Variation in Operating Room production; predictable or not?

If the demand for products or services are stable, then logistics is easy. In any household for example there are repetitive rythms, determined by meal times and working days. Meal times determine the moment that food supplies need to be in the house and working days could determine when there is time to buy these. Weekends differ from week days, and for someone working irregular hours the week pattern of activities could be different. Not every system has to be the same in order for it to be predictable. A variable rythm could be ‘nice’ in the sense that it repeats itself and has a certain flow, fitting for example with a natural life rythm.

I  believe a ‘nice’ rythm or flow is important for any person or system to be effective. So this would be important for an OR department as well. But what is the rythm of an OR department? And if we could define it, is it known to anyone working in the OR department? And do nursing departments or a sterilization unit know the rythm of the OR and do they adjust to this? Or does the OR adjust to the rythm of these ‘suppliers’ of patients and materials? Or do they each work in their own rythm, not matching the others?

First of all I therefore analysed whether the OR production data shows any patterns at all.

Looking at the weekly pattern of production, as shown below, there is variation. Each line represents production levels per week in a year. Each year has the same ups and downs in the production. These coincide with the school holidays in the Netherlands. The large dip, roughly between weeks 28 and 35, are the summer holidays. In the Netherlands regions do not all have the same school holidays and they shift every year. That is visible in weeks 7 to 10 for example: in this periode there is a recurring holiday, which takes place every year, but not always in the same week.

Blog productie patroon

Although the fact that there are ‘reduction weeks’ seems common use in the hospital world – at least I never heard anyone mentioning it as odd -, I find it remarkable that production varies based on school holidays. In contrary to for instance the education sector, demand for health care does not necessarily have a link with schools or children. The average age of patients in this OR is 54 years old. Do they want to be in surgery outside holiday periods? Or just before it? Or is (un)availability of staff the factor in this pattern?

Then there is a weekly pattern. In the figure below for each week day the total number of surgeries on a week day is presented, for 5 consecutive years: 2013 to 2017. Sunday is 1, Monday 2 etcetera. So in 2013 (blue column) the Tuesday was the day with the most surgeries and for 2017 (green column) this was Monday.

Blog productie weekpatroon

There are only emergency cases in the weekends (day 1 and 7). Friday appears to be a day with the least surgeries planned. Is that because one aims to have low occupancy rates in the nursing departments in the weekends? Is the expected length of stay a factor for planning surgeries on specific week days? Why is every year (or week) different?

This leads to several questions:

  • Is this year production pattern universal – in the sense that it is linked to national holidays for other hospitals as well? 
  • How could this production pattern be explained? Is patient demand or resource availability leading? 
  • Does this rythm serve a purpose (and if so, what purpose) or is it ‘just the way it is’?
  • How come that the variation in production changes for week days?

Please let me know by sending me a message what are your thoughts on this.

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