Hemodynamic changes with high infusion rates of lipid emulsion. Experimental study in swine1

Artur Udelsmann, Marcos De Simone Melo

To evaluate hemodynamic changes caused by sole intravenous infusion of lipid emulsion with doses recommended for treatment of drug-related toxicity. Large White pigs underwent general anesthesia, tracheal intubation was performed, and mechanical ventilation was instituted. Hemodynamic variables were recorded using invasive blood pressure and pulmonary artery catheterization. Baseline hemodynamic measurements were obtained after a 30-minute stabilization period. An intravenous bolus injection of 20% lipid emulsion at 1.5 ml/kg was administered. Additional hemodynamic measurements were made after 1 minute, followed by a continuous intravenous lipid infusion of 0.25 ml/kg/min. Further measurements were carried out at 10, 20 and 30 minutes, when the infusion was doubled to 0.5 ml/kg/min. Assessment of hemodynamic changes were then made at 40, 50 and 60 minutes. Lipid infusion did not influence cardiac output or heart rate, but caused an increase in arterial blood pressure, mainly pulmonary blood pressure due to increased vascular resistance. Ventricular systolic stroke work consequently increased with greater repercussions on the right ventricle. In doses used for drug-related toxicity, lipid emulsion cause significant hemodynamic changes with hypertension, particularly in the pulmonary circulation and increase in vascular resistance, which is a factor to consider prior to use of these solutions.