Man Vs Machine – Automated Colonoscopy Withdrawal Time Calculation VS Endoscopist Self-Report

Aims Colonoscopy electronic patient record (EPR) reporting systems are generally reliant on endoscopist self-report to accurately determine procedure withdrawal time – a key metric of high-quality colonoscopy. As the accuracy of self-report vs image-linked timestamping is presently unknown our aim was to investigate this.

Methods All colonoscopy timestamp data 2000-2020 within the HICSS (Hospital Integrated Clinical Support System) database was assembled alongside procedure polyp count. Timestamps of interest included last caecal intubation image, endoscopist self-reported caecal-intubation time and procedure end-time. Empirical cumulative distribution functions (ECDF’s) and interquartile percentiles were plotted for each scenario, both with and without polyps and student’s t-test used to confirm significance. Pearson-R correlations were calculated between polyp number and procedure withdrawal time.

Results 24,367 colonoscopies were performed within the specified time period. Of these 16,093(66 %) had caecal-intubation image timestamps recorded. Mean ‘image-reported’ extubation time was 12.9 minutes vs 14.1 minutes by self-report, (p<0.01). Vs image-report at the 50^th percentile endoscopists over-estimated withdrawal-time by a minute at self-report. Polyps were extremely strongly correlated to withdrawal time (Pearson-R-0.97) with more than three polyps at procedure associated with a mean withdrawal time >30 minutes(+/-1-95 %CI).

To eliminate any polyp-bias the analysis was repeated on 9960(61.9 %) procedures without polyps. Here mean image-linked withdrawal time was 8.8 minutes vs 10.8 minutes by self-report, (p<0.01). In this setting across the board, endoscopists significantly over-estimated withdrawal time by on average 2 minutes as illustrated in [Tab. 1].

Tab. 1 ECDF Percentile withdrawal times across groups.

ECDF Percentile	Image-Linked Withdrawal Time (incl Polyps) [minutes]	Self-Reported Withdrawal Time (incl Polyps) [minutes]	Image-Linked Withdrawal Time (excl Polyps) [minutes]	Self-Reported Withdrawal Time (excl Polyps) [minutes]
25th	7	9	6	8
50th	10	11	8	10
75th	15	16	11	13

Conclusions Endoscopists significantly overestimate colonoscopy withdrawal time at post-procedure self-report. We, therefore, recommend that all endoscopy EPR systems switch to using proof of caecal-intubation image timestamps by default in the future to minimise error in withdrawal-time calculation. Polyps substantially increase withdrawal-time and this should where possible be factored into endoscopy scheduling decisions.

Citation Bhandari M, Hlaing L, Phan H et al. eP121 MAN VS MACHINE – AUTOMATED COLONOSCOPY WITHDRAWAL TIME CALCULATION VS ENDOSCOPIST SELF-REPORT. Endoscopy 2021; 53: S135.

Publication History

Article published online:
19 March 2021