General anaesthetics inhibit the protective reflexes that stop the stomach contents reaching the lungs. In order to prevent the inadvertent inhalation of stomach contents, children are often advised to have nothing to eat or drink from the midnight before surgery. However, the review of trials found that drinking clear fluids up to a few hours before surgery did not increase the risk of regurgitation during or after surgery. Indeed there is an added benefit of a more comfortable preoperative experience in terms of thirst and hunger. Some children are considered more likely to regurgitate under anaesthetic, including those who are obese or have stomach disorders. More research is needed to determine whether these children can also safely drink up to a few hours before surgery.
There is no evidence that children who are denied oral fluids for more than six hours preoperatively benefit in terms of intraoperative gastric volume and pH compared with children permitted unlimited fluids up to two hours preoperatively. Children permitted fluids have a more comfortable preoperative experience in terms of thirst and hunger. This evidence applies only to children who are considered to be at normal risk of aspiration/regurgitation during anaesthesia.
Children, like adults, are required to fast before general anaesthesia with the aim of reducing the volume and acidity of their stomach contents. It is thought that fasting reduces the risk of regurgitation and aspiration of gastric contents during surgery. Recent developments have encouraged a shift from the standard 'nil-by-mouth-from-midnight' fasting policy to more relaxed regimens. Practice has been slow to change due to questions relating to the duration of a total fast, the type and amount of intake permitted.
To systematically assess the effects of different fasting regimens (duration, type and volume of permitted intake) and the impact on perioperative complications and patient well being (aspiration, regurgitation, related morbidity, thirst, hunger, pain, comfort, behaviour, nausea and vomiting) in children.
We searched Cochrane Wounds Group Specialised Register (searched 25/6/09), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2 2009), Ovid MEDLINE (1950 to June Week 2 2009), Ovid EMBASE (1980 to 2009 Week 25), EBSCO CINAHL (1982 to June Week 3 2009), the National Research Register, relevant conference proceedings and article reference lists and contacted experts.
Randomised and quasi randomised controlled trials of preoperative fasting regimens for children were identified.
Data extraction and trial quality assessment was conducted independently by three authors. Trial authors were contacted for additional information including adverse events.
This first update of the review identified two additional eligible studies, bringing the total number of included studies to 25 (forty seven randomised controlled comparisons involving 2543 children considered to be at normal risk of regurgitation or aspiration during anaesthesia). Only one incidence of aspiration and regurgitation was reported.
Children permitted fluids up to 120 minutes preoperatively were not found to experience higher gastric volumes or lower gastric pH values than those who fasted. The children permitted fluids were less thirsty and hungry, better behaved and more comfortable than those who fasted.
Clear fluids preoperatively did not result in a clinically important difference in children's gastric volume or pH. Evidence relating to the preoperative intake of milk was sparse. The volume of fluid permitted during the preoperative period did not appear to impact on children's intraoperative gastric volume or pH contents.