YOKOHAMA — The city of Yokohama decided Thursday to reprimand 31 people involved in a patient mixup at Yokohama City University Hospital in January that resulted in a lung patient undergoing heart surgery and a heart patient lung surgery.

The 31 include university President Yuzo Kato, 18 doctors, 10 nurses and two clerical staffers. The group represents all hospital employees involved in the surgeries and their supervisors. The punishments meted out range from two-month work suspensions to admonitions, city officials said.

Due to the Jan. 11 mixup, a portion of one elderly male patient's lung and a heart valve of another were wrongly removed.

Kanagawa Prefectural Police are continuing their investigation to determine whether it was a case of professional negligence.