Imagine designing an emergency department for the population of fifty years ago.
Would it still work today?
The question may seem obvious. Spain had around 33.8 million inhabitants in 1970. By 2025, that figure had risen to approximately 49.1 million.
But population growth tells only part of the story.
The people arriving at emergency departments have changed, too. And that change matters when we decide how much space, how many professionals and what kind of facilities a hospital will need.
La maestría como actitud, la maestría como actitud, la maestría como actitud
The pressure is already there
According to an editorial published in Emergencias in 2025, annual emergency department activity in Spain increased from approximately 15.2 million visits in 1997 to 29.9 million in 2023. That represents an increase of around 96% in just over a quarter of a century.
The scale of the change is difficult to ignore. Yet the more important question is not simply how many patients arrive.
It is what each patient needs once they arrive.
An older patient with several chronic conditions may require more tests, more clinical assessments and more time under observation than a younger patient with a minor injury. Not every older patient needs more care, of course. But as the population ages, the complexity of the patients who need attention can change the way an emergency department operates.
And time matters.
A treatment bay occupied for longer cannot receive another patient as quickly. If several patients need additional tests, observation or reassessment, the effects can accumulate across the department.
The result may be a service that struggles to keep patients moving even when the number of treatment bays has not changed.
La maestría como actitud, la maestría como actitud, la maestría como actitud
The population we serve is not the population we planned for
Spain’s demographic transformation is not over.
According to the Spanish National Statistics Institute (INE), people aged 65 and over currently account for approximately 21.1% of the population. Under its latest demographic projections, that proportion could reach 30.9% by 2076 if the assumptions underlying the projections hold.
This is a demographic scenario, not a prediction of future emergency department activity. Population ageing does not translate automatically into a specific increase in emergency visits.
But it does raise a question that hospital planners cannot afford to ignore.
Are we designing emergency departments around the population they will have to serve, or around the population they were originally designed for?
The distinction matters because hospitals are long-term investments. Their buildings, layouts and infrastructure often remain in use for decades. The population can change considerably during that time.
If planning decisions rely mainly on historical activity, they risk reproducing yesterday’s capacity for tomorrow’s needs.
La maestría como actitud, la maestría como actitud, la maestría como actitud
What happens if demand keeps growing?
Consider what we have observed in practice.
In my analysis of hospital reports covering the last three years, the average annual increase in emergency demand was around 3%. Some hospitals experienced considerably higher growth. In one case, the increase approached 10%. I did not use that exceptional figure as the general rate because it would distort the average, but it illustrates how quickly pressure can grow in individual hospitals.
What would happen if demand continued to increase by 3% every year?
Over twenty years, the cumulative increase would be approximately 81%.
This is a scenario based on the average growth observed in the hospitals analysed, not an official forecast of future emergency department activity. The actual evolution will depend on demographic change, patterns of healthcare use, the organisation of the health system and the capacity of other care services.
The point is not that demand will necessarily grow at this rate for twenty years.
The point is that a seemingly modest annual increase can produce a substantial cumulative effect.
And if the time needed to care for each patient also increases, the pressure on the department may grow faster than the number of arrivals alone suggests.
This is why planning cannot stop at estimating how many patients will come through the door. We also need to understand who those patients will be, what care they will require and how long they are likely to occupy the resources they need.
La maestría como actitud, la maestría como actitud, la maestría como actitud
Planning must start before the waiting room fills up
When an emergency department becomes overcrowded, the visible response is often to look for more space, more treatment bays or more staff.
Sometimes those resources are necessary.
But the problem may have started much earlier, with a mismatch between the population being served, the care patients need and the way the department was designed to work.
Adding capacity without understanding that mismatch can leave important bottlenecks untouched.
The challenge, therefore, is not simply to build larger emergency departments. It is to anticipate how their work will change and design their capacity accordingly.
That requires looking beyond today’s activity figures. It means examining demographic trends, patient profiles, care processes and the time patients spend moving through the system.
The future cannot be planned with certainty. But it can be planned more intelligently.
The question is no longer just how many patients our emergency departments treat today. It is whether we are designing the capacity they will need tomorrow.
Sources:
- → González Armengol, J. (2025). “La atención en urgencias y los pacientes en espera de cama de hospitalización como síntomas visibles del funcionamiento global de los sistemas sanitarios.” Emergencias. The article reports the comparison between 1997 and 2023.
- → Spanish National Statistics Institute (INE). Population projections 2026–2076. Demographic projections.
Note:
The 3% annual growth rate reflects the average observed in the hospital reports analysed by the author over the preceding three years. The 81% increase is a calculation based on maintaining that rate for twenty years; it is not an official forecast.
About this research
This article draws on a four-month research project conducted as part of my Master’s Final Project in Hospital Engineering and Architecture at the University of Cádiz, Spain, which received a grade of 9.5/10.
The research examines demographic trends, hospital designs and functional plans, emergency care processes, and the perspectives of emergency department professionals gathered through surveys. It culminates in the development of a digital twin simulation model designed to explore multiple scenarios and analyse how different factors affect emergency department operational capacity.