Pre-operative hydration of children admitted for procedures to Leeds Children’s Hospital requiring a general anaesthetic - Standard Operating Procedure

Publication: 26/07/2018  
Next review: 25/08/2024  
Standard Operating Procedure
ID: 5665 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2021  


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.

Pre-operative hydration of children admitted for procedures to Leeds Children’s Hospital requiring a general anaesthetic. Standard Operating Procedure


  • To minimise adverse side effects of restricting fluids pre-anaesthetic by standardising the hydration status of children admitted for procedures under general anaesthesia without increasing the risk of aspiration.
  • To instigate a practice of a clear fluid drink on admission to the ward/department.

LTHT fasting times for children who are admitted for procedures requiring a general anaesthetic.

  • Six hours for food
  • Four hours for breast milk
  • One hour for clear fluid

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Background and indications for standard operating procedure

Background evidence for new fasting times
Excessive fasting can cause a great amount of distress for children and their carers.  The AAGBI1 (Association of Anaesthetists Great Britain and Ireland) states that recommended fasting times are:

  • Six hours for food
  • Four hours for breast milk
  • Two hours for clear fluids

These times as advocated by the AAGBI are employed as the Trust Standard Fasting Time in the adult population.  Recent literature challenges the traditional fasting times.  A recent study of 10,000 children, over a 6-year period, demonstrated that drinking free fluids up until the time of surgery does not increase their risk of aspiration (Andersson et al, 2015).  This is supported by Schmidt et al (2015) who showed there was no change in gastric pH or volume after 1 or 2 hours fasting.  There is also ample evidence from radio-nucleotide studies that the time taken for more than 80% of clear fluid to exit the stomach is less than 1 hour (Malmud et al, 1982).  Furthermore, if glucose is included in children’s clear fluid then gastric emptying is significantly quicker (Schmitz et al, 2012).

  • Restriction of solids and fluids minimises the risk of aspiration of gastric contents on induction of anaesthesia. This SOP sets out the Leeds Teaching Hospitals NHS Trust (LTHT) fasting times for children who are admitted to the Children’s Hospital for a procedure under a general anaesthetic.
  • This SOP sets out how fasting information will be communicated to patients and their families
  • The side effects of fasting, especially in small infants, include thirst, hunger, irritability, hypoglycaemia and dehydration. To minimise discomfort, and some of these potential side effects, much research has been done to rationalise fasting times. Families are advised to maintain hydration up until the requested fasting time for clear fluids to minimise these side effects


  • Clear fluids are defined as water, squash (lemon or orange only, no purple or red coloured drinks as these can interfere with some diagnostic procedures) diluted drinks
  • Clear fluids do not include pure fruit juices, milk including breast or baby formula, fizzy drinks, red or purple drinks, caffeine drinks or hot drinks
  • Milk and sweets are considered as a food
  • Age 1 months is either 1 month post term or 44 weeks post conceptual age for those born prematurely


  • Children who are fluid restricted
  • Delayed gastric emptying
  • Diabetics (individual plan required)
  • Metabolic disorders (individual plan required)
  • Extremely anxious children (require Anaesthetic review)

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Clear fluid on admission

Once the list order has been confirmed children will be allowed to drink up until one hour before surgery.
List order changes, and therefore changes to fasting times, will be communicated to the ward and parents in a timely manner. All decision-making regarding fasting time will be documented in the patients care plan by the ward staff.
The ward staff member will explain to the family that we allow small volume clear drinks in well children. Children will be advised to sip this rather than drink all at once.

Escalation Process
The maximum clear fluid fasting should not exceed four hours, where possible, without another source of hydration.  Where a child has been clear fluid fasted for four hours or more without another source of hydration, the Anaesthetist should be contacted to ask if the child can be given a clear fluid drink. It may be necessary to leave a message if the Anaesthetist is not available. All decision-making regarding fasting must be documented clearly.

LTHT fasting times for children who are admitted for procedures requiring a general anaesthetic.

  • Six hours for food
  • Four hours for breast milk
  • One hour for clear fluids


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Record: 5665
Clinical condition:
Target patient group: Children’s Services Ward Nurses Anesthetists Surgeons Perioperative Practitioners Radiologists
Target professional group(s): Secondary Care Doctors
Allied Health Professionals
Secondary Care Nurses
Adapted from:

Evidence base

Andersson H, Zaren B, Frykholm P.  Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite.  Pediatric Anesthesia 2015; 25 (8) 770-777.

Malmud, LS, Fisher RS, Knight LC et al.  scintigraphic evaluation of gastric empyting.  Semin Nucl Med.  1982; 12: 116-125.

Schmitz A, Kellenberger C, Lochbuehier N et al.  Effect of different quantities of a sugaredclear fluid on gastric empyting and residual volume in children: a crossover study using magnetic resonance imaging.  British Journal of Anaesthesia 2012: 108: 644-7.

Schmidt A, Buehler P, Seglios L et al.  Gastic pH and residual volume after 1 and 2 h fasting time for clear fluids in children.  British Journal of Anaesthesia 2015;114 (3): 477-82


Evidence levels:

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)

Related Clinical Guidelines

Diabetes - Diabetes and surgery in children

Pre-operative fasting in adult patients presenting for elective surgery

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 2.0

Related information

Not supplied

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