Isotonic hydroxyethyl starch is ineffective in restoring blood pressure during experimental septic shock: Implications for fluid resuscitation strategies

Abstract

Objectives: The objectives of the study were to evaluate the effect of isotonic or hypertonic hydroxyethyl starch (HES) solutions on blood pressure and to assess the influence of the neurohypophyseal system on this response during experimental septic shock. Male Wistar rats were randomly allocated to undergo either cecal and ligation puncture (CLP) or a simulated surgical procedure (sham). Materials and Methods: Of 6 h post-surgery, either isotonic saline (0.9% sodium chloride, 4 mL/kg), isotonic (HES; at doses of 4, 8 or 16 mL/kg), or hypertonic saline-HES (HS-HES; 4 mL/kg) was administered through the endovenous route, followed by the recording of blood pressure and heart rate. In addition, the levels of sodium, vasopressin, and oxytocin were evaluated after the fluid infusion. Results: The administration of HES did not have a significant effect on blood pressure in our study. However, the HS-HES solution increased plasma osmolality, sodium, vasopressin, and oxytocin levels. Furthermore, the HS-HES induced a transient elevation in blood pressure immediately after infusion, which could be completely blunted by the pre-administration of a V1-vasopressin antagonist. Conclusion: Our results demonstrate that the infusion of an isotonic blood volume expander during experimental septic shock is ineffective in restoring blood pressure due to blood vessel compliance. In contrast, the infusion of a hypertonic solution stimulates vasopressin secretion and can transiently restore blood pressure.