Parenteral Nutrition

Introduction

Parenteral nutrition rotation is one of the elective modules that you may opt for during provisional registered pharmacist year in hospital setting. In the rotation, you will be

  • Trained in aseptic techniques to compound sterile preparations inside laminar flow cabinet
  • Trained to ensure the appropriateness of the PN solution supplied in terms of its composition.



Key Considerations

Initiating the PN

  • To be started in situations when it is not possible to meet an individual's requirements by the enteral or oral route. Examples:
    • Inadequate gut function, such as bowel obstruction, short bowel syndrome, persistent severe diarrhoea or significant malabsorption.
    • In patients who are malnourished or at risk of developing malnutrition.
    • Premature infants <30 weeks gestation and/or 1000 g.
  • Line access - Peripheral or Central?
    • Peripheral line is for short-term use (<10-14 days) and infusion osmolality is limited to <900 mOsm/L.
    • Since peripheral parenteral nutrition formulations are based on a decreased dextrose concentration and osmolarity (by increasing final volume), patients with fluid restriction should not be candidates for PPN due to the risk of fluid overload to achieve their energy requirements.
    • The use of central vascular access devices allows for the administration of solutions not limited by pH, osmolarity or volume.
    • PN solution and intravenous lipid emulsion (VLE) should be administered using photo-protected tubing set (to prevent photodegradation of some nutrients) and attached with in-line filter. The recommended in-line filters are 0.22 μm filter for aqueous solution and 1.2 μm for lipid containing solution.
  • Regimen - Continuous (running 24 hours a day) or Cyclical (running for a period of between 8 and 18 hours each day)
    • Administration over 24 hours enables less manipulation and a lower infusion rate, limiting the overloading of glucose as well as fluids.
    • Cyclic administration during a portion of the day or night allows the patient freedom from the intravenous tubing and pump apparatus (may improve quality of life), but glycemia should be monitored closely.
  • Nutrition requirements, depending on patient clinical condition: Energy, carbohydrate, fat, protein, fluid, vitamin and trace element.
    • Commercial multichamber bags (MCBs) has advantages over hospital pharmacy compounded bags (HPCBs), including reduced costs, time and labour, and few errors in PN preparation, as well as their stability being guaranteed by the manufacturing company. In addition, electrolytes and nutrients, such as glutamine or omega-3 fatty acids, can be added to MCBs because these criteria have been considered in the development of MCB formulations.
Monitoring when continuing PN
  • Risk of refeeding syndrome
  • Hyperglycaemia and hypoglycaemia
    • Carbohydrates usually provide 50-60% of total daily calories. Decreased glucose utilization occurs with advancing age, liver disease, sepsis, stress (such as trauma, burns or surgery), and medications (such as corticoids, tacrolimus).
    • Continuous dextrose infusion rates in adult patients should be kept at ≤4-7 mg/kg/min to avoid hyperglycaemic episodes if the oxidation glucose rate is overtaken.
  • Hypertriglyceridemia
    • Lipids usually provide 20-30% of total daily calories; higher amounts of lipids might lead to hypertriglyceridemia and fat overload syndrome.
    • General recommendations are to have IVFE doses of no greater than 1 g/kg body weight/day to avoid lipid overload (maximum 2 g/kg/day).
  • Hepatobiliary complications: steatosis, cholestasis and gallbladder sludge/stones.
  • Micronutrient deficiency and toxicity
  • Complications of line access including line infection, bleeding, venous thrombosis and/or stenosis and line obstruction (due to precipitation of infusates and thrombosis)
Ceasing the PN
  • Reduction of PN energy should be considered as tolerance to enteral nutrition/oral intake improves and finally discontinued when the patient is receiving >60% of target energy requirements.
  • Other reasons: Line sepsis or unresolving acute liver failure.



Reference

Internationally, there are many guidelines available, such as ESPEN, ASPEN and BAPEN.

Yet, the recommendations are slightly different. Hence, a national handbook to standardize our practices is very handy.

In 2015, the Pharmaceutical Services Division of the Ministry of Health published the first edition of Pharmacist's Handbook of Parenteral Nutrition in Neonates and Paediatrics to provide guidance for pharmacists in neonates and paediatric management.

  • This was followed by a second edition in 2023.
  • This handbook complements the limited info available in Paediatric Protocols for Malaysian Hospitals.

Comments

Post a Comment