interface pressure mapping

When a person sits, you cannot see where the pressure on their skin is dangerously high — the body hides it. Interface pressure mapping makes that hidden information visible. The person sits on a thin sensor mat full of tiny pressure sensors, and a computer shows the result as a colour 'heat map': blue and green where pressure is low and spread out, red and orange where it is concentrated and worrying.

The mat is placed on the cushion, the person sits on it normally, and the screen lights up with a picture of how their weight is distributed across the seating surface. The clinician looks especially at the spots under the bony parts of the pelvis — the sitting bones (ischial tuberosities) and the tailbone — because these are where skin breaks down. Bright red peaks there flag a problem. The clinician can then change something — swap to a different cushion, re-inflate an air cushion, adjust the seat, add a tilt — and watch in real time whether the red peaks soften and spread. It turns cushion and posture choices from guesswork into something you can actually see and compare.

Pressure mapping is a genuinely useful tool, but it must be read honestly. It measures only the pressure between the skin and the surface at one moment, sitting still. It does not measure the deeper forces inside the tissue, the shear (the dragging, sideways force when someone slides), the moisture, or the time the person stays in one position — and all of those also drive pressure injuries. A low, even map is reassuring but is not a guarantee against skin breakdown; it is one piece of evidence that supports good seating, not a substitute for weight shifts, skin checks, and clinical judgement.