Covid patients may have died due to staff errors while using ventilators, a report has suggested.
An inquest will examine the deaths of two patients at the London Nightingale Hospital in April last year, following claims that staff used the wrong ventilator filters.
A coroner said the deaths came as part of a "cluster" of similar incidents involving breathing system filters in hospital intensive care units more widely.
Kishorkumar Patel and Kofi Aning, 66, died at the Nightingale Hospital in the Excel Centre near Canary Wharf in April 2020.
Although it has not yet been determined whether errors in operating the machines caused the two men’s deaths, the East London Coroner has taken the unusual step of issuing a warning about the risk of future deaths before the inquest has taken place.
In a prevention of future deaths report, coroner Nadia Persaud said that in both of the cases "there was a serious incident in which the wrong filter was found to have been used within the breathing systems of their intensive care ventilator".
She added: "It is understood that these two cases came within a cluster of similar incidents."
The report, sent to the Royal College of Anaesthetists and the Faculty of Intensive Care Medicine, has raised concerns about the awareness of intensive care clinicians of different types of air filters.
The report noted an independent expert had advised: "The non-standardised colour coding used by manufacturers of these filters, the number of different types of filters with different names, the variable optimal position of the filters, and whether a wet or a dry breathing system is being used, results in an extremely confusing situation.
"In my experience, few doctors and nurses working in ICU are knowledgeable about all these different filters and which ones should be used for any given breathing system."
The report added the independent expert had said the classification and colour coding of the filters "is worthy of review, simplification, and standardisation".
The coroner said: "As there are still pressures within the ICU settings and in light of the imminent, planned reduction in covid-19 safeguards, I consider that action should be taken to address this concern at the earliest possible stage."
Barts Health Trust, which ran the Nightingale Hospital in London’s Docklands, declined to comment.