FIGURE 1.

A, A schematic description of the vicious cycle of cell and tissue damage in pressure ulcers/injuries (PUs/PIs), resulting from sustained mechanical deformations (the triggering event), which inflicts the primary, direct deformation damage (first damage event), then leading to secondary inflammatory‐oedema related damage (second damage event), and finally to tertiary ischaemic damage (third damage event). B, Each of these three factors contributes to the cumulative cell and tissue damage, which develops in an escalated manner as a result of the added contributions of the above factors. Of note, while it is likely that the ischaemic damage follows from the inflammatory damage as visualised here, ischaemia per se may also be present prior to the onset of the PU/PI vicious cycle (eg, due to a persistent peripheral vascular disease), or develop independently from, or concurrently with the inflammation (eg, as a result of a thrombotic event in a patient with coronavirus disease 2019). In contrast, localised inflammation may follow from or intensify because of an existing ischaemic condition, especially when reperfusion is allowed (eg, immediately after repositioning). Accordingly, the process of accumulation of tissue damage over time in a forming PU/PI as described here is likely, but is not necessarily a linear one (particularly with regard to the order of the inflammatory and ischaemic damage phases)