Non visualised scan audit

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Abdominal Aortic Aneurysm

Five Rivers AAA Screening ProgrammeReview of Non-Visualised Scans

Caroline Wells (Programme Manager)March 2016

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Overview• National guidance• Local and national performance• Review of 2014/15 and 2015/16 data

– By machine– By user– Reasons for non-visualisation

• Conclusions

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National guidance• NAAASP requires both TS

and LS aortic measurements for the screening test to be classed as successful

• If any part of the infrarenal aorta cannot be visualised it should be recorded as a non-visualised scan

NAAASP (2014) Non-visualised aortas: Guidance for local AAA screening programmes in the management of non-visualised screening results

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National guidance

Reasons for non-visualisation include:•High body mass index•Excessive bowel gas •Ambiguity regarding calliper placement and aortic diameter measurement•Unusual anatomy or pathology

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National guidance

NAAASP (2015) Pathway Standards for NHS Abdominal Aortic Aneurysm Screening Programme

Standard 9 •Percentage of screening encounters where aorta could not be visualised

Rationale•A high non-visualised rate may be due to a training issue, equipment maintenance issues or it may be a reflection of the population being screened

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Performance

Five Rivers AAA Screening Programme•Increase in the number of non-visualised scans over the last year:

– 0.53% in 2014/15 (21 scans)– 1.16% up to the end of Q3 2015/16 (28 scans)

•Nationally:– 1.41% of scans were non-visualised in 2014/15– 1.39% up to the end of Q3 2015/16

•Thresholds: Acceptable ≤ 3% Achievable ≤ 1%

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Number of non-visualised scans by machine(as a percentage of total scans completed per machine)

Sonosite machines in use since April 2012Green and blue systems were replaced in April 2014

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Number of non-visualised scans by user(as a percentage of total scans completed per Screening Technician)

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Reasons for non-visualisation

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Reasons for non-visualisation

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Conclusions• No obvious pattern with equipment or user

• It may be possible to minimise the number of non-visualised scans due to bowel gas – Use of techniques such as breathing exercises and

movement to help move the gas– Further analysis of possible causes of bowel gas e.g.

medication