News from the ESAIC Guideline Task Force on Perioperative Fasting in Adults

“We cannot solve our problems with the same thinking we used to create them!” 

The quote attributed to Albert Einstein 

Even in the early days of anaesthesia, clinicians recognised that prolonged preoperative fasting exacerbated existing states of exhaustion [1]. This changed radically in 1946 when the obstetrician Mendelson described 66 cases of aspiration of gastric contents during anaesthesia among 44,016 pregnant women [2]. Mendelson hypothesised that the longer the fasting period, the emptier the stomach and the lower the risk of aspiration. However, 2 pregnant women died due to aspiration of solid food. Due to the lack of data on the optimal duration of preoperative fasting, “nil per os after midnight” became ubiquitous in the following decades as an intervention to prevent “Mendelson’s syndrome”. Notably, no distinction was made between fasting for solids and fasting for clear liquids despite the dramatically different physiology of gastric emptying. 

More recently, with the understanding that clear liquids leave the stomach very quickly, international guidelines have allowed clear liquids up to two hours before the induction of anaesthesia. The most recent European guidelines, published in 2011, specifically encourage patients to drink clear liquids for up to 2 hours before the start of anaesthesia [3]. Despite this, patients are still fasting for a median of 9-12 hours for clear liquids [4,5]. 

Many attempts have been made to reduce fasting for liquids, but these measures have generally failed. The traditional idea of nil per os from midnight is deeply rooted in the clinical workflow; the operating theatre schedules are too variable, and surgeons are too concerned that “the anaesthetist” could cancel or postpone the case if strict liquid fasting times are not met. Only concepts that allow the intake of clear liquids less than 2 hours before anaesthesia have achieved a significant reduction in liquid fasting times [5,6]. However, there is insufficient evidence to support this approach [7]. 

In 2022, the European Society of Anaesthesiology and Intensive Care (ESAIC) established a working group with experts from Europe and the USA to develop an updated guideline on perioperative fasting in adults. After reviewing approximately 25,000 studies published since 2010, the guideline committee developed recommendations through more than 50 online meetings and a standardised Delphi process. Initial recommendations were presented by Prof. Federico Bilotta, chairman of the guideline taskforce, in May 2024 at the “Euroanaesthesia” Congress in Munich. 

A review of the available literature, which took almost two years of intensive work, investigated the consequences of prolonged fasting, which was found to result in clinically meaningful harm. The key challenge encountered by the task force is that, in modern practice, the risk of aspiration is extremely low and poorly quantified, especially in elective patients. Furthermore, most aspirations occur because the risk factors for aspiration have not been identified, and anaesthetic techniques have not been adapted accordingly [8]. To date, no study has investigated the relationship between preoperative consumption of clear liquids and the risk of aspiration. With an incidence of aspiration of 1:10,000 in elective patients [9], hundreds of thousands of patients would have to be enrolled [10], making it very difficult to conduct such a study. 

However, the consequences of prolonged liquid fasting, such as dehydration, insulin resistance, increased stress response, delirium, and other postoperative complications, have long been ignored [7]. More recent studies have shown that the average preoperative liquid fasting time is still significantly longer than required. A large observational study of over 900 patients undergoing oncological surgery in 2023 showed an average preoperative liquid fasting time of nine hours instead of the recommended two hours [4]. Shorter fasting times for liquids are associated with better patient well-being, fewer postoperative complications, a smoother perioperative course, shorter hospital stays, cost savings, and improved environmental sustainability. 

The Guideline Task Force continues to recommend drinking clear liquids for up to approximately 2 hours before anaesthesia. During preoperative communication with the patient, it is important to mention the possible adverse effects of fasting for liquids for significantly longer than 2 hours. According to the suggestions* developed by the guideline task force, clinicians should not consider postponing or cancelling a procedure based solely on the intake of clear liquids less than 2 hours preoperatively. The guideline taskforce also recommends that hospitals develop protocols to shorten liquid fasting time. 

According to the information presented at Euroanaesthesia, there are also minor changes to the fasting limits for solid foods. Fasting for light food is recommended for approximately 6 hours or longer, and food rich in fat/protein for approximately 8 hours or longer. By adding “or longer”, the Guideline Task Force emphasised that individual consideration of specific patient groups and pathologies is more important than general advice. Some diseases or medications, such as diabetic gastroparesis or GLP-1 agonists, may delay gastric emptying of solid foods. However, the gastric emptying of liquids is not usually delayed. High-calorie meals, especially those high in fat, can also remain in the stomach for more than 8  hours. 

The complete version of the “ESAIC Guideline on perioperative Fasting in Adults” will be made available to all ESAIC members shortly to collect opinions and comments. The final version of the guideline will then be prepared and submitted to the European Journal of Anaesthesiology for publication. Publication is expected by the end of the year or in early 2025. The publication of this guideline will be accompanied by a comprehensive information campaign for both healthcare professionals and patients. 

*Suggestions are statements with weak supporting evidence, whereas recommendations are statements with stronger supporting evidence. 

Authors

• Corresponding Author: Anne Rüggeberg (MD) – Department of Anaesthesiology and Pain Therapy – Helios Klinikum Emil von Behring
• Anne Rüggeberg, Ehrenfried Schindler, Alexander Nagrebetsky, Anne Marie Camilleri Podesta, Marta Dias, Jamie Elmawieh, Ib Jammer, Barbara Hammer, Simone Silvestrini, Federico Bilotta 

References 

1. Maltby JR. Fasting from midnight – the history behind the dogma. Best Pract Res Clin Anaesthesiol 2006;20:363–78. 
2. Mendelson CL: The Aspiration of Stomach Contents into the Lungs During Obstetric Anesthesia. American Journal of Obstetrics and Gynecology 1946;52:91–205. 
3. Smith I, Kranke P, Murat I, et al. Perioperative fasting in adults and children: guidelines from the European Society of Anaesthesiology. Eur J Anaesthesiol 2011; 28:556–69. 
4. Beck MH, Balci-Hakimeh D, Scheuerecker F, et al. Real-World Evidence: How Long Do Our Patients Fast? – Results from a Prospective JAGO-NOGGO-Multicenter Analysis on Perioperative Fasting in 924 Patients with Malignant and Benign Gynecological Diseases. Cancers 2023; 15:1311. 
5. Rüggeberg A, Nickel EA. Unrestricted drinking before surgery: an iterative quality improvement study. Anaesthesia 2022;12:1386-1394 
6. Marsman M, Kappen TH, Vernooij LM, et al. Association of a liberal fasting policy of clear fluids before surgery with fasting duration and patient well-being and safety. JAMA Surgery 2023;158: 254–63. 
7. Rüggeberg A, Meybohm P, Nickel EA. Preoperative fasting and the risk of pulmonary aspiration—a narrative review of historical concepts, physiological effects, and new perspectives. BJA Open 2024; 10:100282. 
8. Cook TM, Woodall N, Frerk C. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: Anaesthesia. Br J Anaesth 2011; 106:617–31. 
9. Dias Vaz M, Berra L, Bilotta F, et al. Incidence and severity of perioperative pulmonary aspiration: a retrospective analysis of 1.2 million procedures. Poster Euroanaesthesia 2024, München. Eur J Anaesthesiol 2024;41(e-suppl. 62):284 
10. Joshi GP, Abdelmalak BB, Weigel WA, Harbell M, Kuo C, Soriano S, et al: American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting: Carbohydrate-containing Clear Liquids with or without Protein, Chewing Gum, and Pediatric Fasting Duration—A Modular Update of the 2017 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting. Anesthesiology 2023;138: 32–51.