Effect of endotoxin administration on body fluid compartments in the horse.

This study investigates how endotoxin administration impacts the body fluid compartments in horses, revealing significant alterations including a decrease in plasma volume, but negligible changes in extracellular fluid volume and total body water.

Research Methods

• The study was conducted on six conscious adult horses.
• To estimate plasma volume, extracellular fluid volume (ECFV), and total body water (TBW), various test substances were used. These included Evan’s blue dye for plasma volume, sodium thiocyanate for ECFV, and antipyrine for TBW.
• The team made use of pharmacokinetic analysis of plasma concentration juxtaposed with time to determine any changes in body fluid compartments.
• The determining variables of the effect of endotoxin included clinical evaluation, blood chemical changes, and blood gas determinations.

Key Findings

• Endotoxin administration resulted in all horses developing difficulty in breathing within 15 minutes.
• Clinical signs of colic were evident 30 to 45 minutes after the administration of endotoxin.
• There was a significant increase in serum glucose and creatinine concentrations post administration.
• All horses became hypoxic, developed a pronounced metabolic acidosis, and witnessed a reduction in plasma volume by approximately 15%.
• The study found no significant change in ECFV or TBW over the five-hour experimental period.

Conclusions

• The findings indicate that the administration of Escherichia coli endotoxin in horses leads to significant alterations in their body fluid compartments, particularly a marked decrease in plasma volume.
• The fact that all horses became hypoxic and developed metabolic acidosis aligns with previous research indicating the severe impact of endotoxins on metabolic processes.
• However, contrasts were found in regard to the ECFV and TBW; these remained relatively unchanged throughout the study. This refutes the initial hypothesis that endotoxin administration would affect all body fluid compartments.