(CNN) -- An overdose of a blood thinner may have contributed to the death of a Nebraska toddler, the Omaha hospital that treated her said Thursday.
The Nebraska Medical Center is investigating the death Wednesday of 23-month-old Almariah Duque, said hospital spokesman Paul Baltes.
The girl, who lived with her parents in Dallas, Texas, was born with a birth defect and in December had undergone a transplant at the hospital of her small intestine, pancreas and liver, Baltes said.
The hospital has one of the nation's largest intestinal rehabilitation and transplant programs, he said.
The girl was readmitted in February after an infection and died at 5 p.m. Wednesday, the hospital said in a statement.
"It appears an overdose of the blood thinner heparin may have contributed," said the statement, which called the death "a deeply troubling and emotional incident" for hospital personnel. "We all want to extend our deepest apologies to the Duque family for their tragic loss," it added.
Heparin is routinely used after a variety of medical procedures as an anticoagulant.
"The medical center strives to provide the highest level of care and will use this tragic event to continue to improve and find ways to prevent errors in the delivery of complex health care," the statement said.
The medical center is paying for funeral and travel expenses for the girl's parents, Greg and Kenya Duque, who have no other children, Baltes said.
"We just want her voice to be heard and for this to never happen again to any child or adult," said the parents in a statement released by the hospital. "We believe this was an honest mistake but one that needs to be corrected. We love her, we did everything we could for her and we don't want this to ever happen again."