SYNTHETIC COLLOID SOLUTION THERAPY
The crystalloid versus colloid conflict has been debated for many
years. The University Hospital Consortium developed guidelines for the use of albumin,
nonprotein colloid, and colloid solutions.[147]
Unfortunately, no anesthesiologists were represented in the Consensus exercise.
Since 2000, Boldt's[148]
analysis of the literature,
including a Cochrane Group review in 2002, found no consistent difference between
crystalloids (i.e., isotonic and hypertonic) and different types of colloids as a
basis for intravascular volume replacement. There is no doubt that colloids expand
intravascular volume more than crystalloids. (i.e., a smaller amount of colloid
is required for adequate intravascular resuscitation).[149]
However, outcomes (e.g., mortality) do not provide convincing evidence that one
fluid replacement strategy is better than others.
Synthetic Hydroxyethyl Starch
Between 2000 and 2003, Boldt[148]
found 40 original studies with a total of 2454 subjects. The most commonly used
preparation was 6% hydroxyethyl starch (HES, Hespan). Although an effective intravascular
expander, it has not gained widespread popularity probably because of its effects
on coagulation, particularly with regard to increased bleeding and platelet function.
The molecular mass plays some role in the adverse coagulation effects
(i.e., smaller molecular mass has less effect on coagulation). Two new HES preparations
have been developed to decrease coagulation effects. Hextend has been studied extensively.
It is 6% HES but also contains a physiologically balanced medium of electrolytes,
glucose and lactate. It has a similar pharmacokinetic and dynamic profile to other
starch preparations with fewer effects on coagulation.[150]
[151]
Gelatin has also been used, but it has not
been as widely studied as HES.[152]
