CHAPTER 3


the combination of magnesium and calcium must be maintained below a threshold of 20 mEq/ L to reduce the risk of lipid destabilization.24


Calcium


Calcium is a crucial nutrient for bone mineralization and growth; in adults, it may be removed for short periods of time, but at the risk of bone breakdown.19


Although calcium may be provided intravenously as


calcium gluconate or calcium chloride, calcium gluconate is preferred for PN solutions due to improved tolerance and compatibility. (In PN, 4.65 mEq of calcium gluconate is equivalent to 1 g of calcium gluconate.) As noted previously, caution must be used in dosing calcium related to both phosphate and magnesium (in the case of 3-in-1 PN solutions), due to the risk for precipitate formation and lipid destabilization, respectively. In addition, if the patient’s calcium-phosphate product is greater than 55 mg2


/ dL2 (most commonly seen in patients with renal impairment), cal-


cium and phosphate should be limited in the PN solution to reduce the risk of soft tissue calcification.19


Vitamins


Parenteral vitamin preparations are available to meet the requirements outlined by the American Medical Association (AMA) and the US Food and Drug Administration (FDA) that include a daily requirement for vita- min K. Box 3.3 lists the daily requirements for adult parenteral vitamins.17 Multivitamin preparations are available with and without vitamin K to accommodate patients receiving anticoagulation therapy. The need for daily vitamin administration was highlighted in the late


1980s when several cases of thiamin deficiency were reported during a nationwide IV vitamin shortage.25


Although vitamins are typically pro-


vided as a multivitamin product, specific vitamins should be considered for some clinical situations. Vitamin A supplementation beyond that provided by the standard multivitamin preparation should be avoided in patients with acute and chronic renal failure. Excessive dosages of vitamin C (>1 g/ d) should also be avoided in patients with acute renal failure due to impaired excretion of oxalate, a by-product of vitamin C metabolism.26


Additional


thiamin supplementation may be warranted for patients at risk for refeed- ing syndrome. (Refer to Chapter 4 for more on refeeding syndrome.) Experts have expressed growing concern regarding the adequacy of


current dosing for vitamin D. Recommendations for oral intake of vita- min D were increased in 2010,27


increase in recommendations for parenteral vitamin D. In 2012, Vanek et al recommended that a separate vitamin D infusion be made available.28


40 although there has been no concomitant


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