What are the common metabolic complications associated with long-term total parenteral nutrition, and how can they be prevented?

Long-term total parenteral nutrition (TPN) is associated with several common metabolic complications including electrolyte imbalances, hyperglycaemia, liver dysfunction (such as cholestasis and steatosis), micronutrient deficiencies or toxicities, and metabolic bone disease. These complications arise due to the complex nature of intravenous nutrient delivery and the altered physiology in patients dependent on TPN.

Electrolyte imbalances such as abnormalities in sodium, potassium, calcium, magnesium, and phosphate levels are frequent and require regular monitoring and adjustment of TPN formulations to prevent clinical sequelae ².

Hyperglycaemia is common due to the high glucose content in TPN solutions and can be mitigated by careful glucose monitoring and adjusting carbohydrate infusion rates, especially in critically ill or diabetic patients ².

Liver dysfunction is a significant long-term complication, manifesting as cholestasis, steatosis, or fibrosis. Prevention strategies include using composite lipid emulsions with reduced pro-inflammatory components, cycling TPN infusions rather than continuous delivery, and minimizing overfeeding to reduce hepatic fat accumulation ¹,².

Micronutrient imbalances may occur due to inadequate or excessive supplementation of vitamins and trace elements. Regular assessment and tailored supplementation under pharmaceutical control are essential to prevent deficiencies or toxicities ².

Metabolic bone disease can develop from chronic calcium, phosphate, and vitamin D imbalances, necessitating monitoring of bone metabolism markers and appropriate supplementation ².

Prevention of these metabolic complications involves multidisciplinary management with regular biochemical monitoring, individualized TPN prescriptions adjusted to evolving clinical status, gradual initiation and withdrawal of TPN, and patient education. Using standardized protocols for catheter care and TPN administration also reduces risks indirectly by preventing infections that can exacerbate metabolic disturbances ¹,².