Original Research Articles

Can we predict when operating lists will finish in a regional Queensland hospital?

Winner of the Co-Op Bookshop Prize for Best Academic Article in this issue of the AMSJ


Background: Over-running operating lists are a common cause of same-day cancellations of surgery, while under-running operating lists are a common cause of wasted health resources due to the fixed costs of operating suites. The predominant cause of operating lists running off-schedule is not known, but it is believed that if due to booking problems, it should be possible to predict when a list will over- and under-run. Aims: To understand the prevalence of cancellations, over- and under-running operating lists in a regional Queensland hospital, and to test whether over- and under-running lists can be predicted. Methods: A sample of 120 operating lists was prospectively obtained and each list timed from start to finish. A predicted duration was calculated for each list by summing the average durations for each of the operations on the list (including anaesthetic and turn-over durations), derived from past surgical records. Results: Twenty-eight percent of lists suffered a cancellation, of which 79% were predicted to over-run their scheduled duration. Of the lists that did not suffer a cancellation, 45% over-ran, of which 84% were predicted; and 37% under-ran, of which 84% were predicted. Conclusion: The large proportion of predicted over- and under-runs support the hypothesis that booking problems are the main causes of operating lists running off-schedule, as opposed to other factors affecting surgical duration that the model would not have accounted for. This suggests that operating lists running off-schedule can potentially be avoided. Further study is warranted to investigate the reasons behind over- and under-booking.


Getting excited about Evidence-Based Medicine

Significant emphasis is placed upon Evidence-Based Medicine (EBM) during medical school, resulting in student responses ranging from apathy to consternation.

Students take home the importance of systematic reviews and highly populated, well-powered trials, to the apparent exclusion of all else. That these trials often have landmark effects is not disputed, but there remains a paucity of data for many aspects of clinical practice. EBM is well equipped to handle this and hence it is worth re-emphasising the principles at the core of EBM.

In a well known BMJ Editorial, Sackett et. al. defined EBM as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients”. [1] A core principle that is seemingly becoming confused in medical education is that EBM involves utilising the best available, not necessarily the best possible, evidence.

It is essential medical students understand that EBM consists of three strands: several levels of published research, core scientific knowledge, and individual clinical experience. Whilst landmark trials, such as the S4 trial, [2] are easy for students to appreciate as quintessential EBM, smaller general publications, such as John Murtagh’s Practice Tips, [3] equate to a distilled clinical experience that cover many areas of practice and should certainly be considered part of the EBM framework, particularly for students who have limited personal clinical experience.

The challenge is to successfully integrate EBM’s three strands into clinical practice, particularly in scenarios where there is insufficient evidence in one area or even disagreements between data. In these situations, it is imperative to understand EBM’s hierarchy of evidence and to critically appraise evidence; both of which require a sound understanding of the scientific method.

To achieve an optimal outcome in scenarios with conflicting or limited evidence is the hallmark of good EBM practice. As more data is gathered, disagreements are resolved and gaps filled. However, today’s patients cannot wait for this to occur and medical students must develop thorough knowledge of EBM, including statistical analysis and philosophy of science, to allow them to confidently deal with such occurrences.

EBM lies at the core of modern medical practice; we who become doctors also become scientists. Our clinical decisions, based on experience and core knowledge, are moulded by the guiding hand of research. Indeed, it is our duty to integrate the strands of EBM to ensure the best possible outcomes for patients. We applaud the AMSJ on its inauguration as a vehicle to encourage medical students into well-rounded, evidence based clinical practice.


[1] Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ 1996;312:71-2.

[2] Pedersen TR, Kjekshus J, Berk K, Haghfelt T, Færgeman O, Thorgeirsson G, et. al. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian simvastatin survival study (4S). Lancet 1994;344(8934):1383-9.

[3] Murtagh JE. John Murtagh’s Practice Tips. 5th ed. Sydney: McGraw-Hill; 2008.