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Results for “Plasma Volume”

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At least 55 records · Page 3Linked to original sources
PubMed1997

[Measurement of relative plasma volume and plasma refilling rate during ultrafiltration of hemodialysis by measuring apparatus of plasma colloidal osmotic pressure].

BACKGROUND: The objective of this study is the prevention of unexpected hypotension during hemodialysis caused by unsuitable filtration rate. METHODS: The plasma colloidal osmotic pressure (COP) was measured continuously during ultra-filtration, and relative plasma volume (%PV) and plasma refilling rate (PRR) were calculated during 12 ECUMs and one dialysis on twelve patients in early stage of chronic renal failure. Values of %PV and PRR calculated from COP were drawn in graphic curves, and analysed to obtain characteristic pattern. Minimum value of %PV (%PV min), maximum value of PRR (PRRmax) and time for PRR to decrease to 95% (95% PVt) on the curves were documented simultaneously. RESULTS: At the initial stage of %PV curve, obvious fall was observed on 6 of 13 estimation (initial fall of %PV). On the contrary at the initial stage of PRR curve, obvious rise was observed on 5 estimation (initial rise of PRR). A close relationship was indicated between the two phenomenons. In 6 cases with initial fall of %PV and in 5 cases with initial rise of PRR body weight, PRRmax and 95%PVt were lower than another cases without it. The ultra-infiltration velocity was estimated to be relatively high in these groups. In these 8 cases, filtrated water volume was judged as adequate clinically. In 4 of 5 cases without final fall of PRR, it was judged as inadequate and needed to evacuate more 0.9 to 3.0 kg (average of 1.8 +/- 1.07) of water from the patients. CONCLUSIONS: From the above, we concluded that our method is useful for deciding suitable velocity of ultrafiltration and dry weight in hemodialysis therapy.)

Adult↗
PubMed2000

Heat acclimation improves regulation of plasma volume and plasma Na(+) content during exercise in horses.

This study determined the plasma volume (PV) and ion responses to heat acclimation and exercise in six trained Thoroughbred horses during 21 days of exposure to heat and humidity (33 degrees C, 83% relative humidity) for 4 h/day. During the 2nd h on days 0, 3, 7, 14, and 21, horses performed a standardized treadmill test, running at 50% of peak O(2) uptake until pulmonary artery temperature reached 41.5 degrees C. Heat acclimation resulted in an increase in PV from 21.3 +/- 1.1 liters on day 0 to 24.3 +/- 1.0 liters on day 14, returning to 22.6 +/- 0.9 liters on day 21. The corresponding total plasma protein contents were 1,273 +/- 53, 1,455 +/- 81, and 1,377 +/- 57 g, respectively, and increases in total plasma Na(+) plus Cl(-) content were 5,145 +/- 126, 5,749 +/- 146, and 5,394 +/- 114 mmol, respectively. Thus changes in PV were accompanied by direct changes in plasma protein and osmolyte contents. With exercise on day 0, PV decreased by 7.1 +/- 0.7% at 5 min of exercise and remained decreased (-6.7 +/- 1.3%) at 5 min of recovery. By day 21, PV decreased significantly less than on day 0 (by 5.2 +/- 0.9% at 5 min of exercise), was decreased by only 2.0 +/- 1.6% at 5 min of recovery, and was fully restored at 15 min of recovery. Plasma Na(+) concentration increased 3 meq/l during the first 5 min of exercise and was normalized by 5 min of recovery on day 0 and by end exercise on day 21. It is concluded that improved ability to regulate PV during exercise in response to heat acclimatization is associated with an increased PV and an improved conservation of Na(+).

Acclimatization↗
PubMed1993

Fluid restriction prior to cycle exercise: effects on plasma volume and plasma proteins.

The purpose of this study was to test the hypothesis that changes in exercise intensity dominate the PV response to cycle exercise in the heat independent of the initial plasma volume (PV) and total circulating protein (TCP) content. The two experimental treatments (counterbalanced design) were performed by nine trained male cyclists (age = 23 +/- 1 yr, VO2peak = 63 +/- 4 ml.kg-1.min-1) in both a euhydrated (EU) and hypohydrated (HP, 24-h fluid restriction) state. Blood volume was measured (carbon monoxide dilution) 30 min prior to each test and subsequent changes in PV were calculated from serial venous blood samples using hematocrit and hemoglobin concentration. Following 20 min of seated rest in a warm environment (Tdb = 30 degrees C, 50-60% RH), each subject cycled in a semi-reclining posture for 60 min at three successive intensities (60, 120, and 180 W for 20 min each, representing approximately 22, 37, and 53% VO2peak). Fluid restriction reduced (P < 0.05) body weight by 1.4 +/- 0.3 kg (1.8 +/- 0.4%), PV by 353 +/- 73 ml (8 +/- 2%), TCP by 20 +/- 7 g (7 +/- 2%), and elevated serum osmolality by 6 +/- 2 mOsm.kg-1 (2 +/- 1%). After 20 min of passive heat exposure (prior to exercise), TCP content remained lower (P < 0.05) in HP (17 +/- 5 g) compared with EU as PV increased (P < 0.05) in EU (222 +/- 27 ml) but not (P > 0.05) in HP (122 +/- 35 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Relationship between amniotic fluid volume and maternal plasma volume expansion.

Amniotic fluid and maternal plasma volumes were estimated in high-risk obstetric patients suspected of being hypovolemic. Excluding cases of intrinsic maternal or fetal disease, there were good (P less than 0.001) correlations between maternal plasma volume expansion and amniotic fluid volume. In the presence of oligohydramnios, there is usually maternal hypovolemia, and vice versa. Oligohydramnios may often be corrected by vigorous maternal plasma volume expansion, which is sometimes indicated in the treatment of cases of fetal distress. It is presumed that only when maternal plasma volume expansion is normal, is uterine perfusion sufficient to provide amniotic fluid formation in normal amounts. The varying amounts of amniotic fluid seen in normal pregnancies at term probably reflect the varying fetal activities of swallowing and voiding.

Adult↗
PubMedDate not supplied

The effect of large volume paracentesis on plasma volume--a cause of hypovolemia?

Large volume paracentesis, while effectively relieving symptoms in patients with tense ascites, has been generally avoided due to reports of complications attributed to an acute reduction in intravascular volume. Measurements of plasma volume in these subjects have been by indirect methods and have not uniformly confirmed hypovolemia. We have prospectively evaluated 18 patients (20 paracenteses) with tense ascites and peripheral edema due to chronic liver disease undergoing 5 liter paracentesis for relief of symptoms. Plasma volume pre- and postparacentesis was assessed by a 125I-labeled human serum albumin dilution technique as well as by the change in hematocrit and postural blood pressure difference. No significant change in serum sodium, urea nitrogen, hematocrit or postural systolic blood pressure difference was noted at 24 or 48 hr after paracentesis. Serum creatinine at 24 hr after paracentesis was unchanged but a small but statistically significant increase in serum creatinine (+0.1 +/- 0.3 mg per dl, p less than 0.01) was noted at 48 hr postparacentesis. Plasma volume changed -2.7% (n = 6, not statistically significant) during the first 24 hr and -2.8% (n = 12, not statistically significant) during the 0- to 48-hr period. No complications from paracentesis were noted. These results suggest that 5 liter paracentesis for relief of symptoms is safe in patients with tense ascites and peripheral edema from chronic liver disease.

Adult↗
PubMed2006

Erythropoietin treatment elevates haemoglobin concentration by increasing red cell volume and depressing plasma volume.

Erythropoietin (Epo) has been suggested to affect plasma volume, and would thereby possess a mechanism apart from erythropoiesis to increase arterial oxygen content. This, and potential underlying mechanisms, were tested in eight healthy subjects receiving 5000 IU recombinant human Epo (rHuEpo) for 15 weeks at a dose frequency aimed to increase and maintain haematocrit at approximately 50%. Red blood cell volume was increased from 2933 +/- 402 ml before rHuEpo treatment to 3210 +/- 356 (P < 0.01), 3117 +/- 554 (P < 0.05), and 3172 +/- 561 ml (P < 0.01) after 5, 11 and 13 weeks, respectively. This was accompanied by a decrease in plasma volume from 3645 +/- 538 ml before rHuEpo treatment to 3267 +/- 333 (P < 0.01), 3119 +/- 499 (P < 0.05), and 3323 +/- 521 ml (P < 0.01) after 5, 11 and 13 weeks, respectively. Concomitantly, plasma renin activity and aldosterone concentration were reduced. This maintained blood volume relatively unchanged, with a slight transient decrease at week 11, such that blood volume was 6578 +/- 839 ml before rHuEpo treatment, and 6477 +/- 573 (NS), 6236 +/- 908 (P < 0.05), and 6495 +/- 935 ml (NS), after 5, 11 and 13 weeks of treatment. We conclude that Epo treatment in healthy humans induces an elevation in haemoglobin concentration by two mechanisms: (i) an increase in red cell volume; and (ii) a decrease in plasma volume, which is probably mediated by a downregulation of the rennin-angiotensin-aldosterone axis. Since the relative contribution of plasma volume changes to the increments in arterial oxygen content was between 37.9 and 53.9% during the study period, this mechanism seems as important for increasing arterial oxygen content as the well-known erythropoietic effect of Epo.

Adult↗
PubMedDate not supplied

Twin-to-twin transfusion syndrome: polyhydramnios-associated changes in maternal plasma volume and maternal plasma aldosterone concentrations. A preliminary study.

OBJECTIVE: Our aim was to evaluate the consequences of polyhydramnios on maternal plasma volume and maternal serum aldosterone and atrial natriuretic peptide (ANP) concentrations in monochorionic twin pregnancies complicated by twin-to-twin transfusion syndrome (TTTS). METHODS: The maternal plasma volume, ionograms as well as plasma ANP and aldosterone concentrations were compared in normal monochorionic diamniotic twin pregnancies and in TTTS. RESULTS: The maternal plasma volume was normal in TTTS despite severe polyhydramnios. The plasma aldosterone concentration was higher in pregnancies complicated by TTTS. CONCLUSION: The high plasma aldosterone concentration is likely to maintain normal plasma volume despite progressive extravascular volume enhancement. This suggests that TTTS is present early in pregnancy as a chronic phenomenon starting before its clinical expression and may trigger compensatory maternal hyperaldosteronism.

Aldosterone↗