Warning: Distressing photos

A blind toddler nearly died and may have difficulty walking after his foot filled with intravenous fluid which was allegedly left unchecked by hospital staff for seven hours.

Starship Hospital has also admitted to missing some of Lucas' medical documents amid an investigation to understand what went wrong, and has apologised to the family for the failure.

"His foot was swollen like a rubber dog's toy... the IV was leaking into his foot the whole night," Lucas' mum Ginni told the Herald on Sunday.

"That's when they yelled 'code blue, code blue' and everyone rushed in, all the doctors and nurses rushed in to help him, that's when they started taking things seriously."

ACC data provided to the Herald on Sunday showed each year between 400 to 560 people received taxpayer-funded compensation after being harmed by an IV inserted wrongly into the veins or becoming dislodged.

So far this year, 358 treatment injury claims had been accepted by ACC for IV cannulation.

Families like Lucas' have been left traumatised.

Lucas' dad, Mike, said they wanted to stress their only son wouldn't be alive if it wasn't for Starship Hospital and they were hugely grateful for that.

"But that's what makes this situation even worse and hard to swallow because on one hand they saved him but on the other... It's that betrayal of trust."

They were speaking out because they wanted to prevent others from suffering from the same mistake and help make the system better, he said.

On Thursday June 16, Ginni and Mike took their son into Starship Hospital with symptoms of a cold and he was admitted for bronchiolitis.

Lucas was born with a rare condition called septo optic dysplasia, which is a disorder of early brain development, leaving him with special needs and severely vision impaired.

At 15 months old, the age he was when taken into hospital, he had the developmental age of a 5 or 6-month-old, Ginni said.

"He also has a very low immune system which means we have to be extra cautious when he got sick."

While in hospital, an IV line was placed in Lucas' foot as he needed fluids. However, Ginni said it wasn't checked by hospital staff for seven hours.

Hospital protocol required IV lines in children to be checked every hour and signed as part of medical documentation.

"That night Lucas was really unsettled, more unsettled than he was when he first came into hospital and I remember calling the nurses to express my concerns."

Ginni said her son cried himself to sleep and in the morning he started shaking. The next morning, on Sunday, June 19, she says a paediatrician came in, listened to Lucas' chest and assured her Lucas was just cold and there was nothing to worry about.

"I felt like something wasn't right so I did a nappy change and that's when I picked up his foot."

Mike said: "His foot was like a corpse, it was so white with no blood."

Photos seen by the Herald on Sunday showed Lucas' foot the following day, purple, severely blistered and swollen.

The couple said they understood the IV line had been put in correctly but because it was left in for seven hours without being checked, it became displaced.

"This injury isn't horrible because it left terrible scarring and put Lucas through hell, it's terrible because if it had gone on for another hour, he might have been dead," Mike said.

"If I had listened to the doctor who said he was just cold and had just put a blanket over him, he would have died from shock," Ginni said.

Afterwards, Ginni said she was double-checking everything because she was traumatised and didn't trust anyone.

Lucas required debridement surgery and a skin graft on his foot. Mike said the plastic surgeon told them the extent of the nerve damage would potentially be severe.

"This is a special needs kid who is blind and needs every bit of sensory he can get, especially through his feet - and they may have just removed all of that," Mike said.

Lucas had to keep his foot elevated at Starship Hospital before surgery to drain the fluid and keep the blood pumping to his leg. Photo / Supplied

For the next two months, Ginni said Lucas was bedridden, crying constantly and suffering in extreme pain.

"You've taken away three months of my son's life and those are the golden years of him being able to develop," Ginni said.

Mike said he remembered posters in the hospital room saying "if you feel like something is wrong with your child, you know them best, please tell the staff."

"That was completely ignored."

Te Whatu Ora Auckland, formerly the Auckland District Health Board, told the Herald on Sunday they had launched a review of Lucas' care and had received a complaint from his family.

"We can't pre-empt the findings, however we can confirm we will continue to update Lucas' family on the progress of the investigation as well as their complaint," a spokesperson for the hospital said.

On Friday night, the Herald received a letter - from Starship Hospital's medical director Emma Maddren, sent to the family - which said: "Unfortunately, the clinical notes from 17-19 June have not been able to be located."

"This is a failure of our record keeping processes for which we apologise. We are including a review of the absence of the notes within the scope of the case review."

Maddren said the investigation was ongoing and they would continue to look for the medical notes before meeting "with appropriate staff should you find it helpful."

Te Whatu Ora Te Toka Tumai, Auckland's chief medical officer Dr Margaret Wilsher said they were sorry for the distress felt by Lucas and his whānau.

The Herald on Sunday asked why the IV was left unchecked for seven hours and put to them claims that he may never be able to walk properly after this injury.

Wilsher did not respond to this but instead said: "For ethical and privacy reasons we can't comment on details of individual patient care."

"However, as is standard process for an unexpected health outcome for a child in our care, we are fully investigating the care Lucas received," she said.

She said the aim of this review process was to place the child and their whānau at the centre to help them and the hospital understand what happened.

Lucas' foot a few days after it was discovered, prior to surgery. Photo / Supplied

"We want to ensure we had the correct systems in place to support our skilled staff to do their best work for all tamariki within our care," Wilsher said.

She said the hospital had received a complaint from Lucas' family and would be responding to them directly.

"We will be happy to meet with them to discuss the findings of the review, once complete, and answer any questions they may have."

Wilsher said whānau could also contact the Health and Disability Commissioner for an independent review.