scholarly journals Relationship Between Exhaled Na+ and the Diffusion Capacity of the Lungs for Carbon Monoxide (DLCO) and Alveolar‐Capillary Membrane Conductance in Healthy Humans

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Courtney M. Wheatley ◽  
Nicholas A. Cassuto ◽  
William T. Foxx‐Lupo ◽  
Eric C. Wong ◽  
Nicholas A. Delamere ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Membrane Conductance ◽  
Diffusion Capacity ◽  
Healthy Humans ◽  
Capillary Membrane ◽  
Alveolar Capillary

Alveolar–capillary membrane dysfunction in chronic heart failure: pathophysiology and therapeutic implications

2000 ◽  
Vol 98 (6) ◽  
pp. 633-641 ◽  
Author(s):  
Marco GUAZZI
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Membrane Conductance ◽  
Peak Exercise ◽  
Gas Transfer ◽  
Lung Diffusion ◽  
Diffusion Capacity ◽  
Therapeutic Implications ◽  
Capillary Membrane ◽  
Alveolar Capillary

Chronic heart failure (CHF) disturbs the alveolar–capillary interface and increases the resistance to gas transfer. Alveolar–capillary membrane conductance (DM) and capillary blood volume (Vc) are subcomponents of the lung diffusion capacity. Elevation of the capillary pressure causes alveolar–capillary membrane stress failure (i.e. increase in capillary permeability to water and ions, and disruption of local regulatory mechanisms for gas exchange), leading to a decrease in DM, an increase in Vc and subsequent impairment of diffusion capacity. Renewed recent interest in abnormalities in lung diffusion in patients with CHF has brought about new pathophysiological insights. A significant contribution of the altered gas transfer to the pathogenesis of exercise limitation and ventilatory abnormalities has been reported, and DM has been identified as the best lung function predictor of oxygen uptake at peak exercise. This review examines the pathophysiological and clinical significance of assessing lung diffusion capacity in patients with CHF.

scholarly journals Albuterol Improves Alveolar-Capillary Membrane Conductance in Healthy Humans

2016 ◽  
Vol 10 ◽  
pp. CCRPM.S30251 ◽  
Author(s):  
Natalie E. Taylor ◽  
Sarah E. Baker ◽  
Thomas P. Olson ◽  
Sophie Lalande ◽  
Bruce D. Johnson ◽  
...  
Keyword(s):  
Normal Saline ◽  
Membrane Conductance ◽  
Forced Expiratory Volume ◽  
The Body ◽  
Alveolar Cells ◽  
Lung Fluid ◽  
Healthy Humans ◽  
Capillary Membrane ◽  
Capillary Blood Volume ◽  
Alveolar Capillary

Background Beta-2 adrenergic receptors (β2ARs) are located throughout the body including airway and alveolar cells. The β2ARs regulate lung fluid clearance through a variety of mechanisms including ion transport on alveolar cells and relaxation of the pulmonary lymphatics. We examined the effect of an inhaled β2-agonist (albuterol) on alveolar-capillary membrane conductance (DM) and pulmonary capillary blood volume ( VC) in healthy humans. Methods We assessed the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO) at baseline, 30 minutes, and 60 minutes following nebulized albuterol (2.5 mg, diluted in 3 mL normal saline) in 45 healthy subjects. Seventeen subjects repeated these measures following nebulized normal saline (age = 27 ± 9 years, height = 165 ± 21 cm, weight = 68 ± 12 kg, BMI = 26 ± 9 kg/m2). Cardiac output (Q), heart rate, systemic vascular resistance (SVR), blood pressure, oxygen saturation, forced expiratory volume at one-second (FEV1), and forced expiratory flow at 50% of forced vital capacity (FEF50) were assessed at baseline, 30 minutes, and 60 minutes following the administration of albuterol or saline. Results Albuterol resulted in a decrease in SVR, and an increase in Q, FEV1, and FEF50 compared to saline controls. Albuterol also resulted in a decrease in VC at 60 minutes post albuterol. Both albuterol and normal saline resulted in no change in DLCO or DM when assessed alone, but a significant increase was observed in DM when accounting for changes in VC. Conclusion These data suggest that nebulized albuterol improves pulmonary function in healthy humans, while nebulization of both albuterol and saline results in an increase in DM/ VC.

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

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.

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