Tissue storage of 14C-labelled hydroxyethyl starch (HES) 130/0.4 and HES 200/0.5 after repeated intravenous administration to rats

Postmortem evaluation of renal tubular vacuolization in critically ill dogs

OBJECTIVE

To describe the frequency of renal tubular vacuolization (RTV) as a surrogate of osmotic nephrosis and assess hyperosmolar agents as predictors of RTV severity.

DESIGN

Retrospective study (February 2004-October 2014).

SETTING

Veterinary teaching hospital.

ANIMALS

Fifty-three client-owned, critically ill dogs that had a postmortem examination.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The frequency, severity, and location of RTV were determined in small group of critically ill dogs postmortem. Logistic regression was performed to assess cumulative 6% HES (670/0.75) and mannitol dose as predictors for RTV severity with presenting serum creatinine concentration, cumulative furosemide dose, and duration of hospitalization as covariates. RTV was noted in 45 (85%) of 53 critically ill dogs and was most commonly located to the medullary rays (68%). Cumulative 6% HES (670/0.75) dose (P = 0.009) and presenting serum creatinine concentration (P = 0.027) were significant predictors of RTV severity. For every 1 mL/kg increase in 6% HES (670/0.75) dose that a dog received, there was 1.6% increased chance of having more severe RTV (OR 1.016; 95% CI 1.004-1.029). In addition, for every 88.4 μmol/L (1 mg/dL) increase in presenting serum creatinine, there was a 22.7% increased chance of having more severe RTV (OR 1.227; 95% CI 1.023-1.472). Cumulative mannitol (P = 0.548) and furosemide (P = 0.136) doses were not significant predictors of RTV severity.

CONCLUSION

In a small group of critically ill dogs, there was a high frequency of RTV identified on postmortem examination. Administration of 6% HES (670/0.75) and presenting serum creatinine concentration were significant predictors of RTV severity. Larger prospective studies are needed to determine the etiology and significance of RTV in dogs.

Raman-based detection of hydroxyethyl starch in kidney allograft biopsies as a potential marker of allograft quality in kidney transplant recipients

In brain-dead donor resuscitation, hydroxyethyl starch (HES) use has been associated with presence of osmotic-nephrosis-like lesions in kidney transplant recipients. Our aim was to determine whether the presence of HES in protocol renal graft biopsies at three months (M3) after transplantation is associated with renal graft quality. According to the HES administered to the donor during the procurement procedure, two groups of patients were defined according graft exposition to HES: HES group, (N = 20) and control group (N = 6). Detection and relative quantification of HES was performed by Raman spectroscopy microimaging on M3 protocol renal graft biopsies. Statistical analyses were used to investigate the association between Raman data and graft characteristics. HES spectral signal was revealed negative in the control group, whereas it was positive in 40% of biopsies from the HES group. In the HES group, a stronger HES signal was associated with a lower risk of graft failure measured by the Kidney Donor Risk Index (KDRI) and was correlated with the allograft kidney function. Thus, HES accumulation in donor kidney, as probed by Raman biophotonic technique, is correlated with the quality of donor kidney and consequently the graft renal function and graft survival.

Perioperative clinical and economic outcomes associated with replacing first-generation high molecular weight hydroxyethyl starch (Hextend®) with low molecular weight hydroxyethyl starch (Voluven®) at a large medical center

Background

Several plasma volume expander alternatives exist to enhance intravascular volume status in patients undergoing surgery. The optimal intravascular volume expander in the perioperative setting is currently unknown. Low molecular weight hetastarch, Voluven® (130/0.4), may have a better safety profile than high molecular weight hetastarch, Hextend® (450/0.7). We examined the clinical and cost outcomes of converting from Hextend® to Voluven® in a large tertiary medical center.

Methods

Using a large electronic database, we retrospectively compared two different time periods (2009 and 2010) where the availability of semisynthetic colloids changed. Perioperative and postoperative outcomes including the use of red blood cells (RBC), platelets and coagulation factors, length of stay in the postoperative acute care unit (PACU), intensive care unit and hospital, as well as 30-day and 1-year mortality were compared. In addition, direct acquisition costs of all intraoperative and PACU colloids and crystalloid use were determined.

Results

A total of 4,888 adult subjects were compared of which 1,878 received Hextend® (pre-conversion) and 2,759 received Voluven® (post-conversion) during two separate 7-month periods within 1 year apart, with the remainder receiving Plasmanate. The patients were similar in terms of patient demographics, preoperative comorbidities, ASA status, emergency surgery, types of surgery, intraoperative, and PACU times. In unadjusted outcomes, patients in the Hextend® group received more lactated Ringer’s than in the Voluven® group (2,220 + 1,312 vs. 1,946 ± 1,097 ml; P < 0.0001). The use of albumin (Plasmanate) was reduced from 10.5% of patients to 1.1% when Voluven® was substituted for Hextend®. Unadjusted outcomes were similar in each group including hospital LOS, percent change from baseline creatinine and receipt of intraoperative and PACU blood product administration. However, overall unadjusted total fluid costs were greater in the Voluven® compared to Hextend® group ($116.7 compared to $59.3; P < 0.001).

Conclusions

Conversion from Hextend® to Voluven® in the perioperative period resulted in decreased albumin use and was not associated with changes in clinical outcomes and short- and long-term mortality. The conversion was associated with decreases in crystalloid use and an increase in colloid use and hence IV fluid acquisition costs in the Voluven® group.

Contribution of Raman spectroscopy in nephrology: a candidate technique to detect hydroxyethyl starch of third generation in osmotic renal lesions

Raman spectroscopy, a candidate tool for detection of HES, a volume expander administrated after hemodynamic instability, in the kidney.

Hydroxyeyhyl starch: Controversies revisited

Hydroxyethyl starch (HES) family has been one of the cornerstones in fluid management for over four decades. Recent evidence from clinical studies and meta-analyses has raised few concerns about the safety of these fluids, especially in certain subpopulations of patients. High-quality clinical trials and meta-analyses have emphasized nephrotoxic effects, increased risk of bleeding, and a trend toward higher mortality in these patients after the use of HES solutions. Scientific evidence was derived from international guidelines, aggregated research literature, and opinion-based evidence was obtained from surveys and other activities (e.g., internet postings). On critical analysis of the current data available, it can be summarized that further large scale trials are still indicated before HES can be discarded.

Hydroxyethyl starch: a review of pharmacokinetics, pharmacodynamics, current products, and potential clinical risks, benefits, and use

OBJECTIVE

To review and summarize the pharmacokinetics and pharmacodynamics of hydroxyethyl starch (HES), as well as reported risks and benefits of HES infusion, and to provide administration and monitoring recommendations for HES use in dogs and cats.

DATA SOURCES

Veterinary and human peer-reviewed medical literature, including scientific reviews, clinical and laboratory research articles, and authors' clinical experience.

SUMMARY

HES solutions are the most frequently used synthetic colloid plasma volume expanders in human and veterinary medicine. The majority of research in human medicine has focused on the adverse effects of HES infusion, with emphasis on acute kidney injury and coagulation derangements. The studies often differ in or fail to report factors, such as the type, amount, interval, and concentration of HES administered; the patient population studied; or concurrent fluids administered. Currently, there is no definitive clinical evidence that the reported adverse effects of HES use in human medicine occur in veterinary species. There is little information available on HES administration techniques or simultaneous administration of additional fluids in human and veterinary medicine. The rationale for HES use in small animals has been largely extrapolated from human medical studies and guidelines. A controlled approach to intravenous fluid resuscitation using crystalloid and HES volumes titrated to reach desired resuscitation end point parameters is outlined for small animal practitioners.

CONCLUSION

The extrapolation of data from human studies directly to small animals should be done with the knowledge that there may be species variations and different pharmacokinetics with different HES solutions. Veterinary reports indicate that bolus and continuous rate infusions of 6% hetastarch solutions at moderate doses are well tolerated in feline and canine subjects. Further research in domesticated species is necessary to better define and expand the knowledge regarding use of HES solutions in small animal medicine.

Accumulation of hydroxyethyl starch in human and animal tissues: a systematic review

PURPOSE

To systematically review clinical and preclinical data on hydroxyethyl starch (HES) tissue storage.

METHODS

MEDLINE (PubMed) was searched and abstracts were screened using defined criteria to identify articles containing original data on HES tissue accumulation.

RESULTS

Forty-eight studies were included: 37 human studies with a total of 635 patients and 11 animal studies. The most frequent indication for fluid infusion was surgery accounting for 282 patients (45.9%). HES localization in skin was shown by 17 studies, in kidney by 12, in liver by 8, and in bone marrow by 5. Additional sites of HES deposition were lymph nodes, spleen, lung, pancreas, intestine, muscle, trophoblast, and placental stroma. Among major organs the highest measured tissue concentration of HES was in the kidney. HES uptake into intracellular vacuoles was observed by 30 min after infusion. Storage was cumulative, increasing in proportion to dose, although in 15% of patients storage and associated symptoms were demonstrated at the lowest cumulative doses (0.4 g kg(-1)). Some HES deposits were extremely long-lasting, persisting for 8 years or more in skin and 10 years in kidney. Pruritus associated with HES storage was described in 17 studies and renal dysfunction in ten studies. In one included randomized trial, HES infusion produced osmotic nephrosis-like lesions indicative of HES storage (p = 0.01) and also increased the need for renal replacement therapy (odds ratio, 9.50; 95% confidence interval, 1.09-82.7; p = 0.02). The tissue distribution of HES was generally similar in animals and humans.

CONCLUSIONS

Tissue storage of HES is widespread, rapid, cumulative, frequently long-lasting, and potentially harmful.

General anesthesia in horses on fluid and electrolyte therapy

The purpose of this article is to update the community of veterinarians performing general anesthesia in horses on fluid therapy. The rationale behind intraoperative fluid therapy, fluid dynamics, and various fluid options (crystalloids, hypertonic saline, colloids) is discussed. Additionally, electrolytes (calcium, potassium, and sodium) are included in the discussion in relation to general anesthesia and intraoperative fluid management.

Effect of rapid plasma volume expansion during anesthesia induction on haemodynamics and oxygen balance in patients undergoing gastrointestinal surgery

AIMS

To investigate the reasonable dose of Voluven for rapid plasma volume expansion during the anaesthesia induction patients receiving gastrointestinal surgery.

METHODS

Sixty patients were randomly divided into three groups (n=20): Group A (5 ml/kg), Group B (7 ml/kg) and Group C (9 ml/kg). HES 130/0.4 was intravenously transfused at a rate of 0.3 ml/kg/min) at 30 min before anaesthesia induction. Besides standard haemodynamic monitoring, cardiac index (CI), systemic vascular resistance index (SVRI) and stroke volume variation (SVV) was continuously detected with the FloTrac/Vigileo system. Haemodynamic variables were recorded immediately before fluid transfusion (T0), immediately before induction (T1), immediately before intubation (T2), immediately after intubation (T3) and 5 min, 10 min, 20 min and 60 min after intubation (T4-T7). Arterial and venous blood was collected for blood gas analysis, Hb and Hct before volume expansion (t0), immediately after volume expansion (t1) and at 1 h after volume expansion (t2). Oxygen delivery (DO2), oxygen extraction ratio (ERO2) and volume expansion rate were calculated.

RESULTS

1) MAP and CI decreased in Group A in T2~T7 and remained changed in Group B and C. 2) CVP increased in three groups after fluid infusion without significant difference. 3) The decrease in SVRI was more obvious in Group B and C than that in Group A after induction and more obvious in Group C than in Group B in T2-T4 and T6~T7. 4) SVV was lower in Group B and C than that in Group A after intubation, and lower in Group C than that in Group B in T3-T6. 5) Hb and Hct decreased after fluid infusion, and the decrease in Hb and Hct was in the order of C>B>A. 6) Volume expansion rate was in the order of C>B>A. 7) ScvO2, PaO2 and DO2 increased in three groups after fluid infusion and the increase in DO2 was in the order of C>B>A.

CONCLUSIONS

Rapid plasma volume expansion with Voluven at 7-9 ml/kg can prevent haemodynamic fluctuation during anaesthesia induction, maintain the balance between oxygen supply and oxygen consumption during gastrointestinal surgery, and Voluven at 9 ml/kg can improve the oxygen delivery.

Assessment of hemodynamic efficacy and safety of 6% hydroxyethylstarch 130/0.4 vs. 0.9% NaCl fluid replacement in patients with severe sepsis: the CRYSTMAS study

Introduction

Inadequate initial treatment and delayed hemodynamic stabilization (HDS) may be associated with increased risk of death in severe sepsis patients.

Methods

In order to compare the hemodynamic efficacy and safety of 6% HES 130/0.4 and NaCl 0.9% for HDS in patients with severe sepsis, we designed a prospective, multicenter, active-controlled, double-blind, randomized study in intensive care units.

Results

174 out of 196 patients reached HDS (88 and 86 patients for HES and NaCl, respectively). Significantly less HES was used to reach HDS vs. NaCl (1,379 ±886 ml in the HES group and 1,709 ±1,164 ml in the NaCl group (mean difference = -331± 1,033, 95% CI -640 to -21, P = 0.0185). Time to reach HDS was 11.8 10.1 hours vs. 14.3 ±11.1 hours for HES and NaCl, respectively. Total quantity of study drug infused over four consecutive days, ICU and hospital LOS, and area under the curve of SOFA score were comparable. Acute renal failure occurred in 24 (24.5%) and 19 (20%) patients for HES and NaCl, respectively (P = 0.454). There was no difference between AKIN and RIFLE criteria among groups and no difference in mortality, coagulation, or pruritus up to 90 days after treatment initiation.

Conclusion

Significantly less volume was required to achieve HDS for HES vs. NaCl in the initial phase of fluid resuscitation in severe sepsis patients without any difference for adverse events in both groups.

ClinicalTrials.gov

NCT00464204

Hydroxyethyl starch 130/0.42/6:1 for perioperative plasma volume replacement in 1130 children: results of an European prospective multicenter observational postauthorization safety study (PASS)

INTRODUCTION

Third-generation hydroxyethyl starch (HES) is now approved also for the use in children, but safety studies including large numbers of pediatric patients are still missing. Therefore, we performed an European multicentric prospective observational postauthorization safety study (PASS) to evaluate the use of HES 130/0.42/6:1 in normal saline (ns-HES) or a balanced electrolyte solution (bal-HES) in children undergoing surgery.

METHODS

Children aged up to 12 years with ASA risk scores of I-III receiving ns-HES (Venofundin 6%; Braun) or bal-HES (Tetraspan 6%; Braun) were followed perioperatively. Demographic data, surgical procedures performed, anesthesia, hemodynamic and laboratory data, adverse events (AE), and adverse drug reactions (ADR) were documented using a standardized case report form.

RESULTS

Of 1130 children studied at 11 European pediatric centers from 2006 to 2009 (ns-HES, 629 children; bal-HES, 475 children; mean age, 3.6 ± 3.8 [range, day of birth-12 years]; and body weight, 15.4 ± 13 [0.9-90 kg]), 1104 were included for analysis. The mean infused HES volume was 10.6 ± 5.8 (0.83-50) ml·kg(-1). In the 399 (36.1%) cases with blood gas analysis before and after HES infusion, hemoglobin and strong ion difference decreased significantly in both groups, whereas bicarbonate and base excess (BE before infusion: ns-HES -1.8 ± 3.1, bal-HES -1.2 ± 3.3 mm; after infusion: ns-HES -2.5 ± 2.8; bal-HES -1.1 ± 3.2 mm, P < 0.05) decreased only with ns-HES but remained stable with bal-HES. Chloride concentrations increased in both groups and were significantly higher with ns-HES (Cl before infusion: ns-HES 105.5 ± 3.6, bal-HES 104.9 ± 2.9 mm; Cl after infusion: ns-HES 107.6 ± 3.4, bal-HES 106.3 ± 2.9 mm, P < 0.05). For the AE/ADR rates, dose-response but no age relationships could be demonstrated. No serious and no severe ADR directly related to HES (i.e. anaphylactoid reaction, clotting disorders, renal failure) were observed.

CONCLUSION

Moderate doses of HES 130/0.42/6:1 for perioperative plasma volume replacement seem to be safe even in neonates and small infants. The probability of serious ADR is lower than 0.3%. Changes in acid-base balance may be decreased when HES is used in an acetate-containing balanced electrolyte solution instead of normal saline. Caution should be exercised in patients with renal function disturbances and those with an increased bleeding risk.

[Volume replacement in intensive care medicine]

Volume substitution represents an essential component of intensive care medicine. The amount of fluid administered, the composition and the timing of volume replacement seem to affect the morbidity and mortality of critically ill patients. Although restrictive volume strategies bear the risk of tissue hypoperfusion and tissue hypoxia in hemodynamically unstable patients liberal strategies favour the development of avoidable hypervolemia with edema and resultant organ dysfunction. However, neither strategy has shown a consistent benefit. In order to account for the heavily varying oxygen demand of critically ill patients, a goal-directed, demand-adapted volume strategy is proposed. Using this strategy, volume replacement should be aligned to the need to restore tissue perfusion and the evidence of volume responsiveness. As the efficiency of volume resuscitation for correction of tissue hypoxia is time-dependent, preload optimization should be completed in the very first hours. Whether colloids or crystalloids are more suitable for this purpose is still controversially discussed. Nevertheless, a temporally limited use of colloids during the initial stage of tissue hypoperfusion appears to represent a strategy which uses the greater volume effect during hypovolemia while minimizing the risks for adverse reactions.

Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM

BACKGROUND

Acute renal failure on the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques.

METHOD

A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system.

CONCLUSIONS AND RECOMMENDATIONS

Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest specific vasodilators [corrected] under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00134-009-1678-y) contains supplementary material, which is available to authorized users.

Unimolecular micelles based on hydrophobically derivatized hyperbranched polyglycerols: biodistribution studies

We recently reported the synthesis and testing of a new class of unimolecular micelles based on hyperbranched polyglycerols as second generation synthetic plasma expanders and as general drug delivery vehicles. A detailed biodistribution study of two derivatized hyperbranched polyglycerols of different molecular weights derivatized with hydrophobic groups and short poly(ethylene glycol) chains is reported in this article. In mice, these materials are nontoxic with circulation half-lives as high as 31 h, controllable by manipulating the molecular weight and the degree of PEG derivatization. Organ accumulation is low, presumably due to the "pegylation" effect. Thermal degradation and hydrolysis data suggest that these polymers are highly stable with a long shelf life, a major advantage for a pharmaceutical product. Degradation under acidic conditions has been observed for these polymers.

Safety of HES 130/0.4 (Voluven(R)) in patients with preoperative renal dysfunction undergoing abdominal aortic surgery: a prospective, randomized, controlled, parallel-group multicentre trial

BACKGROUND AND OBJECTIVE

Patients with impaired renal function are at risk of developing renal dysfunction after abdominal aortic surgery. This study investigated the safety profile of a recent medium-molecular-weight hydroxyethyl starch (HES) preparation with a low molar substitution (HES 130/0.4) in this sensitive patient group.

METHODS

Sixty-five patients were randomly allocated to receive either 6% hydroxyethyl starch (Voluven); n = 32) or 3% gelatin (Plasmion); n = 33) for perioperative volume substitution. At baseline, renal function was impaired in all study patients as indicated by a measured creatinine clearance < 80 mL min(-1). The main renal safety parameter was the peak increase in serum creatinine up to day 6 after surgery.

RESULTS

Both treatment groups were compared for non-inferiority (pre-defined non-inferiority range hydroxyethyl starch < gelatin + 17.68 micromol L(-1) or 0.2 mg dL(-1). Other renal safety parameters included minimum postoperative creatinine clearance, incidence of oliguria and adverse events of the renal system. Baseline characteristics, surgical procedures and the mean total infusion volume were comparable. Non-inferiority of hydroxyethyl starch vs. gelatin could be shown by means of the appropriate non-parametric one-sided 95% CI for the difference hydroxyethyl starch-gelatin [-infinity, 11 micromol L(-1)]. Oliguria was encountered in three patients of the hydroxyethyl starch and four of the gelatin treatment group. One patient receiving gelatin required dialysis secondary to surgical complications. Two patients of each treatment group died.

CONCLUSION

As we found no drug-related adverse effects of hydroxyethyl starch on renal function, we conclude that the choice of the colloid had no impact on renal safety parameters and outcome in patients with decreased renal function undergoing elective abdominal aortic surgery.

HES 130/0.4 (Voluven) or human albumin in children younger than 2 yr undergoing non-cardiac surgery. A prospective, randomized, open label, multicentre trial

BACKGROUND AND OBJECTIVE

For perioperative volume therapy in infants and young children, human albumin has frequently been the colloid of choice. Recently, HES 130/0.4 (6% hydroxyethyl starch, Voluven; Fresenius Kabi, Bad Homburg, Germany) was developed, which demonstrated improved pharmacokinetics and a favourable safety profile in adults compared with hydroxyethyl starch products with a less rapid metabolization.

METHODS

Our prospective, controlled, randomized, open, multicentre pilot study was designed to obtain data on the effects of HES 130/0.4 compared with human albumin 5% with regard to haemodynamics in children <2 yr scheduled for elective non-cardiac surgery.

RESULTS

A total of 81 patients were treated. Comparable amounts of both study solutions (16.0 mL kg(-1) hydroxyethyl starch 130/0.4 vs. 16.9 mL kg(-1) human albumin 5%) as well as add-on crystalloids were used until 4-6 h postoperatively. No differences were detected between the two treatment groups regarding perioperative stabilization of haemodynamics, coagulation parameters, blood gas analyses or other laboratory values. Blood loss was 96 +/-143 mL for hydroxyethyl starch and 145+/- 290 mL for human albumin (P > 0.05). There were no relevant differences in the amount of red blood cells, fresh frozen plasma or platelet concentrates in both treatment groups. Median length of ICU stay was 3.5 days (range 1-57 days, mean +/- SD 7.6 +/- 11.5 days) in the hydroxyethyl starch group and 6.0 days (range 1-71 days; mean +/- SD 9.1 +/- 14.2 days) in the human albumin group. There was no difference for hospital stay (median: 12 days for both groups).

CONCLUSIONS

Both HES 130/0.4 and human albumin 5% were effective for haemodynamic stabilization in non-cardiac surgery of young infants with no adverse impact on coagulation or other safety parameters in our study population.

HES 130/0.42 shows less alteration of pharmacokinetics than HES 200/0.5 when dosed repeatedly

BACKGROUND

Hydroxyethyl starches (HES) accumulate in the circulation when administered repeatedly. Accumulation is thought to be partly responsible for undesirable effects (tissue storage, blood coagulation impairment, and itching). HES 130/0.42 with low molecular weight and a low level of substitution has recently been developed in order to reduce those risks.

METHODS

In healthy volunteers, the pharmacokinetics of HES 130/0.42/6:1 were investigated using a crossover design with HES 200/0.5 serving as control. Fifty grams of either HES were administered in 4 h day-1 for a period of five consecutive days. HES serum concentrations were used for computation of pharmacokinetic coefficients. Change between the first and fifth infusion in the area under the concentration curve (AUC) served as the primary measurement.

RESULTS

Although the circulation was freed from the load with HES 130/0.42 within 20 h after end of the previous infusion, the amount of HES 200/0.5 increased continuously from one administration to the other. AUC and elimination half-life (t1/2) were significantly lower with HES 130/0.42. AUC and t1/2 of HES 200/0.5 showed an increase between the first and the fifth administration whereas only a minimal shift was present with HES 130/0.42. Haemodilution via HES 200/0.5 did not change over time.

CONCLUSIONS

Repeated administration of HES 130/0.42 shows no accumulation and fewer tendencies to time-dependent changes in pharmacokinetic parameters than HES 200/0.5. The improved reproducibility may improve drug safety, particularly as the accumulation of residual starch with HES 200/0.5 does not contribute to the colloid's volume effect, but may rather increase the risk of undesired reactions.

Pharmacodynamics and organ storage of hydroxyethyl starch in acute hemodilution in pigs: influence of molecular weight and degree of substitution

OBJECTIVE

To determine the differential influence of molecular weight and the degree of substitution of HES solutions on pharmacodynamics and pharmacokinetics including organ storage in a model of acute hemodilution in pigs.

DESIGN

Prospective controlled randomized animal trial.

INTERVENTIONS

After bleeding, 20 ml/kg, animals were substituted with 6% HES preparations (200/0.62, 200/0.5, and 100/0.5).

MEASUREMENTS AND RESULTS

We did not observe any significant differences in the ability to sufficiently achieve plasma volume expansion and restoration of macrocirculation, nor maintenance of indicators of microcirculation between the groups. Urine production was significantly higher in HES-treated animals and highest in animals substituted with HES 100/0.5. Plasma clearance was measured under steady-state conditions with significantly reduced clearance for the HES 200/0.62 group compared with HES 100/0.5 and HES 200/0.5 (6.6 vs. 13.2 and 13.9 ml/min; P < or = 0.001), thus being dependent on the degree of substitution. Even after only 6 h, the amount of infused HES not detectable in either blood or urine was significantly higher in HES 200/0.62-treated animals (50.7% compared with HES 200/0.5 (28.8%), P = 0.020 and HES 100/0.5 (28.4%), P = 0.018), with its proportion rising over time. Finally, we could demonstrate considerable amounts of all HES solutions being stored in liver, kidney, lung, spleen and lymph nodes.

CONCLUSIONS

All preparations analyzed sufficiently restored macro- and microcirculation; however, for all solutions relevant tissue storage of HES was observed after only 6 h.

Hemodilution Therapy With Hydroxyethyl Starch Solution (130/0.4) in Unilateral Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVE

Obtain and analyze first data on hydroxyethyl starch (HES 130/0.4) as monotherapy in acute idiopathic sudden sensorineural hearing loss (ISSNHL).

DESIGN

Randomized, double-blind, Phase-II, dose-finding study.

SETTING

Twenty-five ENT centers in Germany, the Czech Republic, Romania, and Austria.

PATIENTS

Two hundred and ten inpatients with first-time ISSNHL of at least 20 dB at two or more frequencies and 95 dB or less at all of the speech frequencies (0.5, 1.0, 2.0, 3.0, and 4.0 kHz) with respect to the other (normal) ear for up to 7 days (d).

INTERVENTION

Infusion of 750 mL/d with 45 (Group H), 30 (Group M), or 15 g/d HES (Group L), or glucose 5% (Group G) acting as "placebo" control during 6 days. MAIN ENDPOINT: Gain in average auditory threshold (in dB) from baseline to Day 7. RESULTS (MEDIANS): Average hearing loss at baseline was 24 dB, and infusions started 2 days after ISSNHL onset. No relevant group difference was observed in hearing gain or adverse treatment events, including pruritus. Half of all patients recovered completely by Day 7. SECONDARY ANALYSIS: In patients who started treatment within 2 days after the onset of symptoms and who had systolic blood'pressure (RRsyst) of less than 140 mm Hg, hearing at Day 90 had improved in all 28 cases under glucose 5%; for those who started treatment later and/or had RRsyst of 140 mm Hg or more, the risk for failing to recover under placebo was 29.2% (7/24). Comparing all 118 (51.9%) of 208 patients at such risk, outcome at Day 7 was markedly better in all HES subgroups than in the G'subgroup'(nH:nM:nL:nG = 32:29:32:24, Kruskal-Wallis, p = 0.0221).

CONCLUSION

All treatment groups were equivalent, including adverse treatment events. The secondary analysis showed that ISSNHL patients at risk for not improving under placebo (i.e., patients who started treatment more than 48 h after ISSNHL onset and/or with elevated RRsyst) recovered markedly better under infusions of HES 130/0.4.

Pruritus precipitated by hydroxyethyl starch: a review

Hydroxyethyl starch (HES) is widely used for fluid management in broad populations of patients, particularly in the surgery and intensive care settings. Pruritus, often manifested as pruritic crises, is increasingly being recognized as a common major adverse effect of HES administration. This iatrogenic form of pruritus is frequently severe and protracted with a serious negative impact on patient quality of life, including sleep disturbance, disruption of daily routine and mental distress. Such pruritus is generally refractory to available therapies and can persist for up to 12-24 months. All currently clinically available HES solutions entail the risk of pruritus, including those of diverse molecular weights and substitutions. Although dose dependent, HES-induced pruritus nevertheless can often be provoked by relatively low routine doses. The pathophysiological basis for pruritus is the widespread tissue deposition of HES, prominently in macrophages. HES tissue deposits are long lasting and sometimes massive. Usually several weeks elapse between HES exposure and the onset of pruritus. Consequently, it is important to inquire about prior HES exposure in the diagnostic evaluation of pruritus sine materia. Awareness about the scope of the pruritus problem needs to increase among physicians administering HES. Well-designed clinical outcome studies are needed to assess more fully the incidence, dose dependency and mechanisms of pruritus with particular HES solutions.

Pharmacokinetics of Hydroxyethyl Starch

Hydroxyethyl starch has recently become the subject of renewed interest because of the introduction of a new specification, hydroxyethyl starch 130/0.4, as well as the clinical availability of a solution using a previous hydroxyethyl starch type (hydroxyethyl starch 670/0.75) with a carrier other than 0.9% saline. Various types of hydroxyethyl starch show different pharmacokinetic behaviour. Since hydroxyethyl starch is a polydisperse solution acting as a colloid, pharmacodynamic action depends on the number of oncotically active molecules, not on the plasma concentration alone; therefore, solutions with a lower in vivo molecular weight contain more molecules at similar plasma concentrations. On the other hand, high plasma concentrations as well as high in vivo molecular weight can affect blood coagulation, especially factor VIII and von Willebrand factor. Hydroxyethyl starch types with a molar substitution >0.4 accumulate in plasma after repetitive administration, most pronounced with hetastarch (hydroxyethyl starch 670/0.75). Correspondingly, tissue storage as measured by (14)C tracer studies in animals showed significantly higher values for hydroxyethyl starch 200/0.5 compared with hydroxyethyl starch 130/0.4 (about 4-fold at the latest timepoint after the last administration), and considerably higher values for hetastarch compared with both hydroxyethyl starch 130/0.4 and 200/0.5. Hydroxyethyl starch 130/0.4 does not accumulate in plasma after single- and multiple-dose administration in contrast to all other available hydroxyethyl starch specifications. Plasma clearance of hydroxyethyl starch 130/0.4 is at least 20-fold higher than that for hetastarch, and considerably higher than for pentastarch. In patients with renal insufficiency, pharmacokinetic data are only available for hydroxyethyl starch 130/0.4. Cumulative urinary excretion, even in the presence of severe non-anuric renal failure, is higher for hydroxyethyl starch 130/0.4 than values published for older hydroxyethyl starch specifications. Hydroxyethyl starch 130/0.4 may be given to patients with severe renal impairment as long as urine flow is preserved. The pharmacodynamics with respect to the volume effect does not directly mirror pharmacokinetics in the case of hydroxyethyl starch solutions. Equivalent volume efficacy has been proven for hydroxyethyl starch 130/0.4 compared with 200/0.5. Prolonged persistence of hydroxyethyl starch in plasma and tissues can be avoided by using rapidly metabolisable hydroxyethyl starch types with molar substitution <0.5. Influence on coagulation is minimal with hydroxyethyl starch 130/0.4, and no adverse effects on kidney function have been observed even with large repetitive doses when used according to the product information.

[Hydroxyethylstarch (HES)]

Adequate volume replacement therapy is a mainstay of managing the critically ill. The ideal kind of volume replacement in this situation still remains a challenge. In spite of an immense number of contributions to this problem there is still no definite answer. The ideal volume replacement strategy should not only aim at maintaining stable systemic hemodynamics, organ perfusion and microcirculation should be guaranteed or even improved as well. Due to its excellent efficacy, hydroxyethylstarch (HES) preparations are widely used to treat hypovolemia. The different physico-chemical properties of the available HES solutions, however, should be taken into account. Anphylactoid reactions as well as negative effects on coagulation, kidney/liver function and on the immune system are frequently used arguments against the administration of HES, but they can virtually be neglected when using modern HES preparations to correct hypovolemia. There are, however, still open questions concerning the use of HES in children, pregnant patients, patients with altered kidney function and in burn patients.