Reduced Preoperative Fasting in Children

University dissertation from Uppsala : Acta Universitatis Upsaliensis

Abstract: Preoperative fasting is recommended in order to reduce the risk of perioperative pulmonary aspiration. However, preoperative fasting may have negative effects on patient wellbeing and homeostasis. In this thesis, more lenient regimens for preoperative fasting in elective paediatric patients were assessed, with the aim to further improve preoperative fasting regimens.Paper I investigated if paediatric patients allowed to drink clear fluids until called to surgery, had an increased risk of pulmonary aspiration. The incidence of perioperative pulmonary aspiration in children allowed free clear fluids until called to surgery was 3 in 10 000, as compared to 1-10 in 10 000 in previous studies where longer fasting intervals were studied. Hence, no increase of incidence for pulmonary aspiration was found.Paper II investigated actual fasting times for clear fluids when applying two-hour fasting for clear fluids, and zero-hour fasting for clear fluids. When applying two-hour fasting, children were fasted median four hours for clear fluids. After transitioning to zero-hour fasting, median fasting time decreased to one hour, and the incidence of children fasting for more than six hours decreased from 35 % to 6 %. Abandoning the time limit for clear fluids significantly reduced the proportion of patients fasting for extended periods.Paper III assessed gastric content volume after a light breakfast in children scheduled for elective general anaesthesia. Patients were examined with gastric ultrasound four hours after a light breakfast. Of the 20 patients included in the study, 15 had an empty stomach, 4 had clear fluids < 0.5 ml kg-1 and one had solid content in the stomach. A light breakfast preoperatively might be safe, but amount and caloric restriction is needed to avoid the risk of perioperative pulmonary aspiration.Paper IV investigated preoperative weight loss, glucose level and ketone bodies in paediatric patients presenting for elective surgery. The outcomes were tested for correlation to preoperative fasting times. Of the 43 children enrolled in the study, three had weight loss of more than 5 %, five children presented with blood glucose level < 3.3 mmol l-1, and 11 children presented with ketone bodies > 0.6 mmol l-1. There was no correlation between fasting time, and the respective outcomes. Even with a lenient fasting regimen, there is risk of mild preoperative dehydration, hypoglycaemia and ketogenesis.In conclusion, the results obtained in the present thesis supports the shift to more lenient preoperative fasting regimens for clear fluids in elective paediatric patients.