Possible Incompatibility between Amino Acids and Copper in Solutions for Pediatric Parenteral Nutrition

Parenteral Nutrition Overview

Parenteral nutrition (PN) is a life-saving intervention for patients where oral or enteral nutrition (EN) cannot be achieved or is not acceptable. The essential components of PN are carbohydrates, lipids, amino acids, vitamins, trace elements, electrolytes and water. PN should be provided via a central line because of its hypertonicity. However, peripheral PN (with lower nutrient content and larger volume) can be administered via an appropriate non-central line. There are alternatives for the compounding process also, including hospital pharmacy compounded bags and commercial multichamber bags. PN is a costly therapy and has been associated with complications. Metabolic complications related to macro and micronutrient disturbances, such as hyperglycemia, hypertriglyceridemia, and electrolyte imbalance, may occur at any time during PN therapy, as well as infectious complications, mostly related to venous access. Long-term complications, such as hepatobiliary and bone disease are associated with longer PN therapy and home-PN. To prevent and mitigate potential complications, the optimal monitoring and early management of imbalances is required. PN should be prescribed for malnourished patients or high-risk patients with malnutrition where the feasibility of full EN is in question. Several factors should be considered when providing PN, including timing of initiation, clinical status, and risk of complications.

Physical stability of an all-in-one parenteral nutrition admixture for preterm infants upon mixing with micronutrients and drugs

Objectives

The main objective was to investigate Y-site compatibility of intravenous drugs with one standard total parenteral nutrition (TPN) admixture for preterm infants. Since micro-precipitation was observed in the water phase after addition of trace elements, the concentration effect on micro-precipitation formation developed as a sub-goal.

Methods

Seven drugs (ampicillin, ceftazidime, fluconazole, fosphenytoin, furosemide, metronidazole and paracetamol) were mixed in three mixing ratios with one preterm TPN admixture. Samples were investigated within 1 hour and again after 4 hours. Precipitation was studied in a lipid-free version called TPN_aq by light obscuration, turbidimetry and visual examination. Emulsion stability data were assessed by light obscuration and laser diffraction. pH was measured to assess the theoretical risk of precipitation and emulsion destabilisation. The influence of different concentrations of trace elements on precipitation was investigated by visual examination, turbidimetry and light obscuration.

Results

Ampicillin, ceftazidime, fosphenytoin and furosemide led to precipitation after mixing with TPN_aq. In some samples of TPN and fluconazole, metronidazole and paracetamol, the emulsion droplet size was above the acceptance limit, although this might also be inherent to the TPN admixture. An unexpected formation of micro-precipitate correlating with increasing amounts of added trace elements might be caused by an interaction of cysteine and copper, and complicated the compatibility assessment with drugs.

Conclusions

The micro-precipitate resulting from the addition of trace elements should be investigated further. This study did not provide sufficient evidence to recommend Y-site infusion of the tested drugs and the preterm admixture; however, it might offer some additional support to other compatibility data.