[Hydroxyethylstarch (HES)]

Are renal adverse effects of hydroxyethyl starches merely a consequence of their incorrect use?

BACKGROUND

Clinical studies such as VISEP-study, which show a negative outcome after the administration of hydroxyethyl starch (HES), are often criticized for an "incorrect" use of HES. It is argued that HES used in these studies differed from usual practice and that recommendations for maximal dosage, duration, and creatinine values were ignored, not enough "free water" was provided and more modern HES solutions should have been used. These comments imply that renal adverse events in clinical studies are the consequence of an inappropriate use of HES. We therefore searched for evidence whether these suggested measures are beneficial.

METHODS

Narrative review; post hoc statistical analysis of epidemiologic data from a representative nationwide survey.

RESULTS

It is evident from published clinical studies that the renal risk of HES increases with cumulative dose and rising serum creatinine values, but no safe upper dose limit or creatinine threshold is known. Suggested safety measures were not able to prevent HES-induced renal failure in clinical studies. Published clinical trials with modern HES solutions are not suited to prove its assumed increased safety because of small sample sizes, low cumulative doses, short observation periods, and inadequate control fluids. Use of HES in a clinical study with negative outcomes conformed to clinical practice, indicating the generalizability of study results.

CONCLUSION

There is no evidence for the assumption that HES-associated renal impairment may be avoided by accompanying measures. Because HES use does not improve clinical outcome, the question arises whether it should be used at all in patients at risk.

[Study protocol of the VISEP study. Response of the SepNet study group]

In the commentary by Zander et al. the authors appear concerned about the methods and results of our, at that time, unpublished sepsis trial evaluating hydroxyethyl starch (HES) and insulin therapy. Unfortunately, the authors' concerns are based on false assumptions about the design, conduct and modes of action of the compounds under investigation. For instance, in our study the HES solution was not used for maintenance of daily fluid requirements, so that the assumption of the authors that this colloid was used "exclusively" is wrong. Moreover, the manufacturer of Hemohes, the HES product we used, gives no cut-off value for creatinine, thus the assumption that this cut-off value was "doubled" in our study is also incorrect. Other claims by the authors such as that lactated solutions cause elevated lactate levels, iatrogenic hyperglycemia and increase O(2) consumption are unfounded. There is no randomized controlled trial supporting such a claim - this claim is neither consistent with our study data nor with any credible published sepsis guidelines or with routine practice worldwide. We fully support open scientific debate. Our study methods and results have now been published after a strict peer-reviewing process and this data is now open to critical and constructive reviewing. However, in our opinion this premature action based on wrong assumptions and containing comments by representatives of pharmaceutical companies does not contribute to a serious, unbiased scientific discourse.

Renal impact of fluid management with colloids: a comparative review

BACKGROUND AND OBJECTIVES

Colloids such as hydroxyethyl starch (HES), gelatin, dextran and albumin are useful for maintaining renal perfusion and function. The comparative renal effects of colloids have not been previously reviewed.

METHODS

Computer searches of the MEDLINE and EMBASE bibliographic databases and the Cochrane Library were conducted using the search terms: colloids; hetastarch; gelatin; dextrans; serum albumin; kidney failure; cardiac surgical procedures; and kidney transplantation. Relevant studies were also sought through hand searching and examination of reference lists. Results of identified studies were qualitatively summarized with account taken for potential confounding factors.

RESULTS

The three artificial colloids HES, gelatin and dextran all exhibited troublesome renal side-effects. Randomized trials have demonstrated adverse renal effects of HES in sepsis and surgery. Undesirable renal effects are common to all available HES solutions regardless of molecular weight, substitution or C2/C6 ratio. While some of its effects may be less severe than those of HES, gelatin also can adversely affect the kidney. A negative renal impact of dextran is well-established, although this colloid is now less extensively used than formerly. As the normal endogenous colloid, albumin exhibits a wide margin of renal safety, although albumin overdose needs to be avoided. Albumin also appears to exert protective effects on the kidney such as inhibition of apoptosis and scavenging of reactive oxygen species.

CONCLUSIONS

Colloids display important differences in their actions on the kidney. These contrasting renal effects should be considered in making fluid management decisions.