TPN

Total parenteral nutrition (TPN) is the intravenous provision of nutrients to meet a patient’s caloric and substrate needs when the gastrointestinal tract cannot function or cannot safely support feeding. It bypasses the gut and is delivered via a central venous catheter, though short-term peripheral lines may be used in some cases.

A TPN solution supplies carbohydrate energy from glucose, amino acids for protein, and lipids for essential fats, plus electrolytes, vitamins, and trace elements. Formulations may be prepared as three-in-one (all-in-one) solutions or assembled separately; quantities are tailored to the patient’s energy requirements, organ function, and fluid status.

Administration considerations include central venous access for high-osmolar formulations, risk of catheter-related infection, and careful monitoring of glucose and electrolyte balance. Dosing is individualized, usually by weight, with aims for adequate calories and protein and appropriate micronutrient supplementation.

Common complications include catheter-related infection, metabolic disturbances (hyperglycemia, electrolyte abnormalities), liver dysfunction with long-term use, and hypertriglyceridemia. Refeeding syndrome can occur in malnourished patients. Regular monitoring and timely adjustments are essential.

Monitoring involves daily weight, intake and output, and labs such as glucose, electrolytes, liver enzymes, and triglycerides. The regimen is gradually adjusted as the patient’s GI function returns, with a plan to transition to enteral or oral feeding when feasible.

History and context: TPN emerged in the mid-20th century and became a standard medical technology for patients with nonfunctional GI tracts or those unable to meet needs by mouth or enteral feeding.