Safety and Dose Escalation Study of Intravenous Zinc Supplementation in Pediatric Critical Illness.

BACKGROUND

Critically ill children have low plasma zinc (pZn), correlating with organ failure. Since Zn influences inflammation, immune function, and glucose control, Zn supplementation is a plausible therapeutic modality. We sought to determine a safe dose of intravenous (IV) Zn to restore pZn in critically ill children.

METHODS

Stepwise dose escalation study of IV Zn supplementation at a tertiary children's hospital. All children (<10 years) admitted to the pediatric intensive care unit with a Pediatric Risk of Mortality III score >5, or ≥1 new organ failure were eligible. After consent, patients were sequentially enrolled into 4 dosing groups: (1) no zinc, (2) Zn250: 250 mcg/kg/d ZnSO4, (3) Zn500: 500 mcg/kg/d ZnSO4, or (4) Zn750: 750 mcg/kg/d ZnSO4 ZnSO4 was administered 3 times daily for 7 days. pZn was measured at baseline, end of first ZnSO4 infusion, 1 hour postinfusion, and 7 hours postinfusion on day 1, then daily through days 2-7. Interleukin-6 (IL-6), C-reactive protein (CRP), and lymphocyte subsets were measured on days 1 and 3. Glucose was measured 3 times daily for 7 days.

RESULTS

Twenty-four patients were enrolled. Baseline demographics were similar among groups. Baseline pZn was low in all patients (mean [SD], 41.8 [16.0] mcg/dL). pZn increased over the study period in supplemented groups; however, mean pZn in the Zn750 group exceeded the 50th percentile. pZn was not associated with IL-6, CRP, or lymphocyte subsets among groups. Degree of hyperglycemia did not differ among groups. No patient had a study-related adverse event.

CONCLUSIONS

IV zinc supplementation at 500 mcg/kg/d restores pZn to near the 50th percentile and is well tolerated.