Hemodynamic Effects of Intravenous, High-Dose Lipid Emulsion With and Without Metoprolol Infusion in Healthy Volunteers: A Randomized Clinical Trial

In a double-blinded, randomized, crossover trial, we investigated the hemodynamic effects of high-dose intravenous lipid emulsion (ILE) with/without metoprolol. Ten healthy volunteers each completed 4 trial days (placebo + ILE; metoprolol + placebo; metoprolol + ILE; placebo + placebo) in random order. Metoprolol was administered as an initial bolus (10 mg), followed by an infusion (50 mg) from 5 to 30 minutes. ILE was administered as a bolus at 12.5 minutes (2.5 mL/kg), followed by a 15-minute infusion (0.25 mL/kg per minute). On metoprolol + ILE days (compared with metoprolol + placebo) after 120 minutes, mean heart rates were significantly higher (difference, 5.5 beats per minute (bpm); 95% confidence interval (CI), 3.0-8.1 bpm; P < 0.001), and average relative cardiac output was higher (difference, 10 percentage points; 95% CI, 5-15 percentage points; P < 0.001). The hemodynamic effect of ILE developed gradually. ILE had no effect on plasma metoprolol or major adverse events. In conclusion, high-dose ILE has relatively marginal and delayed hemodynamic effects that may have limited clinical relevance in the short-term clinical toxicological setting.