Children do well with shorter fast before surgery

Apr 27 2005

Children facing surgery can be made more comfortable with little risk by allowing them to have certain liquids up to two hours before the operation, a new review of recent studies has found.

Like adults, children are often required to go without food or drink up to a half-day before surgery to prevent their stomach contents from being regurgitated or sucked into the lungs under general anesthesia.

In the review of 43 randomized controlled trials involving 2,350 children, only one case of regurgitation or aspiration of food or drink into the lungs was reported, according to Marian Brady of the Glasgow Caledonian University in Scotland and colleagues.

The review appears in the April issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

There is no evidence to suggest that children given liquids two hours before surgery have higher stomach volumes or more acidic stomach contents than those who undergo longer fasts, the researchers found. Stomach volume and acidity are two factors thought to influence the risk and severity of aspiration.

Although most research evidence now supports relaxed fasting standards, “kick-starting an evolution in fasting policies remains a difficult task,” Brady says. She notes that some hospitals still require patients to eat or drink nothing after midnight the day of surgery, a “practice that should no longer be tolerated,” she says.

“Most children can safely drink clear liquids until two hours before surgery, although more research is needed for some groups of children,” Brady and colleagues write.

Not surprisingly, children allowed a drink closer to surgery said they were less hungry and thirsty and more comfortable. Physicians also reported that these patients were better behaved.

Children who are obese, diabetic or have stomach disorders may be more likely to regurgitate, and Brady says more studies are needed to show whether these children can safely drink up to a few hours before surgery.

“Nurses and anesthesiologists are anxious to ensure the safety of children, so they are sticking to what they know to be safe fasting policies. Things are beginning to change but change is slow,” Brady says.

Dr. Donna Caniano, a pediatric surgeon at Children's Hospital of Columbus, Ohio, and chairperson of the American Academy of Pediatrics surgery section, says preoperative fasting times among children “can be very variable,” depending on where the patients are waiting for surgery and whether food and drink are available.

In her hospital, Caniano says, guidelines about preoperative fasting are strictly followed “and if they are violated, we will not go ahead with surgery.” At Children’s Hospital of Columbus, patients can drink clear liquids up to two hours before surgery and eat solid foods eight hours before surgery.

The evidence for allowing solid food closer to surgery is less definitive, Brady and colleagues conclude. Although no cases of regurgitation or aspiration were reported in the studies in which children ate plain cookies or cooked rice cereal, there was some evidence that stomach volumes were higher among these children.

“At present, the available evidence does not support a shift in practice from the current established guidelines which permit children solid food up to six or eight hours preoperatively,” Brady and colleagues write.

The researchers found very few studies on milk drinking before surgery, which was “especially surprising given the reliance of younger children on this form of nutritional intake,” Brady says. More studies could help researchers determine how milk contributes to stomach volume and acidity, since milk curdles in the stomach and acts more like a solid than liquid, she notes.

Many of the studies examined in the review only reported stomach volume and acidity, without noting any adverse effects on surgery. “I think one of the most vital things to include in future studies in this area would be to encourage researchers to report the incidence of aspiration, regurgitation or any adverse events related to fasting regimes,” Brady says.

The American Society of Anesthesiologists 1999 guidelines recommend a two-hour fast from clear liquids, a four-hour fast from breast milk and a six-hour fast from formula and a six- to eight-hour solid food fast for infants and children before surgery.