A comparative analysis of isotonic versus hypertonic solution volume replacement in septic rats

Sepsis severity and mortality risk require aggressive therapy which includes hemodynamic support. The best fluid for volume replacement, however, is controversial. This study aimed to compare 0.9% isotonic saline solution versus 7.5% hypertonic saline solution as volume replacement fluid in sepsis induced by cecum ligation plus puncture rats.

This experimental trial included 30 rats divided into three groups: Control group (CG, n = 10), isotonic (ISG, n = 10) and hypertonic solution (HSG, n = 10). Fifteen hours after cecum ligation and puncture, all animals underwent respiratory rate, mean arterial pressure, renal and hepatic blood flow and weight evaluation, plus blood collection for TNF-α measurement. The ISG and HSG treatment groups received volume replacement 60 minutes before the procedure with either 0.9% or 7.5% saline solution, respectively.

Two animals died. Significant differences were found for the animals' mean weight after 15 hours (p=0.018), particularly relevant when ISG and HSG are compared (p=0.003). Renal blood flow was also significantly different for the CG versus HSG (p=0.002) and CG versus ISG (p=0.008), but not significantly different for ISG versus HSG. No mean arterial pressure improvement was found for HSG (0.054). Other variables were not significant.

Although no mean blood pressure, hepatic flow or TNF-α improvements were detected, the rats with sepsis 15 hours after cecum ligation and puncture showed significantly increased renal blood flow which was 0.9% isotonic saline solution or of 7.5% hypertonic solution use independent.