Oliver Rodriguez-Ocampo, like any infant, was more interested in playing with his cake than eating it, even though the treat marked a major milestone in the 515 days since he was born.

Dressed in a black cap and gown, Oliver was “graduating” from intensive hospital care at HCMC in downtown Minneapolis, marking the longest stay for a preemie at the hospital for the past 18 years.

He was born at 25 weeks on July 20, 2017, and doctors were initially concerned that he would not survive. “We don’t know how we got to here but it is a miracle,” said his mother, Manuela Ocampo of Bloomington. “The doctors didn’t think that he would be able to make it.”

That was back when Oliver weighed just 1.2 pounds. Now he is at 22.5 pounds, and apart from a nasal cannula stretched across his face that supplies oxygen, there are few outward signs that the hospital is the only home he has known. Just minutes before the congratulatory cake was cut, Oliver was acting as if he were some infant motivational leader, clapping his hands to get a round of responses from his care team that had gathered around. They clapped and laughed in response, at the same time capturing the moment on their cellphone cameras.

“I am not exaggerating — he has been the happiest baby,” said Lindsay Powell, one of the registered nurses who has cared for him. “He makes everybody laugh constantly. It is going to be so weird without him.”

After being born at the hospital, formerly known as Hennepin County Medical Center, he spent his first 10 months in the newborn intensive care unit. He was one of the only five to eight premature babies born at 25 weeks that HCMC cares for each year.

Most preemies are discharged by the time they reach what would have been 40 weeks gestation, which is the typical length of a pregnancy.

But every baby is different and Oliver stayed longer. He eventually outgrew the newborn unit and was transferred to the pediatric intensive care unit, which cares for children of all ages, including accident victims.

Initially it was hoped he would stay on the new unit for just a short time before he was sent home, where he could continue recovery with round-the-clock skilled nursing care. But a staffing shortage extended his hospital stay.

“He would have been out months and months ago if Minnesota had an adequate supply of nurses for small babies who need 24/7 nursing,” said Dr. Tina Slusher, a pediatric critical care doctor.

The inability to send him home with nurses undoubtedly drove up the total costs of his care, which are very high for premature babies.

The hospital was not able to provide a cost estimate on Oliver’s care, but neonatal intensive care at major Twin Cities hospitals runs about $9,000 to $10,000 a day, according to the Minnesota Hospital Association. Those charges do not include the bills submitted by physicians.

Going forward, Oliver is expected to do fine, but he will need many follow-up visits.

“He has a chronic lung disease,” said Slusher, “but that is expected to get better as he grows.”

The two biggest challenges in the short-term are to help him learn how to eat more solid foods, she said, and to prevent him from catching any kind of infection that would be difficult for his lungs to handle.

Having been connected to a mechanical breathing machine and then a tracheal tube for much of his life, Oliver has been unable to move much on his own, which has inhibited his muscle development.

“He wants to walk and he wants to crawl,” said Powell. And since the tracheal tube was removed from his neck, he’s been thrilled to laugh and begin to talk.

“I am very happy and very excited,” said Ocampo. “This has been very hard because of my work, but I have been at the hospital every day.”

Registered nurse Sarah Ghizoni said the boy has received much support from his mother and family.

“This is the most dedicated mom I have ever seen,” said Ghizoni.

Ocampo said the first six months were the most difficult because there was a lot of uncertainty about her child’s survival. But now she sees a bright future.

“He has gone through so much,” she said. “He will make it because he has a mission in his life.”