We recently published estimates of total surgical and anesthetic times for 31 common general surgical and urologic procedures from our center in the United Kingdom,1and suggested that others in different centers should also publish similar estimates to assess whether our times were unit specific or were more widely applicable. We are pleased that Silber et al.  2have extended this work and published relevant time estimates. Theirs is an impressively larger database and includes data from 183 hospitals in Pennsylvania; our data were derived from a more modest combination of estimates provided by professional staff and our own operating room database. Despite such self-evident differences, comparing their estimates with ours shows that for procedures examined by both studies, any differences are very small (table 1).

Table 1. Summary of Procedure Times from the Two Studies 

Table 1. Summary of Procedure Times from the Two Studies 
Table 1. Summary of Procedure Times from the Two Studies 

The remarkable similarity of the operative times is significant. First, it confirms our conclusion—and that of others3—that experienced surgeons and anesthesiologists can predict operation times very well. Second, because the times reported by the two studies were from very different centers located in different countries, it suggests that these estimates that can be more widely applied. If this is the case, it follows that these estimates can be reasonably applied to the booking of operating lists. This should reduce the incidence of overrunning, which,4as we reported in the United Kingdom, can affect approximately 50% of operating lists and result in approximately 14% of patients being cancelled.1,5 

We note that Silber et al.  also reported that procedure time varies with hospital (a conclusion which is at odds with the similarity of their data with our United Kingdom data, because we might expect wider disparity between the two countries than between different hospitals in the same country). However, it is unclear from their article whether the statistical influence of hospital affected all procedures or just some specific procedures, or whether the between-hospital variability for any (or all) procedures was different from the within-hospital variability.

John Radcliffe Hospital, Oxford, United Kingdom. jaideep.pandit@dpag.ox.ac.uk

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Silber JH, Rosenbaum PR, Zhang X, Even-Shoshan O: Influence of patient and hospital characteristics on anesthesia time in Medicare patients undergoing general and orthopedic surgery. Anesthesiology 2007; 106:356–64
Wright I, Kooperberg C, Bonar B, Bashein G: Statistical modelling to predict elective surgery time: Comparison with a computer scheduling system and surgeon-provided estimates. Anesthesiology 1996; 85:1235–45
Kelly MJ, Eastham A, Bowling GS: Efficient OR scheduling: A study to decrease cancellations. AORN J 1985; 41:565–7
Rai M, Pandit JJ: Day of surgery cancellations after nurse-led preassessment in an elective surgical centre: The first 2 years. Anaesthesia 2003; 58:692–9