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Waking up during surgery is certainly one of the scariest things that can happen to a patient on an operating-room table. To make matters worse, patients are usually injected with a temporary paralyzing agent to hold them still during the operation. That means they can't cry out or even wiggle to let the surgeons know they are conscious.

It happens rarely, but patients who have lived through the horrific experience say they are left emotionally scarred for life. Some can recall every painful knife cut.

Patient advocacy groups have been urging doctors to adopt better methods to ensure that people remain out like a light during the entire procedure. And, in particular, they have called for the use of new electronic equipment that is supposed to measure the level of consciousness by monitoring a patient's brain waves.

But a new study, published this week in The New England Journal of Medicine, represents a major setback for patient advocates. It found the new method is no better than the old one.

For the study, researchers at the Washington University school of medicine in St. Louis, Mo., compared 2,000 patients. Half of them were hooked up to the newer brain-scanning equipment. The other half were monitored the traditional way, using breath analysis.

The results revealed that the same number of patients - two in each group - experienced some degree of awareness, regardless of the method used to check for consciousness.

Deciphering DEET

More than 50 years ago, the U.S. Army developed DEET to help protects soldiers fighting in bug-infested jungles. DEET quickly became popular at family picnics and summer campgrounds, too. And it remains the unrivalled king of bug repellents. But scientists were never quite sure how the stuff actually drove away the pesky critters.

Now, a team of researchers says they have solved the mystery. "The common wisdom is that it smells bad to mosquitoes, but our work definitively shows that it acts by blocking the insects' sense of smell," said lead researcher Leslie Vosshall of the Rockefeller University in New York.

Mosquitoes and other blood-sucking insects use smell to find food, she noted. They can zero in on chemicals produced in human sweat. DEET (chemically known as N,N-diethyl-m-toluamide) essentially clogs the odour receptors of insects so they can't clue in to the fact that people have the aroma of a tasty meal.

The findings, published in today's issue of the journal Science, could lead to new and improved bug repellants, which may help prevent mosquito-borne diseases such as malaria and West Nile virus.

"Not everyone likes DEET on their skin. It feels greasy to some people ... It also melts plastics and is not recommended for infants," Dr. Vosshall said.

"Perhaps we can develop new compounds that act on the same molecular targets but don't have the unpleasant qualities of DEET."

Magnetic danger

Here is a lesson from the school of hard knocks: Five-year-old Braden Eberle underwent emergency surgery last April after swallowing powerful but tiny magnets no bigger than pills. The California boy gulped down the first magnet, which came loose from a toy building set. His mother thought it was no big deal, expecting the object would pass through his body the natural way. The next day, Braden accidentally swallowed a second magnet - from the same toy. The two magnets, in different loops of his intestines, somehow found a way to clump together. The magnets became stuck, causing pain. His mother took him to the Lucile Packard Children's Hospital in Stanford, Calif., where Sanjeev Dutta performed surgery to free the boy of the potentially life-threatening magnets.

Dr. Dutta has now written a report about the case in the journal Archives of Pediatric & Adolescent Medicine to serve as a cautionary tale for other physicians as well as parents.

He noted that many of the magnets in today's toys contain neodymium, a metal with an unusually strong magnetic force. "These rare-earth magnets are so much more powerful than the magnets we used to play with as kids," Dr. Dutta said in a statement released by the hospital.

Intestinal tissue pinned together between the objects can disintegrate, causing infection or other digestive problems. Furthermore, the affected part of the intestine can twist, cutting off the blood supply to part of the bowel.

"These magnet toys are ubiquitous," Dr. Dutta said. "They're recommended for older children, but many of these kids have younger siblings." Braden, for instance, was playing with his older brother's building set.

ptaylor@globeandmail.com