Suggested monitoring parameters and schedule for parenteral nutrition in children

ALT: alanine aminotransferase; AST: aspartate aminotransferase; BUN: blood urea nitrogen; CBC: complete blood count; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GGTP: gamma-glutamyl transpeptidase; INR: international normalized ratio; PT: prothrombin time; PTT: partial thromboplastin time; TBA: thyroxine-binding prealbumin; TSH: thyroid-stimulating hormone; TIBC: total iron-binding capacity.

* Metabolically unstable patients may need more frequent checks.

¶ Prealbumin is also known as TBA or transthyretin. It is an index of the short-term adequacy of protein intake. However, prealbumin is also suppressed by the acute phase response, so it is not useful as a measure of adequate protein intake in the setting of inflammatory disease.

Δ Iodine deficiency can cause hypothyroidism. If parenteral nutrition is the sole source of nutrition, the child should be screened periodically for hypothyroidism by measuring serum TSH. If TSH is elevated, then iodine status should be evaluated by measuring 24-hour urinary iodine or spot urinary iodine and creatinine. Spot urinary iodine concentrations can be interpreted as follows: severe deficiency <20 micrograms/L; moderate deficiency 20 to 50 micrograms/L; mild deficiency 51 to 99 micrograms/L.

◊ Iron indices are serum iron (Fe), TIBC, ferritin, and/or soluble transferrin receptor levels.

§ Adequacy of trace elements is monitored by measuring whole-blood or erythrocyte manganese (Mn), copper (Cu), serum zinc (Zn) and alkaline phosphatase, and plasma selenium (Se). Chromium (Cr) concentrations should be monitored periodically in patients on long-term parenteral nutrition with kidney function impairment.

¥ Fat-soluble vitamins are measured as serum retinol (for vitamin A), 25-hydroxyvitamin D (for vitamin D), and alpha-tocopherol (for vitamin E). Serum concentrations of alpha-tocopherol are strongly influenced by concentrations of serum lipids, so the effective vitamin E levels are calculated as the ratio of alpha-tocopherol:(cholesterol + triglycerides), where a normal ratio is >0.8. For vitamin K, measurements of PT and PTT are used to screen for deficiency.