Benjamin J Blaise introduces a new study which is using POCT technology to address an underrecognised risk in paediatric anaesthesia.
Preoperative fasting is an essential component of safe anaesthetic practice, reducing the risk of pulmonary aspiration during general anaesthesia. However, while fasting protocols are well established, less attention has traditionally been paid to their metabolic consequences, particularly in children.1
Children have limited glycogen reserves and higher metabolic demands compared with adults, making them more vulnerable to fasting-induced hypoglycaemia and ketosis.2
Despite this physiological reality, perioperative glucose monitoring is not routinely performed in many healthcare settings, and metabolic disturbances may go undetected during anaesthesia.
Recognising this gap, investigators across the United Kingdom launched the Fasting Induced Hypoglycaemia in Anaesthetised Paediatric Patients (FIGS) study, one of the largest prospective studies ever undertaken to evaluate the metabolic effects of preoperative fasting in children. The project aims to generate evidence that could influence future perioperative care pathways and inform the potential role of glucose and ketone monitoring in paediatric patients.3
Why metabolic monitoring matters
Current paediatric perioperative guidelines acknowledge the risk of fasting related metabolic complications.1
The Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) has recommended that children undergoing surgery may receive intravenous fluids without dextrose supplementation and that blood glucose monitoring should be considered when dextrose is not administered.6
While severe hypoglycaemia is relatively uncommon, even mild-to moderate reductions in blood glucose can have clinical significance. Prolonged fasting may also trigger ketone production, indicating a metabolic shift toward fat utilisation. Elevated ketone levels can occur before clinically apparent hypoglycaemia and may therefore serve as an early indicator of metabolic stress.4
In routine clinical practice, both hypoglycaemia and ketosis can remain unrecognised during anaesthesia, when patients are unable to communicate symptoms.5
This creates a compelling rationale for objective biochemical monitoring during the perioperative period.
The FIGS study
The UK FIGS study is a multicentre observational project involving approximately 2,900 children across 25 UK centres. The study examines blood glucose and ketone levels in children undergoing fasting before general anaesthesia, providing unprecedented insight into the prevalence and predictors of fasting related metabolic disturbances.3
Designed as an opt-out multicentre cohort study, FIGS enrolled children aged one month to 17 years undergoing elective procedures under general anaesthesia. The study included a broad spectrum of everyday paediatric practice, ranging from diagnostic imaging and dental procedures to general surgical interventions. Children with known endocrine or metabolic disorders, those receiving glucose-containing intravenous fluids, and patients undergoing emergency or oncology procedures were excluded to minimise confounding factors and better characterise fasting-related metabolic changes in otherwise healthy paediatric populations.3
The primary objective of FIGS is to identify the glycaemic threshold that may trigger changes in anaesthetic management. Secondary objectives include determining clinically relevant glucose and ketone thresholds, assessing the prevalence of metabolic abnormalities, and identifying risk factors that may predispose children to hypoglycaemia or ketosis.3
The scale of FIGS reflects an exceptional national collaboration among paediatric anaesthetists, researchers, and clinical teams. Recruitment centres included major UK children’s hospitals, tertiary institutions and numerous other NHS organisations across England, Scotland, Wales, and Northern Ireland.3
In total, the study achieved recruitment of 2,902 patients, making it one of the most comprehensive datasets ever assembled to investigate fasting related metabolic changes in paediatric anaesthesia. Such broad participation ensures that the findings will be highly representative of contemporary paediatric perioperative practice throughout the United Kingdom.
The importance of ketones
Traditionally, clinicians have focused primarily on glucose measurement when considering fasting complications. However, glucose alone may not fully reflect the metabolic impact of prolonged fasting.7,8
Ketone production is a natural adaptive response to reduced carbohydrate availability. In young children, ketone accumulation can occur rapidly and may precede measurable hypoglycaemia. Consequently, ketone monitoring may offer additional insight into the metabolic response to fasting or physiological stress, helping to identify patients who could be considered for further evaluation before significant glucose depletion develops.9,10
This dual-marker approach is particularly relevant in paediatrics because fasting durations frequently exceed planned timelines due to surgical delays, logistical challenges, or operating theatre scheduling pressures. Understanding the relationship between glucose concentrations, ketone levels, fasting duration, and patient characteristics could enable clinicians to identify those most at risk and tailor perioperative management accordingly.
Enabling metabolic assessment
A notable aspect of the FIGS study is the use of the StatStrip Xpress 2 Glucose/Ketone Meter for point-of-care measurement of blood glucose and ketones.11,12 Conducting a large multicentre patient cohort study requires reliable and standardised testing methods that can be used consistently across numerous healthcare institutions.13
Point-of-care technology provides immediate results at the bedside while minimising workflow disruption within busy perioperative environments.14 The availability of rapid glucose and ketone measurements has enabled investigators to collect real-world metabolic data on a scale that would have been challenging using conventional laboratory testing alone.
Beyond its contribution to the study, this approach reflects a broader trend toward near-patient testing and data-driven clinical decision-making, particularly in time-sensitive environments such as operating theatres and recovery units.
Potential impact on future practice
The findings of FIGS have the potential to influence several aspects of paediatric perioperative care.
First, they may help establish evidence based thresholds for intervention when low glucose or elevated ketone levels are identified before anaesthesia.
Second, the study could improve understanding of which children are most susceptible to metabolic complications. Factors such as age, fasting duration, procedure type, and timing of surgery may ultimately inform risk stratification strategies.
Third, depending on the study findings, the results may contribute to discussions regarding the potential role of metabolic monitoring in selected paediatric populations, particularly those undergoing prolonged fasting or procedures associated with a higher metabolic risk.
The final results are expected toward the end of 2026 and are anticipated to provide important evidence regarding the prevalence and clinical significance of fasting-induced hypoglycaemia and ketosis in children.
Conclusions
The FIGS study is a large multicentre investigation of the metabolic consequences of preoperative fasting in children. By combining a substantial cohort with systematic glucose and ketone measurements, the study addresses an important area of paediatric anaesthesia that has received relatively limited attention to date.
While the final study results have not yet been published, the FIGS study is expected to enhance understanding of fasting-related hypoglycaemia and ketosis in children. Given that the study was not designed to assess whether glucose and ketone monitoring improves clinical outcomes, its findings should be interpreted primarily in the context of characterising the metabolic effects of preoperative fasting.
Depending on the results, the study may contribute to future discussions regarding perioperative monitoring practices and the development of evidence-based guidance in paediatric anaesthesia.
For a full list of references: https://www.pathologyinpractice.com/story/52637/perioperative-metabolic-monitoring-in-children
Dr Benjamin J Blaise MD PhD is a Consultant Paediatric Anaesthetist at Evelina London Children’s Hospital, which operates under the Guy’s and St Thomas’ NHS Foundation Trust. He is also an Honorary Senior Lecturer at King’s College London.
Further details of the FIGS study can be found at: www.bjaopen.org/article/S2772 6096(26)00337-0/fulltext