Simultaneous Two-Compartmental Analysis of Ventilation-Perfusion Unevenness and Diffusing Capacity in the Lungs

2015 ◽  
pp. 222-224
Author(s):  
T. Kawashiro ◽  
K. Yamaguchi ◽  
T. Yokoyama
Keyword(s):  
Compartmental Analysis ◽  
Diffusing Capacity

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Lung Diffusing Capacity

2005 ◽  
pp. 157-165
Author(s):  
J.C. de Jongste ◽  
P.J.F.M. Merkus ◽  
H. Stam
Keyword(s):  
Diffusing Capacity

Diffusing Capacity in Healthy Elderly Chinese

Gerontology ◽  
1989 ◽  
Vol 35 (5-6) ◽  
pp. 315-322 ◽  
Author(s):  
J. Woo ◽  
J. Pang
Keyword(s):  
Diffusing Capacity ◽  
Healthy Elderly ◽  
Elderly Chinese

scholarly journals Analysis of 13NH4+ Efflux in Spruce Roots (A Test Case for Phase Identification in Compartmental Analysis)

1995 ◽  
Vol 109 (2) ◽  
pp. 481-490 ◽  
Author(s):  
H. J. Kronzucker ◽  
M. Y. Siddiqi ◽  
ADM. Glass
Keyword(s):  
Compartmental Analysis ◽  
Test Case ◽  
Phase Identification

Ventilation Heterogeneity in Asthma and COPD: The Value of the Poorly Communicating Fraction as the Ratio of Total Lung Capacity to Alveolar Volume

Respiration ◽  
2021 ◽  
pp. 1-7
Author(s):  
Roberta Pisi ◽  
Marina Aiello ◽  
Luigino Calzetta ◽  
Annalisa Frizzelli ◽  
Veronica Alfieri ◽  
...  
Keyword(s):  
Total Lung Capacity ◽  
Airflow Obstruction ◽  
Diffusing Capacity ◽  
Body Plethysmography ◽  
Alveolar Volume ◽  
Asthmatic Patients ◽  
Lung Capacity ◽  
Copd Patients ◽  
Ventilation Heterogeneity ◽  
Patient Groups

<b><i>Background:</i></b> The ventilation heterogeneity (VH) is reliably assessed by the multiple-breath nitrogen washout (MBNW), which provides indices of conductive (<i>S</i><sub>cond</sub>) and acinar (<i>S</i><sub>acin</sub>) VH as well as the lung clearance index (LCI), an index of global VH. VH can be alternatively measured by the poorly communicating fraction (PCF), that is, the ratio of total lung capacity by body plethysmography to alveolar volume from the single-breath lung diffusing capacity measurement. <b><i>Objectives:</i></b> Our objective was to assess VH by PCF and MBNW in patients with asthma and with COPD and to compare PCF and MBNW parameters in both patient groups. <b><i>Method:</i></b> We studied 35 asthmatic patients and 45 patients with COPD. Each patient performed spirometry, body plethysmography, diffusing capacity, and MBNW test. <b><i>Results:</i></b> Compared to COPD patients, asthmatics showed a significantly lesser degree of airflow obstruction and lung hyperinflation. In asthmatic patients, both PCF and LCI and <i>S</i><sub>acin</sub> values were significantly lower than the corresponding ones of COPD patients. In addition, in both patient groups, PCF showed a positive correlation with LCI (<i>p</i> &#x3c; 0.05) and <i>S</i><sub>acin</sub> (<i>p</i> &#x3c; 0.05), but not with <i>S</i><sub>cond</sub>. Lastly, COPD patients with PCF &#x3e;30% were highly likely to have a value ≥2 of the mMRC dyspnea scale. <b><i>Conclusions:</i></b> These results showed that PCF, a readily measure derived from routine pulmonary function testing, can provide a comprehensive measure of both global and acinar VH in asthma and in COPD patients and can be considered as a comparable tool to the well-established MBNW technique.

scholarly journals Updated Estimates of Vitamin a Total Body Stores in Healthy Young Adults Determined by Compartmental Modeling with Vitamin a Intake Added as Data (FS06-07-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Jennifer Ford ◽  
Georg Lietz ◽  
Anthony Oxley ◽  
Joanne Green ◽  
Michael Green
Keyword(s):  
Young Adults ◽  
Vitamin A ◽  
Model Prediction ◽  
Simulation Analysis ◽  
Geometric Mean ◽  
Compartmental Analysis ◽  
Science Research ◽  
European Ancestry ◽  
Retinyl Acetate ◽  
Total Body

Abstract Objectives We applied a new modeling approach to generate estimates of vitamin A total body stores (TBS) for previously-studied subjects (Green et al. J Nutr 2016;146:2129–36) who were consuming moderate amounts of preformed vitamin A. Based on recent work, we hypothesized that inclusion of an estimate of vitamin A dietary intake (DI) during modeling would help compensate for the less-than-optimal study duration (14 d). Methods We reanalyzed retinol kinetic data collected after ingestion of [13C10]retinyl acetate by 26 young adults of European ancestry for whom estimates of DI were available. To predict TBS by compartmental analysis, geometric mean (GM) data on fraction of dose in plasma versus time plus estimated intake (2.9 µmol retinol activity equivalents/d) were analyzed using the Simulation, Analysis and Modeling software in light of previously-established models. We also used modeling to estimate coefficients (“FaS”) used in retinol isotope dilution (RID) equations and calculated TBS for the group and individuals. Results TBS predicted by the model without DI data included was 98 µmol; when the GM DI was included in the modeling data stream, predicted TBS was 273 µmol. Including DI data during modeling also resulted in lower predictions of intake [2.9 versus 8.7 µmol/d without DI, compared with the average RDA for adults (2.8 µmol/d)] and longer predicted days of vitamin A stores (125 versus 15 d). Using the FaS at 7 d (0.90) predicted by the model with DI, RID-predicted TBS agreed with the model prediction (GM, 274 µmol, range 106–889 µmol). Conclusions Results indicate that including an estimate of DI during modeling provides more realistic predictions of TBS for studies of short duration and improves confidence in model prediction of vitamin A status. Funding Sources Original human studies were supported by Biotechnology and Biological Science Research Council (grant BB/G004056/1 to GL) and Cancer Research UK; current analyses were supported by College of Health and Human Development, Penn State University.

Acute Changes in Lung Diffusing Capacity After Training in Elite Swimmers

2021 ◽  
Vol 57 (4) ◽  
pp. 306-307
Author(s):  
Iker García ◽  
Franchek Drobnic ◽  
Victoria Pons ◽  
Ginés Viscor
Keyword(s):  
Diffusing Capacity ◽  
Elite Swimmers ◽  
Acute Changes

scholarly journals Which Analysis Approach Is Adequate to Leverage Clinical Microdialysis Data? A Quantitative Comparison to Investigate Exposure and Reponse Exemplified by Levofloxacin

2021 ◽  
Author(s):  
David Busse ◽  
André Schaeftlein ◽  
Alexander Solms ◽  
Luis Ilia ◽  
Robin Michelet ◽  
...  
Keyword(s):  
Drug Exposure ◽  
Visual Predictive Check ◽  
Model Performance ◽  
Compartmental Analysis ◽  
Community Acquired Pneumonia ◽  
Target Site ◽  
Clinical Pharmacokinetics ◽  
Time Integral ◽  
Dosing Regimens ◽  
Therapeutic Decision Making

Abstract Purpose Systematic comparison of analysis methods of clinical microdialysis data for impact on target-site drug exposure and response. Methods 39 individuals received a 500 mg levofloxacin short-term infusion followed by 24-h dense sampling in plasma and microdialysate collection in interstitial space fluid (ISF). ISF concentrations were leveraged using non-compartmental (NCA) and compartmental analysis (CA) via (ii) relative recovery correction at midpoint of the collection interval (midpoint-NCA, midpoint-CA) and (ii) dialysate-based integrals of time (integral-CA). Exposure and adequacy of community-acquired pneumonia (CAP) therapy via pharmacokinetic/pharmacodynamic target-attainment (PTA) analysis were compared between approaches. Results Individual AUCISF estimates strongly varied for midpoint-NCA and midpoint-CA (≥52.3%CV) versus integral-CA (≤32.9%CV) owing to separation of variability in PK parameters (midpoint-CA = 46.5%–143%CVPK, integral-CA = 26.4%–72.6%CVPK) from recovery-related variability only in integral-CA (41.0%–50.3%CVrecovery). This also led to increased variability of AUCplasma for midpoint-CA (56.0%CV) versus midpoint-NCA and integral-CA (≤33.0%CV), and inaccuracy of predictive model performance of midpoint-CA in plasma (visual predictive check). PTA analysis translated into 33% of evaluated patient cases being at risk of incorrectly rejecting recommended dosing regimens at CAP-related epidemiological cut-off values. Conclusions Integral-CA proved most appropriate to characterise clinical pharmacokinetics- and microdialysis-related variability. Employing this knowledge will improve the understanding of drug target-site PK for therapeutic decision-making.

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