Interface pressure measurements: visual interpretation of pressure maps with MS clients

Pressure mapping systems provide useful information for pressure care assessment. Healthcare professionals tend to rely upon their colour-coded pressure maps to assist clinical decision-making, based on ranking these from best to worst pressure distribution. The current study investigated whether such ranking is an appropriate method of assessment when compared to use of the numerical output of average and maximum pressure values (mmHg), yielded by the system.

This community-based correlational study involved 27 multiple sclerosis clients (15 wheelchair users; 12 non-wheelchair users). Pressure maps were recorded on each participant's current seating surface and on six pressure reducing cushions, using the Force Sensing Array pressure mapping system. Outcome measures included (1) rank order of pressure maps based on visual interpretation by two occupational therapists, (2) average pressure (mmHg) and (3) maximum pressure (mmHg). Visual ranking of the colour-coded pressure maps was correlated with average and maximum pressure values for each map.

Correlations between visual ranking of maps and maximum pressures were high for six out of seven surfaces (p < 0.05) for non-wheelchair users; however, they were much less between average pressures and visual interpretation for the same cohort. Similarly, correlations between visual ranking of maps and average pressures for wheelchair users was minimal and was only noted as being high (p < 0.05) on two surfaces when considering maximum pressures and visual interpretation.

This study contests the usefulness of the visual ranking of pressure maps in interpreting interface pressures with MS clients, especially with wheelchair users. Visual interpretation of pressure maps by clinicians may be useful in eliminating inappropriate support surfaces from a selection, or those that display easily identifiable 'extremes' of pressure values. Clinicians need to incorporate and interpret the numerical data as well as pressure maps when conducting their assessment and making provision.