• Preoperative fasting does not reliably correlate with gastric volume at the point of induction of anaesthesia.

• Reduction of the preoperative fluid fasting period improves patient satisfaction, reduces perioperative nausea and vomiting, and reduces requirement for post operative IV fluids.

• Preoperative clear fluid intake ‘Sip Til Send’ is already safe, standard practice in elective orthopaedics. Non-elective patients are already permitted to take clear fluids with oral medications.

• This guideline permits non-elective (inpatient) trauma and orthopaedic patients to sip up to 170ml (one standard NHS cup) of water per hour until they are sent for by the theatre team, unless they meet exclusion criteria, which includes senior clinician opt out.

This is a controlled document. If you are using a printed copy, check it against the guidelines site to ensure you are using the latest edition. Print copies must be destroyed after use.

Applies to: Adult, non-elective (inpatient) trauma and orthopaedic patients, unless exclusion criteria apply (see below) or specifically opted out by a senior clinician.

Preoperative fasting is common practice ahead of most operations with the expectation for patients to be ‘nil by mouth’ or have a period of starvation prior to an operation requiring general anaesthesia ((NICE), 2020). While practices vary throughout the world and the UK, the basic premise was introduced following a study in the late 1940s to reduce the gastric contents and minimise both the incidence and severity of aspiration of gastric contents during anaesthesia (Mendelson, 1946). While the consequences of aspiration are potentially fatal, the frequency of clinically significant aspiration events are, rare. Current incidence is estimated at between 1 in 900 to 1 event in 10,000 anaesthetic cases (Warner, Warner, & Weber, 1993). Aspiration in procedural sedation is even less common, with only 9 aspiration related deaths recorded in the literature (Green, et al., 2019). The evidence for a 2-hour limit on fasting prior to anaesthesia is limited (Ruggeberg, Meybohm, & Nickel, 2024) with a recent systematic review and meta-analysis showing no association between pre-operative fasting and witnessed pulmonary aspiration (Lam, Cannesson, Osuna-Garcia, & Livingston, 2025) (Marsman, et al., 2023).

Current perioperative fasting guidelines are based on clinical studies which utilise surrogate markers such as gastric volume and gastric pH as markers of aspiration risk. However, these have not been shown to be reliable indicators of aspiration risk (Ruggeberg, Meybohm, & Nickel, 2024), Furthermore, even with prolonged preoperative fasting, some studies have shown that up to one patient in 20 had significant gastric volumes and one patient in 50 had solid gastric content identified on gastric ultrasound (Van de Putte, et al., 2017). This demonstrates that prolonged fasting is no guarantee of gastric emptying and that the presence of gastric contents is not well linked to pulmonary aspiration events below reasonable thresholds (Luo, Jiang, & Xie, 2025). The upper gastrointestinal tract is constantly excreting saliva and gastric juices; cephalic secretion phase (e.g. triggered by the thought of food) can purely increase the gastric secretion by 600ml per hour. Therefore, their fasting status does not ever truly guarantee an empty stomach. Furthermore, available evidence suggests that clear fluids are rapidly emptied from the stomach, can speed up the emptying of the stomach and are not linked to pulmonary aspiration events [ (Marsman, Pouw, Moons, Van Klei, & Kappen, 2021), (Ruggeberg, Meybohm, & Nickel, 2024).

Many trusts and regions including NHS Highlands have already protocolised liberal fasting in the preoperative period (Sands, Wiltshire, & Isherwood, 2022) and the Sip Til Send initiative is already implemented for elective orthopaedic cases (See FHFT Guideline ‘Adult perioperative fasting guidelines for elective surgery’)

Prolonged fluid deprivation is not only associated with discomfort such as thirst, anxiety, fatigue and post-operative nausea but can also be associated with more serious post operative complications such as delirium and cardiovascular events (Ruggeberg, Meybohm, & Nickel, 2024) (Ylinenvaara, et al., 2014). This includes increased risk of hyperglycaemia (which increases the risk of infection and re-operation). Prolonged fluid fasting can also be a modifying precipitating factor for delirium (Ruggeberg, Meybohm, & Nickel, 2024)]. One study found that preoperative dehydration quadruples the number of postoperative complications after hip fracture, especially neurological, cardiovascular, renal or respiratory problems [ (Ylinenvaara, et al., 2014) It is also important to add that fluid deprivation can lead to patient discomfort and increased anxiety and dissatisfaction with pre-operative management (Tosun, Yava, & Acikel, 2015). All the associated harms are likely to be aggravated by the highly variable duration of fasting due to cancellations and unpredictable changes to surgical list order [ (Ruggeberg & Nickel, Unrestricted drinking before surgery: an iterative quality improvement study, 2022). Therefore, implementing ‘Sip Til Send’ can help minimise the risks associated with prolonged starvation.

Current FHFT guidelines already permit preoperative oral medications to be administered with ½ cup of water with no requirement to avoid the 2-hour preoperative window. This Sip Til Send policy therefore represents a small change in the permitted pre-operative fluid administration, while being able to reduce pre-operative fasting times and post operative complications significantly

Exclusion Criteria

• Bowel obstruction or ileus

• Patient taking weight loss drugs which delay gastric emptying e.g. Mounjaro, Ozempic, Wegovy

• Documented history of gastroparesis

• Unsafe swallow or on thickened fluids

• Senior clinician opt out

Pre-operative intake of solids:

• Solid food, including sweets (e.g. lollipops), soup and all feeds given via nasogastric, gastrostomy or jejunal routes must be avoided for 6 hours prior to surgery.

• For patients admitted for morning lists, this means no food from 02:00 on the day of surgery. For patients admitted for afternoon lists, a light breakfast before 07.00 can be consumed.

Pre-operative intake of oral fluids:

• Up to 2 hours before surgery: patients may drink unlimited water.

• From 2 hours before surgery until patient is ‘sent for’ (‘Sip Til Send’): patients may sip up to one standard cup (170mls) of water (no other fluids) per hour until sent for by the theatre team)

Oral medication: See FHFT Guideline ‘Administration of Preoperative Medications for Patients awaiting emergency surgery’

• Regular medication taken orally should be continued preoperatively unless advised otherwise.

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

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.