Joan Blaber died six days after drinking the fluid at the Royal Sussex County Hospital in Brighton last year.
The 85-year-old, from Lewes, East Sussex, was admitted with a minor stroke on 22 August but her condition worsened after the incident on 17 September and she died five days later.
A letter of apology was sent out to public figures by the hospital trust because they were worried about press coverage, the court heard.
Brighton and Hove senior coroner Veronica Hamilton-Deeley criticised the trust for its “disrespectful” letter, signed by Brighton and Sussex University Hospitals NHS Trust’s chief nurse Nicola Ranger.
She said it made the inquest of Joan Blaber sound like the coroner was hosting a “tea party” rather than a formal judicial inquiry.
Ms Hamilton-Deeley expressed concern that some paragraphs contained inaccurate information, or could alternatively suggest testimony given under oath was wrong.
She said the note implied the incident was reported immediately to the police, adding: “This gives an extremely misleading impression as to what actually happened.”
Ms Ranger said: “I would like to say how sorry I am to the Blaber family, this has been devastating for them a year ago and also very difficult for them to have to sit through the coroner’s inquest. After the incident, our clinical staff gave exemplary care to try and do their best for Mrs Blaber.
“We have done a lot of work with our systems, processes and training since then, so I am confident that an incident like that won’t happen again.”
The jury’s conclusion at the inquest criticised the hospital’s management for failings which they say could have led to Blaber’s “safety being compromised”.
It said: ”On 17 September 2017, Mrs Blaber’s clear water jug was replaced with a solid green water jug containing a cleaning fluid. This was later used to dilute cordial which she drank whilst taking her medication. Evidence leads us to believe there was widespread confusion surrounding the water jug system that was in place and that jugs were being misused.
“Understanding and implementation of cleaning procedures were inconsistent and inadequate amongst agency and Trust cleaning staff."
The hospital’s use of different types of water jugs was criticised by Ms Hamilton-Delly who said it was a “complete red herring” because it was “abundantly clear” that none of the staff understood the system.
The conclusion stated that a similar incident had occurred 14 months earlier at the hospital in which a patient had also drank some cleaning fluid.
“Management missed an opportunity to learn and disseminate lessons from a 2016 incident on the same floor of the hospital involving the drinking of cleaning fluid which had been entered into the Datix incident database," it said. “Based on the evidence, we find this contributed to inappropriate practices in the hospital which were not addressed due to a culture of non-reporting.
“Serious communication failures in the hospital opened the way to misunderstanding of procedures, errors in practice and resulted in a failure to implement lessons that could have been learned. We found this contributed to Mrs Blaber’s safety being compromised.”
Additional reporting by Press Association
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