The Impact of Preoperative Duration of Fasting on the Intravascular Volume Status of Children Older than 5 Years of Age: A Prospective, Observational Study.

Objective: Preoperative fasting is a common practice aiming to reduce the risk of pulmonary aspiration during anaesthesia. It is advised to avoid fasting times longer than 6 hours in all children, whenever possible. Prolonged fasting can be uncomfortable for children and may lead to dehydration and other negative outcomes. The primary outcome of the study was the relationship between preoperative duration of fasting and cardiac index (CI) variability, used as a surrogate for intravascular volume status after the induction of anaesthesia, in paediatric patients undergoing surgery.

Methods: Prospective, observational study that included patients over 5 years of age, scheduled for surgery. Passive leg-raising-induced CI variability was evaluated for fluid responsiveness and intravascular volume after anaesthesia induction. Patients were termed fluid responders (Rs) if an increase in CI of >10% was obtained after passive leg raising, and non-responders (NRs) if the CI variability was <10%. CI and aortic peak velocity (V_peak) were measured through the suprasternal notch via an ultrasonic cardiac output monitor.

Results: There were 32 Rs and 53 (NRs). The mean duration of fasting for Rs was 11.53±2.61, while NR had a mean duration of fasting of 10.6±2.93 hours, showing an insignificant difference. Aortic V_peak change was significantly higher in Rs (0.24±0.17) compared to NRs (0.03±0.13) (P < 0.001). Duration of fasting showed no significant correlation with CI variability and peak aortic velocity.

Conclusion: With this study method, it was observed that preoperative fasting time had no effect on intraoperative intravascular volume.