Not necessarily, but “clown doctors” and video games do help, according to a review published recently online by the Cochrane Collaboration, an international nonprofit that provides up-to-date information on health care research.

Dr. Allan M. Cyna, an anesthesiologist at Women’s and Children’s Hospital in Adelaide, Australia, and his team pooled data from 17 studies involving 1,796 children ages 10 months to 17 years, their parents, or both.

Children about to get general anesthesia can be given drugs to calm them down, but the drugs can have side effects. New research was done to see if non-drug methods could also reduce children’s anxiety.

Video games and clowns probably reduced anxiety by “focusing the child’s attention,” as hypnosis does, said Cyna in an e-mail. But “parental presence has neither been shown to be harmful, nor beneficial,” he added.

In one small but intriguing US study included in the review, giving acupuncture to parents – not kids – reduced both parental anxiety and increased the cooperation of the children.

Dr. Mary Ellen McCann, an anesthesiologist at Children’s Hospital in Boston, said, “I routinely tell parents who do not want to be present for the start of their child’s anesthesia, that the literature does not show a benefit from them being there. . . . If a parent is very anxious, the child picks up on that and it may make them more anxious.”

Children’s Hospital has clowns in the holding area outside the operating room “to entertain parents, children, and doctors,” which reduces everybody’s anxiety, says McCann. Children are allowed to choose what flavor they would like put on the mask that goes over their nose and mouth for inhalation of the anesthesia gas. In a frightening situation like being put to sleep for surgery, she says, even “the illusion of control is pretty important.”