from the single-FiO2 method (using DlCO and DlNO) can significantly influence results and should be evaluated within individual laboratories to obtain optimal values.

Theta values for C16O18O and C18O2related to respective pulmonary diffusing capacities

1998 ◽  
Vol 274 (5) ◽  
pp. R1496-R1499
Author(s):  
Hartmut Heller ◽  
Klaus-Dieter Schuster
Keyword(s):  
Isotopic Exchange ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Exchange Reactions ◽  
Text Data ◽  
Single Breath ◽  
Capillary Membrane ◽  
Uptake Rates ◽  
Measured Ratio ◽  
Alveolar Capillary

The single-breath diffusing capacities for singly and doubly 18O-labeled CO2,[Formula: see text]and[Formula: see text], as well as for NO, were determined in seven anesthetized rabbits to investigate whether the theoretically predicted ratio of specific blood uptake rates of both isotopic CO2species,[Formula: see text]/[Formula: see text]= 2.0, can be derived from the measured values of[Formula: see text]and[Formula: see text]. Data of Dl were obtained by inflating the lungs with gas mixtures containing 0.35% C16O18O or 0.8% C18O2or 0.05% NO in nitrogen, with breath-holding periods of 0.05–0.5 s and 2–12 s for the CO2 and NO tests, respectively.[Formula: see text]/[Formula: see text]was calculated by applying the double-reciprocal Roughton-Forster equation to Dl values obtained in each animal and by assuming that NO diffusing capacity represents the gas conductance of the alveolar-capillary membrane. The measured ratio was[Formula: see text]/[Formula: see text]= 1.9 ± 0.2 (mean ± SD), thus comparing reasonably with the predicted one. Therefore, our findings provide evidence that the greater value of[Formula: see text]is mainly due to the twofold higher probability (or theta value) for C18O2than for C16O18O to disappear within red blood cells via isotopic exchange reactions.

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