Patients are getting lost in hospitals across the UK because they are constantly being switched from ward to ward amid pressures on A&E, nurses say.
The situation has got so bad staff are carrying out what have been dubbed "safari rounds", where consultants go searching for their lost patients.
Figures show it is common for patients, particularly elderly ones, to get moved four or five times during their stay.
One nursing union representative said it was a "constant juggle" of patients.
Nurses at the Royal College of Nursing (RCN) conference in Liverpool said the issue was created by pressures on A&E.
Latest data in England shows the number of patients waiting more than four hours is rising.
In the week ending 17 March more than 27,000 patients waited longer than four hours in accident and emergency - double the number from the same week the year before.
The RCN said the problems have been building for years and exacerbated by problems with the rollout of the new non-emergency 111 number, although the bad weather is also likely to have been a factor.
Delays are also being experienced discharging patients from hospital because of the lack of social care support, it said.
In turn staff have to move patients from ward to ward so patients waiting in A&E units can be admitted, nurses said.
Karen Webb, the RCN East of England representative, said it has resulted in what has become known as "safari rounds" in her region.
"The pressure leads staff to move people off the A&E department. They then get lost in the hospital.
"Consultants aren't sure where they are so they have to go looking for their lost patients. It is widespread."
Moved to tears
Other delegates described how some hospitals had started creating jobs known as "queue nurses" solely to look after people waiting to get seen.
RCN general secretary Peter Carter said: "This is where you get chaos in the system.
"It takes time [finding them] and is very concerning for patients. It is the system not working."
Neil Evans, an A&E nurse from south Wales, broke down as he described how he had seen patients left waiting on trolleys for 24 hours at a time.
"It is heart-breaking seeing what our patients are putting up with."
Norman Provan, the RCN's associate director for Scotland, added: "This is happening everywhere up-and-down the country."
Mark Drakeford, health minister for Wales, said he recognised hospitals were under pressure with steep rises in A&E demand coupled with the need for older patients, with more complex conditions, needing to stay in hospital for longer.
"All parts of the UK are experiencing these pressures but Wales has the highest proportion of people over 85."
Meanwhile, NHS England has already announced a review of emergency and urgent care.
Janet Youd, the RCN's emergency care association chairman, said it was a "constant juggle" to accommodate patients appropriately.
"Because of the pressures we have to move them out of the MAU [medical assessment unit], they can get put on an inappropriate ward and then when there is more time they will get transferred to somewhere better.
"But after a while there could be more pressures to move them as more patients get admitted."
Research by the Royal College of Physicians suggests it is common for a patient, particularly an elderly one, to be moved four or five times during their stay.
"No-one comes to work wanting this to happen, we all want to do our best but that is not always possible," said Ms Youd.
A Department of Health spokeswoman said: "The NHS needs to ensure it has proper plans in place to deal with high demand on A&E.
"But it's obvious that this isn't just about A&E services in isolation, it's also about how the NHS works as a whole and how it works with other areas such as social care."