Background:
Pressure ulcers are a common problem in hospital care and long-term care. Pressure ulcers are caused by prolonged compression of soft tissues, which can cause local tissue damage and even lead to serious infections. Pressure ulcers can result in poor prognosis, long-term hospitalization, and increased medical costs, which are especially problematic in an aging society.

Objective:
This study uses a deep learning algorithm to construct a system that diagnoses pressure ulcers and assists in making treatment decisions, thus providing additional reference for first-line caregivers.

Methods:
We performed a retrospective research of medical records to find photos of patients with pressure ulcers at National Taiwan University Hospital from 2016 to 2020. We used photos from 2016 to 2019 for training and after removing the photos which were vague, underexposed, or overexposed, 327 photos were obtained. The photos were then labeled as “cellulitis” or “non-cellulitis” for the first classification task and “extensive necrosis”, “moderate necrosis” or “limited necrosis” for the second, by consensus of three recruited physicians. An Inception-ResNet-v2 model, a kind of Convolutional Neural Network (CNN), was applied for training these two classification tasks to construct an assessment system. Finally, we tested the model with the photos of pressure ulcers taken from 2019 to 2020 to verify its accuracy.

Results:
For the task of classification of cellulitis and non-cellulitis wounds, our CNN model achieved an accuracy of about 98.5%. For the task of classification of necrotic tissues, our model achieved accuracy of about 96.6%.

Conclusion:
Compared with traditional algorithms, our deep learning model achieved higher accuracy, making it applicable in clinical circumstances.