As they prepared for surgery, technicians tallied sponges and blades so they could later be sure that none were left behind. Before taking up his scalpel, Dr. Cole was reminded by the “Time-Out!” towel covering his surgical tray to call for a brief break.

“We have Cynthia here for a left ankle fuse,” he announced. “Does everybody agree?” After all in the room chimed their agreement, he made his incision.

In pre-op, Ms. Kehborn, 48, said it had never occurred to her that patients might be charged for a medical error.

“It should be the hospital’s and doctor’s responsibility to step up to the plate and own up to their mistakes,” she said. “I’d be livid if we had to pay for it.”

The patient safety movement picked up steam in this country in 1999, when the Institute of Medicine, a prestigious advisory group, estimated that 44,000 to 98,000 Americans died each year from preventable medical errors.

In response, at least 20 states have passed laws requiring hospitals to report mistakes or preventable infections publicly, according to the National Conference of State Legislatures. The federal Centers for Medicare and Medicaid Services now requires hospitals to report on 42 quality measures. Hospitals that do not fully report may be docked up to 2 percent of their reimbursement.

In 2002, the National Quality Forum, a standard-setting consortium for the health care industry, compiled a list of 27 largely preventable adverse events, a list that grew to 28 in 2006 with the addition of “artificial insemination with the wrong donor sperm or egg.” In 2003, Minnesota became the first state to require reporting of all errors on the list, and last year the state’s hospital association became the first to announce that its members would not bill for them.