Cardiac output by rebreathing in patients with cardiopulmonary diseases

1987 ◽  
Vol 63 (1) ◽  
pp. 201-210 ◽  
Author(s):  
M. C. Kallay ◽  
R. W. Hyde ◽  
R. J. Smith ◽  
R. L. Rothbard ◽  
B. F. Schreiner
Keyword(s):  
Cardiac Output ◽  
Pulmonary Blood Flow ◽  
Obstructive Lung Disease ◽  
Volume Ratio ◽  
Indicator Dilution ◽  
Pulmonary Diseases ◽  
Normal Lung ◽  
Uneven Ventilation ◽  
Gas Volume ◽  
Source Of Error

Noninvasive estimates of cardiac output by rebreathing soluble gases (Qc) can be unreliable in patients with cardiopulmonary diseases because of uneven distribution of ventilation to lung gas volume and pulmonary blood flow. To evaluate this source of error, we compared rebreathing Qc with invasive measurements of cardiac output performed by indicator-dilution methods (COID) in 39 patients with cardiac or pulmonary diseases. In 16 patients with normal lung volumes and 1-s forced expiratory volumes (FEV1), Qc measured with acetylene [Qc(C2H2)] overestimated COID insignificantly by 2 +/- 9% (SD). In subjects with mild to moderate obstructive lung disease, Qc(C2H2) slightly overestimated COID by 6 +/- 15% (P = 0.11). In patients with restrictive disease or combined obstructive and restrictive disease, Qc(C2H2) underestimated COID significantly by 9 +/- 14% (P less than 0.04). The magnitude of the discrepancy between Qc and COID correlated with size of the volume rebreathed and an index of uneven ventilation calculated from helium mixing during rebreathing that determined a dead space to inspired volume ratio (VRD/VI). Rebreathing volumes less than 40% of the predicted FEV or VRD/VI of 0.4 or greater identified all subjects with a discrepancy between Qc(C2H2) and COID of 20% or greater.

Mechanisms of improvement in pulmonary gas exchange during isovolemic hemodilution

1999 ◽  
Vol 87 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Steven Deem ◽  
Richard G. Hedges ◽  
Steven McKinney ◽  
Nayak L. Polissar ◽  
Michael K. Alberts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fractal Dimension ◽  
Gas Exchange ◽  
Spatial Correlation ◽  
Pulmonary Blood Flow ◽  
Minute Ventilation ◽  
Flow Distribution ◽  
Pulmonary Gas Exchange ◽  
Normal Lung ◽  
Blood Flow Distribution

Severe anemia is associated with remarkable stability of pulmonary gas exchange (S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson. J. Appl. Physiol. 83: 240–246, 1997), although the factors that contribute to this stability have not been studied in detail. In the present study, 10 Flemish Giant rabbits were anesthetized, paralyzed, and mechanically ventilated at a fixed minute ventilation. Serial hemodilution was performed in five rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; five rabbits were followed over a comparable time. Ventilation-perfusion (V˙a/Q˙) relationships were studied by using the multiple inert-gas-elimination technique, and pulmonary blood flow distribution was assessed by using fluorescent microspheres. Expired nitric oxide (NO) was measured by chemiluminescence. Hemodilution resulted in a linear fall in hematocrit over time, from 30 ± 1.6 to 11 ± 1%. Anemia was associated with an increase in arterial [Formula: see text] in comparison with controls ( P < 0.01 between groups). The improvement in O2 exchange was associated with reducedV˙a/Q˙heterogeneity, a reduction in the fractal dimension of pulmonary blood flow ( P = 0.04), and a relative increase in the spatial correlation of pulmonary blood flow ( P = 0.04). Expired NO increased with anemia, whereas it remained stable in control animals ( P < 0.0001 between groups). Anemia results in improved gas exchange in the normal lung as a result of an improvement in overallV˙a/Q˙matching. In turn, this may be a result of favorable changes in pulmonary blood flow distribution, as assessed by the fractal dimension and spatial correlation of blood flow and as a result of increased NO availability.

Physiological parameters of indicator dilution curves

1977 ◽  
Vol 233 (3) ◽  
pp. H350-H355
Author(s):  
L. D. Homer ◽  
A. Small
Keyword(s):  
Cardiac Output ◽  
Satisfactory Agreement ◽  
Single Injection ◽  
Time Lag ◽  
Volume Of Distribution ◽  
Physiological Parameters ◽  
Indicator Dilution ◽  
Diethylenetriaminepentaacetic Acid ◽  
Alternative Techniques ◽  
Dilution Curves

A model incorporating the effects of recirculation time lag, cardiac output, clearance, volume of distribution, and the variance of the distribution of recirculation times is applied to the analysis of indicator dilution curves. Experiments on dogs with use of radioactively labeled diethylenetriaminepentaacetic acid were done to evaluate the model. This five-parameter model can be fitted to data obtained during the period from less than 1 min to 3 h after a single injection of indicator. Estimates of cardiac output and clearance are in satisfactory agreement with estimates obtained by alternative techniques. Estimates of the time lag and volume of distribution are of physiologically plausible magnitude. The variance of the distribution of recirculation times is a new parameter, of which the possible usefulness to physiologists is discussed.

The need to complement in vitro gas production measurements with residue determinations from in sacco degradabilities to improve the prediction of voluntary intake of hays

1997 ◽  
Vol 64 (1) ◽  
pp. 71-75 ◽  
Author(s):  
M. Blümmel ◽  
P. Bullerdieck
Keyword(s):  
Volume Ratio ◽  
Gas Production ◽  
Published Data ◽  
Fatty Acid Production ◽  
Residue Determination ◽  
In Vitro Gas Production ◽  
Gas Volume ◽  
In Sacco Degradability ◽  
In Sacco

AbstractThe need to complement in vitro gas production measurements with residue determination is demonstrated by the recalculation and reassessment of published data on in vitro gas production, in sacco degradabilities and voluntary dry matter intake (DMI). The in sacco degradability — gas volume ratio was determined at 24 and 48 h of incubation, termed partitioning factor (PF) and combined with rate and extent parameters of in sacco degradability and in vitro gas production to predict DMI. In vitro gas production and in sacco degradability characteristics (a + b) and c as described by the equation y = a + b(1−ect) explained 0·373 and 0·668 respectively of the variation in DMI of 19 legume and grass hays. The complementation of gas production parameters by the PF24 increased the R2 value to 0·744 with PF24 accounting for 0·407 of the variation in DMI, the rate of gas production (c) for 0·218 and the extent of gas production (a + b) for 0·119 of the variation in DMI. As a single parameter, PF48 showed the highest correlation (R2 = 0·597) with DMI but the combination of PF4S with rate and extent of in sacco or in vitro gas production measurements did not improve the correlation further, probably due to an intercorrelation between rates of fermentation and PF4S. Hays which were degraded at faster rates had higher PF values indicating proportionally higher microbial yield and lower short-chain fatty acid production per unit substrate degraded. Generally, hays with high in sacco degradabilities but proportionally low gas production i.e. hays with high PF values showed higher DMI.

scholarly journals Mechanisms and consequences of oxidative stress in lung disease: therapeutic implications for an aging populace

2018 ◽  
Vol 314 (4) ◽  
pp. L642-L653 ◽  
Author(s):  
Louise Hecker
Keyword(s):  
Oxidative Stress ◽  
Lung Disease ◽  
Lung Diseases ◽  
The Elderly ◽  
Therapeutic Strategies ◽  
Rapid Expansion ◽  
Pulmonary Diseases ◽  
Normal Lung ◽  
Incidence And Mortality ◽  
And Oxidative Stress

The rapid expansion of the elderly population has led to the recent epidemic of age-related diseases, including increased incidence and mortality of chronic and acute lung diseases. Numerous studies have implicated aging and oxidative stress in the pathogenesis of various pulmonary diseases; however, despite recent advances in these fields, the specific contributions of aging and oxidative stress remain elusive. This review will discuss the consequences of aging on lung morphology and physiology, and how redox imbalance with aging contributes to lung disease susceptibility. Here, we focus on three lung diseases for which aging is a significant risk factor: acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). Preclinical and clinical development for redox- and senescence-altering therapeutic strategies are discussed, as well as scientific advancements that may direct current and future therapeutic development. A deeper understanding of how aging impacts normal lung function, redox balance, and injury-repair processes will inspire the development of new therapies to prevent and/or reverse age-associated pulmonary diseases, and ultimately increase health span and longevity. This review is intended to encourage basic, clinical, and translational research that will bridge knowledge gaps at the intersection of aging, oxidative stress, and lung disease to fuel the development of more effective therapeutic strategies for lung diseases that disproportionately afflict the elderly.

scholarly journals Batch Syngas Fermentation by Clostridium carboxidivorans for Production of Acids and Alcohols

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1075
Author(s):  
Fabiana Lanzillo ◽  
Giacomo Ruggiero ◽  
Francesca Raganati ◽  
Maria Elena Russo ◽  
Antonio Marzocchella
Keyword(s):  
Critical Role ◽  
Volume Ratio ◽  
Liquid Volume ◽  
Syngas Fermentation ◽  
Co Concentration ◽  
Depletion Rate ◽  
Growth Differences ◽  
Gas Volume ◽  
Clostridium Carboxidivorans ◽  
Kinetics Of

Syngas (CO, CO2, and H2) has attracted special attention due to the double benefit of syngas fermentation for carbon sequestration (pollution reduction), while generating energy. Syngas can be either produced by gasification of biomasses or as a by-product of industrial processes. Only few microorganisms, mainly clostridia, were identified as capable of using syngas as a substrate to produce medium chain acids, or alcohols (such as butyric acid, butanol, hexanoic acid, and hexanol). Since CO plays a critical role in the availability of reducing equivalents and carbon conversion, this work assessed the effects of constant CO partial pressure (PCO), ranging from 0.5 to 2.5 atm, on cell growth, acid production, and solvent production, using Clostridium carboxidivorans. Moreover, this work focused on the effect of the liquid to gas volume ratio (VL/VG) on fermentation performances; in particular, two VL/VG were considered (0.28 and 0.92). The main results included—(a) PCO affected the growth kinetics of the microorganism; indeed, C. carboxidivorans growth rate was characterized by CO inhibition within the investigated range of CO concentration, and the optimal PCO was 1.1 atm (corresponding to a dissolved CO concentration of about 25 mg/L) for both VL/VG used; (b) growth differences were observed when the gas-to-liquid volume ratio changed; mass transport phenomena did not control the CO uptake for VL/VG = 0.28; on the contrary, the experimental CO depletion rate was about equal to the transport rate in the case of VL/VG = 0.92.

Effects of ouabain on cardiac output and pulmonary blood flow in dogs

1972 ◽  
Vol 84 (3) ◽  
pp. 371-376 ◽  
Author(s):  
Elmer Treat ◽  
Harvey Ulano ◽  
Marc Pfeffer ◽  
Walter Massion ◽  
Linda L. Shanbour ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Blood Flow

Single-Breath Breath Holding Measurement of Pulmonary Blood Flow: Comparison to Direct Fick Cardiac Output

1986 ◽  
Vol 71 (s15) ◽  
pp. 36P-36P ◽  
Author(s):  
A.H. Kendrick ◽  
A. Rozkovec ◽  
M. Papouchado ◽  
J. West ◽  
J.E. Bees ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Blood Flow ◽  
Breath Holding ◽  
Single Breath

EVALUATION OF IMPEDANCE CARDIAC OUTPUT IN CHILDREN

PEDIATRICS ◽  
1971 ◽  
Vol 47 (5) ◽  
pp. 870-879
Author(s):  
Zuhdi Lababidi ◽  
D. A. Ehmke ◽  
Robert E. Durnin ◽  
Paul E. Leaverton ◽  
Ronald M. Lauer
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Standard Deviation ◽  
Pulmonary Blood Flow ◽  
Impedance Measurement ◽  
Aortic Insufficiency ◽  
Mean Difference ◽  
Dye Dilution ◽  
Impedance Cardiograph ◽  
Indicator Dye

In 20 children without shunts or valvular insufficiency, duplicate dye dilution and impedance cardiac outputs (ICO) were carried out. The duplicate dye dilutions had a standard deviation 0.259 L/min/m2, while duplicate ICO had a standard deviation 0.192 L/min/m2 (F = 1.82, p &lt; 0.05). Of 53 sequential estimates, cardiac outputs measured by both indicator dye dilution and ICO had a 5.5% mean difference. In 21 subjects with left to right shunts, the ICO related well with pulmonary blood flow (r = 0.92) rather than systemic flow (r = 0.21). In 13 subjects with aortic insufficiency, sequential Fick and ICO had a 50% mean difference; the impedance measurement was found to be higher in every case. These data indicate that the impedance cardiograph can provide a noninvasive measure of cardiac output when there are no shunts or valvular insufficiencies. In subjects with left to right shunts the impedance cardiograph provides a measure of the pulmonary blood flow. When aortic insufficiency exists the impedance cardiograph is distorted such that it is consistently higher than Fick cardiac output.

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