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PubMed1995

Re-evaluation of Evans blue dye dilution method of plasma volume measurement.

To simplify the method of plasma volume measurement by Evans blue dye dilution we used, for the first time, the same venous site for injection of dye and collection of samples. In a series of 49 studies the dye decay between 10 and 35 min after injection was highly linear (r = 0.991 +/- 0.01), indicating that contamination of samples is very unlikely. We repeated the measurements after eight weeks in nine patients; the mean difference was 16.4 +/- 19.6 ml, indicating a high degree of reproducibility. We found that extrapolation of the dye decay curve to time zero is required for accurate estimates of plasma volume. There was good agreement between the estimates of plasma volume obtained by extrapolation from only three samples taken at 10, 20 and 30 min after dye injection with the results obtained using all six samples. We also found good agreement between the estimates of plasma volume obtained by using standard curves constructed from four standard dilutions of 1.25, 2.5, 5 and 10 mg/l and those obtained by the use of standard curves constructed from the blank and only one standard dilution of 10 mg/l. We therefore conclude that the Evans blue technique can be simplified with minimal loss of accuracy, by using only one venous site for injection and withdrawal, withdrawing only three samples between 10 and 30 min after injection and using a two point calibration line.

Adult↗
PubMed1986

Increase in plasma volume after the transfusion of washed erythrocytes.

During a four day period, each of 14 healthy mongrel dogs that had splenectomy was twice bled 450 milliliters of blood and twice reinfused with 500 milliliters of isotonic sodium chloride solution. On the sixth day, the dogs were hypovolemic and anemic; they had 10 per cent reductions in total blood volume and 50 per cent reductions in erythrocyte volume, but no change in plasma volume. Seven of the dogs were transfused with autologous washed erythrocyte concentrates and seven others with an equal volume of autologous plasma. Two units of autologous washed erythrocyte concentrations with hematocrit values of 80 volumes per cent increased plasma volumes to levels similar to those achieved with 2 units of autologous plasma. The serum oncotic pressure, total protein and albumin concentrations were similar in the two groups, except that, two hours after transfusion, the serum albumin level was significantly higher in the dogs transfused with plasma. These data demonstrate that erythrocyte transfusions increase both the erythrocyte and plasma volumes.

Animals↗
PubMed1986

[Plasma volume changes in essential hypertension patients].

Plasma volume, cardiac output, velocity of blood flow and total peripheral vascular resistance were studied in 180 patients with essential hypertension, stages I, II and III according to WHO classification. Increased plasma volume was established in the majority of the patients with early stage of the disease and in 36 per cent of the patients with advanced essential hypertension. The studies reveal that the changes in plasma volume are of importance for the deviations of the other hemodynamic indices and for the reorganization of the hemodynamics in the patients with essential hypertension.

Adult↗
PubMedDate not supplied

[Changes in blood plasma volume in rats during ontogenesis].

The dynamics of blood plasma volume were studied for the first time in rats during ontogenesis. The significance of blood plasma volume is estimated in the transport of physiologically active substances to cells and target organs during development. The blood plasma volume was measured in male and female rats during embryogenesis on day 18 (E18), perinatal development on E21 and day of postnatal development (P3), and postnatal development on P15 and P30. Body mass was determined in the same animals and correlation was estimated between the blood plasma volume and body mass. The plasma volume increased 1.9-fold from E18 to E21, 1.4-fold from E21 to P3, 2.1-fold from P3 to P15, and 3.4-fold from P15 to P30. The body mass increased 5-fold from E18 to E21, 2-fold from E21 to P3, 2.3-fold from P3 to P15, and 3.2-fold from P15 to P30. The ratio of blood plasma to body mass was the highest on E18 (19%) and decreased twice by E21. This index varied from 5.4 to 4.8% during postnatal development. No sex-related differences in these indices were found in rats. The results obtained make it possible to determine the total content of physiologically active substances on the basis of their plasma concentration and, thereby, estimate the efficiency of secretory organs.

Animals↗
PubMed1982

Plasma volume determination in pregnancies complicated by chronic hypertension and intrauterine fetal demise.

Plasma volume determinations for 9 women with severe chronic hypertension who delivered live-born infants with birth weights appropriate for gestational age (AGA) were compared with those for 7 women with chronic hypertension whose pregnancies ended in intrauterine fetal demise. Plasma volume determinations using Evans blue dye dilution technique were performed at 20 to 25 weeks' gestation (12 patients) and at 26 to 29 weeks' gestation (16 patients). In addition, plasma volume measurements were performed at 8 weeks post partum in 5 patients who had intrauterine fetal demise. Analysis of the clinical course, laboratory findings, and pregnancy outcome revealed that the degree of plasma volume expansion was the factor most significantly differing between the 2 groups of patients. The plasma volumes of 9 women who delivered AGA infants were comparable with those values previously reported for normal singleton pregnancy. In contrast, each patient with intrauterine fetal demise demonstrated failure in plasma volume expansion at 20 to 25 weeks' gestation when compared with her own postpartum value. In each of the 6 patients who had a second plasma volume determination at 26 to 29 weeks' gestation, there was a decrease (mean decrease, 13.5%) from the value at 20 to 25 weeks. Plasma volume determinations may be very helpful in making clinical decisions regarding women with severe hypertension. Plasma volume determination may be most helpful in identifying a subgroup of women who are at particular risk for having infants with intrauterine growth retardation and intrauterine fetal demise.

Adult↗
PubMed1997

Dual role for nitric oxide in the regulation of plasma volume and albumin escape during endotoxin shock in conscious rats.

To assess the role of nitric oxide (NO) produced by the constitutive (cNOS) and inducible NO synthase (iNOS) in the regulation of vascular functions, we compared the effects of aminoguanidine, a relatively selective inhibitor of iNOS, and NG-nitro-L-arginine methyl ester (L-NAME), a nonselective NOS inhibitor on blood pressure, plasma volume, and albumin escape during the early and delayed phases of endotoxin shock in conscious, chronically catheterized rats. Red blood cell volume and plasma volume were determined by using chromium-51-tagged erythrocytes and iodine-125-labeled albumin, respectively. Injection of lipopolysaccharide (LPS) 10 mg/kg i.v. resulted in a fall in blood pressure, hemoconcentration, and increased total-body albumin escape, which is reflected by a 25% reduction in plasma volume. When LPS was injected into animals pretreated with L-NAME (7.4 mumol/kg i.v. 15 minutes before LPS), losses in plasma volume and albumin escape were significantly greater than in rats that received LPS alone, despite that L-NAME attenuated the hypotensive action of LPS. Aminoguanidine pretreatment (162 mumol/kg) had no effect on the early responses to LPS, whereas it was as potent as L-NAME in reversing hypotension when injected 70 minutes after LPS. Aminoguanidine treatment also prevented further losses in plasma volume and markedly attenuated total-body and organ albumin escape rates elicited by LPS. L-NAME produced only a slight attenuation of LPS-induced losses in plasma volume and albumin escape in most organs studied, whereas it potentiated albumin extravasation in the lung. These results demonstrate that inhibition of cNOS potentiates, whereas inhibition of iNOS markedly attenuates, losses in plasma volume and albumin escape elicited by LPS, and suggest that selective inhibitors of iNOS may be more effective than nonselective inhibitors of all forms of NOS in the therapy of septic shock.

Animals↗
PubMed2006

Low plasma volume coincides with sympathetic hyperactivity and reduced baroreflex sensitivity in formerly preeclamptic patients.

BACKGROUND: Preeclampsia is associated with enhanced sympathetic activity as well as subnormal plasma volume. Meanwhile, in over 50% of these complicated pregnancies, the subnormal plasma volume has been found to persist for a prolonged period after pregnancy. The objective of this study is to test the hypothesis that in normotensive formerly-preeclamptic women, persistence of a subnormal plasma volume coincides with enhanced sympathetic activity and with it, an altered autonomic control of blood pressure. METHODS: Forty-eight formerly-preeclamptic women participated in this study. After measurement of their plasma volume by iodine 125-albumin indicator dilution, they were subdivided into a group with a normal plasma volume (plasma volume > 48 ml/kg lean body mass) and a group with a subnormal plasma volume (< or = 48 ml/kg lean body mass). We performed spectral analysis on their beat-to-beat blood pressure and heart rate recordings and compared both groups using non-parametric tests. RESULTS: Formerly-preeclamptic women with a subnormal plasma volume had a higher sympathetic activity (P = .001) and a lower baroreflex sensitivity (P = .04) than their counterparts with a normal plasma volume. CONCLUSION: In normotensive formerly-preeclamptic women, a subnormal plasma volume coincides with a higher sympathetic activity in the blood pressure regulation and lower baroreflex sensitivity. Whether these alterations in the autonomic control mechanisms are a cause or effect of the subnormal plasma volume remains to be elucidated.

Adult↗
PubMed2004

Correlation of maternal plasma volume and composition with amniotic fluid index in normal human pregnancy.

OBJECTIVE: Early in human pregnancy, maternal plasma osmolality decreases and plasma volume begins to increase. Continued plasma volume expansion is linked to fetal fluid acquisition, and ultimately normal amniotic fluid volume. Although the mechanisms for these physiological responses are uncertain, we hypothesized that the time course of maternal plasma hypotonicity, plasma volume expansion and amniotic fluid index (AFI) were interrelated. We sought to examine these interrelationships during human pregnancy. METHODS: Normal primiparous pregnant patients had monthly determinations of plasma volume using Evans blue from the second trimester to term, and 8 weeks after delivery. At each visit, fasting, morning blood samples were also drawn to measure hematocrit, osmolality, electrolytes, urea, glucose and creatinine. AFI was determined by ultrasound. RESULTS: Plasma volume, blood volume and AFI demonstrated significant increases with advancing gestational age. There were no significant changes in plasma sodium or osmolality from the second trimester to term. AFI was not associated with either plasma volume or osmolality. CONCLUSION: Although similar factors may therefore be responsible for the initiation of plasma volume expansion and plasma hypotonicity, the magnitude and degree of change of these processes are probably under independent regulation. Individual patient variation in AFI is a result of factors other than maternal blood volume or composition.

Amniotic Fluid↗
PubMed2000

Plasma volume expansion for treatment of women with pre-eclampsia.

BACKGROUND: Plasma volume is reduced amongst women with pre-eclampsia. This association has led to the suggestion that expanding the plasma volume might improve maternal and uteroplacental circulation, and so potentially improve outcome for both the woman and her baby. OBJECTIVES: The aim of this review was to assess the effects of plasma volume expansion for the treatment of women with pre-eclampsia. SEARCH STRATEGY: The register of trials maintained by the Cochrane Pregnancy and Childbirth Group, and the Cochrane Controlled Trials Register Issue 1 1999 were searched for trials meeting the selection criteria. SELECTION CRITERIA: Randomised trials were included. Quasi-random designs were excluded. Participants were women with hypertension during pregnancy, with or without proteinuria. Women who were postpartum at trial entry were excluded. Interventions were any comparison of plasma volume expansion with no expansion, or of one plasma volume expander with another. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two reviewers. Discrepancies were resolved by discussion. There was no blinding of authorship or results. MAIN RESULTS: Three trials involving 61 women were included in this review. All compared a colloid solution with no plasma volume expansion. For every outcome reported, the confidence intervals are very wide and cross the no effect line. REVIEWER'S CONCLUSIONS: There is insufficient evidence for any reliable estimates of the effects of plasma volume expansion for women with pre-eclampsia.

Female↗
PubMed1976

Growth of the pig: changes in red cell and plasma volumes.

In the pig, plasma volume increased from 58.0 +/- 2.53 ml/kg on day 1 to 66.7 +/- 3.35 (P less than 0.05) on day 2, and decreased between days 7 and 9 to 56.4 +/- 1.16 (P less than 0.02). The next significant change in volume occurred at weaning: from 53.1 +/- 1.24 ml/kg at week 4 to 44.16 +/- 2.2 at week 5. It then increased to 56.1 +/- 1.41 ml/kg by week 7 and decreased to 48.5 +/- 1.44 by week 9; then between weeks 10 and 11 it increased to 59.33 +/- 3.01 (P less than 0.005). Red cell volume on day 1 was 32.3 +/- 1.25 ml/kg and decreased to 20.2 +/- 1.37 (P less than 0.01) on day 2. The only other change of significance in red cell volume over the 12-week growth period was a small increasan 0.05) at week 6. The mean for BVRcells was 0.88 +/- 0.01 for the growth period. The pattern of changes in plasma and red cell volumes differed from those for the beagle.

Animals↗
PubMed1995

Time course and mechanisms of decreased plasma volume during acute psychological stress and postural change in humans.

In this study, we examined the effects of psychological stress on calculated plasma volume, the relationship of these changes to changes in hematologic and hemodynamic factors, and the time course of plasma volume changes. Plasma volume changes were assessed using mass densitometry techniques, which measured changes in blood and plasma density. Hematologic and hemodynamic variables were assessed in 40 healthy men and women during a mental arithmetic (math) or benign reading task and during postural change (standing). Results indicated that math and posture change produced a significant decrease in plasma volume (ps < .001) and increases in blood pressure (ps < .001), blood and plasma density (ps < .001), and total plasma protein (p < .001). Correlations were observed between plasma volume changes and changes in systolic (r = .55, p < .0001), diastolic (r = .61, p < .0001), and mean (r = .65, p < .0001) arterial pressure during math; plasma volume and blood pressure returned to baseline within 12 min following the math task. These results suggest that an important mechanism for stress-induced decreases in plasma volume is increased blood pressure leading to increased fluid shifts from the vasculature into the interstitial spaces.

Adolescent↗
PubMed1986

Comparison of methods of plasma volume determination for dose calculation of factor VIII in patients with classic haemophilia.

Plasma volumes have been measured in 12 patients with moderate or severe haemophilia A and compared with plasma volumes derived by calculation using a variety of commonly recommended formulae based on body weight with or without a correction for haematocrit. The mean plasma volume by measurement was 47 ml/kg. A calculated plasma volume using 42 ml/kg and a correction for haematocrit most closely approximated the measured results. The correlation coefficient was 0.9. Ex vivo factor VIII recoveries, following infusion of either lyophilised cryoprecipitate or NZFVIII (controlled pore glass preparation), were then determined based on the observed/expected response assuming different values for plasma volume. Mean recoveries of approximately 100% were associated with a 2.4% FVIII rise per unit/kg administered using cryoprecipitate. Ex vivo recoveries following NZFVIII exceeded 100% with mean values, depending on the technique used for plasma volume determination, up to 131%. Recoveries were not significantly affected by the plasma volume method used and all methods indicated that the labelled potency of NZFVIII is currently being underestimated by at least 20-30%.

Body Height↗
PubMed1986

Plasma volume and proteins in voluntary hyperventilation.

In a controlled study the changes of the plasma volume and plasma proteins induced by voluntary hyperventilation (HV) were investigated in nine splenectomized volunteers. The plasma volume changes were calculated from the changes of the hemoglobin and hematocrit. After 20 min of HV in supine position, which lead to a decrease of the venous CO2 partial pressure by 19 Torr and to an increase of plasma epinephrine and norepinephrine levels, the plasma volume was reduced by 12.9%. The intravascular masses of total protein, albumin, and several other proteins decreased during HV but a similar decrease of these proteins was also observed during the control study (C), i.e., rest in supine position without HV. The differences between changes during HV and C were not significant, indicating that the loss of protein was not due to HV. It is concluded that acute HV leads to a rapidly reversible loss of a virtually protein-free solution from the vascular space. The red cell compartment participated in fluid shifts in that the mean red cell volume decreased by 2.2% (P less than 0.02 compared with C). Comparison with earlier work shows that addition of erythrocytes from the normal spleen does not play a part in the HV-induced increase of hemoglobin and hematocrit.

Adolescent↗
PubMed1977

Transcapillary escape rate of albumin and plasma volume in patients with varying degrees of psoriasis.

Plasma albumin, plasma volume and the transcapillary escape rate of albumin (TERalb), i.e. the fraction of the intravascular mass of albumin that passes to the extravascular space per unit time, were determined using 125I-labelled albumin in 26 patients with varying degrees of psoriasis. For the patients as a group the plasma albumin concentration and the TERalb values were not significantly different from the control group. This contrasts with earlier findings in erythrodermic patients. The plasma volume was significantly reduced whether it was expressed in relation to body weight, height or surface area (P less than 0.001). Thus the intravascular mass of albumin (IVM), determined as the product of the plasma volume and the plasma albumin concentration, was also significantly reduced (P less than 0.001). We found no correlation between the involved skin area and any of the above mentioned parameters. The possible mechanisms in the reduction of the plasma volume and the IVM are discussed. It is suggested that reduced IVM may reflect reduced total albumin mass due to lowered rates of albumin synthesis or increased rates of turnover.

Adolescent↗
PubMed1992

Atrial natriuretic peptide concentrations and hemodynamic effects of acute plasma volume expansion in normal pregnancy and preeclampsia.

Plasma atrial natriuretic peptide (ANP) and circulatory responses were studied during rapid plasma volume expansion with crystalloid solutions. Sixteen women with preeclampsia and 16 healthy controls in the third trimester were compared. Basal mean (+/- standard error of the mean) ANP levels were not significantly higher in the preeclamptics than in controls (13.6 +/- 3.5 versus 6.4 +/- 1.1 pmol/L; not significant), but the increment following volume expansion was more pronounced (12.9 +/- 2.6 versus 6.1 +/- 2.3 pmol/L; P less than .05). The mean plasma volume expansion was less in the preeclamptic group (6.1 +/- 0.8 versus 9.3 +/- 1.1%; P less than .05), reflecting a higher capillary permeability in this disease. Left ventricular posterior-wall thickness in diastole was increased in the preeclamptics under basal conditions as compared with the controls (9.8 +/- 0.3 versus 8.9 +/- 0.3 mm; P less than .05), as was the thickness of the interventricular septum in systole (14.3 +/- 0.5 versus 12.3 +/- 0.6 mm; P less than .05). Systemic vascular resistance was higher in the preeclamptic group (19.7 +/- 0.8 versus 15.1 +/- 1.1 peripheral resistance units; P less than .01). In the controls, cardiac output increased by 23 +/- 4% and systemic vascular resistance decreased by 17 +/- 3%. The preeclamptic women reacted in a similar way. Our results indicate that preeclampsia is associated with an enhanced ANP response despite a less pronounced increase in plasma volume during acute fluid challenge.

Adult↗
PubMed1979

Plasma volumes and hematocrits in rats with chronic sinoaortic denervation hypertension.

Plasma volume changes were assessed in female Wistar rats with neurogenic hypertension induced by sinoaortic denervation, SAD. Tail veins of conscious, restrained rats were used for injection of Evans blue dye and for sampling into microhematocrit tubes. Only at 3 days did total plasma volume of SAD rats show a modest reduction of about 16% (P less than 0.05 vs. sham-operated plus unoperated controls). At 3, 6, and 13 wk, SAD mean body weight, plasma volume, and sodium concentration were similar to sham values. SAD hematocrits, however, like arterial pressures, were elevated at all postoperative times studied. In anesthetized SAD and sham rats, red blood cell (51Cr method) and plasma volumes were the same and so were hematocrits. The latter was unlike the finding in unanesthetized groups. Hematocrits from the same SAD rats were lower after induction of anesthesia than before (P less than 0.025). Thus, elevated hematocrits apparently resulted from the release of sequestered red blood cells into the circulation by unanesthetized SAD rats. In conclusion, plasma volume is within the normal range in SAD rats except for the first few postoperative days. Factors affecting volume regulation at that time are discussed.

Animals↗
PubMed1967

Plasma volume in cirrhosis of the liver: its relation of portal hypertension, ascites, and renal failure.

Plasma volume was measured by using albumin-(131)I- and (51)Cr-labeled erythrocytes in 24 control subjects, 140 patients with hepatic cirrhosis, and 10 patients with various portal-systemic shunts for the relief of noncirrhotic portal hypertension. The cirrhotic patients included subgroups with ascites, functional renal failure, and portacaval anastomoses. Elevated values for plasma volume, by both methods, were found in each group of patients.The lymph space drained by the thoracic duct was measured by a radioisotopic technique in six patients with cirrhosis and ascites. The amount of radioactivity in this space was found to be negligible in accounting for the elevated plasma volume. Similar results were obtained when the degree of leakage of albumin-(131)I into the ascites was determined in 10 patients with cirrhosis.The plasma volume was unusually elevated in patients who had bled from esophageal varices, and paired comparisons before and after portacaval shunt normal values. There was a statistically significant correlation between normal values. There was a statistically significant correlation between plasma volume and wedged hepatic venous pressure measured in 36 patients.We concluded that the elevated values for plasma volume in cirrhosis are valid and are not artifacts due to leakage of albumin-(131)I from the circulation during mixing. We also concluded that portal hypertension is responsible for the plasma volume expansion; however, we were unable on this basis to explain the failure of portacaval shunting to return the plasma volume to normal, unless the shunt or some other factor keeps the plasma volume elevated.

Journal Article↗