Scrawl on the patient with a permanent marker to show where the surgeon should cut. Ask the person’s name to make sure you have the’ right patient. Count sponges to make sure you didn’t leave any in the body.

Doctors worldwide who followed a checklist of such steps cut the death rate from surgery almost in half and reduced complications by more than a third in a large international study of how to avoid blatant operating room mistakes.

The results most dramatic in developing countries — startled the researchers. “I was blown away,” said Dr. Atul Gawande, a Harvard surgeon and medical journalist who led the year-long, eight-nation study, published in today’s New England Journal of Medicine.

U.S. hospitals have been required since 2004 to take some of these precautions. But the 19-item checklist used in the study was far more detailed than what is required or what many institutions do: The researchers estimated that implementing the longer checklist in all U.S. operating rooms would save between $15 billion and $25 billion a year in the costs of treating avoidable complications.

“Most of these things happen most of the time for most patients, but we need to make it so that all these things happen all the time for all patients, because each slip represents an opportunity for harm,” said Dr. Alex Haynes of the Harvard School of Public Health, one of the study’s co-authors.