Effects of slow infusion of a low dosage of endotoxin on systemic haemodynamics in conscious horses.

The research investigates the effects of introducing a low dose of endotoxin into horses’ system through IV infusion. It particularly focuses on the impacts observed on vital parameters of the systemic arterial, right atrial, and pulmonary arterial pressures, heart rate, cardiac output, pulmonary vascular resistance, and total peripheral vascular resistance.

Research Method

• The researchers used four healthy horses for this study. They introduced endotoxin to these horses through intravenous infusions. The cumulative dosage was maintained at 0.03 micrograms per kg of body weight and infused over a duration of 60 minutes.
• They recorded various physiological parameters including systemic arterial, right atrial and pulmonary arterial pressures, heart rate, cardiac output, and the resistance in pulmonary vascular and total peripheral vascular.
• These results were then compared to the effects observed with the intravenous infusion of saline solution, serving as the control treatment.

Research Findings

• The infusion of endotoxin led to a significant increase in heart rate. However, other parameters such as diastolic arterial pressure, systolic arterial pressure, electronically averaged arterial pressure, cardiac output, total peripheral resistance, and right atrial pressure did not display a significant change.
• The average pulmonary arterial pressure, however, also increased significantly on the account of endotoxin infusion.
• They also observed a trend towards increased diastolic pulmonary arterial pressure, systolic pulmonary arterial pressure, and pulmonary vascular resistance, though these increases were not statistically significant (P > 0.05).

Conclusions

• From the observed results, the study suggests that infusion of low dosages of endotoxin can cause pulmonary hypertension. This particular condition is characterized by high blood pressure in the arteries of the lungs.
• Importantly, the low dosage of endotoxin did not result in hypotensive, hypodynamic shock illustrating that it does not make the blood pressure excessively low or lead to reduced blood flow.

In conclusion, the findings provide significant insight into the effect of low dose endotoxin infusion in horses, which indicates pulmonary hypertension. However, there are no severe negative impacts like hypotensive, hypodynamic shock.