The effect of total peripheral resistance on indicator-dilution curves from the central circulation of the dog

The mechanism of the diastolic pressure elevation occurring during left stellate ganglion stimulation was investigated. The cardiac output rose considerably, the heart rate remained essentially unchanged, and the total peripheral resistance fell moderately. The diastolic rise appeared to be due to increased blood flow rather than to any active changes in resistance vessels.

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Simulating a Ground Truth for Transit Time Analysis of Indicator Dilution Curves

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2020-3068 ◽

2020 ◽

Vol 6 (3) ◽

pp. 268-271

Author(s):

Michael Reiß ◽

Ady Naber ◽

Werner Nahm

Keyword(s):

Transit Time ◽

Sampling Rate ◽

Ground Truth ◽

Indicator Dilution ◽

Cross Sectional ◽

In Vivo Measurements ◽

Multiple Indicator Dilution ◽

Transit Times ◽

Dilution Curves

AbstractTransit times of a bolus through an organ can provide valuable information for researchers, technicians and clinicians. Therefore, an indicator is injected and the temporal propagation is monitored at two distinct locations. The transit time extracted from two indicator dilution curves can be used to calculate for example blood flow and thus provide the surgeon with important diagnostic information. However, the performance of methods to determine the transit time Δt cannot be assessed quantitatively due to the lack of a sufficient and trustworthy ground truth derived from in vivo measurements. Therefore, we propose a method to obtain an in silico generated dataset of differently subsampled indicator dilution curves with a ground truth of the transit time. This method allows variations on shape, sampling rate and noise while being accurate and easily configurable. COMSOL Multiphysics is used to simulate a laminar flow through a pipe containing blood analogue. The indicator is modelled as a rectangular function of concentration in a segment of the pipe. Afterwards, a flow is applied and the rectangular function will be diluted. Shape varying dilution curves are obtained by discrete-time measurement of the average dye concentration over different cross-sectional areas of the pipe. One dataset is obtained by duplicating one curve followed by subsampling, delaying and applying noise. Multiple indicator dilution curves were simulated, which are qualitatively matching in vivo measurements. The curves temporal resolution, delay and noise level can be chosen according to the requirements of the field of research. Various datasets, each containing two corresponding dilution curves with an existing ground truth transit time, are now available. With additional knowledge or assumptions regarding the detection-specific transfer function, realistic signal characteristics can be simulated. The accuracy of methods for the assessment of Δt can now be quantitatively compared and their sensitivity to noise evaluated.

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Physiological parameters of indicator dilution curves

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1977.233.3.h350 ◽

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.

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Relative Effects of Heart Chambers, Lungs, and Mitral Insufficiency on the Shape of Indicator Dilution Curves

Circulation Research ◽

10.1161/01.res.7.1.141 ◽

1959 ◽

Vol 7 (1) ◽

pp. 141-146 ◽

Cited By ~ 6

Author(s):

RICHARD W. EMANUEL ◽

WILLIAM W. LACY ◽

ELLIOT V. NEWMAN

Keyword(s):

Indicator Dilution ◽

Mitral Insufficiency ◽

Dilution Curves

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Detection and quantification of small left-to-right shunts by the phase-plane method

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.244.4.h622 ◽

1983 ◽

Vol 244 (4) ◽

pp. H622-H627

Author(s):

A. Fonseca-Costa ◽

P. Magrassi ◽

W. A. Zin ◽

L. J. Romeo

Keyword(s):

Sampling Method ◽

Phase Plane ◽

Sampling Site ◽

Indicator Dilution ◽

Terminal Portion ◽

Systemic Artery ◽

Anesthetized Dogs ◽

Phase Plane Method ◽

High Level ◽

Dilution Curves

Sixty-five pairs of indicator-dilution curves were obtained in five anesthetized dogs. After the injection of indocyanine dye into the left atrium, blood was simultaneously sampled through dichromatic cuvette densitometers from the femoral artery and the distal pulmonary artery. Dye-dilution curves were recorded from dogs with normal cardiovascular systems and after the surgical production of left-to-right shunts of different magnitudes. The percent of blood shunting was calculated according to the double sampling method and compared with a new method based on the deviation observed in the terminal portion of the indicator-dilution phase-plane loop. A high level of correlation was observed between both methods (r = 0.961). The phase plane shows its utility in the quantification of small left-to-right shunts. The use of only one sampling site at a peripheral systemic artery is an important advantage because there is complete mixture between shunted and unshunted blood.

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Elevated Blood Pressure in Adolescence Is Attributable to a Combination of Elevated Cardiac Output and Total Peripheral Resistance

Hypertension ◽

10.1161/hypertensionaha.118.11925 ◽

2018 ◽

Vol 72 (5) ◽

pp. 1103-1108 ◽

Cited By ~ 6

Author(s):

Chloe Park ◽

Abigail Fraser ◽

Laura D. Howe ◽

Siana Jones ◽

George Davey Smith ◽

...

Keyword(s):

Blood Pressure ◽

Cardiac Output ◽

Total Peripheral Resistance ◽

Peripheral Resistance ◽

Elevated Blood Pressure ◽

Elevated Blood

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RSR-13, an allosteric effector of hemoglobin, increases systemic and iliac vascular resistance in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1996.271.2.h602 ◽

1996 ◽

Vol 271 (2) ◽

pp. H602-H613 ◽

Cited By ~ 5

Author(s):

M. P. Kunert ◽

J. F. Liard ◽

D. J. Abraham

Keyword(s):

Cardiac Output ◽

Vascular Resistance ◽

Total Peripheral Resistance ◽

Peripheral Resistance ◽

Experimental Models ◽

Metabolic Demand ◽

Flow Probe ◽

Inositol Hexaphosphate ◽

Control Value ◽

Allosteric Effector

Tissue O2 delivery in excess of metabolic demand may be a factor in the development of high vascular resistance in experimental models of volume-expanded hypertension. This hypothesis was previously tested in rats with an exchange transfusion of red blood cells treated with inositol hexaphosphate or an intravenous infusion of RSR-4, allosteric effectors of hemoglobin. The binding of these drugs with hemoglobin effect a conformational change in the molecule, such that the affinity for O2 is reduced. However, in both preparations, the changes in vascular resistance could have been nonspecific. The present studies used intravenous infusions of RSR-13, which did not share some of the problematic characteristics of RSR-4 and inositol hexaphosphate. Conscious instrumented rats (an electromagnetic flow probe on ascending aorta or an iliac, mesenteric, or renal Doppler flow probe) were studied for 6 h after an RSR-13 infusion of 200 mg/kg in 15 min. This dose significantly increased arterial P50 (PO2 at which hemoglobin is 50% saturated) from 38 +/- 0.8 to 58 +/- 1.4 mmHg at 1 h after the start of the infusion. In the 3rd h cardiac output fell significantly from a control value of 358 +/- 33 to 243 +/- 24 ml.kg-1.min-1 and total peripheral resistance significantly increased from 0.31 +/- 0.03 to 0.43 +/- 0.04 mmHg.ml-1.kg.min. Cardiac output and P50 returned toward control over the next few hours. Neither cardiac output nor total peripheral resistance changed in the group of rats receiving vehicle alone. In a separate group of rats, iliac flow decreased significantly to 60% of control and iliac resistance increased to 160% of control. Iliac flow increased significantly in the group of rats that received vehicle only. Although the mechanism of these changes has not been established, these results suggest that a decreased O2 affinity leads to an increased total peripheral resistance and regional vascular resistance and support the hypothesis that O2 plays a role in the metabolic autoregulation of blood flow.

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Long-term hemodynamic actions of atrial natriuretic factor (99-126) in conscious sheep

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.254.4.h811 ◽

1988 ◽

Vol 254 (4) ◽

pp. H811-H815 ◽

Cited By ~ 4

Author(s):

D. G. Parkes ◽

J. P. Coghlan ◽

J. G. McDougall ◽

B. A. Scoggins

Keyword(s):

Blood Pressure ◽

Cardiac Output ◽

Stroke Volume ◽

Blood Volume ◽

Total Peripheral Resistance ◽

Atrial Natriuretic Factor ◽

Peripheral Resistance ◽

Natriuretic Factor ◽

Atrial Natriuretic

The hemodynamic and metabolic effects of long-term (5 day) infusion of human atrial natriuretic factor (ANF) were examined in conscious chronically instrumented sheep. Infusion of ANF at 20 micrograms/h, a rate below the threshold for an acute natriuretic effect, decreased blood pressure by 9 +/- 1 mmHg on day 5, associated with a fall in calculated total peripheral resistance. On day 1, ANF reduced cardiac output, stroke volume, and blood volume, effects that were associated with an increase in heart rate and calculated total peripheral resistance and a small decrease in blood pressure. On days 4 and 5 there was a small increase in urine volume and sodium excretion. On day 5 an increase in water intake and body weight was observed. No change was seen in plasma concentrations of renin, arginine vasopressin, glucose, adrenocorticotropic hormone, or protein. This study suggests that the short-term hypotensive effect of ANF results from a reduction in cardiac output associated with a fall in both stroke volume and effective blood volume. However, after 5 days of infusion, ANF lowers blood pressure via a reduction in total peripheral resistance.

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