University Hospital of Wales Paediatric Intensive Care Unit Guideline Printed on Wed 23-jul-08
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Last updated January 10, 2013 1:33 PM

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University Hospital of Wales Heath Park
Cardiff
CF14 4XW
02920 747747

TPN

Useful telephone numbers

 

 

Bleep

Ext

Nutrition Pharmacist

Anthony Lewis

6630

3710

PICU Pharmacist

Zoe Taylor

4586

8026

Paediatric Speech Therapist

Bev Curtis/ Karen Sealey

 

20 536807

General principles

Ordering TPN:

Order TPN before 11am, using yellow paediatric PN prescription sheet if > 1 month old or white neonatal prescription sheet if < 1month old.
Order TPN for the weekend before Friday 11 am, prescribe 3 bags (Friday, Saturday, Sunday) and remember to prescribe in advance to cover bankholidays.
TPN is made in a 24hrs-bag, if the patient is very stable consider a 48hrs-bag in view of less infection risks (braking of lines etc)

You will need to know the following to accurately prescribe TPN:

TPN must be written up on the daily PICU fluid chart. Lipid and aqueous-TPN bags should be written up separately.

TPN Lines

TPN may be given peripherally only if glucose concentration <12.5%.
TPN needs a dedicated line.
The lumen that is used for TPN should not be used for blood sampling or giving of other iv drugs or fluids

TPN is built up over several days, during which time the protein, fat and carbohydrate contents are gradually increased.
Complete exclusion of nutrients via the oral route is associated with marked atrophic changes in gut and pancreatic function. It's therefore important to use the gut when ever possible, even when it's just minimal enteral feeds.
When TPN is required during infancy, it's essential that patient maintains an oral experience (e.g. dummies). Queries: ask speech therapist (number above)

Indications for TPN

Nutritional support is aimed at adequately supplying the body's nutritional requirements for growth and development. Infants and children are particularly at risk from effects of under nutrition due to their limited energy reserves e.g. a pre-term infant of 1 kg will survive 4 days if starved compared to 3 months in adults. Survival times are decreased in times of catabolic stress and therefore nutrition must be considered early in all infants and children!

When prolonged GI malfunction can be predicted TPN may be commenced in order to prevent later malnutrition.

Indications may be:
Prematurity
Necrotising enterocolitis
Intestinal failure (e.g. short gut, protracted diarrhoea, chronic intestinal pseudo-obstruction, acute obstruction)
Poor bowel perfusion (e.g. severe sepsis, certain cardiac conditions)
Organ failure (e.g. acute renal or liver failure)
Hypercatabolism (e.g. extensive burns, severe trauma)

  • Fluid Requirement
  • Electrolyte requirement
  • Calorie requirement
  • Worked examples

The body mainly consists of fluid, the percentage of which will decrease in the first few years of life (i.e. 80% in a newborn which decreases to 60% after 1 year). Hence why the fluid requirement is depending on a patient age and weight.

The basic fluid requirement consists of insensible loss (evaporation via skin (2/3) & breathing (1/3)) + water losses (mainly urine).

There are different ways of calculating the daily fluid requirement. Rule 1 is the most used way of doing so (approved by the APLS guidelines). The second way is calculating the insensible and ongoing losses (rule 2), which may be helpful in patients with SIADH etc.

In both cases one has to adjust fluid intake for ongoing losses (i.e. diarrhoea, gastric aspirates, etc)

Rule 1

First 10 kg

100 ml/kg

Second 10 kg

50 ml/kg

Subsequent kg

20ml/kg

Rule 2

Insensible loss

300 ml/m2/day

Faeces

100 ml/m2/day

Urine (2ml/kg/h)

1440 ml/m2/day

 

 

Body Surface Area = sq. root of (body weight (kg) x length (cm))/ 3600 or use the UKSCG chart (on hydrocortisone monograph in the bedside folder)

There are different factors that have their influence on the insensible loss as shown in the next table.

Adjustment of insensible losses

Increased insensible loss

Decreased insensible loss

Hyperventilation

Humidified air (ie ventilation)

Hypertermia (100ml/m2/1°C temp increase /24hours)

Hypothermia

Activity reduced

Sedation

Burns (>10% of BSA: (%burn x weight(kg) x 4ml)/24hr)

Paralysis

Phototherapy

Activity reduced

These increased insensible losses are electrolyte free.

In consideration of TPN prescribing

Consider whether total fluid requirement is to include drugs or whether volume from drugs/infusions is to be allowed in addition
If total fluid includes drugs you will need to calculate the volume left over once daily drugs/infusions have been given and prescribe the TPN to this volume. In this way the patient will get all of their nutrients
Consider the effect any potential increases in drugs/infusions throughout the day may have on the volume available for TPN. Consider prescribing a lesser amount of TPN in view of the possibility of the necessity of increasing drugs throughout the day.
NB Stability of the TPN may affect the minimum volume that can be made. The pharmacist will advise you if this is a problem.

Electrolyte requirement

Basic electrolytes requirement per day (mmol/kg/day)

Body weight

>1 month & < 10kg

10-15kg

16-20kg

21-30kg

> 30kg

Sodium

3

3

3

3

3

Potassium

2.5

2.5

2

2

2

Calcium

0.6

0.2

0.2

0.2

0.2

Magnesium

0.1

0.07

0.07

0.07

0.07

 

Phopsphate

Basic phosphate requirement per day (mmol/kg/day)

 

Day1

Day2

Day3

Day4

>1 month &
< 10kg

0.5

0.58

0.58

0.6

10-15kg

0.23

0.27

0.3

0.3

16-20kg

0.22

0.26

0.26

0.26

21-30kg

0.18

0.26

0.26

0.26

> 30kg

0.18

0.25

0.25

0.25

These standard suggested electrolyte requirements can also be found on the back of the yellow or white TPN charts

In consideration of TPN prescribing

Consider electrolyte boluses given and drug changes made in the 24hr prior.
e.g. if patient was having large furosemide infusions the day before (+ high Potassium intake), but that is discontinued, you should adjust the TPN accordingly.

Remember: Be cautious with electrolytes added to TPN over the weekend because if the electrolytes become unsuitable (e.g. too much potassium), the only option would be to discontinue or reduce the TPN. (It's easier to put less in the TPN and top up with electrolyte infusions if needed)

Normal daily Caloric Needs

Body Weight (kg)

Caloric Needs (kcal/kg/day)

3-5

95-110

6

90

7

85

8-9

80

10-15

75

15-20

65

20-30

60

30-40

50

40-50

45

50-60

40

>60

35

(1 kcal = 4.2 kJoule)

 

 

 

 

 

 

Proteins (vaminolact)= 4kCal/gram (= 0.26kCal/ml)
Carbohydrates (Glucose)= 4kCal/gram (10% = 0.4kCal/ml) (= 100g/L =0.1g/ml)
Fat (intralipid 20%)= 9kCal/gram (=1.8kCal/ml), (= 0.2g/ml)


Nitrogen

Basic requirement per day (g/kg/day)

 

Day1

Day2

Day3

Day4

>1 month &
< 10kg

0.15

0.2

0.3

0.37

10-15kg

0.15

0.2

0.3

0.3

16-20kg

0.15

0.2

0.3

0.3

21-30kg

0.2

0.3

0.3

0.3

> 30kg

0.15

0.2

0.2

0.2

 

Glucose

Basic requirement per day (g/kg/day)

 

Day1

Day2

Day3

Day4

>1 month &
< 10kg

10

12

13

14

10-15kg

5

8

10

10

16-20kg

4

6

8

8

21-30kg

4

8

8

8

> 30kg

3

5

5

5

 

Lipid

Basic requirement per day (g/kg/day)

 

Day1

Day2

Day3

Day4

>1 month &
< 10kg

1

2

2

3

10-15kg

1.5

2

2.5

2.5

16-20kg

1.5

2

2

2

21-30kg

1

2

2

2

> 30kg

1

2

2

2

Standard suggested Nitrogen/ Glucose and Lipid requirements can be found on the back of the yellow or white TPN charts.

Considerations for TPN prescribing

If there is growth failure, there will be a difference between the actual and expected weight. In these circumstances, the mid-point between these two should be used to estimate nutritional requirements.
To promote adequate growth and body composition 200-250 kcal are required per gram of Nitrogen.
If energy needs are not fully met, then the amino acids will be used as energy instead of being available for essential functions and growth.
Although glucose intolerance is uncommon in infants, glucose should be introduced gradually.
If Glucose intolerance does occur then a slight reduction in infusion rate should be attempted as an initial measure. Occasionally it may be necessary to give insulin.
Glucose intolerance should be regarded as an early sigh of sepsis in a previously stable patient.
Rebound hypoglycaemia can occur occasionally if a high glucose rate is abruptly stopped. A stepwise reduction of glucose concentration reduces this risk.
Lipid not always! The administration of lipids to individuals with sepsis, jaundice, thrombocytopenia is much debated in the literature. For specific advice call pharmacy (number above)
Lipid will need to be administered separately (can go pheripherally)
Lipid runs over 20 hrs. (which allows clearance of the lipid emulsion from the plasma avoiding lipid accumulation and avoiding interference with haematological tests)
Other ingredients of TPN are vitamins and trace elements and these will be added to the TPN automatically.

Example 1
Patient: BW 32 kg, Length 130 cm, Urine output 2 ml/kg/h
According to Rule 1: 10x100 + 10x50 + 12x20 = 1740 ml/day
According to Rule 2: BSA = 1.07 m2 => 1.07x300 + 1.07x100 + 1.07x1440 = 1969 ml/day.
However in ITU setting urine output is measured; 1.07x300 + 1.07x100 + 2x32x24 = 1964 ml/day.

Example 2
Patient: BW 32 kg, fluid allowance 80%
Drugs: Noradrenaline 0.7ml/hr, Midazolam 1ml/hr, Morphine 1ml/hr, Total oral drugs (antibiotics etc) 150ml/day
Total daily fluid allowance=(10x100 + 10x50 + 12x20) x 0.8 = 1740 x 0.8 = 1392 ml/day
Total drugs= 0.7x24 + 1x24 + 1x24 + 150 = 214.8 ml/day
Total maximum TPN volume = 1392 – 214.8 = 1177.2 ml/day
So prescribe TPN volume of 1000m/day (the rest of the fluid allowance will have to be prescribed separately on the chart as Dextrose or1/2-1/2 or Normal Saline), so that there is room to increase Noradrenaline and add in other inotropes/drugs as necessary.

Example 3

Patient: BW 32 kg
Fluid allowance: 80%
Drugs: Noradrenaline 0.7ml/hr, Midazolam 1ml/hr, Morphine 1ml/hr, Total oral drugs (antibiotics etc) 150ml/day

Total daily fluid allowance= (10x100 + 10x50 + 12x20) x 0.8 = 1740 x 0.8 = 1392 ml/day
Total drugs = 0.7x24 + 1x24 + 1x24 + 150 = 214.8 ml/day
Total maximum TPN volume = 1392 – 214.8 = 1177.2 ml/day
So prescribe TPN volume of 1000m/day (see above in fluid requirement section for further explanation) & Dextrose5%-NaCl0.45% for 177.2ml/day (= 4.8ml/hr)

TPN Prescription chart (day 1):


Patient's weight (kg)

 

= 32kg

Total fluid volume (ml/kg/day)

1392(see above)÷32

= 43.5

Non-TPN IV fluids (ml/day)

0.7x24 + 1x24 + 1x24
HOWEVER also include oral fluids = +150

= 214.8

Total TPN volume (ml/day)

See above for explanation

= 1000

Aqueous infusion rate (ml/hour)

Total TPN-lipids = (1000-160)÷24

= 35

Infuse Aqueous Over (hours)

 

= 24

Lipid infusion rate (ml/hour)

32 g/day over 20hr =(32x5 ml)÷20

= 8

Infuse lipids Over (hours)

Standard 20hrs

= 20

 

Aqueous Bag

 

 

Nitrogen (g/kg/day)

 

0.15

Glucose (g/kg/day)

 

3

Sodium (mmol/kg/day)

See tables above or on back

3

Potassium (mmol/kg/day)

of the yellow or white TPN charts

2

Calcium (mmol/kg/day)

 

0.2

Magnesium (mmol/kg/day)

 

0.07

Phosphate (mmol/kg/day)

 

0.18

Lipid bag

 

 

Lipid (g/kg/day)

 

1

 

 

 

 

 

So prescribe on PICU daily fluid chart:

 

Dose range

Freq C/O

Instruc-tions

Dr sign

pharm

start

given

check

Drug:
Fluid: TPN
Volume: 35ml/hr

 

 

C

 

 

FSW

 

 

 

 

Drug:
Fluid: Lipids
Volume: 8ml/hr

 

 

C

Over
20 hrs

 

FSW

 

 

 

 

Drug:
Fluid: Dextrose5%-NaCl.45%
Volume: 4.8 ml/hr

 

 

C

 

 

FSW