Doctors "missed opportunities" to save the life of a woman with diabetes, an inquest has found.
Christie Henderson, 29, died of a cardiac arrest at Sunderland Royal Hospital on 26 December 2018 after being admitted with complications from her condition.
Deputy coroner Karin Welsh said her death was "very, very concerning".
South Tyneside and Sunderland NHS Foundation Trust offered its "sincere apologies".
The mother-of-two, who had been diagnosed with type one diabetes seven years earlier, was taken to hospital on 24 December suffering from diabetic ketoacidosis because of a shortage of insulin.
The two-day inquest at Sunderland Civic Centre heard her potassium levels dropped in the hours before her death.
Recording a narrative verdict, deputy coroner Karin Welsh said potassium chloride should have been given to her by doctors on 10 occasions to counteract those levels.
"If potassium chloride had been introduced at an earlier point it may well have been the levels would not have dropped to the level they did," she said.
She added Ms Henderson died after "missed opportunities to counteract falling potassium levels precipitated by diabetic ketoacidosis and its necessary treatment".
The deputy coroner called on the trust to update her on its procedures by the end of the year.
In a statement, the organisation's medical director, Dr Shaz Wahid, said: "There were aspects of Christie's care that fell unacceptably short of the high standards we set ourselves and a number of actions have taken place to prevent this from happening again."
They include a training programme around protocols for patients with diabetes and changes to electronic patient records, he added.
Ms Henderson's family described her as a "loving mother, partner, daughter, sister and friend to many who is greatly missed".