Incidence of hypoglycemia in children when fasting for elective procedures after implementing the 6-4-3-1 fasting recommendations: a descriptive prospective cohort study

Abstract

Background: Preoperative fasting aims to reduce the risk of pulmonary aspiration during anesthesia. However, prolonged fasting negatively impacts children´s well-being and bodily functions. From April 2022, new fasting guidelines were implemented at Landspitali in accordance with recommendation from the European Association of Anesthesiologists. Fasting time for solids remained unchanged at 6 hours, while fasting time for formula was reduced from 6 to 4 hours, breast milk from 4 to 3 hours, and clear fluid from 2 to 1 hour.Objective: To shed light on children‘s fasting times and the incidence of hypoglycemia during anesthesia under the new 6-4-3-1 fasting rule. Additionally, to assess which children are at risk of low blood glucose associated with fasting before anesthesia.Methods: A single-center descriptive prospective cohort study of pediatric patients < 18 years (n = 350) who underwent general anesthesia for elective procedures from October 2023 to May 2024. Capillary blood glucose levels were obtained within five minutes after anesthesia induction and before intravenous fluid administration.Results: The median (range) age of participants was 6.8 (0.1 - 17.9) years, and median body weight was 23.0 (2.9 - 156) kg. Median fasting time for solids was 13.4 (4.0 - 24) hours and 4.0 (0.3 - 8.6) hours for clear fluids. Hypoglycemia (< 3.3 mmol/L) was observed in 1.2% of children [95% confidence interval (CI), 0.3 to 3.0%] or 4 out of 339. Increased odds of hypoglycemia were associated with longer fasting from solid food with a decrease of -0.05 mmol/L change per hour (p < 0.001) but not from clear fluid.Conclusion: Children´s fasting times before anesthesia are longer than recommended. However, the fasting time for clear fluids and the incidence of hypoglycemia have decreased compared to previous research at Landspitali when following earlier guidelines. It´s important to find ways to shorten fasting times for solids and even further reduce clear fluid fasting times.