Dutch operating rooms are extremely well ventilated. When it comes to air quality, no risks are taken. But how well do those ventilation systems work in practice? And can hospitals save costs and energy in a responsible way? Jos Lans investigated such questions for his PhD thesis Operating room ventilation. A view from different perspectives.
Jos Lans can hardly contain his enthusiasm when talking about his profession. ‘I want to test everything. In the Netherlands, we want the cleanest possible air in operating rooms. But how clean should that air be? Can we make the process cheaper or more efficient? After all, we are simultaneously facing rising healthcare costs and a sustainability challenge. I want to investigate assumptions.’
How clean is clean
For his PhD research, Lans investigated many aspects of ventilation systems in operating rooms (ORs). He has worked in the industry for decades, building ORs and laboratories. Lans has a ‘crazy hobby’ of investigating everything he comes across.
He distinguishes between general (conventional) ventilation systems and ultraclean systems, which are used for example during implant operations. These provide extra clean air in the working area around the patient. ‘Manufacturers say you cannot test systems in the same way. Well, I disagree', Lans states.
Manufacturers say you can't test systems in the same way, but I disagree.
Testing in the OR
To measure the performance of ultraclean systems, Lans conducted tests in real operating rooms under realistic conditions. He did this in hospitals such as the Antonius Hospital in Nieuwegein and the Reinier de Graaf Gasthuis in Delft.
Using a test grid of 25 measuring points, he collected data on how quickly air quality recovers after exposure to dust particles. Lans: ‘With these test setups, we can examine exactly how different systems work after contamination.’ He also measured dust particles and micro-organisms during 30 trauma procedures: at less than 5 cm from the wound area, at the instrument table, and further away in the OR.
Is ‘ultraclean’ always necessary?
About 94% of Dutch ORs have ultraclean ventilation systems, but this seems unnecessary, Lans concludes. ‘You can differentiate ORs: some for procedures with ultraclean systems and others with general systems. Or you make them switchable.’
However, many hospitals opt for uniformity and accept the higher cost of ultraclean systems. Lans found that these additional costs range between €62,491 and €139,018 per OR.
Saving energy and costs
Besides air quality, Lans examined the energy consumption of the ventilation systems. ‘An average hospital takes in 2,800 cubic metres of outside air per hour. That air has to be heated, cooled, humidified, or dehumidified, which consumes a lot of energy.’
You can save a lot with simple adjustments, Lans concludes: ‘Effective measures include reducing the amount of outside air and accepting wider margins for humidity. Even simpler adjustments, such as setting clock times for switching ventilation systems on and off, make a big difference. This can yield thermal energy savings of 41%. Overall, hospitals can save up to 78% on thermal energy demand.’
What is ‘expensive’?
Lans constantly seeks to balance cost savings with safety. ‘Ultraclean systems cost 3 to 7% more than standard systems. That seems expensive, but what is expensive? If you can prevent two to four infections in 15 years, the investment has been recouped.’
Still, you cannot investigate whether infections are actually prevented. ‘It would be unethical to deliberately perform high-risk operations outside an ultra-clean environment. But a lack of evidence does not mean that infections are not prevented.’
Lans did find that the number of air changes per hour can often be reduced without compromising safety. ‘The minimum for a general OR is 20 per hour, while ultraclean systems perform an average of 69 air changes. For many situations less is sufficient, both for patient safety and for the comfort of the operating team.’
Fewer air changes are often sufficient to ensure safety and comfort.
Facts over emotion
A key conclusion from Lans' research is that hospitals can save a lot of money by differentiating. For example, by making ORs switchable between ultraclean and conventional ventilation. ‘You can then let the ventilation setting depend on what the situation calls for.’
His research offers new insights, but no ready-made answers. ‘I studied how systems work and what you can do to save costs and energy. What that actually means has to be considered on a situation-by-situation basis. Decisions have to be based on facts, not emotion. Only then can hospitals make the right trade-off between safety, costs, and energy savings.’
More information
- The images in this article are created by and owned by Jos Lans.
- Jos defends his thesis, Operating Room Ventilation: A View From Different Perspectives, on 19 December 2024 at 15:00. Read the full thesis in the repository of the TU Delft.
