Describe the manganese content of current trace element additives for PN?

• A. Less than the current requirement
• B. About the same as the estimated requirement
• C. Greater than five times the current estimated requirement
• D. Ten times the requirement

Answer: (C)

Manganese in parenteral nutrition trace element additives is kept at levels well above what the patient would normally require each day. These premixes were designed to prevent deficiency across a wide range of patients, since PN bypasses the gut and intake is not happening orally, so a fixed, higher manganese dose was chosen as a safeguard. However, manganese is primarily excreted via bile, and in patients with liver dysfunction or cholestasis this excretion is impaired. When manganese accumulates, it can deposit in organs such as the brain and cause neurologic toxicity. Because of this, the amount provided by standard PN trace element additives tends to be more than five times the current estimated daily requirement. That’s why the correct description is that the manganese content is greater than five times what is estimated to be needed.