Stewart, 36, was killed at a Te Atatu home in Auckland's west, where a group of nine women and some of their children had gathered for a boozy pamper party last October 15.
She died from uncontrollable blood loss when Browne plunged a large butcher's knife deep into the left side of her face.
During the trial, pathologist Dr Thambirajah Balachandra, who performed Stewart's autopsy, said a vein in Stewart's neck was severed as the knife cut deep enough to hit the right side of her throat.
He estimated the wound to be about 11cm deep.
The events prior to the extraordinarily bloody episode at about 4pm that Saturday afternoon had provided no indication as to the violence which would unfold, witnesses testified.
Browne had, however, became increasingly agitated as the afternoon progressed.
Some arguments and scuffles ensued, but not enough for any of the women to expect her "disproportionate response", as Crown prosecutor Nick Webby described.
He said witnesses had seen Browne abusing other guests before Stewart came to restrain her.
Stewart dominated and intimidated Browne during the scuffles, telling her, "you f***ing disrespectful b****, my nieces are f***ing here".
"Carly was angry," Stewart's cousin, Patricia Stewart told the court.
"[The stabbing was] due to alcohol, drugs or a combination of the two, or perhaps something more," defence counsel Marie Dyhrberg QC argued in her final address to the jury yesterday.
"[It was] not the violent outburst of someone that has lost it."
She had argued that her client showed no murderous intent and claims she acted unconsciously, suffering from an "automatism".
However, Justice Edwin Wylie told the jury to ignore the automatism claims.
Dyhrberg said Browne was also badly affected by a plethora of alcohol and drugs, but a delayed urine test and no blood samples taken by police made it difficult to determine what was in Browne's system at the time.
"[It was] supposed to be a good day - everyone was looking forward to it," the party's host Emmanuelle Sinclair told the court on the first day of the trial.