An evaluation of factors influencing the assessment time in a nurse practitioner-led anaesthetic pre-operative assessment clinic.

Elective patients undergoing anaesthetic pre-operative assessment are usually allocated the same period of time with a nurse practitioner, leading to potential inefficiencies in patient flow through the clinic. We prospectively collected data on 8519 patients attending a pre-operative assessment clinic. The data set were split into derivation and validation cohorts. Standard multiple regressions were used to construct a model in the derivation cohort, which was then tested in the validation cohort. Due to missing data, 2457 patients were not studied, leaving 5892 for analysis (3870 in the derivation cohort and 2022 in the validation cohort). The mean (SD) pre-operative assessment time was 46 (12) min. Age, ASA physical status, nurse practitioner and surgical specialty all influenced the time spent in pre-operative assessment. The predictive equations calculated using the derivation cohort, based on age and ASA physical status, correctly estimated duration of consultation to within 20% of the maximum predicted time in 74.2% of the validation cohort. We conclude that if age and ASA physical status are known before the pre-operative assessment consultation, it could allow appointment times to be allocated more accurately.