The ability of three pressure-ulcer prevention support-surfaces to maintain physiological transcutaneous gas tensions in the seated patient

Aims

This study evaluates the effectiveness of three seating interventions—static foam (SF), alternating pressure (AP) cushion, and lateral pressure (LP) device—in reducing pressure ulcer (PU) risk among seated individuals by maintaining tissue perfusion levels in buttocks tissue.

Methods

Eight healthy participants were seated on each intervention for 30 min, followed by a 10-min standing recovery period. Transcutaneous tissue oxygen (TcPO₂) and carbon dioxide (TcPCO₂) were measured at the right ischial tuberosity to monitor tissue perfusion. Responses were recorded as a percentage change relative to each participant's unloaded baseline gas tensions and categorised into three levels of risk. Statistical analysis included paired, one-tailed t-tests to compare the impact of each seating intervention on transcutaneous gas tensions.

Results

Both AP and LP devices revealed a lower magnitude of ischemic carbon dioxide compared to the SF cushion, with mean TcPCO₂ increases of 13.8 % ± 12.0 % and 14.3 % ± 12.0 %, respectively, versus 96.5 % ± 106.5 % for SF. The corresponding TcPO₂ decrease was significantly less for AP (−29.2 % ± 15.7 %) and LP (−28.3 % ± 32.6 %) than for SF (−67.8 % ± 29.0 %). Participants spent significantly more time in the lowest risk category on the AP (17.5 min) and LP (18.2 min) devices than on the SF (2.2 min).

Conclusion

The AP and LP devices maintained favourable buttocks tissue perfusion more effectively compared to the SF, indicating their potential benefit in reducing PU risk for seated patients. These findings support the need for further research to confirm the efficacy of interventions across large sample sizes and longer durations.