Procedures at an Iowa hospital are under review following the death of a patient who was trapped in a hospital elevator for nearly three hours.

Officials at Mary Greeley Medical Center in Des Moines say 34-year-old Tamela Sims died Sunday morning after being brought to intensive care from the emergency room. A spokeswoman says Sims’ condition was stabilized in the ICU, but she died a short time later.

The cause of Sims' death was not immediately released, and it was unclear whether being stuck in the elevator early Sunday contributed to her death at the hospital in Ames, about 30 miles north of Des Moines.

Sims and several attendants became stranded between floors around 3 a.m. when the elevator's brake control board malfunctioned, hospital spokeswoman Irina Bassis said.

Bassis said the 34-year-old woman was in stable condition when she reached the ICU at about 6 a.m., and that Sims had access to medical help, equipment and supplies in the elevator. She said full communication with doctors was available through the elevator telephone and an elevator ceiling outlet.

"We are looking into the incident and we are trying to make sure that we are adhering to every policy, procedure and protocol that we have here," Bassis said, adding that the elevators are maintained regularly.

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Sims' mother, Linda Sims, told the Ames Tribune that she got a call from a hospital nurse at 5:58 a.m. Sunday saying medical staff were performing CPR on Tamala Sims and "trying to bring her back." She said her daughter was dead by the time she reached the hospital.

Linda Sims told the paper that her daughter was claustrophobic, and that she questions why she was not called when her daughter first became trapped in the elevator.

Sims said her daughter weighed more than 500 pounds. Bassis said the estimated load in the elevator when it got stuck was well below its 4,000-pound weight limit.

The Iowa Division of Labor Services, an office within Iowa Workforce Development, is responsible for elevator inspections in the state.

IWD spokeswoman Kerry Koonce said the brake circuit that failed had to be replaced to get the trapped people out, and that an inspection conducted after the incident indicated the necessary work to get the elevator functioning again had already been performed.

Iowa law requires elevator inspections once every five years, and the elevator that got stuck was last inspected in October of 2006, Koonce said.

"The report was fine. The inspections were done on time and everything was good," she said.