Effects of Colloid Resuscitation on Peripheral Microcirculation, Hemodynamics, and Colloidal Osmotic Pressure During Acute Severe Hemorrhage in Rabbits

Abstract

We examined the effects of hydroxyethyl starch (HES) on the microcirculation, hemodynamics, and colloidal osmotic pressure in a rabbit model of hemorrhagic shock. A total of 40 rabbits was anesthetized with pentobarbital and isoflurane, and they were mechanically ventilated. An ear chamber was prepared to examine blood vessels by intravital microscopy. Shock was induced by removing nearly half of the circulating blood volume. Twenty rabbits received 20 mL of HES by intravenous infusion immediately after blood letting. Additional HES was then administered intravenously to a total volume of 100 mL. The other 20 rabbits (control) were intravenously given 40 mL of lactated Ringer's solution (LR), followed by additional LR to a total volume of 200 mL, administered under the same conditions as HES. After blood letting, arteriolar diameter decreased similarly in the the HES and LR groups (HES, 40.5% +/- 14.8% of the baseline value versus LR, 43.3% +/- 13.1%). After the completion of infusion, arteriolar diameter significantly recovered to 90.8% +/- 10.2% of the baseline value in the HES group as compared with only 62.6% +/- 10.7% in the LR group (P < 0.005). Recovery of arterial blood flow velocity and blood flow rate was also significantly better in the HES group than in the LR group (P < 0.005). Mean arteriolar pressure, central venous pressure, and plasma colloid osmotic pressure after the completion of infusion were significantly greater in the HES group than in the LR group (P < 0.005). We conclude that intravenous infusion of HES effectively maintains the microcirculation, hemodynamics, and colloidal osmotic pressure in a rabbit model of acute severe hemorrhage.

Early Hemodynamic and Renal Effects of Hemorrhagic Shock Resuscitation with Lactated Ringer’s Solution, Hydroxyethyl Starch, and Hypertonic Saline with or without 6% Dextran-70

“…However, crystalloids are not the best plasma expanders; no more than one-fifth of unexcreted fluid should remain within the plasma volume after equilibration and, for this reason, a large volume is necessary [5]. Especially in high doses, LR dilutes plasma protein, reducing colloid oncotic pressure, and favors capillary filtration [12]. Our data are in agreement with those seen in the literature.…”

Complexity of blood volume control system and its implications in perioperative fluid management

“…It has been reported [32] that hydroxyethyl starch (HES) consistently increases the BV (1 l HES increased BV from 5.30 l to 6.33 l, corresponding to the volume of infusion); thus, we may be able to control BV with colloid. Because colloid remains in the intravascular space much longer than crystalloid, we can expect various favorable effects through colloid fl uid therapy, i.e., patency of vessels in the microcirculation [33], maintenance of urinary output owing to the maintenance of intravascular volume in the kidney, and prevention of the release of infl ammatory factors [34,35]. The discussion comparing colloid and crystalloid needs more space.…”

Permissive range of hypercapnia for improved peripheral microcirculation and cardiac output in rabbits*

“…Vasomotor activity, neural control, and responses of vessels to drugs in an REC are similar to those of in situ vessels 6 wks after attachment to a clear window (6). We have used this model to study the peripheral microcirculation during wound healing (7), systemic agglutination anaphylaxis (8), acute severe hemorrhage during colloid resuscitation (9), and the effects of inspired oxygen concentrations (10).…”