Multiple failures by medical staff and missed opportunities contributed to the tragic death of a three-year-old Sydney girl deemed the "sickest child" one doctor had ever seen before she died from flu complications, a coroner has found.
Caitlin Cruz died at Westmead Children's Hospital on October 23, 2016, less than 24 hours after arriving.
Two days before her father Mitch took her to a medical centre.
The "beautiful, intelligent, loving little girl, full of life and with a wonderful spirit," brought her parents enormous love and joy and was known to be a fighter, with resilience that even surprised them, Deputy State Coroner Derek Lee said.
He acknowledged the hardship her parents Marie and Mitch faced in searching for answers and their devastating loss.
Mr Lee's findings detail her death of "natural causes, in circumstances where a number of critical factors contributed to the tragic outcome."
"These factors include the inaccurate and unreliable transfer of information from a pre-hospital setting to a hospital setting, the inability to perform an electrocardiogram in a timely manner," he told the NSW Coroners Court in Lidcombe on Tuesday. .
"(And) the absence of adequate documentation, and the absence of appropriate escalation of Caitlin's care for review."
This led to missed opportunities for further investigations, more timely recognition of Caitlin's deterioration, and specific supporting therapies being instituted to manage her condition, "that may have altered the eventual clinical course".
Caitlin was three years and nine months when she and her younger sister returned from preschool to their Lidcombe home with fevers.
After a visit to a medical centre, Caitlin's condition deteriorated and she returned on October 22 to Myhealth Rhodes where she collapsed in her father's arms.
GP Sumeena Qidwai screamed at her assistant to call an ambulance.
"She was floppy and blue and her face and body looked pale," she told the court.
"I was extremely concerned she's probably the sickest child I have ever seen."
After Caitlin was taken to hospital she presented with seizure-like activity and an electrocardiogram was organised.
The ECG could not be performed until three-and-a-half hours later because the machine was out of battery, and the results were misinterpreted by a junior doctor with no oversight from a senior practitioner.
A review about 830pm the evening of her death found Caitlin was "tachycardic, floppy, hypotonic and cool to touch".
It was also noted no blood pressure or neurological observations had been documented overnight.
By the time Caitlin was rushed into the intensive care unit Dr Nicholas Pigott remembers her looking very "unwell, shutdown", and "relatively unresponsive".
With a large amount of fluid around Caitlin's heart her condition rapidly deteriorated and an aggressive resuscitation was begun.
The reason for Caitlin's collapse was not obvious to Dr Pigott but he suspected it was a neurological cause.
After she died her ambulance medical record paramedics say they delivered to her bedside was never found.
Caitlin's mother earlier said many people had been fighting for answers and hoped the inquest would shed some light on what happened to her daughter.
"We are not doing this just for Caitlin, we're doing this for her little sister who will never know her," she told reporters outside the Coroners Court in August last year.
Caitlin's father Mitch said he wanted due processes to be examined so no other child "falls through the cracks".
Mr Lee made several recommendations including that NSW medical bodies consider a universal electronic platform for sharing patient information so accurate and timely transfer of clinical information can occur.