BEND, Ore. -

St. Charles Medical Center-Bend acknowledged Monday that doctors used a partially disinfected scope during several patient colonoscopies last year. The revelation comes as one of those patients is suing the hospital for negligence.

According to the suit, filed last week by attorney Jennifer Coughlin, the hospital failed to fully disinfect a scope that had been used on four previous patients last September.

A letter to the woman from St. Charles CEO Jay Henry acknowledged a programming error led to the final disinfecting steps to be skipped.

As a result, the woman must undergo several rounds of ongoing STD (sexually transmitted diseases) tests, including an HIV test.

The lawsuit asks for $250,000 in emotional damages and $20,000 for past and future medical expenses.

Henry told NewsChannel 21 on Monday that the hospital is sorry for the incident, but the safety of the hospital is intact.

"We can say the steps that were used in this process were a two-fold manual process, with anti-bacterial soap," he said. "The third step, which was an automated process ... a six-step cleaning process, and one of the six steps which was not complete."

"Based on our physicians, these patients are at extremely low risk for infection," Henry said.

The suit follows a study last year that showed every hospital in the state, except St. Charles in Bend and Redmond, were using a surgical checklist recommended by the World Health Organization. Henry said the hospital is working diligently on implementing that checklist.

Meanwhile, the woman's attorney said the bottom line is that her client's health remains at risk.

"Although St. Charles may try to downplay the fact that the disinfection step of the colonoscopy procedure may have been missed, other steps may have been taken with this colonoscope," Coughlin said. "But it's of no comfort to our client that the disinfection step was missed and the colonoscopy did happen with a dirty colonoscope."

Henry said that in all, 18 procedures were found to have been done with the partially sanitized scope. He says the hospital has since taken action to fix the cleaning equipment and "improve our monitoring protocols."

All 18 affected patients were notified in October, by phone and letter, Lisa Goodman, the hospital's media and strategic communications coordinator, said Tuesday.

Goodman said the problem surfaced when a caregiver noticed a leak in the colonoscopy equipment.

"We immediately took the equipment offline and contacted our vendor," she said.

"It was when our vendor was servicing the machine that it was discovered one of the six steps of the disinfectant process had been programmed out."

"The standard of practice for the hospital industry is to disinfect -- not sterilize -- colonoscopy equipment, because our bodily orifices are not sterile environments," Goodman explained.

"Surgical equipment, on the other hand, is sterilized because it is used in a sterile environment -- the inside of our chest or abdomen, for example, is sterile," she added.

Goodman said the colonoscopes "were in fact disinfected even prior to going through what should have been a six-step process (and inadvertently ended up only being five)."