Comparative hemodynamic effects of three different parenterally administered lipid emulsions in conscious dogs.

Abstract

To compare the hemodynamic side effects of three structurally different lipid emulsions. Randomized, controlled, prospective animal study. University research laboratory. Six chronically instrumented mongrel dogs. On separate days, all animals were submitted to three different treatments, in a randomized order. After baseline measurements, either a long-chain triglyceride emulsion (treatment 1), a mixed medium-chain triglyceride/long-chain triglyceride emulsion (treatment 2), or an omega3 polyunsaturated fatty acid long-chain triglyceride (PUFA) emulsion (treatment 3) was administered intravenously over 30 mins. Global and regional hemodynamics (sonomicrometry) were recorded for 2 hrs after baseline measurements. Arterial blood gases and plasma concentrations of hemoglobin, triglycerides, total protein, and glucose were recorded for 2 hrs. Long-chain triglycerides did not affect the cardiovascular performance in awake animals. However, medium-chain triglycerides/long-chain triglycerides and omega3 PUFA caused marked increases in systemic vascular resistance (from 1833 +/- 154 to 3277 +/- 163 mm Hg/dynexsec5, p < .05), heart rate (from 89 +/- 6 to 158 +/- 10 beats/min, p < .05), and depressed ventricular performance (wall-thickening fraction [as percentage from baseline] decreased to 53 +/- 9%, p < .05). Commercially available lipid emulsions can cause profound cardiovascular side effects at high doses, depending on their composition. Whereas long-chain triglyceride emulsions have virtually no effects on hemodynamics in normal dogs, medium-chain triglyceride/long-chain triglyceride, and omega3 PUFA emulsions should be used with caution in critically ill patients with compromised cardiovascular function.