Heparin (0.5-1 unit/mL of final PN volume) may be added to PN admixtures for three reasons:

• To maintain catheter patency, although this effect is debated To reduce thrombophlebitis, essentially with PPN infusion

•To enhance lipid particle clearance by acting as a cofactor for the lipoprotein lipase enzyme

The benefits and necessity of adding heparin to PN are unclear, and practices vary between institutions. There are also concerns about the stability and compatibility of IV lipid emulsions with heparin added at concentrations above 1 unit/mL. Heparin should be omitted in patients with active bleeding, thrombocytopenia, heparin-in-duced thrombocytopenia (HIT), or heparin allergy.

Regular Insulin

Regular insulin may be added to PN admixtures for glycemic control. The dose of insulin depends on the severity of hyperglycemia and daily insulin requirements. Generally, once the patient is receiving PN at goal, about 70% of the total insulin administered over the previous 24 hours as sliding scale or continuous infusion can be added to the next PN admixture. The insulin dose should be adjusted based on frequent capillary blood glucose evaluation. Caution should be used when insulin is added to PN to avoid hypoglycemia. Adding insulin to PN rather than administering as a continuous IV infusion does not provide the flexibility of frequent titration of the insulin dose to the desired target blood glucose concentration. As such, severe uncontrolled hyper-glycemia is best treated with a continuous insulin infusion.

Histamine-2-Receptor Antagonists

IV histamine-2-receptor antagonists such as ranitidine, famotidine, and cimetidine are compatible with PN and can be added to the daily PN when indicated (e.g., prevention of stress-related mucosal damage). This provides a continuous acid suppression and reduces nursing time by avoiding intermittent scheduled infusions.

Human Albumin

Human albumin is a colloid used as a plasma volume expander and is not a source of nutrition. Albumin should not be added to the PN admixture and should be administered separately from PN because it may increase microbial growth and infectious risk when mixed in the PN admixture. Further, coinfusion of human albumin at the Y-site injection of IV lipid emulsions and TNAs causes disruption and creaming of the IV lipid emulsion.

Iron Dextran

Iron-deficiency anemia in chronic PN-dependent patients may be due to underlying clinical conditions and the lack of regular iron supplementation in PN. Parenteral iron therapy becomes necessary in iron-deficient patients who cannot absorb or tolerate oral iron. Parenteral iron should be used with caution owing to its infusion-related adverse effects. A test dose of 25 mg of iron dextran should be administered first, and the patient should be monitored for adverse effects for at least 60 minutes. Iron dex-tran then may be added to lipid-free PN at a daily dose of 100 mg until the total iron dose is given. Iron dextran is not compatible with IV lipid emulsions and can cause oiling out of the emulsion. Other parenteral iron formulations (e.g., iron sucrose and ferric gluconate) have not been evaluated for compounding in PN and should not be added to PN admixtures.

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