The rationale for the recommendations of the European Paediatric Fasting Guideline: Improving paediatric anaesthesia and perioperative medicine.

Abstract

This Invited Commentary accompanies the following article: Frykholm P, Disma N, Andersson H, et al. Pre-operative fasting in children: guideline from the European Society of Anaesthesiology and Intensive Care. Eur J Anaesthesiol 2022; 39:4–25. Background The new European Society of Anaesthesiology and Intensive Care (ESAIC) guideline on preoperative fasting in children is published in this issue of European Journal of Anaesthesiology.1 Why a new guideline on preoperative fasting? The first ESA guideline on preoperative fasting published in 2011 was part of a global movement to move away from the nil per os (NPO) from midnight paradigm that had been predominant in the preceding decades.2 A similar guideline was issued by the ASA in 1999,3 and updated in 2017 with no significant changes.4 In contrast to the existing guidelines, the authors of the 2021 ESAIC paediatric guideline have found reasons to recommend reductions to the minimum fasting times for infant formula to 4 h, for breast milk to 3 h and for clear fluids to 1 h. So instead of 6–4–2, the short form of the new guideline is 6–4–3–1 (Table 1). Table 1 - Minimum fasting times for different categories of food and drink in the ASA Practice Guidelines originally published in 1999, the European Society of Anaesthesiology Guideline for Preoperative fasting in Adults and Children published in 2011, and the new European Society of Anaesthesiology and Intensive Care Paediatric Preoperative Fasting Guideline Type of food or drink ASA 1999 ESA 2011 ESAIC 2021 Solids 6 h 6 h 6 h Infant formula 6 h 6 h 4 h Breast milk 4 h 4 h 3 h Clear fluids 2 h 2 h 1 h ESAIC, European Society of Anaesthesiology and Intensive Care. Rationale for the new 6–4–3–1 regimen Why not stick to the old 6–4–2 regimen? Can reducing the minimum clear fluid fasting time from 2 to 1 h really make a difference for real world fasting times? And is it worth potentially increasing the risk of some children having residual fluid in their stomach at induction? The main reason for the change is the growing number of studies showing that real world fasting times are not even close to 2 h for clear fluids. On the contrary, mean clear fluid fasting times ranging from 8 to 15 h have been reported.5–7 It has proven to be surprisingly difficult to reduce fasting times when implementing the 6–4–2 regimen. The main reason may be that both parents and nursing staff are hesitant to give clear fluids if they perceive a risk of postponing the planned surgery and, therefore, choose a more conservative approach, which often results in fasting overnight to be ‘on the safe side’. With a 1 h limit, it is much easier to plan for and permit clear fluid intake on the morning of surgery without the risk of breaking the rule. Two quality improvement projects on both sides of the Atlantic reached strikingly similar conclusions; in spite of a package of educational efforts for parents and staff, and a positive language encouraging intake of clear fluids as close as possible to the 2 h point, it was not possible to reach the goal of reducing unneeded long fasting until the clear fluid limit was reduced to 1 h.8,9 How about the risk of aspiration? Unfortunately, there is a complete absence of randomised controlled studies investigating the incidence of aspiration with different fasting regimens. Noninferiority studies assessing the risk of aspiration require a massive number of participants. However, if we pool studies monitoring fasting time and the incidence of aspiration (n > 30 000), not a single case of confirmed pulmonary aspiration was detected as a result of the recent ingestion of a large volume of clear fluid.8–10 We, therefore, suggest that in children undergoing elective anaesthesia, clear fluid in the stomach at induction does not add significantly to the risk of aspiration. In fact, the risk of regurgitation or aspiration is inherently present for any sedation/general anaesthesia procedure, especially in emergency cases and when there is gastrointestinal obstruction and, as matter of course, anaesthesiologists must be trained to recognise and manage these events adequately. The benefit for numerous patients in the sense of improved comfort and the prevention of dehydration always justifies the necessary flexibility in the procedure in individual cases. Several European institutions (mostly in the Netherlands, Sweden and Germany) currently allow clear fluids less than 1 h before induction.10,11 Although this practice has been audited, the panel chose a more conservative 1 h limit for the recommendation of clear fluid fasting. Importantly, we neither dispute the legality nor the rationale of preoperative fasting regimens allowing clear fluids less than 1 h before anaesthesia induction if mandated by local institutionally approved protocols. Are children special? Why was the task force commissioned to produce a paediatric guideline? Most previous guidelines have included adults and children within the same framework. We can identify four main reasons. (1) During the last decade, we have witnessed a surge of research initiated and performed by paediatric anaesthesiologists, investigating the feasibility and safety of reduced fasting times, including a plethora of gastric emptying studies. (2) Although pulmonary aspiration remains one of the main causes of mortality associated with anaesthesia, death because of aspiration in conjunction with anaesthesia in children has until recently not been reported. The reason for this apparent difference between adults and children remains unclear but the underlying mechanisms may be different in adults (e.g. chronic diabetes leading to autonomic dysfunction). Furthermore, early detection and management of regurgitation with rapid turning of the patient to the lateral position and effective suctioning of the pharynx is almost always possible in a child while this may not be the case in adult patients. (3) Feeding with breast milk and infant formula are specific to paediatrics, and many gastric emptying studies focus on these two entities. (4) The main argument for us remains that feeding and nutrition is a central part of paediatric medicine. ‘Failure to thrive’ is a paediatric concept. Children, especially the youngest, are more prone to suffer from the detrimental effects of prolonged fasting compared with adults. In summary, the net balance between the benefits of shorter fasting time and the minimal risk of morbidity and mortality due to aspiration in children leads to the need for an updated guideline focussing solely on children. Gastric ultrasound Two of the task force groups analysed the evidence for using gastric (antral) ultrasound to ascertain if the stomach is empty or contains fluids and/or solid matter that could pose a risk of regurgitation and pulmonary aspiration. The panel found that gastric ultrasound can be a useful tool for determining gastric content volume. However, although the detection of high echogenic areas in the antrum is a sure sign of a ‘full stomach’, the critical cut-off value for clear fluid content associated with an increased risk of pulmonary aspiration remains unclear. Thus, at this stage, gastric ultrasound should be used with a qualitative, ‘eyeballing’ approach rather than to suggest distinct cut-off values for gastric antral area. Only anaesthetists properly trained in the technique are likely to use it for decision-making, suggesting the need for educational programmes. Conclusion The 2021 ESAIC paediatric guideline on preoperative fasting represents a concerted effort by an international team of experts investigating the evidence from studies of various aspects of preoperative fasting and weighing the balance between risk and benefit. As the experts are all clinicians as well as researchers, the aim has been to produce an evidence-based guideline that is easy to understand and straightforward to implement for clinicians as well as other stakeholders involved in ensuring a child is ready for anaesthesia. We anticipate that the publication of this new ESAIC guideline will stimulate the paediatric anaesthesia community to fill in the knowledge gaps with multicentre studies involving large numbers of patients. Since these guidelines only represent part of the population that anaesthesiologists care for, we hope to trigger the future development of a guideline for adults too, by a similarly agile group of scientists and clinicians. Most adults are not quite as sensitive as our youngest patients but they may also suffer from long fasting periods. In addition, many of the arguments listed for shortening fasting times can be taken in consideration for adult patients. Indeed, there is increasing evidence that a liberal approach with regard to clear liquids is beneficial and safe at all ages.12–14