The concept of surgical operating list ‘efficiency’: a formula to describe the term


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I was interested to see Dr Pandit and colleagues' thoughtful article about theatre efficiency [1]. The structure of their formula is simple, practical and sensible. The authors recommend that the formula should be adopted throughout the NHS as a ‘key performance indicator’. Despite being bold this has merit and at least has the advantage of defining theatre efficiency. At present, although ‘85% theatre efficiency’ is regarded as a goal, the term is incompletely defined and variously interpreted, making it an almost redundant aspiration. In addition the formula acknowledges that other factors beyond occupancy of theatre time are important in running a service that is efficient.

Before Pandit's formula is advanced further I believe it should be modified. At present the inclusion of over-runs and cancellations elegantly allows the effect of these ‘inefficiencies’ to be recognised both in the final figure for efficiency but also through examination of what the authors term ‘isopleths’. However, the definition of theatre ‘utilisation’ used in Pandit's formula is weak. It is easy to measure when a list starts and finishes but that is a remarkably poor measure of whether the time in between was used efficiently. In the discussion Pandit mentions, in passing, the alternative, which is to determine the period of time during an operating list during which anaesthesia (and or surgery) is taking place: that is, the sum of the periods for each patient from ‘needle to skin’ until ‘patient to recovery’. This method of measuring utilisation will identify the existence of problems of efficiency within lists (leading to delays between patients). Space limits the number of such delays one might encounter but these include forgetting to send for patients, patients delayed on wards due to lack of beds or incomplete admission processes, portering delays, equipment and CSSD delays, interruptions to allow surgeon or anaesthetist to ‘slip out of theatre’… ad infinitum. Any formula that ignores such inefficiencies, as Pandit's present formula does, is not capturing the full extent of the problem and is a missed opportunity in setting a standard for ‘efficiency’. Most theatre management systems (computers) should be able to calculate both definitions of utilisation without difficulty. Our experience in Bath is that use of Pandit's definition of ‘utilisation’ overstates the period that the list is being used efficiently by 10–15%. It is in no-one's interests to ignore such problems. Neither definition of utilisation will identify delays within cases, nor address the issues of slow surgeons and slow anaesthetists, but these are far more complex to define (and address). On one level it is not crucial which definition of utilisation is used, provided everyone uses the same definition and goals are set accordingly (for Pandit's definition of utilisation a goal of 100% seems sensible, whereas for the more accurate version 85–90% is likely to be aspirational). However, I think it should be self-evident to clinicians and managers (and even to patients and politicians) that the more precise method of calculating utilisation offers more accurate and useful information. Incorporating this definition into Pandit's formula would allow identification of problems with overbooking, underbooking and with the progress of the list itself, making the formula fit for purpose.