Time From Anaesthetic Start to Surgery Start in Hysteroscopy and Theatre List Overrun in Gynaecology: A Retrospective Observational Study

BackgroundWe evaluated patient-level factors associated with the interval from anaesthetic start to surgery start in hysteroscopy and list-level factors associated with overrun in elective gynaecology lists. MethodsThis retrospective observational study used 2025 nursing pre-assessment and theatre timing records from two hospitals within one National Health Service (NHS) trust.Duration was analysed using a lognormal mixed model with a theatre-list random intercept, adjusting for recorded pre-assessment characteristics, session, site, and mixed-list status.Body mass index (BMI) was modelled using a four-knot restricted cubic spline.Adjusted mean differences were reported in minutes.Secondary analyses used mixed-effects logistic regression for intervals ≥22 minutes and multivariable logistic regression for list overrun, defined as lastpatient departure after the scheduled finish.Sensitivity analyses examined untransformed duration and excluded all-day lists. ResultsAmong 913 hysteroscopies, 890 cases across 491 theatre lists were included in adjusted analyses.BMI was nonlinearly associated with duration (overall p<0.001; nonlinearity p=0.007).Compared with BMI 30 kg/m², adjusted mean intervals were 1.42 minutes longer (95% confidence interval (CI) 0.46-2.43)at 40 kg/m² and 4.67 minutes longer (95% CI 2.56-6.90)at 50 kg/m².These contrasts were similar in sensitivity analyses.Among 611 gynaecology lists, 302 (49.4%) overran.Lists combining minor and major procedures had higher odds of overrun than lists containing only minor procedures (adjusted odds ratio (OR) 3.10; 95% CI 2.00-4.80).Afternoon lists had lower odds than morning lists (OR 0.23; 95% CI 0.15-0.34),while odds were higher at University Hospital Lewisham than Queen Elizabeth Hospital (OR 2.18; 95% CI 1.49-3.20).Lists in which at least half of minor cases had prolonged intervals also had higher odds of overrun (OR 1.52; 95% CI 1.04-2.23),but evidence for this association was less certain after excluding all-day lists (OR 1.40; 95% CI 0.92-2.11). ConclusionsHigher BMI was associated with longer intervals from anaesthetic start to surgery start in hysteroscopy.Lists combining minor and major procedures had higher odds of overrun.Prospective studies should evaluate whether accounting for preparation requirements and list composition improves scheduling.These findings do not establish a BMI threshold or booking rule.