Clinical audit

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Clinical Audit

• There is a standard/guideline against which the service or outcome is measured against.

How we have used audit

• As part of gathering baseline data.
• Identifying current standard achievable without the S4A bra.
• To look for areas where the standard was not met-provides evidence and support for the innovation

What did we do

• Audit Aim: To quantify random and systematic errors for breast irradiation in one centre utilisng a standard breast board (both arms raised) without additional breast immobilisation. Specifically we were interested in identifying any relationship between set up errors and breast volume that would guide whether a breast immobilisation intervention should be reserved for women with larger breasts.

Audit method

• Thirty consecutive women were assessed using on-treatment 2D imaging. Images were assessed on days 1-5 and day 12.
• A total of 180 images were assessed.
• Random and systematic errors were calculated using standard methods.

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Audit minimising bias

• All images were assessed by one radiographer and a proportion of images were independently assessed by a 2nd member of staff. Inter-rater reliability ranged from r=0.85-1.0.
• To ensure accurate data entry, data input was by one member of the project team and checked by three others.

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Audit -results

• Thirty women with a range of breast volumes (340-3045.7cm3) were studied. For central lung depth and cranial lung distance, population systematic errors were within the set-up error level of 3mm. However, the measures that are more likely to indicate breast movement or breast change (rather than thorax or chest wall movement derived from lung depth measures) indicate larger population systematic errors (from 3.16 - 4.13mm). Population random errors were primarily within 3mm except for central irradiated width, again which maybe a reflection of breast tissue displacement or breast tissue swelling. A third of patients had random and systematic errors greater than 3mm for central irradiated width, and two thirds had systematic errors greater than 3mm for cranio-caudal distance. This indicates that for a proportion of patients reproducibility maybe outside recommended set-up errors. In all cases where errors were larger than 3mm no trend could be seen between errors and breast volume.

Other examples of useful audit data

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