scholarly journals CLINICAL STUDIES OF THE BLOOD VOLUME. II. THE RELATION OF PLASMA AND TOTAL BLOOD VOLUME TO VENOUS PRESSURE, BLOOD VELOCITY RATE, PHYSICAL MEASUREMENTS, AGE AND SEX IN NINETY NORMAL HUMANS

1937 ◽  
Vol 16 (3) ◽  
pp. 317-328 ◽  
Author(s):  
John G. Gibson ◽  
William A. Evans
Keyword(s):  
Blood Volume ◽  
Clinical Studies ◽  
Venous Pressure ◽  
Blood Velocity ◽  
Total Blood Volume ◽  
Total Blood ◽  
Physical Measurements ◽  
Normal Humans ◽  
Age And Sex

Blood volume, the venous system, preload, and cardiac output

1986 ◽  
Vol 64 (4) ◽  
pp. 383-387 ◽  
Author(s):  
Clive V. Greenway ◽  
W. Wayne Lautt
Keyword(s):  
Cardiac Output ◽  
Blood Volume ◽  
Venous Pressure ◽  
Venous System ◽  
Right Atrial ◽  
Total Blood Volume ◽  
Total Blood ◽  
Stressed Volume ◽  
Unstressed Volume ◽  
Ventricular Compliance

Cardiac output is determined by heart rate, by contractility (maximum systolic elastance, Emax) and afterload, and by diastolic ventricular compliance and preload. These relationships are illustrated using the pressure–volume loop. Diastolic compliance and Emax place limits determined by the heart within which the pressure–volume loop must lie. End-diastolic and end-systolic pressures and hence the exact position of the loop within these limits are determined by the peripheral circulation. In the presence of minimal sympathetic tone, some 60% of total blood volume is hemodynamically inactive and constitutes a blood volume reserve (the unstressed volume). The remainder of the blood volume (the stressed volume) and the compliance of the venous system determine the venous pressure. This venous pressure together with venous resistance determines venous return, right atrial pressure, cardiac preload, and hence cardiac output. Venoconstriction causes conversion of unstressed volume to the stressed volume, the blood volume reserve is converted into hemodynamically active blood volume. After hemorrhage this replaces the lost stressed volume, while in other situations where total blood volume is not reduced, it allows a sustained increase in cardiac output. The major blood volume reserve is in the splanchnic bed: the liver and intestine, and in animals but not man, the spleen. A major unsolved problem is how the conversion of unstressed volume to stressed volume by venoconstriction is reflexly controlled.

scholarly journals Venous Function and Central Venous Pressure

2008 ◽  
Vol 108 (4) ◽  
pp. 735-748 ◽  
Author(s):  
Simon Gelman ◽  
David S. Warner ◽  
Mark A. Warner
Keyword(s):  
Central Venous Pressure ◽  
Blood Volume ◽  
Venous Return ◽  
Venous Pressure ◽  
Compartment Model ◽  
Total Blood Volume ◽  
Central Venous ◽  
Total Blood ◽  
Two Compartment Model ◽  
Venous Function

The veins contain approximately 70% of total blood volume and are 30 times more compliant than arteries; therefore, changes in blood volume within the veins are associated with relatively small changes in venous pressure. The terms venous capacity, compliance, and stressed and unstressed volumes are defined. Decreases in flow into a vein are associated with decreases in intravenous pressure and volume, and vice versa. Changes in resistance in the small arteries and arterioles may affect venous return in opposite directions; this is explained by a two-compartment model: compliant (mainly splanchnic veins) and noncompliant (nonsplanchnic veins). Effects of intrathoracic and intraabdominal pressures on venous return and central venous pressure as well as the value of central venous pressure as a diagnostic variable are discussed.

Observations on Cardiac Output and ”Pulmonary Blood Volume” in Normal Man by External Recording of the Intracardiac Flow of 131I Labelled Albumin

1961 ◽  
Vol 1 (04) ◽  
pp. 353-379
Author(s):  
Jacques Lammerant ◽  
Norman Veall ◽  
Michel De Visscher
Keyword(s):  
Cardiac Output ◽  
Blood Volume ◽  
Normal Subjects ◽  
Published Data ◽  
Total Blood Volume ◽  
Total Blood ◽  
Pulmonary Blood Volume ◽  
Intracardiac Flow ◽  
Normal Man ◽  
Mean Circulation

Summary1. The technique for the measurement of cardiac output by external recording of the intracardiac flow of 131I labelled human serum albumin has been extended to provide a measure of the mean circulation time from right to left heart and hence a new approach to the estimation of the pulmonary blood volume.2. Values for the basal cardiac output in normal subjects and its variations with age are in good agreement with the previously published data of other workers.3. The pulmonary blood volume in normal man in the basal state was found to be 28.2 ± 0.6% of the total blood volume.4. There was no correlation between cardiac output and pulmonary blood volume in a series of normal subjects in the basal state.5. The increase in cardiac output during digestion was associated with a decrease in pulmonary blood volume equal to 6.3 ± 1.2% of the total blood volume, that is, about 280 ml.6. The increase in cardiac output during exercise was associated with a decrease in pulmonary blood volume equal to 4.5 ± 1.0% of the total blood volume, that is, about 200 ml.7. The increase in cardiac output attributed to alarm is not associated with a decrease in pulmonary blood volume, the latter may in fact be increased.8. The total blood volume is advocated as a standard of reference for studies of this type in normal subjects in preference to body weight or surface area.9. The significance of these results and the validity of the method are discussed.

Heterogeneity of gut capillary transit times and impaired gut oxygen extraction in endotoxemic pigs

1996 ◽  
Vol 81 (2) ◽  
pp. 895-904 ◽  
Author(s):  
M. F. Humer ◽  
P. T. Phang ◽  
B. P. Friesen ◽  
M. F. Allard ◽  
C. M. Goddard ◽  
...  
Keyword(s):  
Blood Volume ◽  
Transit Time ◽  
Volume Flow ◽  
Oxygen Extraction ◽  
Control Group ◽  
Total Blood Volume ◽  
Oxygen Extraction Ratio ◽  
Total Blood ◽  
Transit Times ◽  
Critical Oxygen

We tested the hypothesis that endotoxin increases the heterogeneity of gut capillary transit times and impairs oxygen extraction. The gut critical oxygen extraction ratio was determined by measuring multiple oxygen delivery-consumption points during progressive phlebotomy in eight control and eight endotoxin-infused anesthetized pigs. In multiple 1- to 2-g samples of small bowel, we measured blood volume (radiolabeled red blood cells) and flow (radiolabeled 15-microns microspheres) before and after critical oxygen extraction. Red blood cell transit time (= volume/flow) multiplied by morphologically determined capillary/total blood volume gave capillary transit time. During hemorrhage, capillary/total blood volume did not change in the endotoxin group (0.5 +/- 4.5%) but increased in the control group (17.6 +/- 2.5%; P < 0.05) due to a decrease in total gut blood volume. Flow decreased significantly in the endotoxin group (36 +/- 10%; P < 0.05) but not in the control group (12 +/- 10%). Capillary transit-time heterogeneity increased in the endotoxin group (12.3 +/- 4.9%) compared with the control group (-5.8 +/- 7.4%; P < 0.05), predicting a critical oxygen extraction ratio 0.14 lower in the endotoxin group than in the control group (K. R. Walley. J. Appl. Physiol. 81: 885–894, 1996). This matches the measured difference (endotoxin group, 0.60 +/- 0.04; control group, 0.74 +/- 0.03; P < 0.05). Increased heterogeneity of capillary transit times may be an important cause of impaired oxygen extraction.

scholarly journals Biologia de Rhodnius stali, Lent, Jurberg & Galvão e Rhodnius pictipes Stål (Hemiptera, Reduviidae, Triatominae) em condições de Laboratório.

2014 ◽  
Vol 7 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Solange Ribeiro Peixoto ◽  
José Jurberg
Keyword(s):  
Mortality Rate ◽  
Blood Volume ◽  
Blood Meal ◽  
Development Time ◽  
Total Blood Volume ◽  
Total Blood ◽  
Male And Female ◽  
Disease Vector ◽  
Artificial Environment ◽  
Biological Aspects

Rhodnius stali Lent, Jurberg & Galvão vetor da Doença de Chagas domiciliado na região do Alto Beni, Bolívia é uma espécie com a biologia pouco conhecida. Com o objetivo de ampliar o conhecimento acerca de sua biologia, observamos parâmetros de seu ciclo de vida, nos estádios de ninfa, comparando-os com Rhodnius pictipes Stål, espécie morfologicamente semelhante e filogeneticamente próxima. Os seguintes parâmetros foram observados: tempo de eclosão dos ovos, ciclo biológico de ovo-adulto (em machos e fêmeas separadamente), taxa de mortalidade, idade do primeiro repasto sanguíneo e volume de sangue ingerido pelas ninfas. De maneira geral observou-se que as R. stali tem um ciclo de vida mais longo do que R. pictipes e, em ambas espécies, o tempo entre a eclosão do ovo até a fase adulta é menor em fêmeas. Curiosamente para R. stali, que é sabidamente capaz de colonizar domicílios, foi observada uma taxa de mortalidade das ninfas mais alta que em R. pictipes, algo inesperado para a espécie que coloniza estruturas artificiais e foi observada em ambiente artificial. Para R. stali, o primeiro repasto sanguíneo ocorreu, em média, quatro dias mais tarde do que em R. pictipes, espécie que ingeriu um volume total de sangue maior, possivelmente pelo fato de seu corpo ser maior. Conhecendo-se com profundidade os aspectos biológicos dessas espécies será possível direcionar o controle vetorial com mais precisão, principalmente em regiões onde colonizam casas, como no Alto Beni, Bolívia. Biology of Rhodnius stali Lent, Jurberg & Galvão and Rhodnius pictipes Stål (Hemiptera, Reduviidae, Triatiminae) in Laboratory Conditions Abstract. Rhodnius stali Lent, Jurberg & Galvão is a Chagas Disease vector that colonize houses in the Alto Beni region, Bolivia and its biology is poorly known. Aiming to enhance the understanding about their biology, we observed a few parameters of its life cycle, at nymphal stages, comparing them with Rhodnius pictipes Stål a morphologically similar and phylogenetically close species. The following parameters were observed: time of hatching, development time from egg to adult (male and female separately), mortality rate, age at first blood meal and blood volume ingested by nymphs. In general, it was observed that the R. stali has longer cycle than R. pictipes, and in both species, the time between hatching the egg to adult in females is lower. Interestingly for R. stali, which is known to be capable of colonizing households, the mortality rate of nymphs was higher than observed in R. pictipes, something unexpected for species that colonize artificial structures and was observed in artificial environment. For R. stali, the first blood meal was, on average, four days later than for R. pictipes, species that ingested a greater total blood volume, possibly because of its bigger size. By knowing in depth the biological aspects of these species it will be possible to direct vector control more accurately, especially in regions where they colonize houses, as in the Alto Beni, Bolivia.

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