A state investigation has faulted a Cold Spring, Minn., nursing home in the death of an elderly resident who suffocated after her head became lodged between a mattress and bed railing.

Staff at the Assumption Home failed to conduct a required assessment of the woman, who had a history of dementia and falls, to determine whether she needed a bed railing, the Minnesota Department of Health announced Wednesday. The woman’s neck became lodged between the rail and mattress at some point between a nursing check and when she was found 40 minutes later, according to a state incident report.

The victim was 91-year-old Helmi Laitinen, according to an official at the Ramsey County medical examiner’s office, which conducted her autopsy. Laitinen was a Menahga, Minn., native who raised five children, worked as a welder at an Oregon shipyard during World War II, and loved to knit slippers, pick berries and make wine, according to her obituary.

Laitinen died Jan. 26 at Assumption. The home has since taken steps to prevent future tragedies, and those efforts were confirmed by state health inspectors when they conducted a follow-up visit in March.

“Obviously we had deep regret over the whole incident,” said Jan Luthens, the administrator of the 82-bed home. “It was very, very sad. We have expressed our condolences to the resident’s family.”

Laitinen’s son, Milo, declined to comment on Wednesday.

While bed rails offer perceived benefits in terms of preventing falls, they also present risks of entrapment and strangulation. State Health Commissioner Ed Ehlinger said he hopes Laitinen’s death will motivate all nursing homes to review their use of bed rails.

“Nursing homes are entrusted with the care of vulnerable adults,” Ehlinger said, “and a death like this is totally unacceptable.”

The state’s investigative report, which did not name Laitinen, indicated that she had limited mobility, weakness and chronic pain, and that she had suffered falls in the past.

Two months before the death, she had fallen out of bed and staff found her with the lower half of her body on the floor and the upper half pressed against the bed railing, according to the state report. Investigators determined that the home did not reassess her need for a bed rail at that point or add any new interventions to prevent her from falling.

Luthens declined to comment on the circumstances of Laitinen’s death or the state’s findings, but said the home had always used bed rails judiciously and has added several steps to increase safety: the way assessments are conducted has changed, and the staff also conducts clinical assessments of residents every morning and afternoon to ensure they are safe and their care needs are met.

Luthens said she would also be working with the home’s family council to teach residents’ relatives about the risks of bed rails because many assume they are safe and demand their use. (No such demand was made in this case, though, she said.)

Bed rails were introduced as safety innovations to prevent falls, but their use declined dramatically after studies showed their risks. The U.S. Food and Drug Administration issued safety warnings about them in the mid-1990s.

More than 800 incidents related to bed rails, most of which involved deaths, were reported to the FDA between 1985 and 2009. However, bed rail usage has declined from around 75 percent of nursing home residents in 1990 to 15 percent now, said Dr. Steven Miles, a University of Minnesota expert who has published research on the issue.

Miles said any safety benefits of bed rails are more than outweighed by the risk of injury. Research has suggested that the only people who benefit from rails are those who are cognitively intact and are able to move around on their own. But they are commonly used for patients who shouldn’t have them, particularly those with dementia and limited mobility.

Innovations such as lower beds, concave mattresses and motion alarms have been introduced to reduce the need for bed rails and restraints. Nursing home rules have also stressed that homes are still required to assess the risks and benefits of rails even if relatives request them for residents or doctors order them.

“All of that stuff has been done,” Miles said. “And yet there are still some facilities that don’t pay attention to the regulations.”