The Scottish Liberal Democrats called on ministers to act on the letter.
Their health spokesman, Adam Harley MSP, said: “This letter is chilling. The Scottish government needs to wake up to the crisis at the QEUH and intervene.
“We cannot accept this constant crisis as the status quo.
“That patients who need resuscitation at one of our busiest hospitals cannot take their safety for granted shows an utter failure of accountability, and proves that our NHS is in dire need of rescue.”
NHS Greater Glasgow and Clyde (NHSGGC) said they continued to address the issues raised in the letter.
A statement said a programme of improvement work was ongoing to deal with patient flow and numbers.
It said: “NHSGGC recognises that, despite the work to date, further support is required in the Queen Elizabeth University Hospital (QEUH). In recognising this, the continuation of our improvement work, including a refreshed whole system approach, is a priority .
“We recognise that some patients continue to wait too long within the emergency department, particularly when there are pressures on hospital capacity and delays in discharging patients who are clinically ready to leave, and improving this situation for both our patients and colleagues is really important to us.”
The board said the department continued to be under pressure and patient safety remained their highest priority.
The Scottish government has been approached for comment.
