Pre-surgery: How long do children need to fast before an operation?

Some hospitals do not let children have anything to drink for two hours before an operation. Others do not allow them to drink for more than five hours, but such a long fast has not been proven necessary. Children who are allowed to drink water or clear juice up to two hours before an operation feel better and stay calmer than children who have to fast longer.

Usually an automatic reflex prevents stomach contents or acids from regurgitating, or coming back up the throat. However, general anaesthetics put this reflex out of action. This means that it is easier for stomach contents to come up the throat and get into the windpipe during an operation. If it is then breathed into the lungs, it can cause a life-threatening infection.

Because of this, children and adults are often asked not to eat or drink anything in the last few hours before an operation. But there are widely varying opinions on how long this fast should be. Between four and eight hours is a common fasting period. This can be a very long time for children.

In order to find out how long children need to fast before surgery, researchers from the Cochrane Collaboration, an international network of researchers, looked for trials on this topic. They were specifically interested in trials that involved children and teenagers up to the age of 19 who were to have a general anaesthetic. They found 23 trials altogether and did an analysis of the combined results. Some of the children in the trials still had something to drink a short time before the operation, and some had some light food to eat.

These trials showed that children who had water or apple juice up to two hours before the operation did not have more contents or acids in their stomachs than those children who fasted longer. That suggests that those children were not at increased risk of regurgitating than the other children.

The parents and children were also asked how much of a burden the time without food and drink was for the children. Those who only had to fast for two hours before the operation felt better and were more patient than children who fasted longer.

In March 2009 we looked for the latest research in this area to update this article. We did not find any trials that contradict the information given here.


Author: German Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care)