Pre-operative fluid fasting (Guidelines)

Warning

This document outlines the protocol for the management of pre-operative fasting (or “nil by mouth”) for all elective and emergency surgical procedures, including paediatric and obstetric procedures), patients undergoing non-surgical procedures requiring general anaesthesia, or sedation. This protocol seeks to address and resolve inconsistencies in pre-operative fasting, and give guidance to ALL staff within NHS Highland to ensure practice is evidence based.

This protocol excludes:

  • patients who are “nil by mouth” for the medical management of dysphagia/stroke.
  • patients attending for upper GI endoscopy.

Background

Responsibilities and organisational arrangements 

Directors/ Assistant Directors /General Managers/ Lead Nurses for the Health and Social Care Partnerships (or equivalent) are responsible for the distribution of this protocol to staff within their area/directorate/business unit; ensuring information given to patients is consistent with this change in policy.

Senior Clinical Nurses are responsible for ensuring this protocol is implemented within their area and to monitor compliance.

All clinical staff are responsible for their own compliance with the guidance contained within this protocol, identifying their own training needs and attending appropriate training when provided.

Background 

The requirement for all adult surgical patients undergoing general anaesthesia to be in the fasted state has been considered one of the fundamental cornerstones for safe peri‐operative care, (Fawcett & Thomas 2018). This has been challenged, and many now accept that the morbidity caused by prolonged fluid fasting is no longer acceptable and offers no safety benefit (Morrison et al 2020).

Pre-operative fasting is the time during which a patient is “nil by mouth” before a planned procedure or emergency surgery, and continues until the patient regains consciousness post operatively and is able to take fluids orally (RCN 2005). The aim is to have an empty stomach so as to avoid the event of the patient aspirating (stomach contents entering the lungs) whilst under general anaesthesia or deep sedation.

Evidence has demonstrated that some patients are at greater risk from prolonged fasting, specifically those who are diabetic, pregnant women, those that have peptic ulcer, gastric reflux, stress, pain, or who habitually take narcotics or alcohol (AAGBI, 2010, Robinson & Davidson (2014)
It was historical practice to fast patients from food for for 6–8 h and from fluids for 2 hours prior to anaesthesia to reduce this risk of aspiration, but there is little evidence for these cut-offs (Morrison et al 2020, Maltby 2006).

Given the unpredictable nature of operating room scheduling and inevitable delays, patients are waiting and fasting much longer (NHST Survey Pre-op fluid fasting May 2021, NHSH Survey Pre-op fluid fasting in trauma, Feb 2022) than expected, which is a common cause of patient morbidity and anxiety.

Prolonged fluid fasting is an inappropriate way to prepare for the stresses of surgery and can be detrimental to patients, (BADS 2013; Lambert & Carey 2015). Not only can prolonged fasting result in significant discomfort for patients including increased feelings of thirst and hunger (Crenshaw 2011, Pimenta & Aguilar-Nascimento 2013, Lambert & Carey 2015), but can also lead to hypotension on induction of anaesthesia, and evidence of a catabolic state (Fawcett & Thomas 2018) and is associated with an increased incidence of postoperative nausea and vomiting, (Thomas & Engelhardt 2017).

In 1999, The American Society of Anesthesiology took the first step towards liberalising pre-operative fluid fasting guidelines and both randomised control trials and reviews in the past decade have shown that there is little or no evidence that the volume or pH of gastric contents differed significantly whether patients were permitted a shortened pre-operative fluid fast or had a standard fast from fluids.

In 2005 the RCN endorsed clinical practice guidelines demonstrating that free clear fluids could be safely administered until 2 h before surgery in adults (RCN 2005) and it was envisaged that this would have had patient benefits including; increased wellbeing, reduced side effects like headache, dry mouth, sore throat, and nausea (Smith et al. 2011, Chon et al. 2017).

Unfortunately, local audits have shown that the 2 hr fluid fast has failed to reduce median fluid fasting times which often significantly exceed 6 hours.

The NHS Highland anaesthetic department implemented a policy for reduced fasting times among a cohort of patients awaiting surgery for neck of femur fracture repair. Patients were highlighted on admission and provided with a 170ml cup with a jug of water by their bed-space. Patients were allowed to sip clear fluid up until the point of being summoned for their procedure. This policy was termed ‘Sip Til Send’. These patients exhibited a much reduced fluid fasting time with no increased incidence of complications eg aspirations.

Results from the subsequent audit were presented at a local departmental meeting of anaesthetists at NHS Highland with support for extending this protocol to wider emergency and elective patients awaiting surgery.

Elective surgery patients have fewer variables regarding pathology, physiology, timing, risk and mode of anaesthesia and are often on an enhanced recovery pathway. Patients undergoing elective surgery may gain from improved recovery consequent to this policy change. Sip Til Send will be the default for the National Treatment Centre.

NHS Tayside having adopted the Sip Til Send policy in December 2021 for all surgical areas across all sites. now have a cohort of over 2000 cases with no adverse events such as aspiration. 

Sip Til Send

NHS Highland anaesthetists collectively agreed in September 2022 to further liberalise pre-anaesthetic fluid fasting to a “Sip Til Send” policy, which allows patients to drink water right up until the point at which they are summoned for their procedure. This was in the light of audit evidence that actual mean fluid fasting times were over 6 hours (A. Wei, D. Sharpe and R. Tallach. February 2022), Sip Til Send will become the new default fluid fasting policy across NHS Highland for all procedures involving input from an anaesthetist.

The ‘Sip Til Send’ protocol becomes the normal default for oral fluids before surgery or procedures involving anaesthesia or sedation and should be followed unless specific instructions by an anaesthetist are given to the contrary. This is consistent across all surgical disciplines and across adult and paediatric care.

Pre-operatively before the patient is transferred to theatre the ward nurse will complete the Pre-operative checklist to include confirmation of last food and drink.

NB If individual anaesthetists want patients to deviate from the Sip Til Send policy, for whatever reason, they must inform the attending nursing team to adopt bespoke fluid fasting instructions. In these cases, the patient will be treated as Nil By Mouth (no food or fluids) and a red laminated sign will be placed on their bed-table. These red laminated signs already exist.

Pre-Operative fasting

Minimum fast for clear fluids

See: Sip Til Send

  • Hot Drinks:
    • Patients can have one morning cup of tea or coffee that can include up to three teaspoons / 15mL of milk on the morning of their procedure, anytime before 07:00.
  • Thereafter, allowed fluids include 170mL per hour of:
    • still water
    • clear fruit juices (without pulp e.g. apple juice) or diluting juice
  • Fluids to avoid:
    • fruit juices containing pulp (e.g. fresh orange juice)
    • milk/milky drinks
    • alcohol containing drinks should not be consumed within the 24 hours prior to surgery
    • any carbonated drinks, including sparkling water

Minimum fast for solids

  • The NHS Highland policy on preoperative fasting for solids remains unchanged.
  • Patients for a morning list should eat nothing for six hours before surgery; this includes sweets.
  • Patients for an afternoon list should have a light breakfast at least 6 hours prior to the start of the list (i.e. finished by 7.00 am).

Light breakfast:

  • a small bowl of cereal with milk and any non-alcoholic drink
    OR
  • 1-2 slices of toast with spread and any non-alcoholic drink

Patients requiring regional anaesthesia only

  • Sip Til Send also applies.

Procedures requiring local anaesthesia only

  • No fasting required. Patients should eat and drink normally.

Use of sedation

  • Sip Til Send applies to patients requiring intravenous sedation.
  • Fasting for solids pre-operatively, as per guidance above

Unscheduled surgery

Sip Til Send is the default, but bespoke fluid fasting instructions may be necessary depending on the clinical scenario. The attending clinicians must communicate alternate fluid fasting instructions for specific patients to the responsible nursing staff.

Close coordination between theatre and ward nursing staff is required for emergency surgery patients.

Post-operative fasting

Healthy patients undergoing elective surgery, under general anaesthesia, not involving the gastrointestinal tract should resume normal intake post-operatively as soon as possible and ideally in the post anaesthesia recovery room. This remains unchanged and is already the default for NHS Highland.

Medications

Many medications may be continued before and after surgery without any problems. As a rule; routine medicines should be given to all patients, including up to the time of surgery with a small amount of water. 

For further information see: UKCPA - Handbook of Perioperative Medicines (ukclinicalpharmacy.org)

Consent

No consent is required for this protocol

Authorised professionals

All staff within NHS Highland that are involved in the assessment of patients must at all times act in accordance with their professional code of practice. Sip Til Send will be the NHSH default but various reasons may require deviation from the policy, eg, obstructed abdomen with active vomiting. Therefore the anaesthetist responsible for anaesthetising the patient will have final say in pre-operative fluid regimen.

Education and training

No formal training is required however all staff are required to update their practice regularly and ensure that practice is evidence based.

NHS Highland should invest in educating all areas involved in this policy change in the evidence and reasoning behind it. This may require publicity posters or banners, Sip Til Send ‘Champions’ in each area, involvement of lead nursing staff and presentation to senior leadership.

Patient information

Written, verbal and electronic information given to patients will need to be consistent with Sip Til Send. This includes pre-op information sent to patients, information on the wards (inclusive of medical wards where there may be surgical outliers) and information available on the NHSH website.

  • NHS Highland Pre-operative fasting leaflet (see resources). 

References

  • British Association of Day Surgery (BADS) (2013) Patient Safety in the Ambulatory Pathway. London: BADS.
  • Chon, T., Ma, A, and Mun-Prce, C. (2017) Perioperative Fasting and the Patient Experience, Cureus. May; 9(5): e1272.
  • Crenshaw. J.T. (2011) Preoperative Fasting: will the evidence ever be put into practice? American Journal of Nursing, 111 (10), pp.38-43.
  • Department of Health (2010 a) Reference Guide to Consent for Examination or Treatment. London: DoH.
  • Department of Health (2010 b) Delivering Enhanced Recovery: Helping Patients get better sooner after surgery. London: DoH.
  • Dornan K.J., Thompson, D.M., Conn, A.R., Wittmann, B.K., Stiver, H.G. and Chow, A.W. (1982) Toxic shock syndrome in the postoperative patient. Surgery, Gynaecology and Obstetrics, 154(1), pp. 65-68.
  • Fawcett, W.J. and Thomas, M. (2018) Pre‐operative fasting in adults and children: clinical practice and guidelines, Anaesthesia, 30 November.
  • Fasting from midnight – the history behind the dogma J.Roger Maltby Best Practice & Research in Clinical Anaesthesiology 2006: 20(3); 363-378.
  • Gustafsson, U. O., Scott, M. J., Schwenk, W., Demartines, N., Roulin, D., Francis, N. and Ljungqvist, O. (2013) Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS(R)) Society recommendations. World Journal of Surgery, 37(2), pp.259-284.
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  • Irwin, R., Gyawali, I. et al (2020) An ultrasound assessment of gastric emptying after team with milk in pregnancy – a randomized controlled trial. European Journal Anaesthesioly: 37:303-308. Document Control Document
  • Morrison, C.E., Ritchie-McLean, S., Jha. A., and Mythen, M. (2020) Two hours too long: time to review fasting guidelines for clear fluids. British Journal of Anaesthesia 124(4) 363-366.
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  • Pimenta G.P, & Aguilar-Nascimento, J.G., (2013) Prolonged Preoperative Fasting in Elective Surgical Patients, Why Should We Reduce It? Nutrition in Clinical Practice, Vol: 29, 1: 22-28.
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  • Thomas M, Engelhardt T. Think drink! Current fasting guidelines are outdated. British Journal of Anaesthesia 2017; 118: 291–3. Document Control Document: NHS Tayside FFNC Policy Section 1.2: 1.2.3 Version: 7.6 Version Date: Aug 2021 Policy Manager: Dietetic Consultant in Public Health Page 13 of 41 Review Date: Aug 2024
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Editorial Information

Last reviewed: 25/04/2024

Next review date: 30/04/2028

Author(s): Dept of Anaesthesia.

Version: 1.1

Approved By: TAMSG of the ADTC

Reviewer name(s): Rosel Tallach, Consultant Anaesthetist, Douglas Sharpe, Jane Halcrow, Consultant Anaesthetist .

Document Id: TAM632

References

Patient information