Ultrasound Assessment of Gastric Residual Volume in Children Scheduled for Elective Surgery After Clear Fluids Fasting for One Versus Two Hours; a Comparative Study

Introduction:

The traditional 2-hour clear fluid fasting time was recommended by almost all anesthesia societies [1-3] to decrease the risk of pulmonary aspiration. However, these recommendations are based on historical adult literature [4,5] that may not be applicable to the pediatric population. Moreover, recent studies have shown that these recommendations may not be properly applied, and many children could have been starving for long intervals before surgery with the current guidelines [6-8] which was associated with increased risk of post induction hypotension during surgical preparation [9,10] There is a growing evidence that more liberal clear fluids intake does not result in significant increase in the risk of pulmonary aspiration [11,12] while children may have less thirst, hunger, anxiety, postoperative nausea and vomiting[13-15] also, limiting the fasting time may improve the perioperative inflammatory response in children [16].

Hence, a consensus statement was issued by the Association of Pediatric Anesthetists of Great Britain and Ireland (APAGBI), the European Society of Pediatric Anesthetists and the French-Language Society of Pediatric Anesthesiologists; encouraging clear fluids to be given up to 1 hour before elective general anesthesia [17] which was followed by the Canadian Pediatric Anesthesia Society (CAPS) statement in 2019 [18], however, these statements have not been translated into guidelines to date until further evidence is released.

Gastric residual volume GRV can be used as a preoperative tool for assessment of the risk of perioperative pulmonary aspiration in clinical practice [19]. Many methods have been used to assess gastric volume in pediatrics including nasogastric aspiration [20] , magnetic resonance imaging (MRI) and ultrasound[19,21]. Of these, only ultrasound is of clinical utility because it is simple, bedside, reliable [22], safe tool and allows both qualitative and quantitative assessment of gastric contents [19,23,24].

So, we aim to assess GRV in pediatrics having clear fluids fasting for one hour before elective surgery. We hypothesize that clear fluids fasting for one hour will not result in a clinically significant increase in GRV compared to two hours fasting for children scheduled for elective surgery under general anesthesia.