Starch solutions for volume resuscitation in intensive care units.

Fluid resuscitation is a fundamental part of the care of a critically ill patient.(1) Most patients admitted to intensive care units will eventually undergo volume challenge. The optimum type of fluid resuscitation product has been debated for the last four decades.(1,2) Crystalloid solutions are widely available and affordable and are therefore used as the basis of the standard volume expansion strategy in many intensive care units (ICUs). The most commonly used colloid solutions include human albumin, synthetic starches, dextrans and gels;(3) of these types, starch solutions are preferred.(3) Starch solutions are more commonly used in European countries than in the United States of America.(4) Colloids offer the theoretical advantage of a longer intravascular time, which would result in better fluid expansion, therefore requiring lower infusion volumes.(4) However, colloid administration is not without risk, and serious concerns regarding the effects of colloids on coagulation and renal function should be considered.(4) Starches (hydroxyethyl starches – HES) are becoming popular and are preferred by several clinical services.(4) Starches are cornor potatoderived glycogen-like polysaccharides, composed of polymerized D-glucose with branches for 20 glucose monomers. Hydroxyl groups are replaced by hydroxyethyl groups to prevent degradation by blood amylase. These hydroxyethyl groups are bound to variable carbon chain positions (mainly C2, C3 and C6). The more substituted and more C2 carbon substitutions (instead of C6), the longer the circulating starch half-life will be.(4) In addition, degradation will be slower for starches with higher molecular weights. The starch name includes its molecular weight and its substitution rate (e.g., 6% 130/0.40). The first available starch products had high molecular weights (between 480-670 kDa) and were highly substituted (above 0.7); these starches are referred to as hetastarches. These were long half-life products and had significant coagulation effects.(4) The last decades witnessed the development of progressively lower mean molecular weight and less substituted modern starches. ‘Modern’ starches (referred to as tetrastarches) have molecular weights of approximately 130 kDa and are approximately 0.40 substituted (6% HES 130/0.40). Possible harmful effects of starches include coagulation effects and renal injury, in addition to anaphylactic reactions and itching due to subcutaneous deposits.(4) Starch-induced coagulation effects appear to Fernando Godinho Zampieri1,2, Luciano César Pontes Azevedo1,3