Non visualised scan audit

1. aaa.screening.nhs.uk
National programme website – aaa.screening.nhs.uk
Abdominal Aortic Aneurysm
Five Rivers AAA Screening Programme
Review of Non-Visualised Scans
Caroline Wells (Programme Manager)
March 2016

2. aaa.screening.nhs.uk
Overview
• National guidance
• Local and national performance
• Review of 2014/15 and 2015/16 data
– By machine
– By user
– Reasons for non-visualisation
• Conclusions

3. aaa.screening.nhs.uk
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

4. aaa.screening.nhs.uk
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

5. aaa.screening.nhs.uk
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

6. aaa.screening.nhs.uk
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%

7. aaa.screening.nhs.uk
Number of non-visualised scans by machine
(as a percentage of total scans completed per machine)
Sonosite machines in use since April 2012
Green and blue systems were replaced in April 2014

8. aaa.screening.nhs.uk
Number of non-visualised scans by user
(as a percentage of total scans completed per Screening Technician)

9. aaa.screening.nhs.uk
Reasons for non-visualisation

10. aaa.screening.nhs.uk
Reasons for non-visualisation

11. aaa.screening.nhs.uk
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