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Administering Parenteral Nutrition

Considerations for Methods of Parenteral Nutrition Delivery

In the planning of parenteral nutrition (PN), the proper route of access is crucially important. PN solutions are administered either via a central venous catheter or via peripheral venous cannulas.1

The delivery of PN may be classified according to different aspects, such as insertion site, insertion method, or duration of treatment.2

The choice of the appropriate administration route, i.e., peripheral or central venous, must be based on the following criteria:134

  • Condition of the patient (type of illness, current state of health, etc.)
  • Accessibility of the venous system
  • Composition of the infused solution and amount of energy to be administered
  • Osmolarity of PN products
  • Planned duration of PN (short-term or long-term)

Central Venous PN Route of Access

According to the recommendations of the European Society for Clinical Nutrition and Metabolism (ESPEN), central venous access is indicated in the majority of patients with the following conditions:134

Need for long-term nutritional support of greater than one month

  • Poor peripheral veins
  • Need for hyperosmolar solutions (osmolarity greater than 850 mosmol/l)
  • Glucose concentration greater than 12.5%2
  • High nutrient requirements
  • Severe fluid restriction
  • Administration of solution with pH lower than five or greater than nine
  • Need for multiple lumen intravenous treatment

In the case of central venous PN, the catheter type needs to be considered as well. Different catheter types are used in response to specific patient conditions.234

Central catheters are usually inserted into a central vein, with the catheter tip being located in the lower third of the superior vena cava, the femoral vein or in the upper right atrium.4

Peripheral Venous PN Route of Access

The decision to administer via peripheral or central venous access depends if the solution is hypertonic, isotonic or hypotonic. The osmolarity of the parenteral solution, which refers to the number of osmotically active particles in one liter of solution, is a crucial factor in determining the feasibility of peripheral PN (PPN). When a PN solution with a high osmolarity is introduced into a small vein with a low blood flow, the mixture becomes hypertonic and fluid from the surrounding tissue moves into the vein due to osmosis.

Lipid emulsions are isotonic with blood and exert a soothing effect on the veins. For this reason, PN admixtures containing lipid emulsions are less hypertonic than emulsions based solely on glucose as an energy source, and, consequently, more suitable for PPN.3

Prevention of peripheral vein thrombophlebitis according to ESPEN can be reached by4

  • Aseptic techniques during catheter placement and care
  • Choice of the smallest gauge possible
  • Use of polyurethane and silicone catheters
  • Use of lipid based solutions
  • Appropriate osmolarity of the solution
  • Administration of solutions with pH between five and nine
  • Adequate fixation (transparent adhesive membranes or sutureless fixation devices)