Milk Fasting Times and Aspiration in Infants.
Paediatric anaesthesia
Submitted June 2026 by Dr Erika Strazdins
Review summary
Paediatric anaesthestists may overestimate aspiration risk while underestimating the physiological and behavioural consequences of prolonged fasting. Fasting time is a key factor of operating theatre scheduling, driven by concern for the morbidity and potential mortality associated with rare event of pulmonary aspiration. These fasting times are shaped by professional guidelines, and many clinicians feel medicolegally vulnerable when deviating from them, even where guidelines allow clinical discretion. This editorial challenges the arguably disproportionate anxiety surrounding aspiration risk in infants and neonates, arguing that excessive adherence to restrictive milk fasting guidelines may create more common and immediate harms such as hypovolemia, hypoglycaemia, and distress at induction, than the aspiration events they seek to prevent.
Key findings
Pulmonary damage depends on the volume, acidity, and particulate content of aspirated gastric contents.
The authors highlight that the commonly cited critical volume for pulmonary injury derive from animal and primate studies, making it an imperfect measurement. In humans, although gastric emptying varies with age, feed volume, and route of feeding, normal liquid gastric emptying in infants and children younger than five exceeds 80% by three hours. Milk (both breast and formula) demonstrates a slower decline than clear fluids, but importantly, the variability of gastric emptying is similar between milk and clear fluids. Thus, the traditional assumption that milk behaves like a solid in the stomach and therefore require prolonged fasting is poorly supported.
As anaesthetists, we know that there are other factors aside from gastric volume and contents that contribute to the volume aspirated into the lungs. The authors highlight the findings from a prospective one-year survey of nearly 120, 000 children at eleven specialist pediatric hospitals in the UK. Firstly, inadequate anesthesia or poor control of the airway during induction, maintenance, and emergence all contribute to aspiration risk. Moreover, patient factors such as raised intra-abdominal pressure and comorbidities impact on aspiration incidence. This shifts focus from rigid fasting times toward high quality airway management and thoughtful preoperative assessment.
Strengths
A key strength of the editorial format is its ability to provide expert interpretation and clinical context around a topic where evidence is limited and practice is often guided by tradition rather than strong science. The authors challenge entrenched assumptions and translate the literature into practical recommendations for paediatric anaesthesia.
The short, narrative style makes the article accessible and engaging. It invites reflection on routine fasting practices and encourages readers to question whether current habits are evidence based or driven by dogma and defensive medicine. The authors add considerable authority. The primary author is a leader in original research around paediatric fasting, and other two authors are well established figures in paediatric anaesthesia research. These authors’ backgrounds span America, England, and Oceania. Their combined expertise makes this editorial a persuasive and credible call for reassessment of milk fasting guidelines in infants.
Limitations
The editorial format has intrinsic limitations. As an expert opinion piece, it reflects the authors’ interpretation of the literature and their clinical experience, rather than presenting new primary data. Their argument is persuasive, but it relies heavily on synthesis and extrapolation from older animal studies, observational studies, and physiologic reasoning.
The limited word count of an editorial restricts exploration of how more liberal fasting strategies could be balanced against patient comorbidities, emergency surgery, or babies and infants with delayed gastric emptying. While the editorial advocates flexibility, translating this safely into routine practice still requires clinician judgment and organisational support.
Bottom line
Strict adherence to fasting guidelines may not always serve the best interests of infants and neonates. Excessive fasting has known and common risks including operating theatre delays, hunger, dehydration, hypoglycaemia, and greater behaviorual distress at induction.
One practical strategy proposed is offering clear fluids after the final milk feed in babies and infants on milk-based diets, such as warmed 5% or 10% glucose solutions. This may improve hydration, calorie intake, and reduce preoperative distress.
In this vulnerable population, a more liberal provision of fluids is not simply about comfort, it may also mitigate common risks in anaesthesia. The authors argue that the greater danger may lie not in pulmonary aspiration itself, but the sequelae from the culture of fear surrounding it.
