Ella, now 8, was diagnosed with a tumour on January 4, 2010 which she would have had since before birth.
"You think, 'oh no, what did I do when I was pregnant?' But there was no reason, it was bad luck when the foetus was forming. A couple of cells didn't do what they should have done."
Because the tumour had gotten so big in Ella's cerebellum, it was causing a build-up of fluid in her brain called hydrocephalus, which caused the virus-like symptoms.
Doctors operated for seven hours the next day to remove the tennis ball-sized tumour.
Bartley said her daughter lost a lot of blood during the major surgery and needed a blood transfusion.
The family know they were very lucky to have the New Zealand Blood Service there for their little girl at the time.
Although Ella only received one transfusion, Bartley knew it was life-changing and would be forever thankful.
Bartley said it was reassuring to know the NZ Blood Service would still be there for them.
"We are so well looked after in New Zealand by services like the Blood Service and Starship. We don't know what the future holds so if there is a another operation we are comforted by knowing they are there if we need them."
Bartley wondered where families like hers would be if the service was not there.
"What if there wasn't enough blood? We were very lucky because it is life-saving."
Jodie Houltram, New Zealand Blood Service donor recruiter, said the number of whole blood donations in Tauranga had been declining for a number of years.
Last year, the centre received 5718 donations compared with 7907 donations in 2013.
However, plasma donations are rising.
The gift of life only took about 45 minutes for a person to donate, she said.
"The needle is in your arm for only five to 10 minutes. [For] some people it can be over within five minutes, it just depends on the person."
Plasma donations were a bit different with the needle in the donor's arm for about 45 minutes but the process took about the same amount of time.
Houltram said they were appealing to people to give back.
"We are asking for about an hour of a person's time. It's an easy thing to do and you're giving life. It's not donating, you're giving a life.
"You are giving a bit of your self to help someone else."
THE FACTS:
* Blood lasts only 35 days
* 42,000 patients are treated with blood or blood products in New Zealand each year
* Each donation can save up to three lives
* 3000 donations are needed every week to meet hospital needs
* The NZ Blood Service is the sole provider of blood products to hospitals in New Zealand
* Less than four per cent of us roll up our sleeves and donate.