Some sources of error in the calculation of relative change in plasma volume

Harrison, M. H.; Graveney, M. J.; Cochrane, Lindy

doi:10.1007/bf00952240

Cited by 67 publications

(47 citation statements)

References 22 publications

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“…Second, there should be uniform mixing of erythrocytes and plasma throughout the circulation. This assumption is not true because Ht in the microcirculation is lower than in the macrocirculation (7,8). The lack of uniform mixing of erythrocytes throughout the circulation would probably not induce a great error in ⌬RBV measurements as long as the difference in Ht between the different vascular beds would remain constant during HD-in other words, if the F cell ratio would not change (19,23).…”

Section: Discussionmentioning

confidence: 99%

“…⌬RBV devices that are based on hemoconcentration of afferent blood can adequately represent ⌬TBV only in case of uniform mixing of plasma and erythrocytes throughout the different vascular beds of the circulation (4 -6). However, this assumption is not valid: The whole-body hematocrit (Ht) is lower than the Ht of arterial or venous blood (7,8). The difference is due to a dynamic reduction in microvascular Ht in capillaries and venules (Ͻ200 m), known as the Fahraeus effect (9).…”

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confidence: 99%

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Relative Blood Volume Changes Underestimate Total Blood Volume Changes during Hemodialysis

Dasselaar

Hooge

Pruim

et al. 2007

Clinical Journal of the American Society of Nephrology

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Background: Measurements of relative blood volume changes (⌬RBV) during hemodialysis (HD) are based on hemoconcentration and assume uniform mixing of erythrocytes and plasma throughout the circulation. However, whole-body hematocrit (Ht) is lower than systemic Ht. During HD, a change in the ratio between whole-body to systemic Ht (F cell ratio) is likely to occur as a result of a net shift of low Ht blood from the microcirculation to the macrocirculation. Hence, ⌬RBV may differ significantly from total blood volume changes (⌬TBV). Therefore, this study compared ⌬RBV and ⌬TBV during HD.Design, setting, participants, and measurements: Plasma and erythrocyte volumes were measured using 125 I-and 123 Iradioiodinated albumin and 51 Cr-labeled erythrocytes, respectively. After validation of the standardized method in two patients on a nondialysis day, seven patients completed the protocol during HD.125 I-albumin and 51 Cr-labeled erythrocytes were administered 20 min before the start of HD.123 I-albumin was administered at 160 min into the HD session to quantify and correct for 125 I-albumin leakage. ⌬RBV was measured continuously throughout HD. The F cell ratio was derived from whole-body and systemic Ht.Results: Total ultrafiltration volume was 2450 ؎ 770 ml. TBV declined from 5905 ؎ 824 to 4877 ؎ 722 ml during HD. Thus, TBV declined 17.3 ؎ 4.4%, whereas the RBV decline was only 8.2 ؎ 3.7% (P ‫؍‬ 0.001). The F cell ratio increased from 0.896 ؎ 0.036 to 0.993 ؎ 0.049 during HD (P ‫؍‬ 0.002).Conclusions: ⌬RBV significantly underestimates ⌬TBV during HD. The rise in F cell ratio strongly suggests that during HD, blood translocates from the microcirculation to the macrocirculation, probably as a cardiovascular compensatory mechanism in response to hypovolemia.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Relative Blood Volume Changes Underestimate Total Blood Volume Changes during Hemodialysis

Dasselaar

Hooge

Pruim

et al. 2007

Clinical Journal of the American Society of Nephrology

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“…Finally, the method of Dill and Costill (6) was used for determinations of relative plasma volume changes. This requires that the distribution of red cells throughout the vascular bed is similar between LBNP and BL (13). However, the distribution of red blood cells throughout the vasculature might have been different between protocols leading to underestimation of changes in plasma volume.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Coagulation changes during lower body negative pressure and blood loss in humans

Helmond

Johnson

Curry

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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van Helmond N, Johnson BD, Curry TB, Cap AP, Convertino VA, Joyner MJ. Coagulation changes during lower body negative pressure and blood loss in humans. Am J Physiol Heart Circ Physiol 309: H1591-H1597, 2015. First published September 9, 2015; doi:10.1152/ajpheart.00435.2015.-We tested the hypothesis that markers of coagulation activation are greater during lower body negative pressure (LBNP) than those obtained during blood loss (BL). We assessed coagulation using both standard clinical tests and thrombelastography (TEG) in 12 men who performed a LBNP and BL protocol in a randomized order. LBNP consisted of 5-min stages at 0, Ϫ15, Ϫ30, and Ϫ45 mmHg of suction. BL included 5 min at baseline and following three stages of 333 ml of blood removal (up to 1,000 ml total). Arterial blood draws were performed at baseline and after the last stage of each protocol. We found that LBNP to Ϫ45 mmHg is a greater central hypovolemic stimulus versus BL; therefore, the coagulation markers were plotted against central venous pressure (CVP) to obtain stimulus-response relationships using the linear regression line slopes for both protocols. Paired t-tests were used to determine whether the slopes of these regression lines fell on similar trajectories for each protocol. Mean regression line slopes for coagulation markers versus CVP fell on similar trajectories during both protocols, except for TEG ␣°angle (Ϫ0.42 Ϯ 0.96 during LBNP vs. Ϫ2.41 Ϯ 1.13°/mmHg during BL; P Ͻ 0.05). During both LBNP and BL, coagulation was accelerated as evidenced by shortened R-times (LBNP, 9.9 Ϯ 2.4 to 6.2 Ϯ 1.1; BL, 8.7 Ϯ 1.3 to 6.4 Ϯ 0.4 min; both P Ͻ 0.05). Our results indicate that LBNP models the general changes in coagulation markers observed during BL. blood coagulation; hemorrhage; lower body negative pressure; blood coagulation tests; humans; central hypovolemia NEW & NOTEWORTHYOur study provides noteworthy data that directly compare blood coagulation activation induced by lower body negative pressure to those observed during blood loss in conscious humans.HEMORRHAGE IS ONE OF THE LEADING causes of accidental death (1) and is the leading cause of death on the battlefield (8, 9). Activation of the coagulation system is vital following a hemorrhagic injury to reduce the risk of exsanguination. Consequently, studying the activation of the coagulation system during blood loss (BL) is of upmost importance so new therapies and treatment algorithms, such as fluid resuscitation, can be developed. However, using invasive methods to experimentally induce BL is challenging to perform in humans.Lower body negative pressure (LBNP) is a technique that is used as a noninvasive surrogate to study many of the physiological responses to BL (4, 15, 18). LBNP sequesters circulating blood in the lower body, thereby reducing central blood volume and mimicking hemodynamic responses generated during BL (4,15,18). However, it is unclear if markers of coagulation system activation respond similarly during these protocols. Reductions in central blood volume by LBNP (38) ...

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“…Instruments). Changes in blood plasma volume (%∆PV) were evaluated using Dill and Costill formula (10) modified by Harrison et al (16). Blood hemoglobin (Hb) and glucose levels were measured in Sysmex XE 2100 device, whereas hematocrit (Hct) was evaluated using MPW 251 centrifuge (MPW Med.…”

Section: Anaerobic and Aerobic Testsmentioning

confidence: 99%

Effect of creatine malate supplementation on physical performance, body composition and selected hormone levels in spinters and long-distance runners

Tyka¹,

Chwastowski

Cisoń³

et al. 2015

Acta Physiologica Hungarica

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Purpose: The aim of the study was to determine whether creatine malate (CML) supplementation results in similar ergogenic effect in sprinters and long-distance runners. The other goal was to compare changes in body composition, physical performance and hormone levels after six-week training in athletes, divided into subgroups supplemented with creatine malate or taking placebo. Results: Six-week supplementation combined with physical training induced different effects in athletes. Significantly higher increases in relative and absolute peak power and total work (p < 0.05) were found in sprinters compared to other groups. Except for growth hormone, post-exercise venous blood serum hormone levels exhibited no statistically significant differences in athletes. After CML loading period, a significant increase in growth hormone was found in the group of sprinters. Conclusions: A significant ergogenic effect was found in sprinters, which was reflected by the increase in anaerobic exercise indices and morphological indices and elevated growth hormone level, after graded exercise testing. The significant increase in the distance covered during graded test was only observed in supplemented long-distance runners, whereas no significant changes in maximal oxygen uptake, relative peak power and relative total work were noticed. This could be caused by later anaerobic threshold appearance in exercise test to exhaustion.Keywords: long-distance runners, sprinters, creatine malate supplementation, body composition, maximal oxygen uptake, peak power output, growth hormone, cortisol, testosteroneThe effect of creatine on physical performance development is a subject of interest among many researchers. Since its discovery in 1832 by Chevreul, the effect of creatine on the human body has been investigated in numerous laboratories all over the world. The welldocumented properties of creatine include its biosynthesis and distribution in human body (19,39), its role in energy conversion in skeletal muscles and delayed fatigue (18,20,40), pattern and the effect of creatine intake on ability to perform physical exercise (2,7,12,13).

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Some sources of error in the calculation of relative change in plasma volume

Cited by 67 publications

References 22 publications

Relative Blood Volume Changes Underestimate Total Blood Volume Changes during Hemodialysis

Relative Blood Volume Changes Underestimate Total Blood Volume Changes during Hemodialysis

Coagulation changes during lower body negative pressure and blood loss in humans

Effect of creatine malate supplementation on physical performance, body composition and selected hormone levels in spinters and long-distance runners

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