Advantages of a narrow-range, medium molecular weight hydroxyethyl starch for volume maintenance in a porcine model of fecal peritonitis

Comparative Assessment of the Effects of Hydroxyethyl Starch and Normal Saline on Severe Hypotension in Patients with Aluminum Phosphide Poisoning: A Retrospective Study

Background

Aluminum phosphide poisoning is one of the most common forms of poisoning which requires immediate and urgent treatment.

Objective

This study aimed to compare the efficiency of two solutions, including hydroxyethyl starch and normal saline, in treating hypotension in patients with aluminum phosphide poisoning.

Methods

This retrospective cohort study was conducted on 35 patients with aluminum phosphide poisoning. We reviewed the profile of 18 patients treated with hydroxyethyl starch and 17 patients treated with normal saline. Within-group and between-group differences in systolic blood pressure before and after treatment were compared using paired t-test and independent t-test, respectively.

Results

The mean ± standard deviation (SD) age of the subjects in the starch and normal saline groups was 27.06 ± 9.72 and 27.88 ± 9.08, respectively. The levels of blood pressure in the two groups were not significantly different before the treatment; the mean ± SD of systolic blood pressure in the starch and normal saline groups was 72.67 ± 14.49 and 68.59 ± 8.3, respectively (P=0.313). After the treatment, it was significantly increased to 94 ± 24.45 and 85.18 ± 19.9 in the starch group (P=0.001) and the normal saline group (P=0.004), respectively. However, there was no significant difference between the two groups (P=0.245). Only one person survived in each group.

Conclusion

According to the results of this study, although there was no significant difference between the two groups in terms of their effects on hypotension, these treatments could not prevent mortality.

Prevention of post-traumatic clinical capillary leak syndrome

Systemic capillary leak is an early feature of the inflammatory response to localized injury, and is proportional to the severity of the inflammatory insult. Loss of local control of inflammation leads to an exaggerated systemic inflammatory response known as systemic inflammatory response syndrome (SIRS). SIRS is associated with multiple organ failure and death when there is failure to maintain homeostasis.

Whilst the application of molecular biology and recombinant techniques have produced major advances in our understanding of the mediation of the inflammatory response, there is no agent currently available which will prevent SIRS and reduce the incidence of post-traumatic multiple organ failure. In the meantime, a more practical approach to the avoidance of SIRS and its attendant capillary leak syndrome is to attempt to reduce the deleterious effects of interstitial oedema by tailoring treatment to the rapid changes in capillary permeability.

Crystalloids and colloids for volume replacement

For many years there has been a debate about whether crystalloids or colloids should be used for resuscitation. Some years ago, albumin was the gold standard against which all other solutions were compared. This continues to be the case, despite the fact that other solutions are as effective for volume replacement. This paper stresses the need for a proper understanding of the properties of solutions that may influence the choice for volume replacement. Different classes of solutions are discussed in detail, with special reference to their effects on cardiovascular and oxygen transport parameters. Other important properties such as side-effects and effect on coagulation are also considered.

Physical plugging does not account for attenuation of capillary leakage by hydroxyethyl starch 130/0.4: a synthetic gel layer model

Hydroxyethyl starch (HES) solutions, widely used plasma substitutes, reportedly attenuate capillary leakage via physical plugging of capillary defects. We investigated how 2% HES solutions of different molecular weights (HES(70): 70 kDa, HES(130): 130 kDa, HES(200): 200 kDa, and HES(670): 670 kDa) affect dye release from polyacrylamide gels (PAGs) as a model of endothelial glycocalyx. We assessed dye release from 4% PAG with varying concentrations of albumin [0, 1, 2, 4, and 8% (w/v)] by measuring the change in dye absorbance (ΔAbs) at 5 h for each HES solution. For PAG containing no albumin, ΔAbs for HES(130) was 30% lower than that for HES(70) and HES(200), and 50% lower than that for HES(670). At concentrations of 1-8% albumin, ΔAbs at 5 h with HES(70), HES(130), and HES(200) solutions were almost half that with the HES(670) solution, but no significant differences were noted in ΔAbs at 5 h among HES(70), HES(130), and HES(200) solutions. The inhibition of dye release by HES(670) is likely due to the hindering effect of HES molecules partitioned into gel pores. However, a unique property of HES(130) , including the heavy hydroxyethylation at the C(2) position, may promote specific interactions with PAG and thereby inhibit solute release.

Could hydroxyethyl starch be a therapeutic option in management of acute aluminum phosphide toxicity?

Acute aluminum phosphide poisoning is a serious toxicity and results in high mortality rate despite the progress of critical care. After ingestion, phosphine gas is released and absorbed quickly, causing systemic poisoning and cell hypoxia. Excessive thirst, severe hypotension, arrhythmias, tachypnea, and severe metabolic acidosis are the common clinical manifestations. We think acute metabolic response which characteristically occurs in severe injury also happens in aluminum phosphide poisoning. Necropsy examinations indicate congestion in almost all vital organs because of leakage of fluids from intravascular to extravascular space. The most favorable type of fluid for intravascular volume resuscitation persists and is disputed. Colloids remain in the intravascular space rather than crystalloids, and provide more rapid hemodynamic stabilization. Furthermore, hydroxyethyl starch solution may have other benefits e.g. it can reduce the extra vascular leak of albumin and fluids from an endothelial injury site. As refractory hypotension and cardiovascular collapse, because leakage of fluids from intravascular to extravascular space are common cause of death in this toxicity, we propose that hydroxyethyl starch can dominate this refractory hypotension and consequently acute metabolic response.

Combined therapy of pentastarch, dexamethasone, and dibutyryl-cAMP or beta 2-agonist attenuates ischaemia/reperfusion injury of rat lung

We hypothesised that combined therapy with macromolecules that seal endothelial damage [pentastarch (Penta)], an anti-inflammatory agent [dexamethasone (Dex)], and an agent that reabsorbs alveolar fluid [beta(2)-agonist or dibutyryl-cAMP (Bt(2)-cAMP)] would have additive ameliorating effects on ischaemia/reperfusion (I/R) injury of the lung. We perfused one of the following solutions into isolated rat lungs in a closed circulating system, either prior to I/R injury (groups 1-5) or following 60 min of ischaemia (groups 6-10): (1) 0.9% normal saline (NS), (2) Penta, (3) Penta+Dex, (4) Penta+Bt(2)-cAMP, (5) Penta+beta(2)-agonist inhalation, (6) Penta+Dex, (7) Penta+Bt(2)-cAMP, (8) Penta+beta(2)-agonist inhalation, (9) Penta+Dex+Bt(2)-cAMP, or (10) Penta+Dex+beta(2)-agonist inhalation. Haemodynamics, lung weight gain (LWG), capillary filtration coefficient (K(fc)), cytokine mRNA levels, and lung pathology were assessed. Results showed that Dex, Bt(2)-cAMP, or beta(2)-agonist as an additive to Penta decreased K(fc) and LWG below values seen with Penta alone. Furthermore, LWG and K(fc) values in groups with three protective agents were lower than those in groups with two protective agents. Significantly lower levels of TNF-alpha and IL-1 mRNAs were observed in groups treated with Dex. Histopathological studies showed decreased injury profiles for all combined therapy groups. We conclude that the addition of Dex, Bt(2)-cAMP, or beta(2)-adrenergic agonist to Penta solution promoted attenuation of I/R injury. Furthermore, combination therapy with three protective agents (Penta+Dex+beta(2)-adrenergic agonist) caused the greatest attenuation of I/R.

Attenuation of capillary leakage by hydroxyethyl starch (130/0.42) in a porcine model of septic shock

OBJECTIVES

Capillary leakage, a frequent complication in septic shock, is characterized by loss of intravasal fluid resulting in generalized edema and hemodynamic instability despite massive fluid therapy. We have shown that administration of an established colloid 200/0.5 hydroxyethyl starch (HES) stabilized plasma volume in a porcine septic shock model. Recently, a new HES with a low molecular weight (130 kD) and lower molar substitution (0.42) has been developed. In this study, we compared effects of HES 130/0.42 and HES 200/0.5 on capillary leakage in porcine septic shock.

DESIGN

Prospective randomized, controlled animal study.

SETTING

University department of anesthesiology.

SUBJECTS

Fourteen pigs (22.9 +/- 2.8 kg).

INTERVENTIONS

Anesthetized and mechanically ventilated pigs were observed over 6 hrs.

MEASUREMENT AND MAIN RESULTS

Septic shock was induced with fecal peritonitis (0.75 g.kg of body weight autologous feces). Animals were allocated to volume-replacement therapy with either HES 130/0.42 (n = 5) or HES 200/0.5 (n = 5) and compared with nonseptic controls receiving HES 130/0.42 (n = 4). Infusion rate was titrated to maintain a central venous pressure of 12 mm Hg. Albumin escape rate was calculated using iodine 125-labeled albumin. Plasma volume was determined using chromium-51-tagged erythrocytes. Albumin escape rate increased significantly in both groups in comparison to controls (HES 200/0.5, 45% +/- 3; HES 130/0.42, 38% +/- 5), but this increase was significantly smaller with HES 130/0.42. Both HES 200/0.5 (-14%, not significant) and HES 130/0.42 (-1%, not significant) stabilized plasma volume compared with controls. Systemic oxygenation was not significantly altered in either group.

CONCLUSIONS

In this porcine septic shock model, HES 130/0.42 attenuated capillary leakage significantly more effectively than HES 200/0.5.

Resuscitation from septic shock with capillary leakage: hydroxyethyl starch (130 kd), but not Ringer's solution maintains plasma volume and systemic oxygenation

There is evidence suggesting that early fluid resuscitation is beneficial in the treatment of septic shock. The question as to which solution should be used remains controversial. Using a porcine septic shock model, we tested the effects of a new synthetic colloid hydroxyethyl starch (HES 130 kD) and a crystalloid regimen with Ringer's solution (RS) on plasma volume (PV) maintenance as well as on systemic and regional hemodynamics. Fourteen anaesthetized mechanically ventilated pigs received 0.75 g kg body weight of feces into the abdominal cavity to induce sepsis. They were randomly allocated to receive 6% HES 130 kD (n = 5) or RS (n = 5) and were compared with nonseptic controls receiving 6% HES 130 kD (n = 4). The infusion rate was titrated to maintain a central venous pressure of 12 mmHg. PV was determined by chromium-51-tagged erythrocytes and hematocrit. Albumin escape rate (AER) was calculated using iodine-125-labeled albumin. Arterio-intramucosal pCO2 gap, systemic hemodynamics, and oxygenation were obtained before and 6 h after induction of sepsis. AER increased in the HES (+38%) and RS groups (+38%) compared with control. PV was reduced in the RS group (-39%), but was maintained in the HES group (-1%). After 6 h of sepsis, HES 130 kD-treated animals had a significantly higher cardiac output (166 +/- 28 mL min kg vs. 90 +/- 18 mL min kg, P < 0.05), and a significantly higher mixed-venous oxygen saturation (65% +/- 8% vs. 40% +/- 14%, P < 0.05) than RS animals. In this porcine septic shock model with concomitant capillary leakage syndrome, resuscitation with HES 130 kD but not RS could maintain PV and preserve systemic hemodynamics and oxygenation.

Fluid resuscitation with colloids of different molecular weight in septic shock

OBJECTIVE

The aim of this study was to investigate the short-term effect of fluid resuscitation with 4% modified fluid gelatine (GEL) versus 6% hydroxyethyl starch (HES) on haemodynamics and oxygenation in patients with septic shock and acute lung injury (ALI).

DESIGN

Prospective randomised clinical trial.

SETTING

Twenty-bed intensive care unit in a university hospital.

PATIENTS

Thirty hypovolemic patients (intrathoracic blood volume index, ITBVI <850 ml/m(2)) in septic shock with ALI were randomised into HES (mean molecular weight: 200,000 Dalton, degree of substitution 0.6) and GEL (mean molecular weight: 30,000 Dalton) groups (15 patients each).

INTERVENTIONS

For fluid resuscitation 250 ml/15 min boluses (max. 1,000 ml) were given until the end point of ITBVI >900 ml/m(2) was reached. Repeated haemodynamic measurements were done at baseline (t(b)), at the end point (t(ep)) then at 30 min and 60 min after the end point was reached (t(30), t(60)). Cardiac output, stroke volume, extravascular lung water (EVLW), and oxygen delivery was determined at each assessment point. For statistical analysis two-way ANOVA was used.

MEASUREMENTS AND RESULTS

ITBVI, cardiac index, and oxygen delivery index increased significantly at t(ep) and remained elevated for t(30) and t(60), but there was no significant difference between the two groups. The increase in the ITBVI by 100 ml of infusion was similar in both groups (HES: 26+/-19 ml/m(2) vs GEL: 30+/-19 ml/m(2)). EVLW, remained unchanged, and there was no significant difference between the groups (HES, t(b): 8+/-6, t(60): 8+/-6; GEL, t(b): 8+/-3, t(60): 8+/-3 ml/kg). The PaO(2)/FiO(2) did not change significantly over time or between groups (HES, t(b): 207+/-114, t(60): 189+/-78; GEL, t(b): 182+/-85, t(60): 182+/-85 mmHg).

CONCLUSION

The results of this study indicate that both HES and GEL infusions caused similar short-term change in ITBVI in septic shock, without increasing EVLW or worsening oxygenation.

Fluid therapy in sepsis with capillary leakage

Sepsis is associated with a profound intravascular fluid deficit due to vasodilatation, venous pooling and capillary leakage. Fluid therapy is aimed at restoration of intravascular volume status, haemodynamic stability and organ perfusion. Circulatory stability following fluid resuscitation is usually achieved in the septic patient at the expense of tissue oedema formation that may significantly influence vital organ function. The type of fluid therapy, crystalloid or colloid, in sepsis with capillary leakage remains an area of intensive and controversial discussion. The current understanding of the physiology of increased microvascular permeability in health and sepsis is incomplete. Furthermore, there is a lack of appropriate clinical study end-points for fluid resuscitation. This review considers critically the clinical and experimental data analysing the assessment of capillary leakage in sepsis and investigating the effects of different fluid types on increased microvascular permeability in sepsis.

Septic shock, multiple organ failure, and acute respiratory distress syndrome

In 1914, Schottmueller wrote "Septicemia is a state of microbial invasion from a portal of entry into the blood stream which causes signs of illness." In the last few decades, the evidence that sepsis results from an exaggerated systemic inflammatory host response induced by infecting organisms is compelling; inflammatory mediators are the key players in the pathogenesis of septic shock and multiorgan failure. Sepsis and its sequelae represent a continuum of clinical syndrome encompassing systemic inflammation, coagulopathy, and hemodynamic abnormalities. Severe sepsis and septic shock continue to be the major causes of morbidity and mortality in the United States; sepsis deaths currently match mortality from myocardial infarction. Despite significant advances in our understanding of the pathophysiology and technological innovations in the supportive management, mortality from septic shock remains excessive. After many disappointments with strategies to manipulate the inflammatory response, modulation of coagulation cascade to decrease sepsis mortality has become a clinical reality. This review will highlight and discuss recent advances in the pathophysiology and management of sepsis.

Which fluid to give?

Crystalloids are generally accepted, as the initial fluid of choice during trauma patient resuscitation but the pragmatic approach is to give a combination of both crystalloid and colloid. Plasmalyte 148 has advantages over both saline and lactated Ringer’s. Medium-or low-molecular weight hydroxyethyl starch may be the colloid of choice. In the future, haemoglobin-based oxygen carriers are likely to play a prominent role in trauma resuscitation.

Effect of hydroxyethyl starch infusion on colloid oncotic pressure in hypoproteinemic horses

OBJECTIVE

To determine the effect of hydroxyethyl starch (HES) on colloid oncotic pressure (pi) during fluid resuscitation of hypoproteinemic horses and to evaluate the clinical usefulness of direct and indirect methods for determination of pi before and after infusion of a synthetic colloid.

DESIGN

Prospective clinical study.

ANIMALS

11 hypoproteinemic horses.

PROCEDURE

Horses received IV infusions of 8 to 10 ml of a 6% solution of HES/kg (3.6 to 4.5 ml/lb) of body weight during fluid resuscitation. Blood samples were obtained for determination of plasma measured colloid oncotic pressure (pi meas) and plasma total protein and albumin (A) concentrations. Plasma globulin concentration (G) was calculated as the difference between plasma total protein and albumin concentrations. Calculated values for colloid oncotic pressure (piA + G) were determined by use of a predictive nomogram previously developed for horses.

RESULTS

There was no significant difference between the means of pi meas and piA + G at the beginning of HES infusion. After HES infusion, the mean of pi meas was increased significantly from baseline for 6 hours. Mean plasma total protein and albumin concentrations and piA + G were decreased significantly from baseline for 24 hours. Differences between mean pi meas and piA + G after HES infusion were significant for 24 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

There was good agreement between plasma pi meas and piA + G in blood samples obtained from hypoproteinemic horses immediately before infusion of HES. Use of a predictive nomogram did not, however, account for the oncotic effect of HES. Results of comparison of pi meas to piA + G after HES infusion suggest that a significant oncotic effect was maintained for 24 hours in the study horses.

Fluid resuscitation for the trauma patient

Attempts at prehospital fluid replacement should not delay the patient's transfer to hospital. Before bleeding has been stopped, a strategy of controlled fluid resuscitation should be adopted. Thus, the risk of organ ischaemia is balanced against the possibility of provoking more bleeding with fluids. Once haemorrhage is controlled, normovolaemia should be restored and fluid resuscitation targeted against conventional endpoints, the base deficit, and plasma lactate. Initially, the precise fluid used is probably not important, as long as an appropriate volume is given; anaemia is much better tolerated than hypovolaemia. Colloids vary substantially in their pharmacology and pharmacokinetics and the experimental findings from one cannot be extrapolated reliably to another. We still lack reliable data to prove that any of the colloids reduce mortality in trauma patients. In the presence of SIRS, hydroxyethyl starch may reduce capillary leak. Hypertonic saline solutions may have some benefit in patients with head injuries although this has yet to be proven beyond doubt. It is likely that one or more of the haemoglobin-based oxygen carriers currently under development will prove to be valuable in the treatment of the trauma patient.

[Role of albumin in pulmonary edema and septic shock, plasma volume expansion excluded]

Patients with septic shock deserve a global approach. Intravascular volume loading is part of the treatment. However several questions remain open: what are the respective contributions of volume expansion and vaso-active drugs in the restoration of blood pressure and increase of cardiac output, which volumes and type of solutions should be used, which pulmonary capillary wedge pressure should be targetted, and which evaluation criteria are the most appropriate? Few experimental and clinical studies provide evidence of a superiority of colloids over crystalloids, although none of them has documented a reduction of mortality, length of stay in ICU or duration of mechanical ventilation. There are no data support-ing a superiority of albumin over artificial colloids, which are also much cheaper. Moreover, hydroxyethylstarch could have promising properties in case of increased capillary permeability. In summary and in agreement with the North American consensus conference, albumin should not be recommended for the treatment of septic shock, whether associated with non cardiogenic pulmonary oedema or not.

Pentafraction for superior resuscitation of the ovine thermal burn

OBJECTIVE

To determine if a new hydroxyethyl starch, pentafraction, will cause better capillary retention of fluid in thermally burned and nonburned tissues when compared with some currently used volume expanders.

DESIGN

Randomized, controlled, experimental study.

SETTING

University research laboratory.

SUBJECTS

Twenty-one healthy adult range ewes.

INTERVENTIONS

Sheep, surgically prepared for chronic study, were randomly assigned to one of three colloid groups for the resuscitation of thermal injuries: a) ovine fresh-frozen plasma group; b) pentastarch group; and c) pentafraction group. Twenty-one sheep were subjected to a 40% total body surface, third-degree flame burn under anesthesia (1.5% to 2% halothane). When awakened, the sheep received 15 mL/kg of one of the above colloids, and then lactated Ringer's solution (2 mL/hr/kg). All animals survived and were killed at 48 hrs after burn injury.

MEASUREMENTS AND MAIN RESULTS

We found that cardiac index decreased and systemic vascular resistance increased in the pentastarch and plasma groups. However, cardiac index increased in the pentafraction group, while systemic vascular resistance increased by only half as much as in the other two groups. Cardiac index in the plasma group decreased significantly for the first 8 hrs, and did not return to the baseline value for 48 hrs. Systemic vascular resistance increased significantly for the first 8 hrs in both the plasma and pentastarch groups. Prefemoral lymph flow was significantly more increased in the pentastarch group, while the lung lymph/plasma oncotic gradient was maintained only by the pentafraction group.

CONCLUSIONS

Pentafraction is as good, or even superior, for volume resuscitation in the burn patients, when compared with pentastarch and plasma. This conclusion is made most evident by the attenuated changes in systemic vascular resistance and cardiac index. Pentafraction decreases the fluid flux and potential subsequent edema significantly in burned tissues and effectively maintains the pulmonary microvascular integrity.

The effect of hydroxyethyl starch and other plasma volume substitutes on endothelial cell activation; an in vitro study

OBJECTIVE

To study the effect of medium molecular weight hydroxyethyl starches on endothelial cell and neutrophil activation in vitro.

SETTING

Laboratory analysis.

METHODS

The effects of albumin and hydroxyethyl starch on the neutrophil adhesion molecule (CD11bCD18), with and without lipopolysaccharide stimulation, were studied in whole blood. E-selectin expression on human umbilical vein endothelial cells was stimulated with lipopolysaccharide alone and in the presence of either albumin or hydroxyethyl starch. The effect of albumin and hydroxyethyl starches on rapid endothelial cell activation was studied using von Willebrand factor release as a marker.

MEASUREMENTS AND RESULTS

Hydroxyethyl starches but not albumin inhibited stimulated vWF release in a dose dependent manner. No effect was seen on endothelial E-selectin or neutrophil CD11bCD18 expression.

CONCLUSIONS

these results suggest a possible beneficial role of hydroxyethyl starches in the inhibition of endothelial activation thus preventing neutrophil adhesion during sepsis syndrome.

Effect of hydroxyethyl starch on alveolar flooding in acute lung injury in dogs

The efficacy of hydroxyethyl starch (HES) in limiting alveolar flooding after acute lung injury was investigated using ethchlorvynol (ECV)-induced low pressure pulmonary edema in dogs. Harvested autologous plasma (PL) (control, n = 8) or 6% HES (n = 8) was infused (25 ml/kg) along with packed cells to result in an isovolemic, normochromic preparation before the administration of ECV. Extravascular thermal volume significantly increased after ECV administration in both groups of animals (6.6 to 13.4 ml/kg in PL, 6.5 to 15.0 ml/kg in HES). Systemic arterial PO2 decreased from 216 +/- 4 to 113 +/- 20 mm Hg, and venous admixture increased from 2.8 to 12.8% in the PL group but was not significantly changed in the HES group (219 +/- 5 to 203 +/- 8 mm Hg, and 2.9 to 4.4%, respectively). Epithelial lining fluid volumes after ECV administration increased in both groups but were elevated in the PL group to a greater extent than in the HES group (13.5 ml in HES versus 24.8 ml in PL). In the HES group there appeared to be no difference in the ability of plasma proteins to move across the alveolar epithelium. These results suggest that HES attenuates the flooding of the alveolar space and the resulting alterations in gas exchange during the development of low pressure pulmonary edema. The replacement of the plasma proteins with HES and the apparent inability of HES to cross the epithelial barrier into the alveoli may account for the protective effect of HES in these experiments.

A narrow range, medium molecular weight pentastarch reduces structural organ damage in a hyperdynamic porcine model of sepsis

OBJECTIVE

to compare diafiltered 6% pentastarch (Pentafraction--PDP, MWn 120,000 and MWw 280,000) and native pentastarch (Pentaspan--PSP, MWn 63,000 and MWw 264,000 dalton) in a porcine model of faecal peritonitis.

DESIGN

Randomised prospective study in 12 adolescent pigs.

INTERVENTIONS

Prior to infection the study solution was infused to increase Qt by 25%. Thereafter adjustments in infusion rate were made (up to 1 l/h) in an attempt to maintain Qt at 25% above baseline values.

MEASUREMENTS AND RESULTS

Animals were sacrificed at 8 h. Tissue was excised from the right lobe of liver and from the right lung and fixed for later electron microscopy and digital morphometric analysis. Patent sinusoidal lumen was significantly greater in group PDP compared to PSP (11.3% +/- 2.3% of liver tissue versus 4.8% +/- 1.1%, p < 0.05) and this was accounted for by a significantly lower proportion of sinusoidal lumen occluded with white cells (2.1% +/- 0.6% versus 6.6% +/- 1.9%, p < 0.05). Similarly, patent capillary represented a significantly higher proportion of lung tissue for group PDP versus PSP (26.2% +/- 1.9% versus 18.5% +/- 2.7%, p < 0.05). The arithmetic mean alveolar capillary barrier thickness was significantly greater in group PSP than in group PDP (4.3 +/- 0.3 microns versus 2.5 +/- 0.3 microns, p < 0.01).

CONCLUSIONS

The molecular weight profile of Pentafraction was associated with less structural organ damage including less tissue oedema and less white cell occlusion.

[Efficacy and tolerance of Elohes in plasma exchanges]

This study aimed to compare two plasma substitution regimens used during plasma exchanges (PE). It was a prospective cross-over randomized trial. Each patient (n = 12) had two PE at a 48 h interval. During one PE, only albumin was administered (PEA), and during the other one, equal volumes of albumin and low molecular weight hydroxyethylstarch (HES) (Elohes) were given (PEA+E). The order in which these different protocols were used was random. Plasma was separated by filtration, and the total volume extracted was one and a half the plasma volume. The parameters recorded every 15 min until 1 h after the end of PE, were heart rate, blood pressure and central venous pressure (CVP). Plasma volume, calculated from the mean body haematocrit and blood volume, was measured before and after PE. The clinical and biological tolerance of the rapid infusion of a large volume of HES was also assessed. PE characteristics were similar in both groups. For PEA and PEA+E, PE lasted 152 +/- 21 min and 154 +/- 25 min; the plasma volume extracted was 3,907 +/- 772 ml and 3,933 +/- 717 ml; the volume of plasma substitute infused was 4,097 +/- 617 ml and 3,933 +/- 717 ml, respectively. As haemodynamic and biochemical values were not significantly different in both groups, they were pooled together irrespective of the order of PE.(ABSTRACT TRUNCATED AT 250 WORDS)