From the Guidelines
Total parenteral nutrition (TPN) can indeed cause hyponatremia, particularly if the sodium content in the TPN solution is insufficient relative to the free water content, as evidenced by the guidelines on pediatric parenteral nutrition 1. This risk is highlighted in the context of pediatric care, where maintenance parenteral fluids have traditionally been administered as hypotonic saline, leading to a risk of hospital-acquired hyponatremia and potentially fatal hyponatremic encephalopathy if not managed properly 1. Key factors contributing to the development of hyponatremia in patients receiving TPN include:
- Insufficient sodium content in the TPN solution relative to free water
- Excessive free water administration
- Glucose content driving intracellular water shifts
- Protein breakdown products increasing free water
- Underlying conditions such as impaired renal function, heart failure, or medications affecting water excretion Regular monitoring of serum electrolytes is crucial, and adjustments to the TPN formulation may be necessary to prevent or manage hyponatremia, such as increasing sodium content or decreasing free water 1. The use of isotonic fluids (Na 140 mmol/L) for maintenance hydration in hospitalized children, in addition to PN if needed, is supported by substantial evidence as a means to reduce the risk of hyponatremia 1.
From the Research
Total Parenteral Nutrition and Hyponatremia
- Total parenteral nutrition (TPN) can cause hyponatremia, as evidenced by several studies 2, 3, 4.
- A case study published in 1993 described a patient who developed hyponatremia while receiving TPN, due to the administration of large amounts of sodium-free fluids 2.
- A study published in 2018 found that 81% of patients receiving TPN developed hyponatremia when serum sodium levels were corrected for total protein levels, compared to 43% without correction 3.
- Another study published in 2019 found that 18% of non-critically ill patients developed hyponatremia during TPN, with independent risk factors including female gender, severe malnutrition, opiate use, and nausea/vomiting 4.
Mechanisms and Risk Factors
- The development of hyponatremia in patients receiving TPN can be caused by various factors, including the administration of sodium-free fluids, hypoproteinemia, and the composition of the TPN solution 2, 3.
- Severe malnutrition, opiate use, and nausea/vomiting have been identified as independent risk factors for the development of hyponatremia in patients receiving TPN 4.
- The correction of serum sodium levels for total protein levels is important to accurately diagnose hyponatremia in patients receiving TPN 3.
Prevention and Management
- The prevention and management of hyponatremia in patients receiving TPN require careful monitoring of serum sodium levels, fluid balance, and electrolyte intake 2, 5.
- The optimal monitoring and early management of imbalances are crucial to prevent and mitigate potential complications associated with TPN 5.
- Nurses play a vital role in supporting optimal response to parenteral therapy and minimizing complications, including the development of hyponatremia 6.