Must fat emulsions and parenteral nutrition solutions be given through separate circuits?

To test the stability of fat emulsions with parenteral nutrition (PN) solutions, 10% soybean fat emulsion (FE) was suspended in PN solutions containing amino acids, electrolytes, vitamins, and different glucose concentrations. Six different mixtures were prepared and analyzed after 15 minutes or 24 hours, under transmission electron microscope: 10% fat emulsion (FE); FE + PN solution with 5% glucose (15 minutes); FE + PN solution with 5% glucose (24 hours); FE + PN with 12.5% glucose (24 hours); FE + PN with 25% glucose (24 hours); and FE + pure glucose 50% (24 hours). The addition of FE to PN solutions containing 5% to 25% glucose did not cause coalescence, aggregation, or confluence of the liposomes or damage to their surface in the first 24 hours after admixture. However, the suspension of fat emulsion in a 50% glucose solution coalesced liposomes and the droplets were nearly all aggregated. We conclude that mixtures of FE with PN solutions with glucose are stable for at least 24 hours and are suitable for clinical use.