The Effect of Hetastarch on Serum Colloid Oncotic Pressure in Hypoalbuminemic Dogs

Abstract

The purpose of this study was t o determine the duration of action of a single dose of hetastarch. a synthetic colloid, in hypoalbuminemic dogs. Thirty hypoalbuminemic dogs (albumin concentration, 52.0 g/dL) received l dose of hetastarch each, with an average dose of 18.1 mL/kg. Doses ranged from 7.7 t o 43.9 mL/kg, with the majority of doses (n = 26) in the range of 10 t o 25 mL/kg. Dogs were allotted t o one of several groups: all dogs, dogs with acute gastrointestinal protein loss, dogs with chronic gastrointestinal protein loss, all dogs with gastrointestinal protein loss, and dogs with nongastrointestinal protein loss. Colloid oncotic pressure was measured immediately before and immediately after hetastarch administration, and 12 hours after hetastarch administration. There was a significant ( P < .001) increase in the mean colloid oncotic pressure after hetastarch treatment in all groups, except in the group with acute gastrointestinal protein loss. Twelve hours after hetalbumin (69,000 d) is the principal oncotic protein in A blood, contributing about 75% of normal colloid oncotic pressure; globulins and fibrinogen contribute the remainder.'.' Oncotic pressure of the interstitium of the lung is approximately 50% to 70% that of plasma.' The plasma colloid oncotic pressure helps maintain vascular volume and prevent edema formation, but vascular integrity and normal lymphatic drainage are also important. Interstitial edema will result if the plasma colloid oncotic pressure approaches or decreases below that of the interstitium, or if vascular permeability is altered or lymphatic drainage is compromised. The sequelae to a decrease in colloid oncotic pressure, such as pulmonary or cerebral edema, can be life threatening.Both crystalloid and colloid fluids have been used therapeutically to increase plasma volume.'^' Only about 30% of crystalloid fluids remain in the vascular space 30 minutes after admini~tration.~.' The amount of crystalloid fluid that remains in the vascular space is even less (as low as 10%) in hypo-oncotic patient^.^.' Therefore, treatment of hypooncotic patients with crystalloid solutions increases the risk of development of pulmonary and cerebral In fact, low plasma colloid oncotic pressure has been shown to be associated with increased mortality in critically ill people.',' In light of these findings, colloid solutions are being used to treat hypovolemia, especially in hypo-oncotic patients.Hetastarch is a synthetic polymer of amylopectin that has been hydroxylated,'.' and was originally developed for the effective treatment of hyp~volemia.~ During the past 20 years, hetastarch has been used in humans as an adjunct to pressure was not significantly ( P < ,001) different from the baseline mean colloid oncotic pressure in any of the groups. Twenty-three dogs (77%) survived their illness and were sent home, whereas, 7 (23%) died or were euthanized. The effect of a single dose of hetastarch on raising colloid oncotic pressure in dogs with hypoalbuminemia decreases significantly within 12 hour...

The Efficacy and Safety of Colloid Resuscitation in the Critically Ill

“…Basically, the perfusion of fluid with high oncotic pressure is supposed to better fill the vascular system, adding to the given volume a proportion of volume expanded from extravascular tissue. 4,5 As a result, a smaller fluid volume has to be given to achieve adequate vascular fluid replacement. This wellacknowledged concept is supported by physiology, because plasma contains a large amount of proteins, particularly albumin, creating a physiological oncotic pressure of approximately 25 mm Hg.…”

Effects of 6% hetastarch (600/0.75) or lactated Ringer’s solution on hemostatic variables and clinical bleeding in healthy dogs anesthetized for orthopedic surgery

“…When a significant increase in COP occurs after hetastarch administration, the increase occurs rapidly after administration and dissipates quickly. One study in hypoalbuminemic dogs reported that COP had returned to pre‐infusion values 12 hours after hetastarch administration (Moore & Garvey 1996). At 24 hours post‐infusion there was no difference in COP either between groups or within a group compared to the baseline in our study.…”

“…2001) so it just dilutes out the plasma proteins, hence causing the decrease in COP. Previous studies have shown either no change in COP (Muir & Wiese 2004) or a modest impact on COP (Smiley & Garvey 1994; Moore & Garvey 1996; Chan 2008) after administration of hetastarch. The COP of 6% hetastarch as used in this study is reported to be 32.7 ± 0.2 mmHg (Chan et al.…”

Fluid therapy with artificial colloids: complications and controversies

“…However, this refers to plasma colloid concentrations and not to the duration of plasma volume expansion. In hypoalbuminaemic dogs, COP was not significantly different from baseline 12 hours after the infusion of hydroxyethyl starch (Moore & Garvey 1996) and this may occur because equilibration of COP is often rapid: interstitial fluid is drawn into, or retained in, the intravascular space by colloidal particles. Gelatins have a duration of action that is shorter than other colloids and often only just longer than crystalloids.…”

“…Hydroxyethyl starch limits peripheral oedema and ascites in hypoalbuminaemic dogs (Smiley & Garvey 1994). However, it is important to diagnose and treat underlying causes of hypoproteinaemia rather than indiscriminately administer palliative colloid therapy, because this may be ineffective if there are large ongoing losses (Moore & Garvey 1996) and there may be risks. While albumin supplementation is recommended in people because low serum albumin concentration is held to indicate a poor prognosis, most investigations of clinical albumin supplementation have failed to demonstrate a beneficial effect.…”