Investigation on the Deformation of Cutaneous Blood Vessel in Relation to Pressure Ulcer Formation by Computational Modelling

Pressure ulcer is a serious injury which affects the skin integrity of patients and is a financial burdens to healthcare providers worldwide. Pressure ulcers are usually caused either by excessive stress or ischemia which appears as deep tissue injury and superficial pressure ulcers respectively. Some of the pressure ulcers are known to be caused by the application of medical devices. These medical device related pressure ulcers are usually superficial and contribute to a significant numbers of the total number of pressure ulcers. The engineering community often focuses on the aetiology of excessive stress by developing computational models and investigating the in vivo conditions when a patient is subject to high loads. Limited attempts have been made on developing computational models for the aetiology of ischemia. Hence, it is the aim of the study to develop computational model to investigate the deformation of the cutaneous blood vessels in relation to the formation of superficial pressure ulcers.

This study provides information on the magnitudes of interface pressure experienced by patients in clinical setting experimentally by using pressure mapping system on both static and dynamic mattresses. Computational models are developed to demonstrate the in vivo cutaneous conditions and the relationship of mechanical loadings and the deformation of cutaneous blood vessels is established. The computational results is further correlated to a set of physiological data acquired by using laser Doppler technique to enhance the clinical relevance. The computational models and the established correlation is applied in three situations including; evaluating the effect of oxygen facial delivery masks on patients’ skin; understanding the effect of same magnitude mechanical load on different skin conditions, and converting an external parameter, interface pressure from mattresses testing, into a physiological parameter.

The overall study provides a novel tool for the medical device developers in evaluating the effects of their devices on patients’ skin in relation to the formation of superficial pressure ulcers. The computational models and the established correlation with the physiological data allows the clinicians to understanding the in vivo cutaneous conditions of patients rather than just evaluating an external parameter.