Intravenous Fluids and How to Prescribe them on Neonatal Unit

Publication: 02/07/2007  --
Last review: 08/12/2017  
Next review: 08/12/2020  
Standard Operating Procedure
ID: 1113 
Approved By:  
Copyright© Leeds Teaching Hospitals NHS Trust 2017  


This Standard Operating Procedure is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Intravenous Fluids and How to Prescribe them on Neonatal Unit.

This guideline now incorporates Maintenance Intravenous Fluids Protocol (LGI and St James's) guideline 553 and Neonatal fluid prescriptions and correcting electrolyte and glucose abnormalities in the neonate Guideline 1113 and is based on the new NICE guidance NG29

Summary of Guideline

This guidance provides information regarding

  • How to correct electrolyte abnormalities in situations when pharmacy aseptics is not open
  • How to request patient specific intravenous fluids (‘designer fluids’) during normal working hours.

During normal working hours of 8am to 7:30pm Monday to Friday and 8am to 6pm weekends and bank holidays pharmacy aseptics is available to prepare patient specific intravenous fluids (‘designer fluids’).

Back to top

Assessment and monitoring of IV fluid requirements

Use the actual weight where possible. If a working weight is used, the actual
weight should be used as soon as clinically possible

Fluid balance
Calculate or review the fluid input, output and balance over the previous 24 hours. Consider any special instructions for prescribing, including relevant history (e.g. renal impairment). Review all available charts including:

The fluid and electrolyte prescription (in ml per hour), with clear signatures, dates and times.
Types and volumes of fluid input and output (urine, gastric and other), recorded hourly and with running totals.
12-hourly fluid balance subtotals.
24-hourly fluid balance totals.
12-hourly reassessments of the fluid prescription and the current hydration status

Reassess whether oral fluids can be started on a daily basis.

Babies on IV fluids require U&E every 24 hours
Babies with electrolyte instability should have more regular electrolyte levels checked. Review and document Sodium, Potassium, Chloride, Creatinine and Urea levels
Point of care testing can be used if correlating well with laboratory results. A laboratory sample should be sent every 24-48 hrs.
In unstable patients ensure that you have blood results available before 5pm to enable pharmacy aseptic to manufacture a designer fluid if needed. Pharmacy is not able to manufacture fluid requests outside the normal working hours.

Routine Maintenance

The fluid volumes required by each infant should be adjusted daily on an individual basis, determined by their clinical condition, previous fluid balance, sodium balance and renal and cardiac function. Fluids should be restricted to the minimum to cover losses during the acute phase of RDS. The following table is a guide to the daily maintenance fluid requirements.

Maintenance fluid volumes

Infants >28 weeks gestation and >1000g














Only exceed >150ml/kg iv after careful assessment

Infants ≤28 weeks or ≤1000g or any preterm infant nursed on a heated platform














Only exceed >150ml/kg iv after careful assessment


  • **In Infants ≤28 weeks or ≤1000g progress to 150 ml/kg on day 3 only after review of U&E and weight change. Some babies may require less fluid volume.
  • *Infants should only be prescribed iv fluids in excess of 165 ml/kg after careful assessment of their fluid balance and ongoing requirements.
  • Infants with a symptomatic patent ductus arteriosus (PDA) should not exceed 150mls/kg/day
  • Post-operative fluid requirements should be discussed carefully with the surgical and neonatal team and fluid restriction may be required.
  • Infants in established renal failure may need to be restricted to 40mls/kg/day plus urine output.
  • Infants with SIADH (e.g. secondary to cerebral oedema, hypoxic ischaemic encephalopathy) will need fluid restriction. This requires careful individual clinical assessment.

Maintenance fluids should be delivered via a central line (UVC or long-line), where available. The maximum glucose (dextrose) concentration to be administered via a peripheral intravenous cannula (or other peripheral access) is 10%. 12.5% should be used only after a documented risk assessment.

Choice of intravenous fluids

0-24 hours: 10% glucose or Babiven Startup PN (if less than 28 weeks gestation or 1000g)

24- 72 hours: Glucose 10% with sodium chloride 0.18% (500mL) or Parenteral nutrition - as indicated. The ongoing requirement for intravenous fluids should be reviewed daily.
Note: In patients with low potassium use Glucose 10%, sodium chloride 0.18% with 10mmol potassium in 500mL (due to limited availability this fluid should not be prescribed as the routine short term fluid in patients with normal potassium levels).

Over 72 hours -28 days CGA: (0.45% sodium chloride with 10% glucose.
(see guidance to prepare 0.45% sodium chloride with 10% glucose)

In term babies and preterms beyond term + 28 days corrected age and in all patients on paediatric wards beyond 28 day refer to ‘Intravenous Fluid Therapy in Term Neonates, Children and Young People in Hospital

Fluid resuscitation
Assess for signs of shock
Administer 10-20ml/kg bolus of 0.9% sodium chloride over 10 minutes depending on clinical signs, and assess response. In preterm babies use 10ml/kg aliquots.

Management of specific electrolyte abnormalities

Back to top


Most neonates retain normal calcium levels even if not supplemented for a period of time1.

The normal calcium requirement for a neonate is approximately 1mmol/kg/day1.

When requesting laboratory calcium, adjusted calcium should be requested.
When a laboratory calcium level is unavailable ionized calcium on a blood gas analysis may be used as an indicator of calcium levels.

Some degree of hypocalcaemia is common in the first few days of life, especially if there is intrapartum asphyxia or respiratory distress. Late onset hypocalcaemia at 4–10 days after birth may be secondary to vitamin D deficiency, hypoparathyroidism or hypomagnesaemia and may present with seizures.

Seizures are usually associated with a serum calcium of less than 1.7mmol/L and more specifically an ionized calcium of less than 0.64mmol/L. In hypocalcaemia hypomagnesaemia is often also present. Most such babies have a corrected QT (QTc) of greater than 0.2 seconds on their ECG1,2.

There is no evidence that hypocalcaemia causes permanent neurological damage and little evidence that an asymptomatic baby with transient hypocalcaemia requires any treatment1.

Where possible correct hypocalcaemia with oral calcium supplementation (Calcium carbonate/Sandocal®) as per the BNFc or LTHT Paediatric Calcium Monograph.
If intravenous calcium is required to correct hypocalcaemia also consider correction of hypomagnesaemia (see neonatal formulary).

To correct hypocalcaemia follow guidance in the neonatal formulary

Calcium containing fluids are irritant; where possible do not run calcium containing fluids via a peripheral cannula. Consider central venous access.

Back to top


The sodium requirement for most healthy neonates is approximately 3 mmol/kg daily. Preterm neonates, particularly below 30 weeks gestation, may require up to 6 mmol/kg daily1,2. Hyponatraemia may be caused by excessive renal losses of sodium; it may also be dilutional and restriction of fluid intake may be appropriate1. Sodium supplementation is likely to be required if the serum sodium concentration is significantly reduced.

Hypernatraemia (>145 mmol/l)


  • Transepidermal water loss in preterm babies in the first 48-72 hours. This can be minimised by ensuring adequate humidity in the incubator.
  • Phototherapy can increase water loss by heat (older machines)or diarrhoea.
  • Hyperglycaemia resulting in osmotic urinary losses if the blood sugar is >10mmol/L.
    (often associated with weight loss)
  • Excess sodium input from infusions, sodium bicarbonate and flushes


Serum sodium greater than 150mmol/L but <160mmol/L

  • If possible reduce sodium intake by 2 mmoL/kg/day
  • Increase fluids by 20 - 30 mL/kg/day with a sodium free solution e.g. glucose 5%
  • Recheck sodium after 6 - 8 hours

Serum sodium greater than 160mmol/L

This is an emergency as the baby is at risk from intracerebral fluid changes.
Sodium should be corrected slowly (reduction of no more than10mmol/L every 12 - 24 hours)1,2.

  • Minimise sodium intake by selecting a low sodium maintenance fluid (the neonatal fluid calculator can be used to aid your fluid choice)
  • Increase fluids by 20 - 30 mL/kg/day
  • Recheck sodium after 4 hours
  • Review prescription of diuretics
  • Review fluid balance
  • Review the diluents of all continuous infusions (e.g. morphine etc); consider switching the diluent to glucose - the neonatal formulary provides information about drug compatibility.

Hyponatraemia (<135 mmol/L)


  • Water excess (usually associated with weight gain / oedema)
  • Inappropriate ADH secretion: (eg HIE, severe pneumonia, RDS)
  • Inadequate sodium intake
  • Increased sodium loss secondary to immature kidneys (usually second week of life onwards)


  • Review any changes in weight
  • Review urine output
  • Review urinary sodium concentration
  • Review and consider stopping all diuretics
    Increase sodium intake by 3-5mmol/kg/day. In a preterm baby (usually over 1 week old) sodium supplementation 10 to15 mmoL/kg/day may be required.
  • Sodium intake can be increased by
    • Adding oral sodium supplements,
    • Altering the neonatal maintenance fluid (the neonatal fluid calculator can be used to aid your fluid choice) or
    • Run part of the total fluid requirement as 0.9% sodium chloride - 20mL/kg/day of 0.9% sodium chloride provides 3mmol/kg/day of sodium (the neonatal fluid calculator can be used to aid your fluid choice).
0.9% Sodium Chloride Sodium Supplementation

Infusion rate

Sodium mmol/kg/day









  • Review fluid intake
    If water excess likely, fluid restrict by 30 - 50 mL/kg/day, in fluid restricted patients ensure blood sugar concentration is maintained. If required glucose can be added to ready prepared intravenous solutions as per the neonatal formulary.
  • Review the diluent of all continuous infusion (e.g. morphine etc); consider switching the diluent to 0.9% sodium chloride; the neonatal formulary provides information about drug compatibility.

**Hypertonic sodium chloride solutions (sodium concentration of greater than 150mmol/L) should only be used with the prior consent of a neonatal consultant**

Back to top


Although potassium is predominantly an intracellular ion, it is potassium serum concentration that is of immediate importance in therapy.

The usual potassium requirements for a neonates is (Evidence level B)

Gestational age

mmol/kg/day potassium

Less than 30 weeks


30-36 weeks




Hyperkalaemia (see also hyperkalaemia guideline)

  • Recheck potassium from a free flowing venous sample.
  • Assess for signs of renal failure (history, urine output and urea and creatinine levels)
  • Monitor ECG (look for peaked T waves)

Potassium 6.0 - 7.0 mmoL/L

  • Reduce potassium intake by 1-2mmol/kg/day or use potassium free intravenous maintenance solution (see fluid calculator)
  • Review all diuretics

Potassium > 7.0 mmoL/L

  • Follow hyperkalaemia guideline


Follow Neonatal hypokalaemia guideline

Back to top



For hypoglycaemia in the neonate who is just newborn or enterally fed refer to the ‘prevention and management of hypoglycaemia of the newborn guideline’.

The following is applicable to babies managed mostly or entirely on intravenous fluids.

Blood sugar < 2.6 mmol/L

  • Treat with 2.5 mL/kg bolus 10% glucose
  • Increase intravenous fluids by 15 to 30 mL/kg/day or
  • Consider prescribing an intravenous maintenance fluid containing a higher concentration of glucose.
  • If the child requires maintenance solution containing both electrolytes and glucose use the fluid calculator to select an appropriate fluid. Alternatively concentrated glucose can be added to a standard infusion bag to increase the glucose concentration by 2.5 or 5% - see the neonatal formulary.

NOTE: Glucose concentrations of more than 10% may require central access and more than 12.5% should always be infused through a central venous catheter

Back to top

Choice of IV fluids

Pre-made intravenous solutions

A number of pre-made solutions are available on the neonatal units, a list of the currently available can be found on the neonatal formulary.

Back to top

Neonatal fluid calculator

The neonatal fluid calculator can be used to aid the choice of maintenance fluids when designer fluids are not available

The neonatal fluid calculator is available via the net formulary and can be accessed via the following link:

To use the neonatal fluid calculator

Complete the ‘what you want’ box on the top right hand corner of the first tab entitled ‘fluid selector’

Any fluids that are a near match to the requirements you have specified are highlighted in amber, those with a close match are highlighted in green.

If you would like the calculator to show you the mmol/kg/day of electrolytes provided by a specified fluid use the second tab entitled ‘printout’

The calculator is provided as a tool to aid fluid selection; it should be used in conjunction with clinical knowledge. It is advised that you print out the appropriate page check the calculations manually and place the printout in the patient’s medical notes.

Back to top

Designer fluid request

To request a patient specific or ‘designer fluid’. The designer fluid calculator is available via the net formulary and can be accessed via the following the following link.

Please note that designer fluids are only available within normal working hours.

To use the neonatal designer fluid request template

Open the excel tool accessed via the link above.

On the first tab titled ‘designer fluid request form’ complete all the sections highlighted in green.


  • For stability reasons fluids cannot contain both calcium and phosphate
  • Hypertonic sodium chloride solutions (sodium concentration of greater than 150mmol/L) should only be used with the prior consent of a consultant
  • Glucose concentrations of more than 12.5% should always be infused through a central venous catheter

Ensure you are happy with the combination of electrolytes in the new fluid, if you have shown what fluids are currently running then the changes will be shown on the right hand side of the form.

Print out both the first tab ‘designer fluid request form’ and the second tab ‘aseptics order form’.

The electronic fluid request form should be used in conjunction with clinical knowledge. Calculations on the ‘Designer fluid request’ form should be checked by the prescriber, the print out should be signed by the prescriber and placed in the patients clinical notes. The aseptics order form should be given to the ward pharmacists.

Back to top


Record: 1113


To improve the management of electrolyte abnormalities in patients on the neonatal units at LTHT


  • Provide information regarding suitable intervals to measure electrolytes in patients on the neonatal unit.
  • Provide information regarding normal reference ranges of sodium, potassium and calcium in the neonate
  • Provide a guide to indicate when electrolyte abnormalities should be treated
  • Provide information to the prescriber regarding ready-made solutions that are available on the neonatal unit
  • Provide tools to help the prescriber select appropriate fluids
  • Provide an electronic tool to assist the prescriber request a designer fluid (within working hours only).
Clinical condition:

Electrolyte and glucose abnormalities in the neonate

Target patient group: Neonates on the LTHT neonatal unit only
Target professional group(s): Secondary Care Doctors
Adapted from:

This guideline now incorporates Maintenance Intravenous Fluids Protocol (LGI and St James's) guideline 553 and Neonatal fluid prescriptions and correcting electrolyte and glucose abnormalities in the neonate Guideline 1113 and is based on the new NICE guidance NG29

Evidence base

References and Evidence levels:


  1. Hey E. Neonatal Formulary: Drug Use in Pregnancy and the First Year of Life, 6th Edition. January 2011, BMJ Books [evidence level C]
  2. Paediatric Formulary Committee. BNF for Children 2013. London: BMJ Group, Pharmaceutical Press, and RCPCH Publications; 2013. [evidence level C]
  3. Intravenous fluid therapy in children and young people in hospital, NICE Guidelines:

A. Meta-analyses, randomised controlled trials/systematic reviews of RCTs
B. Robust experimental or observational studies
C. Expert consensus.
D. Leeds consensus. (where no national guidance exists or there is wide disagreement with a level C recommendation or where national guidance documents contradict each other)

Document history

LHP version 1.0

Related information

Not supplied

Equity and Diversity

The Leeds Teaching Hospitals NHS Trust is committed to ensuring that the way that we provide services and the way we recruit and treat staff reflects individual needs, promotes equality and does not discriminate unfairly against any particular individual or group.