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Ask most service users what an “ambulatory emergency care unit” is and you’ll most likely get a quizzical look and a shrug of the shoulders.

But system leaders are optimistic they can free up a substantial amount of beds this winter by driving up the number of patients seen in AEC units, in which patients are treated and discharged on the same day without admission to a bed.

Around 30 per cent of emergency department admitted patients have conditions appropriate for handling within ambulatory care rather than in beds on wards. But the Society of Acute Medicine estimated only around 18 per cent of admitted patients are actually dealt within AECs.

The remainder, including patients with deep vein thrombosis, low risk pulmonary embolisms and other conditions, can end up needlessly being admitted to a bed.

So, system leaders have set out a new “ambition” for every acute hospital with an ED to have an ambulatory emergency care unit open at least 12 hours a day by September 2019 in guidance published last week.

Senior clinicians welcomed the emphasis on ambulatory care. But opinions varied about the impact which could be made this winter, and indeed next winter, largely because of a shortage of staff and cash to pay them.

There is a huge variation across the system as to how many patients are seen in AEC units, which at the most sophisticated end are fitted out with diagnostic equipment for rapid turnaround. Indeed, a minority of hospitals still do not have an AEC unit at all.

But even within existing constraints, the Society for Acute Medicine estimated the proportion of patients ambulated could be increased to around 23 per cent of admissions.

The society’s president Nick Scriven told HSJ: “[The new ambition] is welcome, but it will require trusts to have increased staffing resource. Most NHS trusts have an AEC running 12 hours a day on weekdays, but are closed or much reduced over the weekend because they do not have the staff.

“There is certainly considerable room for improvement within existing resources. But getting to 30 per cent across the system would take a significant increase in funding and available staff.”

In absolute terms, if 30 per cent of the estimated 65 admissions a day at an average hospital went to an AEC instead of a bed, this would be around 3,500 across the circa 180 acute hospitals in the English NHS (around 1.3 million a year).

The current estimated level of 18 per cent accounts for about 2,100 a day – the gap is a potential 1,400 avoidable ward admissions every day.

Lifting the ambulated share by 5 percentage points would stop a further 800 ward admissions per day (292,000 admissions in a year against a total of around 4.3 million).

To help this process, some capital might be made available to trusts ahead of winter for developing ambulatory services, although a final decision is yet to be made, as HSJ revealed this week.

Royal College of Physicians clinical vice president David Oliver, a leading geriatrician, was also supportive of efforts to increase ambulatory care provision, and the idea of using some capital funding to help develop facilities, but like Dr Scriven, he viewed the workforce shortage as the major barrier.

“You need skilled practitioners, acute physicians, acute geriatricians, nurse practitioners, occupational therapists, who can manage people in their clothes and enable them to return home the same day without admitting them to a bed. And there is a huge shortage of these people,” he said.

Developing more robust referral systems and signposting patients to the most appropriate care setting, so patients bypass busy EDs altogether would also help, added Professor Oliver. “There’s a lot more work to be done around how we signpost patients around what is a very complex system,” he said.

There are also problems with financial incentives. There is no tariff for ambulatory care and payment arrangements vary greatly across the country. Putting certainty around the payments could incentivise trusts to invest the required revenue and capital, but this will take time.

No one is viewing growing ambulatory care as a silver bullet. But coupled with a drive on length of stay and continued improvements on delayed discharges it could eke out more precious capacity in the system.