The calcium phosphate precipitation and microemboli via TPN
If a patient is receiving total parental nutrition (TPN) and develops respiratory compromise, TPN should be immediately stopped and inspected for any precipitation. The calcium phosphate precipitates, although rare can form and when infused acts like microemboli. A filter can be utilized to overcome the problem when infusing TPN. Other ways to avoid the problem
- Infuse TPN within 24 hours of preparation.
- Use Ca-gluconate instead of CaCl.
- Keep the Ca:PO4 ratio greater than 1:2.
- Keep the total amount of Ca and PO4 less than 45 mEq/L.
Read case report and very extensive discussion on this topic: Microvascular Pulmonary Emboli Secondary to Precipitated Crystals in a Patient Receiving Total Parenteral Nutrition - Chest. 1999;115:892-895
References (Clickable):
1. Calcium and phosphates compatibilities in parenteral nutrition admixtures Tunis Med. 2006 Nov;84(11):677-82
2. Intravenous in-line filters: filtering the evidence. Curr Opin Clin Nutr Metab Care. 2003 May;6(3):319-25
3. Total parenteral nutrition associated crystalline precipitates resulting in pulmonary artery occlusions and alveolar granulomas. Dig Dis Sci. 2003 Jul;48(7):1352-4.
4. Pulmonary deposition of calcium phosphate crystals as a complication of home total parenteral nutrition, Journal of Parenteral and Enteral Nutrition, Vol 13, Issue 2, 209-213
