Netherlands Journal

netherlands journal of critical care
Table 1: Characteristics of HES products
HES 70/0,5 HES 130/0,4 HES 200/0,5 HES 200/0,5 HES 200/0,62 HES 450/0,7
Concentration in % 6 6 6 10 6 6
Volume Effect in % 80 100 100 140 100 100
Effect duration in hours 1-2 2-3 3-4 3-4 5-6 5-6
Mean mol. weight in kD 70 130 200 200 200 450
Degree of substitution 0,5 0,4 0,5 0,5 0,62 0,7
C2/C6 ration 4:1 9:1 6:1 6:1 9:1 4,5:1
Table 2: Fluids for true hypovolemia
Author/Trial name Number of patients Design Kind of fluid used Renal outcome Evidence
London MJ et al. 94 RCT 10% HES vs. 5% albumin no difference level I
Stockwell MA et al. 475 RCT albumin vs. polygelin no difference level I
Vogt NH et al. 41 RCT HES vs. albumin no difference level II
Beyer R 46 RCT HES vs.3% gelatine no difference level II
Kumle B et al. 60 RCT LMW HES vs. MMW HES vs. Gelatine no difference level II
Allison KP et al. 45 RCT HES vs. Gelatine HES better level II
Boldt J et al 20 RCT HES 130/0,4 vs. HES 200/0,5 no difference level II
Dehne MJ et al. 60 RCT lactated ringer vs. 3 different HES no difference level II
Sedrakyan A et al. 19578 retrospective albumin vs. non-protein colloids albumin renders survival benefit level III
Winkelmayer W. et al 238 retrospective HES 670/0.75 vs. no HES reduced GFR level III
Neff TA et al. 31 RCT HES 130/0,4 vs. HES 200/0,5 + albumin no difference level III
filtration as well as osmotic nephrosis (osmotic tubular damage) if
insufficient free water accompanies administration.Four types of
colloids are used: albumin, gelatins and hydroxy-ethyl starch.
Human albumin (HA)
Human albumin (HA) is the natural colloid present in human circulation
and therefore may appear to be the ideal substitution in
hypo-oncotic hypovolaemia. Furthermore albumin decreases inflammatory
cytokine expression after haemorrhagic shock [14;15] and is
necessary for delivery of furosemide to the thick ascending limb of
Henle for effective diuresis [16]. However, albumin is expensive, and
due to its relative small size (69 kD) its intravascular effect may be
reduced in states of endothelial damage and capillary leakage. Albumin
is derived from pooled plasma and potentially carries the risk of
infection. Despite earlier concerns about safety a recent large multicentre
RCT using 4% albumin did not show any difference in either
outcome parameter including renal function when compared to normal
saline [17].
Gelatins
Gelatins usually have an average molecular weight around 30 kD
which is even smaller than albumin. Thus, its intravascular volume
effect is even shorter at around 2 hours. The advantage of this substance
is absence of adverse effects on renal function [18;19]. Problems
associated with gelatin, however, are the possibility of prion
transmission, their capacity to release histamine and their negative
influence on the coagulation system [20;21].
Dextrans
Dextrans are single chain polysaccharides with a size comparable
to albumin (40 , 60 or 70 kD) and a reasonably high volume effect.
However, main disadvantages include anaphylactic reactions and serious
interference with coagulation system at doses higher than 1.5
g/kg/day [22;23]. Additionally, case reports on the occurrence of ARF
after dextran administration have been published [24;25].
Hydroxyethyl starch (HES)
Hydroxyethyl starches (HES) are highly polymerised sugar molecules.
They are characterised by their molecular weight, grade of
substitution, concentration and C2/C6 ratio. Their volume effect is
significantly longer than that of albumin especially when larger size
HES are used (Table 1). Degradation occurs by hydrolytic cleavage
which results in smaller molecules which will finally be eliminated
by the reticular endothelial system or filtered and eliminated by the
kidney. In this way these degradation products may be reabsorbed
and contribute to osmotic nephrosis and probably to medullary hypoxia
[26;27]. Another problem associated with administration of
HES is pruritus [28].
Recently there was a review of fourteen studies investigating the
use of various colloids on renal function [29]. Although no statistical
analysis was performed in this study owing to the heterogeneity of
the studies selected, the authors stated that rapidly degradable HES
preparations (degree of substitution (DS) 0.4 or 0.5) appear to have
less risk for impairing renal function than HES with a high DS (0.62
or 0.7).
Whereas albumin appears to be safe [17], recent data indicate
possible impairment of renal function by HES [19]. This is further
supported by a cohort study in patients undergoing coronary artery
bypass graft surgery (CABG and demonstrating moderate reduction
of glomerular filtration rate (GFR) after administration of HES [30]
Clinical situations in which renal protection/renal
recovery by volume expansion appears feasible and
supported by clinical studies
We performed a systematic MEDLINE search for randomised controlled
trials (RCT) addressing the use of different types of hydration
regimens to prevent deterioration of renal function in adult patients
at risk for ARF.
• The following clinical conditions were considered: major surgery,
sepsis, shock, use of potentially nephrotoxic drugs, radiocontrast
media and renal transplantation.
• The following terms and text words were used: kidney failure,
acute, kidney failure, acute/prevention and control, renal, cardiac
surgery, sepsis, contrast, shock, liver cirrhosis, normal saline,
hydroyethyl starch, colloids, crystalloids, gelatine, human albumin.
neth j crit care • volume 10 • no 5 • october 2006
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