Purpose and scope
The purpose of this guideline is to assist clinicians in managing fasting times for clear liquids for patients who are undergoing general anaesthesia and/or procedural sedation. This will result in a reduction of prolonged fasting times for patients across Victoria (current estimates average 12 hours). It will also prevent excessive fasting times in the future, which are known to cause harm and distress to patients. Fasting times for solids and non-clear liquids remain at 6 hours for adults(1).
A local hospital policy, led by anaesthetists, should be developed based on this guidance. This should include its rationale and implications and be communicated to all clinicians utilising this guidance.
Intended audience
This guideline is intended for any clinician caring for patients who are undergoing general anaesthesia and/or procedural sedation. This includes, but is not limited to, anaesthetists, surgeons, gastroenterologists, cardiologists, emergency medicine, day surgery staff, preoperative anaesthetic clinic, radiology staff, and all nursing and midwifery staff.
Expected outcomes
- Reduction in fasting times for clear liquids for most patients undergoing procedures/surgery.
- Improved patient outcomes including:
- safe fasting period pre-procedure minimising aspiration and regurgitation
- reduced distress, dehydration and associated haemodynamic and metabolic effects
- improved patient experience.
Definitions
| Preoperative oral liquids | Describes clear liquids that can be ‘seen through’ when held up to light in a transparent vessel. This includes water, glucose-based drinks, cordials, clear juices, black tea and black coffee. For simplicity, water is often recommended. This does not include any liquids containing fat, protein and insoluble fibre. In addition, clear soups, thickened fluids and jelly that are included in a ‘clear fluid diet’ are not suitable preoperative oral fluids. Please see table below for further clarification regarding acceptable and not acceptable fluids. |
|---|---|
| Sip Til Send | A term used to describe the continuation of preoperative oral liquids up until the time patients are sent to operating theatre. |
| Fluid fasting time | Time from last consumption of liquids until commencement of anaesthesia or sedation. |
| Solid fasting time | Time from last consumption of solids until commencement of anaesthesia or sedation |
Background
Fasting audits have repeatedly shown that patients fast for liquids much longer than the recommended 2 hours (2,3). Recent evidence has questioned the need for a 2 hour fast, and several institutions have adopted policies that allow clear fluids until the patient is sent for (3,4). Studies have also shown the multifactorial nature of aspiration of gastric contents and the rarity of events that lead to morbidity or death (5,6). A preoperative fluid diet does not provide adequate nutrients and should not be used as the sole source of nutritional support for longer than one day.
Several institutions have adopted policies that allow clear liquids until the patient is sent for. Published evidence so far has shown improved outcomes and no detectable increase in regurgitation or aspiration (1,4,5).
Sip Til Send guideline
Sip Til Send is the permitted oral intake of clear liquids from a standard cup at volumes of up to 200 mL per hour for an adult until the time they are called to theatre or the procedural area.
Children may sip preoperative clear oral fluids at a rate of 3 mL per kg per hour up until the time they are called to theatre or the procedural area. Specific guidance for infants and for children having breast milk can be found elsewhere (6).
Exclusions
Liaise with the treating team for requirements in the case of the following:
- Patients with a surgical or medical order for Nil by Mouth (NBM), or thickened fluids or fluid restriction for a reason other than fasting for anaesthesia or sedation.
- If the procedural anaesthetist communicates or documents otherwise. All patients should continue to receive assessment of aspiration risk as part of their routine anaesthetic assessment and the anaesthetic planned accordingly.
- If the patient does not want to drink.
- Some patients having specific endoscopic procedures will need to avoid fluids that are red, blue or purple coloured.
- Patients with diabetes may require diet versions of preoperative diet fluids. If in doubt seek guidance based on blood sugar levels.
- Patients requiring sedation or anaesthesia for a PET scan can only have water for Sip Til Send (glucose not allowed).
- If a patient is on a GLP-1 agonist, consultation with the treating anaesthetist is advised to determine whether the time interval since the medication was last taken indicates whether the patient is eligible for Sip Til Send.
- Patients with conditions leading to delayed gastric emptying or ileus.
| ALLOWED - Preoperative Oral liquids | NOT ALLOWED - liquids |
|---|---|
|
|
Education notes
Pre-procedure fasting
Preoperative and pre-procedural fasting is necessary for all patients undergoing procedural sedation or general anaesthesia to protect the patient from possible regurgitation and aspiration of gastric contents (7,8).
All patients undergoing general anaesthesia or procedural sedation should fast for solids for at least six hours. This guidance is unchanged.
It is important, however, that patients are not fasted for extended lengths of time before a surgical procedure as this will increase surgical stress response, catabolic state associated with starvation, insulin resistance, risk of hypoglycemia in patients with diabetes, and general discomfort.
Patients waiting for emergency surgery are at particular risk of repeated and prolonged fasting because of the uncertainty of timing of access to emergency theatres and possibly repeated cancellations.
Patients who are fasted from preoperative oral fluids for extended periods also become dehydrated, making it difficult to gain IV access, increase the intraoperative fluid requirements and increase the risk of sodium overload. It also increases preoperative thirst, hunger, anxiety and nausea.
Clinical patient outcomes are improved when preoperative clear liquids are continued until the patient is sent for theatre (compared to prolonged fasting) including (9,10):
- replacing/maintaining the body’s water balance
- easier peripheral cannulation
- improved post-operative nausea and vomiting
- improved patient comfort
- enhanced post-operative recovery.
References
- Guideline on pre-anaesthesia consultation and patient preparation 2024 Appendix 1 Available from: https://www.anzca.edu.au/safety-advocacy/standards-of-practice/policies,-statements,-and-guidelines
- Checketts M, 2023; Anaesthesia, Fluid fasting before surgery: the ultimate example of medical sophistry?, 2023, 78, 147-149. doi:10.1111/anae.15925.
- R. Zaklama, K. Lo, M. Pendyala. 2022, “Preoperative fasting times—an audit on patient compliance and understanding at a major Australian tertiary hospital”, Westmead Hospital Departments of Anaesthesia and Intensive Care, Sydney, Australia.
- Ruggeberg A, Nickel E.A, Anaesthesia, Unrestricted drinking before surgery: an iterative quality improvement study, 2022, 77, 1386–1394.
- Marsman, M et al. JAMA Surgery, Association of a liberal fasting policy of clear fluids before surgery with fasting duration and patient well-being and safety. 2023, 158(3), 254-263.
- Brady MC, Kinn S, Ness V. Preoperative fasting for adults to prevent perioperative complications (review). Cochrane Database of Systematic Reviews 2003; 4: CD004423
- Kluger, M.T, Culwick, M.D, Moore, M.R, Merry, A.F. Anaesthesia and Intensive Care, Aspiration during anaesthesia in the first 4000 incidents reported to wedAIRS. 2019, 47(5), 442-251.
- Van de Putte P, Vernieuwe L, Jerjir A, Verschueren L, Tacken M, Perlas A. When fasted is not empty: a retrospective study of gastric content in fasted surgical patients. British Journal of Anaesthesia 2017; 118: 363–71.
- NSW Agency for Clinical Innovation (ACI), May 2016. Key Principles: Preoperative fasting in NSW pubic hospitals.
- Prince of Wales/Sydney-Sydney Eye Hospitals and Health Services Pre-Operative/Procedural Fasting for Patients Undergoing Anaesthesia and Procedural Sedation POWH/SSEH CLIN043