Operator fatigue appears to affect the adenoma detection rate during elective colonoscopies.

According to a poster of merit presented at Australian Gastroenterology Week 2018, the adenoma detection rate falls between the beginning and end of procedure lists.

The study, first authored by gastroenterology registrar Dr Tianhong Wu from Brisbane’s Prince Charles Hospital, used late timing of colonoscopy as a surrogate for operator fatigue.

The retrospective case-control study compared 266 procedures performed after 11am on a morning list or after 4pm on an afternoon list with 366 procedures performed before 9am in the morning or before 1pm in the afternoon.

It found adenoma detection rates dropped from 55.7% to 39.7% (p=0.007) across the morning lists and 56.7% to 41.1% (p=o.oo6) during the afternoon lists.

There was also a lower mean adenoma count in the late afternoon procedures compared to earlier on the list (1.7 v 1.2; p=0.04).

“Colonoscopies performed later in the list had lower adenoma detection rates and lower mean adenoma counts, especially in the afternoon,” the poster said.

There was no significant difference between late and early procedures in the detection rates of serrated sessile adenomas, quality of bowel prep or the number of significant adverse events.

However larger datasets were required, the study said.

In an accompanying poster, the same team compared 74 colonoscopies performed on Saturdays with 1,142 colonoscopies performed on weekdays during the same time period in 2017.

Adenoma detection rates were similar in both groups of patients (51% v 47%).

Patients scoped on a Saturday were typically 6.3 years younger than other patients and were three times more likely to have a low anaesthetic risk.

There was also a trend to a higher quality bowel prep on the weekend and a higher adenoma detection rate.

There were no significant post-procedure complications on the weekend.

The findings demonstrate that appropriate methods are being used to select low risk patients for weekend procedures when there may be less access to other medical and nursing staff, clinical and auxiliary services.