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At least 937 records · Page 52Linked to original sources
PubMed1999

Distribution of normal saline and 5% albumin infusions in septic patients.

OBJECTIVE: To determine the relative distribution of fluid within the extracellular fluid volume (ECFV) after infusing either normal saline or 5% albumin in septic, critically ill patients. DESIGN: Prospective, randomized, unblinded, interventional study. SETTING: Intensive care unit in a 450-bed, tertiary care, teaching hospital. PATIENTS: Septic, critically ill patients (n = 18). INTERVENTIONS: Infusion of either normal saline or 5% albumin to a hemodynamic end point determined by the patient's clinician. MEASUREMENTS AND MAIN RESULTS: Plasma volume (PV), ECFV, cardiac index, and arterial oxygen content were measured immediately before (baseline) and after each fluid infusion. PV and ECFV were measured by dilution of 131I-albumin and 35S sodium sulfate, respectively. Interstitial fluid volume (ISFV) was calculated as ECFV - PV. Baseline values for PV, ISFV, ECFV, and oxygen delivery index did not differ between treatment groups. Infusion of normal saline increased the ECFV by approximately the volume infused, and the expansion of the PV to ISFV was in a ratio of 1:3. Infusion of 5% albumin increased the ECFV by double the volume infused, with both the PV and ISFV expanding by approximately equal amounts. Oxygen delivery index did not increase after either infusion due to the effect of hemodilution. CONCLUSION: Expansion of the ECFV in excess of the volume of 5% albumin infused suggests that fluid may move from the intracellular fluid volume to the ECFV in septic patients who receive this fluid.

APACHE↗
PubMed2001

Dextran, gelatin, and hydroxyethyl starch do not affect permeability for albumin in cat skeletal muscle.

OBJECTIVE: To evaluate the effects of the three commercially available colloid solutions, 6% dextran 70, 6% hydroxyethyl starch (HES) 200/0.5, and 3.5% urea-linked gelatin on permeability for human albumin in a skeletal muscle in vivo model by evaluating their effects on the reflection coefficient for albumin. DESIGN: Controlled laboratory study. SETTING: University research laboratory. SUBJECTS: Eighteen adult cats. INTERVENTIONS: The autoperfused and denervated calf muscles of the cat hindlimb were placed in a plethysmograph. The transvascular fluid absorption induced by an increase in the colloid osmotic pressure following a fixed intravenous bolus of human albumin was analyzed, first before start of, and then during an intra-arterial infusion to, the muscle preparation of the synthetic colloid to be analyzed. Capillary filtration coefficient as a measure of microvascular fluid permeability (conductance) was analyzed before and after start of the synthetic colloid. MEASUREMENTS AND MAIN RESULTS: Arterial blood flow, arterial and venous blood pressures, total vascular resistance, tissue volume changes, capillary filtration coefficient, and plasma volume were measured before and during the colloid infusion. According to the Starling fluid equilibrium, the ratio between the reflection coefficients for albumin on two occasions (before and after infusion of the synthetic colloid) can be calculated from the maximum osmotic absorption rates induced by a fixed intravenous bolus infusion of albumin and from the capillary filtration coefficients. Obtained data were adjusted for different plasma volume at the two occasions. We found that none of the three synthetic colloids analyzed had any significant effect on the reflection coefficient for albumin. CONCLUSION: An effect on albumin microvascular permeability of the synthetic colloids dextran 70, HES 200/0.5, and urea-linked gelatin could not be shown by a method analyzing their effect on the reflection coefficient for albumin.

Analysis of Variance↗
PubMed1984

Fall in blood pressure in response to volume expansion in pregnancy-associated hypertension (pre-eclampsia): why does it occur?

The infusion of 500 ml of a volume expanding solution caused a significant fall in blood pressure for up to 72 h in 35 women with pregnancy-associated hypertension of varying grades of severity. The response to the infusion was not obviously related to the clinical severity of the underlying disorder, nor to the extent of plasma volume expansion produced. The plasma volume of oedematous women increased, while there was no significant change in non-oedematous women in response to the infusion. Changes in other measurements were similar in oedematous and non-oedematous women. There was no evidence for prostacyclin release into the circulation in response to the infusion as a mediator of the blood pressure response. Both 6-keto-prostaglandin F1 alpha levels and 13,14-dihydro-15-keto-prostaglandin F (PGFM) levels fell significantly, suggesting suppression of prostaglandin release by the infusion. The antihypertensive effect of volume expanders in pregnancy-associated hypertension is mediated by a factor other than simple volume expansion.

Adult↗
PubMed1989

Attenuation of the baroreceptor reflex by propofol anesthesia in the rat.

The effect of the intravenous (i.v.) short-acting anesthetic propofol on baroreflex control of heart rate (HR) was examined in normotensive rats. Propofol was infused at a fixed rate of 9 mg/kg.h immediately after a bolus dose of 10 mg/kg. Blood pressure (BP) was maintained with a plasma substitute. Conscious rats were used for comparisons. Reflex HR response were recorded after i.v. doses of the pressor agent phenylephrine and the depressor agent sodium nitroprusside. Baroreceptor reflex parameters were determined by sigmoidal computerized curve-fitting. Propofol produced tachycardia at rest and atropine increased HR only moderately. In addition, a limitation in the bradycardiac response to artificial BP increases (lower plateau) was shown. This set of data indicated a vagal depression. The sympathetic component of the baroreflex was equally affected, since the maximal tachycardia resulting from artificial BP decreases (higher plateau) was shifted toward lower values. A marked diminution of the baroreflex gain resulted from the reduced activity of both vagal and sympathetic components. The mechanism for this decrease in the baroreflex-dependent total autonomic effector output (HR range) probably reflects the interaction of propofol with the baroreceptor pathways.

Anesthesia↗
PubMed1996

Hemodynamic, plasma volume, and prenodal skin lymph responses to varied resuscitation regimens.

The theoretical efficacy of hypertonic saline (HS) resuscitation for hemorrhagic shock purportedly stems from the osmolar extraction of intracellular fluid into the plasma. This hypothesis presumes a concomitant expansion of the interstitial fluid space. Colloid resuscitation, in theory, expands the plasma volume by extracting interstitial fluid. These hypotheses were tested in a canine-modified Wigger's model of hemorrhagic shock. Forty, male, splenectomized dogs were anesthetized and instrumented. Animals underwent a baseline equilibration period followed by shock for 120 minutes. Each animal was randomized to one of four groups and received equal amounts of Na+ either as lactated Ringer's (LR) solution, 10% dextran 40 (Dex) in normal saline, 7.5% saline (HS), or 7.5% saline plus Dex (HSD). Parameters measured at baseline, shock, and at postresuscitation 30 minutes, 60 minutes, 90 minutes, and 120 minutes, included: mean pressure (MAP), output, pulmonary capillary wedge pressure, prenodal skin lymph flow, serum and lymph albumin, wet-to-dry skin ratios, and plasma volume. MAP, cardiac output, and plasma volume were most quickly restored with LR and Dex resuscitation (MAP = 106 and 118 mm Hg) compared to HS and HSD (MAP = 98 and 92 mm Hg). Lymph flow and lymph albumin flux were best restored with LR and HSD (mean = 85 and 48 microL/min) compared to Dex and HS (mean = 36 and 37 microL/min). Wet/dry skin ratios were greatest at 60 minutes in the LR group but similar at 120 minutes in all four groups. These data suggest that interstitial fluid space remains contracted during the first hour after HS, HSD, and Dex resuscitation compared with LR resuscitation, even though the restoration of plasma volume, MAP, and cardiac output is greatest with the Dex regimen. Further studies with total body water and intracellular water are needed in this model.

Animals↗
PubMed1998

Preoperative volume expansion improves tolerance to carotid artery cross-clamping during endarterectomy.

OBJECTIVE: The benefit of carotid endarterectomy for carotid artery stenosis relates to both appropriate patient selection and careful surgical technique. Critical to the latter is the ability to afford intraoperative neuroprotection during carotid cross-clamping, although the optimal strategy to assure this protection remains debated. This report describes the impact of adding preoperative colloid volume expansion to a surgical algorithm that includes electroencephalographic (EEG) monitoring and barbiturate-induced burst suppression for EEG lateralization refractory to hypertension. METHODS: The incidence of ischemic EEG change during carotid cross-clamping was observed. The results of an initial series of patients (n = 45) reported before incorporation of volume expansion were compared with the results of the current series (n = 155) of carotid endarterectomies, which included preoperative volume expansion with 6% hetastarch (500 or 1000 cc). RESULTS: With preoperative volume expansion, there was a 40% decrease in the incidence of EEG lateralization during carotid cross-clamping (17.4 versus 28.9%, P < 0.05) and a 63% decrease in the EEG lateralization refractory to induced hypertension (5.8 versus 15.6%, P < 0.05). The combined perioperative stroke and death rate was 1.3%. CONCLUSION: These results support the use of preoperative colloid volume expansion in carotid endarterectomy as a means of increasing the cerebral tolerance to carotid cross-clamping.

Adjuvants, Anesthesia↗
PubMed1999

Vascular permeability increase and plasma volume loss induced by endotoxin was attenuated by hypertonic saline with or without dextran.

Endotoxin given intravenously is known to cause plasma leakage and subsequent loss of circulating plasma volume. Hypertonic saline resuscitation has been successfully applied in hemorrhagic and traumatic shock, but its application for the treatment or prevention of septic or endotoxin shock is less well studied. Our aim was to investigate the effects of endotoxin on plasma leakage in hamsters when administered in two different ways: applied locally to the hamster cheek pouch microcirculation or systemically by i.v. injection. The cheek pouch was studied by intravital microscopy using FITC-labeled dextran as a tracer of plasma leakage. Escherichia coli lipopolysaccharide (LPS) was continuously added into the superfusion buffer of the cheek pouch preparation during 120 min in two control groups (each n = 6) and two further groups (each n = 6) treated with either hypertonic saline (HS) or hypertonic saline and dextran (HSD). Treatment was given as an i.v. injection 0.35 mL NaCl 7.5%/100 g b.w. during 4 min starting 15 min prior to the start of endotoxin application. Endotoxin caused a reversible increase in the number of postcapillary venular leaks with a maximal response at 70 min after start of endotoxin application. The maximal responses were reduced to 36% in the HS-treated and to 37% in the HSD-treated group in comparison to what was seen in the control groups. In the second part of the study endotoxin was given i.v. 0.3 mg/kg to anesthetized hamsters (n = 41) and arterial blood samples were collected at 0, 60, 120, and 180 min after endotoxin injection for measurement of hematocrit and plasma FITC-dextran concentration. Hamsters were divided into seven groups: untreated control group (n = 6); HSC control group given only an i.v. injection of hypertonic saline (n = 6); LPS group given endotoxin 0.3 mg/kg during 1 min (n = 9); HSp group given hypertonic saline (NaCl 7.5%) 10 min prior to i.v. endotoxin (n = 6); HSa group given hypertonic saline 10 min after i.v. endotoxin (n = 6); HSD group given hypertonic saline with dextran 40, 10 min prior to i.v. endotoxin (n = 6); HSD control group given only i.v. hypertonic saline + dextran and no endotoxin (n = 2). Injection of endotoxin caused a significant increase in hematocrit, which was counteracted by hypertonic saline treatment, with or without dextran, probably due to reduced extravasation of plasma in postcapillary venules.

Animals↗
PubMed2000

Blood volume, aerobic power, and endurance performance: potential ergogenic effect of volume loading.

OBJECTIVE: Blood volume (BV) and hemoglobin concentration ([Hb]) play important roles in oxygen transport. Manipulation of both BV and [Hb] can markedly affect systemic oxygen transport and maximal aerobic capacity (VO2max). However, the role of BV in oxygen transport and aerobic performance is not well understood. It has recently been postulated that an acute expansion of BV using plasma volume (PV), independent of changes in [Hb], may represent a potential ergogenic property. Therefore, the primary objective of this review was to determine the potential ergogenic properties of volume loading. DATA SOURCES: An extensive research of Medline and Sport-Discus along with cross-referencing was conducted. Articles were included on the basis of their relevancy to the purpose of this review. Only articles published in English were included in the analysis. STUDY SELECTION: All study designs using human participants were reviewed. DATA EXTRACTION: A systematic analysis of data regarding the effect of BV on the determination of oxygen transport, aerobic capacity, and endurance performance was conducted. Particular emphasis was given to articles that examined BV as the key independent variable. Articles relevant to the evaluation of the impact of BV on aerobic capacity and endurance performance were reviewed according to the strengths of the individual study designs. RESULTS: Seven investigations evaluated the impact of acute changes in BV, independent of changes in [Hb], on VO2max. Of these investigations, three revealed that acute manipulations of BV result in no change or a slight reduction in VO2max. Three investigations revealed a significant improvement in VO2max after acute PV expansion. One investigation revealed a nonsignificant increase in VO2max after acute PV expansion. Seven investigations evaluated the impact of acute changes in BV, independent of changes in [Hb], on endurance performance: two revealed a significant improvement in endurance performance after acute PV expansion, and five revealed an unchanged or reduced endurance performance after acute PV expansion. The majority of investigations showing an improvement in VO2max and/or endurance performance after acute PV expansion were conducted using untrained individuals. CONCLUSION: Volume loading does not result in an improvement in VO2max and/or endurance performance in endurance athletes. Volume loading in untrained individuals may improve VO2max, but does not bring these individuals to the aerobic capacity of endurance-trained athletes. Also, volume loading generally does not lead to improvement in endurance performance, irrespective of its effects on VO2max.

Adult↗
PubMed2006

Plasma volume expansion and transcapillary fluid exchange in skeletal muscle of albumin, dextran, gelatin, hydroxyethyl starch, and saline after trauma in the cat.

OBJECTIVE: To compare 5% albumin, 6% dextran 70, 3.5% gelatin, 6% hydroxyethyl starch 130/0.4, and saline regarding their plasma volume expanding effect after a surgical skeletal muscle trauma and their simultaneous effects on transvascular fluid exchange in skeletal muscle. DESIGN: Controlled, prospective, randomized laboratory study. SETTING: University research laboratory. SUBJECTS: Thirty-six adult cats. INTERVENTIONS: Systemic arterial pressure and tissue volume variations of and blood flow to a surgically isolated and autoperfused calf muscle placed in a plethysmograph were recorded. Arterial and venous pressures to the muscle were kept constant. After preparation, plasma volumes were determined by a I albumin tracer technique just before and 3 hrs after a bolus infusion of the plasma expander (25 mL/kg). MEASUREMENTS AND MAIN RESULTS: Plasma volume was 20.9 +/- 2.9 mL/kg (n = 36) just before infusion of the plasma expander (normal plasma volume for the cat is 34-37 mL/kg). The remaining volume expansion of the infusion after 3 hrs was 6.8 mL/kg for albumin, 11.2 mL/kg for dextran, 1.8 mL/kg for gelatin, 2.2 mL/kg for hydroxyethyl starch, and 0.9 mL/kg for saline. Plasma volume decreased by 1.1 mL/kg when no solution was given (n = 6 per group). Colloid osmotic pressure was better preserved with dextran and albumin than with the other solutions. Albumin and dextran reduced muscle volume by absorption after 3 hrs, whereas the initial absorption turned to net filtration in the gelatin and hydroxyethyl starch groups. Saline infusion increased muscle volume by filtration for about 20 mins, followed by an approximately constant volume. CONCLUSION: The relatively poor plasma expansion for all solutions analyzed can most likely be explained by increased transcapillary leakage due to increased microvascular permeability following trauma. Under such circumstances, for equal volumes, plasma expansion was better preserved with 6% dextran 70 than with 5% albumin, which was better than 3.5% gelatin, 6% hydroxyethyl starch 130/0.4, and saline.

Animals↗
PubMed2004

Plasma volume changes associated with two hydroxyethyl starch colloids following acute hypovolaemia in volunteers.

This randomised double blind prospective study compared the effective intravascular volume expansion and maintenance, with two types of starches following induced haemorrhagic hypovolaemia. Twenty healthy male volunteers aged between 18 and 65 year were bled 10% of their total blood volume in fully monitored conditions and under the supervision of a trained specialist doctor and research nurse. The lost blood volume was replaced using one of the starch solutions. Effective intravascular volume expansion was monitored hourly using the (51)Cr radio-labelled red blood cell dilution technique, we compared the effects of two hydroxyethyl starch colloid preparations, one a high molecular weight and the other a low molecular weight preparation, on the plasma volume changes over time. The large molecular weight starch (Hextend) provided a less well-sustained volume expansion effect than the smaller one (Voluven)

Acute Disease↗
PubMed2005

Fluid shift is moderate and short-lived during acute crystalloid hemodilution and normothermic cardiopulmonary bypass in piglets.

BACKGROUND: Crystalloids are commonly used as priming solutions during cardiopulmonary bypass (CPB). Consequently, hemodilution is a regular occurrence at the start of a CPB. This study describes the time-course variations of hemodynamic parameters, plasma volume (PV) and fluid exchange following crystalloid hemodilution at start of normothermic CPB. METHODS: Forty-five anesthetized piglets were given 60-min normothermic CPB. Ringer's solution was used as priming solution and maintenance fluid. Fluid input/losses, PV, colloid osmotic pressures (plasma/interstitium), hematocrit, and s-proteins were measured, and fluid extravasation rates (FER) and intravascular protein-masses calculated. RESULTS: Start of CPB resulted in a 25-30% hemodilution. To keep the fluid level of the CPB-reservoir constant after start of bypass, fluid addition [2.08 +/- 0.36 (mean +/- SEM) ml kg(-1) min(-1)] was necessary during the first 5 min. Thereafter the fluid needs to be leveled off [0.17 +/- 0.03 ml kg(-1) min(-1) (10-60 min), P < 0.001]. Fluid extravasation rate increased immediately following hemodilution from a baseline value of 0.08 +/- 0.01 to 1.75 +/- 0.34 ml kg(-1) min(-1) with a delayed decrease compared to fluid additions, to reach a 'steady-state' level of 0.22 +/- 0.03 ml kg(-1) min(-1) after 30 min (P < 0.001). Differences in time-course variations between fluid added and fluid extravasated were accompanied by changes in PV and mean arterial pressure. The colloid osmotic gradient decreased about 50% throughout the study and could partly explain the increased FER. CONCLUSION: Acute crystalloid hemodilution contributes to fluid overload during normothermic CPB. The resulting increase in fluid extravasation is, however, moderate, short-lived and levels off to baseline values within 30 min.

Animals↗
PubMed1994

Blood safety in developing countries.

This study, based on responses to a questionnaire, was undertaken to define problems in and formulate solutions for improving blood safety in developing countries as part of an effort to monitor the status of blood transfusion services globally. Despite improvements between 1988 and 1992, only 66% of developing countries (DGCs) and 46% of least developed countries (LDCs) screen all blood donations for antibodies to human immunodeficiency viruses; 72% DGCs and 35% LDCs test all donations for hepatitis B surface antigen and 71 and 48%, respectively, for syphilis. The antihuman globulin test is performed routinely in 62% DGCs and 23% LDCs, and inadequate quality assurance in all aspects of preparatory testing is a major weakness in many countries. The blood supply is usually insufficient: none of the LDCs and 9% of the DGCs collect 30 units or more per 1,000 of the population annually. Blood donor systems are totally voluntary and non-remunerated in 15% DGCs and 7% LDCs; 80% DGCs and 93% LDCs rely totally or partially on replacement donors and 25% of both groups on paid donations. The proportion of repeat donors is low (medians: 47% in DGCs, 20% in LDCs), and discard rates for collected blood are often high (up to 33%). Most of the blood collected is transfused as whole blood, and most DGCs and LDCs have inadequate supplies of plasma substitutes for management of acute haemorrhage. The reasons for these problems and suggested solutions are discussed.

AIDS Serodiagnosis↗
PubMed1963

PLASMA VOLUME EXPANSION BY RAPID INFUSION OF A LOW MOLECULAR WEIGHT DEXTRAN.

Large infusions of a 10% solution of dextran of molecular weight 40,000 were given to dogs during 3 min using a specially designed apparatus. The initial expansion of plasma volume was about twice the volume of solution injected. Plasma volume then fell rapidly (with a half life of about 2 hr), more rapidly than the fall in dextran concentration (half-life of about 4.5 hr). Fluctuations in plasma volume and protein concentration were repeatedly observed during the return towards normal values. At 5 to 6 hr renal excretion accounted for 40% of the infused dextran, about 20% was intravascular and the remaining 40% was presumably extravascular. No dextran was found in the cerebrospinal fluid.

Animals↗