Total Parental Nutrition

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Nutritional Assessment:

ABCDS

Calculations

ESPEN – Surgical 25‐30kcal/kg IBW – Critical care 25kcal/kg – Gastroenterology 25‐30kcal/kg

Choosing a Formula

At FMC we use ready made bags 3 chamber bags – 24 hour hang time

• FMC pharmacy has a compounding service – Custom bags ie those with no lipid or ‘special recipes’

– Micronutrient additions

– may run separately at other sites

• Don’t need to consider osmolality due to use of CVC/PICC – Maybe an issue at other sites if using a peripheral line

Formula: Amino acids

• Often expressed in terms of nitrogen content (Nx6.25= total weight protein)

• Decreased protein content increases bag stability

• Manufacturer recommendations less than 0.1g/hour/kg body weight

• For example a 70kg person should not exceed 7g per hour and 168 for the day

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Formula: CHO

Daily minimum of 2g/kg body weight req’d to meet the needs of cells that can’t use other fuels

– eg brain, kidney, erythrocytes

• Exceeding the maximum rate of glucose oxidation can cause complications

– hyperglycaemia, fatty liver and respiratory problems

– 4‐7mg/min/kg body weight – equates to approx 5‐10 g/kg/day – 70 kg person 350‐700g/day • Higher levels can be better tolerated on cyclic regimens – home TPN

• Rate of clearance from the blood does not indicate tolerance, normal BGLs do not guarantee appropriate infusion rate

Formula: Lipids

• Lipid emulsion provides essential fatty acids

• No clinical evidence in giving greater than 30% energy from lipid

• No clear measurable limit to its utilisation

• Thought that excess parenteral lipid can lead to impaired immune function, liver dysfunction, coagulopathy, abnormal lung function

• Rec. to keep to 1g/kg/day – based on studies done with soybean oil emulsions and the level at which complications occur – 70 kg person 70g fat/day

• Maybe better tolerated with different types of emulsions

• Sites that restrict lipid may result in EFA deficiency

suppliers

Baxter

Fresenius

• 3 chamber bags, +/‐ electrolytes

• Trace elements and vitamins need to be added separately via compounding service or run as separate entities

Continuous – FMC 63‐83ml/hr • In preparation for home TPN may be cyclic i.e. over night only – Up to 300ml/hr • At home may be cyclic but often intermittent where pt receives TPN infusion on some nights and hartmanns on others

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BGL

Sepsis and stress increase BGL’s – Hyperglycaemia is associated with poorer outcomes • Moderate control 6‐10 whilst on TPN appears to improve outcomes – Use insulin rather than decreasing the infusion. – Careful not to induce hypoglycaemia. • If greater than 20 may need to halve or stop the infusion

High triglycerides

• Check infusion of fat and CHO • Rates above 5mg/min/kg body weight for CHO and 0.11g/hour/kg lipid have been associated with complications – Higher volumes may be tolerated in cyclic • Levels up to 4.5mmol/L are acceptable when bloods taken with continuous lipid infusion • Check pre feeding levels

Increased transaminases

• AST/ALT • Check glucose infusion rate • Cells glucose oxidation rate exceeded at 5mg/minute/kg body weight • Excessive CHO can lead to fatty liver and high triglycerides

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Ceasing TPN

• No need to taper infusion – Unless no other nutrition provided – Consider insulin provision • Doesn’t need to be stopped for surgery but often is to minimise infusions running