1.1 A period of fasting prior to anaesthesia is necessary to prevent aspiration/regurgitation of stomach contents which has the potential to be fatal ^[1], however, clinically significant pulmonary aspiration during general anaesthesia is rare in healthy patients undergoing elective surgery. The largest study reports an incidence of 1 in approximately 10,000 patients, with no deaths in more than 200,000 ^[2]. The majority of serious cases of pulmonary aspiration occur in emergency cases, particularly trauma, obstetrics and abdominal surgery in which delayed gastric emptying may be further prolonged by administration of opioid analgesics ^[2]. There has been limited recent evidence regarding the optimal fasting time pre-anaesthetic to ensure an empty stomach. However, the detrimental effects of prolonged pre-operative fasting ^[3] such as irritability, headache, dehydration, hypovolaemia and hypoglycaemia ^[3,4] have been seen as increasingly important.

Two editorials and one paper about fasting before surgery concluded that in patients scheduled for an elective operation the rule 'nil by mouth after midnight' should be abandoned ^[5,6,7]. Patients may have a light meal 6 hours before theatre and continue clear fluids until 2 hours before surgery ^[8,9]. Evidence has shown that small amounts of milk may be added to tea or coffee without affecting gastric emptying ^[10]. Chewing gum has been shown to have clinically insignificant effects on stomach volume and pH ^[11].

June 2021 Update

Following recent changes to national guidance for fasting in paediatric patients, there have been renewed calls to update adult fasting guidance for fluid intake prior to surgery ^[12,13]. Although the AAGBI had stipulated clear fluids up to 2 hours prior to anaesthesia, the British Association of Day Surgery and GIRFT advocate allowing patients to drink fluids up to the point of anaesthesia based on a cohort of >11 000 patients studied retrospectively in a UK centre ^[14,15]. They also recommend actively embracing the European and AAGBI guidance to allow elective patients to have a tea/coffee with small amount of milk 2 hours prior to anaesthesia.

1.2 Patients who use services will benefit from clear procedures followed in practice, monitored and reviewed to ensure they

• Are only subject to fasting (for example before an operation or procedure) for the minimum possible period, and the service will ensure they have adequate hydration as soon as possible afterwards.

• Are given nutrition as soon as possible after procedures requiring fasting are cancelled.

Scope

The guideline applies to all adults undergoing elective surgery under anaesthesia delivered by an anaesthetist, e.g., general or regional anaesthesia. Patients undergoing procedures that require conscious sedation should also be fasted according to this policy unless the responsible consultant anaesthetist has specifically indicated and recorded in the patient notes that fasting is not necessary.

Patients with obesity, gastro-oesophageal reflux and diabetes and pregnant women not in labour can safely follow this guideline. These factors may, however, alter their overall anaesthetic management.

For postoperative fasting, patients undergoing surgery involving the gastrointestinal tract or major abdominal surgery are not covered by this guideline. These patients should have specific post-operative instructions that should be followed.

Recommendations for patients with impaired swallowing are not covered by this guideline.

2.1 Clinical Staff

It is the shared responsibility of healthcare professionals to ensure safe and effective fasting procedures and reduce unnecessary discomfort to patients. Following procedures and guidance for good practice has been shown to decrease the risk of patients being exposed to errors and is an important component of risk management.

All staff must be aware of their roles and responsibilities under the current legislation and adhere to the safe practices outlined in this guideline. Staff should also make themselves familiar with local policies and procedures for their specific area of work.

2.2 Non-clinical staff

All administrative staff that provide information to patients prior to procedures, such as admissions managers or medical secretaries, are to be familiarised with this guideline on commencement of employment at local induction.

Excessive fasting can cause a great deal of stress for patients. Although the AAGBI ^[16] (Association of Anaesthetists Great Britain and Ireland) stated that recommended fasting times are six hours for food and two hours for clear fluids, many units are now offering clear fluids up to the time when patients leave the ward for theatre. There is evidence this causes minimal harm and may reduce post-operative nausea, vomiting and the improve the patient experience ^[15]. This approach minimises the risk of prolonged starvation as it can be difficult to reliably predict exactly when a patient is due for surgery.

It is a mistake to think that the stomach is empty just because the patient has been fasted. The upper gastrointestinal tract is constantly excreting saliva and gastric juices therefore the stomach will always contain some of these fluids.

5.1 Pre-operative intake of solids

Solid food, including sweets and all feeds given via nasogastric, gastrostomy or jejunal routes must be avoided for 6 hours prior to elective surgery.

For patients admitted for morning lists, this means no food from midnight on the day of surgery. For patients admitted for afternoon lists, a light breakfast before 07.00hr can be consumed.

5.2 Pre-operative intake of oral fluids

See Appendix 1 for patient instructions prior to arriving to hospital on the day of surgery.

Patients awaiting surgery may drink water until they are called to theatre for induction of anaesthesia. They may have a cup of tea or coffee with a small amount of semi-skimmed/skimmed milk up to 2 hours prior to anaesthesia.

All patients for elective surgery should be provided with a jug containing 250ml of water on admission and a cup so they can help themselves to water. They can drink water up to the point of being called to theatre.

5.3 Chewing gum and sweets during preoperative fasting

Sweets (including lollipops) are solid food. Patients must refrain from eating sweets within six hours of anaesthesia ^[16].

Chewing gum does not cause an increase in gastric volumes or acidity ^[11]. Chewing gum within the six hour starvation period will not result in surgery being delayed.

5.4 Oral medication

Regular medication taken orally should be continued preoperatively unless there is advice to the contrary. See Trust Guidelines on pre-operative medicines for elective patients ^[19].

Patients may drink water to take their medication throughout the whole fasting period.

5.5 Premedication

Pre-medication prescribed by the anaesthetist can and should be given even within the last hour of fasting. Note all adult patients will be given oral paracetamol prior to elective surgery as per Trust guidance. It is acceptable to drink water to help swallow the paracetamol tablets.

5.6 Delayed elective operations

Where an operating list is known to be over-running, the anaesthetist should be contacted to obtain a revised fasting time.

Keeping list order alterations to a minimum will reduce unnecessary thirst and dehydration. If an elective operation is delayed, the responsible nurse, anaesthetist and/or surgeon will review the fasting period.

5.7 Postoperative resumption of oral intake

When ready to drink, patients should be encouraged to do so, providing there are no medical, surgical or nursing contraindications.

6.1 Information on the fasting regimen will be given by a healthcare professional who has received suitable training.

6.2 Clear signage will be visible at the patient’s bed space indicating the fasting regimen that is being followed.

6.3 All patients will be provided with written information on fasting guidance prior to arrival in hospital.

7.1 This guideline represents the normal standard of care for perioperative fasting in adults. It will be the responsibility of the anaesthetist to inform the nursing staff if there is a clinical need or evidence to deviate from the guideline.

7.2 The guideline will be supported by ward-based teaching. The role of Consultant Surgeons, Anaesthetists, Ward Sisters and Charge Nurses is pivotal to the implementation of this guideline.

7.3 The guideline will be included in the Induction Programme for all relevant junior doctors and nurses joining the Trust.

7.4 All staff are expected to comply with this guideline and the attached guidelines.

8.1 There will be an audit of preoperative fasting times within six months of the introduction of the guideline undertaken on a minimum of 10 patients in each care group undertaking surgery.

8.2 Regular analysis of complaints and incident data relating to this issue will also be reviewed by care groups through routine governance processes and lessons learnt from this will be used to improve guideline and practice.

8.3 The guideline will be reviewed every three years or earlier if there are changes in national guidelines.

1. Jester R, Williams S. Pre-operative fasting: putting research into practice. Nursing Standard 1999; 13 (39): 33-35

2. Warner MA, Warner ME, Weber JG. Clinical significance of pulmonary aspiration during the perioperative period. Anaesthesiology1993; 78 (1): 56-62

3. Hung P. Pre-operative fasting. Nursing times1992; 88 (48): 57-60

4. Yogendran, S et al. A prospective randomised double-blinded study of the effect of intravenous fluid therapy on adverse outcomes on outpatient surgery. Anaesthesia and Analgesia 1995;80 (4): 682-686

5. Strunin L. How long should patients fast before surgery? Time for new guidelines. British Journal of Anaesthesia1993; 70 (1): 1-3

6. Brock-Utne JG. Clear fluids, not breakfast, before surgery. Acta Anaesthesiologica Scandinavica1996; 40 (5): 507-508

7. Phillips S et al. Preoperative drinking does not affect gastric contents. British Journal of Anaesthesia 1993;70 (1): 6-9

8. Practice guidelines for preoperative fasting and the use of pharmacological agents for the prevention of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology; 114(3): 495-511. Available at https://doi.org/10.1097/ALN.0b013e3181fcbfd9

9. Brady MC, Kinn, S, Stuart P, Ness V. Pre-operative fasting for adults to prevent perioperative complications. Cochrane Database of Systematic Reviews 2003, Issue 4. Art. No: CD0044223. DOI:10.1002/14651858.CD004423.

10. Hillyard S, Cowman S, Ramasundaram R, Seed PT, O'Sullivan G. Does adding milk to tea delay gastric emptying? British Journal of Anaesthesia 2014; 112(1):66-71. Available at: 10.1093/bja/aet261

11. Bouvet L, Loubradou E, Desgranges FP, Chassard D. Effect of chewing gum on gastric volume and emptying: a prospective randomized crossover study. British Journal of Anaesthesia 2017; 119 (5) 928-933. https://doi.org/10.1093/bja/aex270

12. Morrison C, Ritchie-Maclean S, Jha A, Mythen M. Two hours too long: time to review fasting guidelines for clear fluids. British Journal of Anaesthesia 2020; 124 (4): 363-366. Available at: https://doi.org/10.1016/j.bja.2019.11.036

13. Hewson DW, Moppett I. Pre-operative fasting and prevention of pulmonary aspiration in adults: research feast, quality improvement famine. British Journal of Anaesthesia 2020: 124 (4): 361-363. Available at: https://doi.org/10.1016/j.bja.2019.12.018

14. GIRFT National Day Surgery Delivery Pack (Sept 2020). Available at: https://www.gettingitrightfirsttime.co.uk/wp-content/uploads/2020/10/National-Day-Surgery-Delivery-Pack_Sept2020_final.pdf.

15. McCracken G, Montgomery J. Postoperative nausea and vomiting after unrestricted clear fluids before day surgery: A retrospective analysis*. Eur J Anaesthesiol 2018; 35:337–342.* Available at: http:dx.doi.org/10.1097/EJA.0000000000000760

16. Schmitz A, Kellenberger C, Lochbuehier N et al. Effect of different quantities of a sugared clear fluid on gastric emptying and residual volume in children: a crossover study using magnetic resonance imaging*. British Journal of Anaesthesia* 2012; 108 (4) 644-7. Available at: https:/doi.org/10.1093/bja/aer497

17. AAGBI safety Guideline: Preoperative Assessment and Patient Preparation – The role of the Anaesthetist (2010). The Association of Anaesthetists of Great Britain and Ireland. Available at: https://www.aagbi.org/sites/default/files/preop2010.pdf

18. Smith I et al. Perioperative fasting in adults and children: guidelines from the European Society of Anaesthesiology. European Journal of Anaesthesiol June 2011; 28 (8) 556-569. Available at: https://doi.org/10.1097/eja.0b013e3283495ba1

Rapid evidence search (2011-21) – systematic reviews, guidelines, RCTs

Yip A, Hogan S, Carey S Interventions Aimed at Reducing Times in Acute Hospital Patients: A Systematic Literature Review Nutrition in Clinical Practice Feb 2021: 36 (1): 133-152

Gomes P C et al Residual gastric volume evaluation with ultrasonography after ingestion of carbohydrate – or carbohydrate plus glutamine-enrihed beverages: a randomized, crossover clinical trial with healthy volunteers Arquivos de gastroenterologia 2017; 54 (1): 33-36.

Lambert E, Carey S. Practice Guideline Recommendations on Perioperative Fasting: A Systematic Review J Parenter Enteral Nutr Nov 2016; 40 (8): 1158-1165.

Smith  MD, McCall  J, Plank  L, Herbison  GP, Soop  M, Nygren  J. Preoperative carbohydrate treatment for enhancing recovery after elective surgery. Cochrane Database of Systematic Reviews 2014, Issue 8. Art. No.: CD009161. DOI: 10.1002/14651858.CD009161.pub2. (Accessed 16 September 2021.)

Association of Anaesthetists (2011) Perioperative fasting in adults and children: guidelines from the European Society of Anaesthesiology, Available at: https://anaesthetists.org/Portals/0/PDFs/Guidelines%20PDFs/Guideline_perioperative_fasting_in_adults_and_children_2011_final.pdf?ver=2018-07-11-163756-007&ver=2018-07-11-163756-007 (Accessed 16/09/21)

This guideline has been registered with the Trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt, contact a senior colleague or expert. Caution is advised when using guidelines after the review date. This guideline is for use in Frimley Health NHS Foundation Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.

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