Continuous measurements of changes in pulmonary capillary surface area with 201Tl infusions

1994 ◽  
Vol 77 (5) ◽  
pp. 2093-2103 ◽  
Author(s):  
R. M. Effros ◽  
A. Hacker ◽  
E. Jacobs ◽  
S. Audi ◽  
C. Murphy
Keyword(s):  
Surface Area ◽  
Left Atrial ◽  
High Flow ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Low Flow ◽  
Capillary Surface ◽  
Pulmonary Capillary ◽  
Permeability Surface ◽  
Area Product

The impact of physiological and pathological processes on metabolism and transport of a variety of substances traversing the pulmonary vasculature depends in part on the capillary surface area available for exchange, and a reliable method for detecting changes in this parameter is needed. In this study, a continuous-infusion approach was used to investigate the response of the pulmonary capillary surface area to increases in flow and left atrial pressure. Isolated rat lungs were perfused with an acellular perfusion solution containing 125I-labeled albumin (an intravascular indicator) and 201Tl, a K+ analogue which is concentrated within lung cells. The extraction of 201Tl from the perfusate was 61% greater at low flow (8.5 ml/min) than at high flow (26 ml/min), and rapid changes in extraction were observed when flow was altered. In contrast, the permeability-surface area product was 76% greater when lungs were perfused at high flow than at low flow, suggesting comparable increases in pulmonary capillary surface area in these zone 2 lungs (airway pressure = 5 cmH2O, left atrial pressure < 0 cmH2O). In a second group of experiments, increases in left atrial pressure to 14 cmH2O (zone 3 lungs) at a constant flow of 8.5 ml/min increased the permeability-surface area product by only 18% despite increases in average intravascular pressure that were at least as high as those associated with high perfusion rates. 201Tl infusions provide a useful method for detecting and quantifying changes in pulmonary capillary surface area.

Effect of lymphatic cannula outflow height on lung microvascular permeability estimations

1984 ◽  
Vol 57 (5) ◽  
pp. 1412-1416 ◽  
Author(s):  
G. A. Laine ◽  
R. E. Drake ◽  
F. G. Zavisca ◽  
J. C. Gabel
Keyword(s):  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Lymph Vessel ◽  
Percent Change ◽  
Permeability Surface ◽  
Percent Increase ◽  
Anesthetized Dogs ◽  
Area Product ◽  
Lung Lymph

Estimates of the pulmonary microvascular membrane reflection coefficient (sigma) and permeability-surface area product (PS) are frequently made with the assumption that a percent change in transmicrovascular fluid flux (Jv) will be represented by an equal percent change in the lymph flow rate (QL) from a single cannulated lung lymph vessel. To test this, we measured QL in seven anesthetized dogs with the outflow end of the lymph cannula set at several heights (H) above and below the lung hilus. The left atrial pressure was then elevated to increase Jv, and QL was again measured at several H's. The percent increase in QL at elevated left atrial pressure depended on H. We used the QL data and lymph and plasma protein concentrations to estimate sigma and PS with a modified form of the Kedem and Katchalsky equations. The calculated values varied considerably with H. Our results indicate that changes in Jv are not represented by equal changes in QL. Therefore, techniques for estimating permeability that depend upon QL as an estimate of Jv may lead to erroneous estimates of sigma and PS.

Pulmonary vascular resistance distribution and recruitment of microvascular surface area

1994 ◽  
Vol 77 (2) ◽  
pp. 845-855 ◽  
Author(s):  
K. A. Overholser ◽  
N. A. Lomangino ◽  
R. E. Parker ◽  
N. A. Pou ◽  
T. R. Harris
Keyword(s):  
Surface Area ◽  
Capillary Surface ◽  
Perfusion Rate ◽  
Capillary Recruitment ◽  
Diffusion Limited ◽  
Pulmonary Capillary ◽  
Permeability Surface ◽  
Longitudinal Resistance ◽  
Zone Ii ◽  
Area Product

To test the hypothesis that the distribution of hemodynamic resistance is involved in the control of pulmonary capillary surface area, we measured permeability-surface area product (PS) and longitudinal resistance distribution (LRD) as functions of perfusion rate in isolated rabbit lungs under zone II conditions (n = 10) and through the zone II-III transition (n = 4). PS, considered to be indicative of functioning capillary surface area, was measured with the aid of the diffusion-limited tracer [14C]propanediol, whereas LRD was determined using a viscous bolus technique. LRD was seen to change character with increasing flow and increasing PS/surface area, becoming bimodal with low central resistance as full capillary recruitment was approached in zone III. Effects of hypoxic ventilation were studied in zone II in five lungs; it was found that hypoxia altered the LRD and eradicated the normoxic dependence of PS/surface area on perfusion rate. It was concluded that LRD is involved in the determination of functioning capillary surface area.

The pulmonary capillary wedge pressure accurately reflects both normal and elevated left atrial pressure

2014 ◽  
Vol 167 (6) ◽  
pp. 876-883 ◽  
Author(s):  
Anikó I. Nagy ◽  
Ashwin Venkateshvaran ◽  
Pravat Kumar Dash ◽  
Banajit Barooah ◽  
Béla Merkely ◽  
...  
Keyword(s):  
Pulmonary Capillary Wedge Pressure ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Pulmonary Capillary ◽  
Wedge Pressure

scholarly journals Hemodynamics of the diastolic pressure gradients in acute heart failure: implications for the diagnosis of pre-capillary pulmonary hypertension in left heart disease

2018 ◽  
Vol 9 (1) ◽  
pp. 204589401881543 ◽  
Author(s):  
Doron Aronson ◽  
Emilia Hardak ◽  
Andrew J. Burger
Keyword(s):  
Heart Failure ◽  
Heart Disease ◽  
Acute Heart Failure ◽  
Left Atrial ◽  
Diastolic Pressure ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Left Heart ◽  
Left Heart Disease ◽  
Pulmonary Capillary

The diastolic pressure gradient (DPG) has been proposed as the metric of choice for the diagnosis of pulmonary vascular changes in left heart disease. We tested the hypothesis that this metric is less sensitive to changes in left atrial pressure and stroke volume (SV) than the transpulmonary gradient (TPG). We studied the effect of dynamic changes in pulmonary capillary wedge pressure (PCWP), SV, and pulmonary artery capacitance (PAC) on DPG and TPG in 242 patients with acute heart failure undergoing decongestive therapy with continuous hemodynamic monitoring. There was a close impact of PCWP reduction on TPG and DPG, with a 0.13 mmHg (95% confidence interval [CI] 0.07–0.19, P < 0.0001) and 0.21 mmHg (95% CI 0.16–0.25, P < 0.0001) increase for every 1 mmHg decrease in PCWP, respectively. Changes in SV had a negligible effect on TPG and DPG (0.19 and 0.13 mmHg increase, respectively, for every 10-mL increase in SV). Heart rate was positively associated with DPG (0.41-mmHg increase per 10 BPM [95% CI 0.22–0.60, P < 0.0001]). The resistance-compliance product was positively associated with both TPG and DPG (2.65 mmHg [95% CI 2.47–2.83] and 1.94 mmHg [95% CI 1.80–2.08] for each 0.1-s increase, respectively). In conclusion, DPG is not less sensitive to changes in left atrial pressure and SV compared with TPG. Although DPG was not affected by changes in PAC, the concomitant increase in the resistance-compliance product increases DPG.

scholarly journals Correlation of pulmonary capillary wedge pressure with left atrial pressure in patients with mitral stenosis undergoing balloon valvotomy

2016 ◽  
Vol 68 (2) ◽  
pp. 143-146 ◽  
Author(s):  
Desabandhu Vinayakumar ◽  
Uppalakal Bijilesh ◽  
C.G. Sajeev ◽  
Gopalan Nair Rajesh ◽  
Cicy Bastion ◽  
...  
Keyword(s):  
Pulmonary Capillary Wedge Pressure ◽  
Mitral Stenosis ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Pulmonary Capillary ◽  
Balloon Valvotomy ◽  
Wedge Pressure

Are transient changes in capillary surface area required to explain peritoneal transport in renal failure patients?

2020 ◽  
Vol 40 (6) ◽  
pp. 587-592 ◽  
Author(s):  
Matthew B Wolf
Keyword(s):  
Renal Failure ◽  
Surface Area ◽  
Glucose Concentration ◽  
Effective Radius ◽  
Capillary Surface ◽  
Dialysis Fluid ◽  
Permeability Surface ◽  
Model Predictions ◽  
Patient Groups ◽  
Area Product

Background: Waniewski postulated a transient increase in peritoneal capillary surface area to fit their model predictions to experimental data of Heimburger measured in renal failure (RF) patients undergoing peritoneal dialysis (PD) but with only a 3.86% glucose dialysis fluid. The present aim is to propose a new mathematical model of the patient PD procedure that could closely fit the complete Heimburger measurement set without this postulate. Methods: The three-pore model of Rippe was used to describe transient changes in peritoneal volume and solute concentrations during a PD dwell. The predialysis, RF patient, plasma solute concentrations were assumed to remain constant during the dwell. The model was validated using the 3.86% glucose Heimburger measurements. Permeability surface area product parameters were chosen to match only the end-dwell peritoneal fluid glucose concentration and the end-dwell amounts of urea, creatinine, and Na+ removed from this simulated patient group. Then, this model was used to predict additional measurements by Heimburger on two other patient groups dialyzed with glucose concentrations of 2.27% and 1.36%, respectively. Parameters were unchanged when simulating these other patient groups. Results: To match the shape of the transient changes in drained volume and dialysis fluid glucose concentration for the 3.86% glucose group, it was necessary for only one parameter, the effective radius of glucose, to vary linearly in proportion to the dialysis fluid glucose concentration. This description was unchanged in the other two groups. Conclusion: Postulated transient increases in peritoneal capillary surface area were unnecessary to predict the entire Heimburger measurements.

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