Evaluation of the Effect of Gluteus Maximus Contraction by Electrical Stimulation on Interfacial Pressure in Supine Bed Positions.

Objectives: This study investigated the impact of neuromuscular electrical stimulation (NMES) to the gluteus maximus in the bed flat position (F position) and 30-degree head elevation position (30 HE position) on sacral pressure.

Methods: Twenty volunteers consented to participate in this study. Sacral pressure was measured in the F position and at the 30 HE position with and without NMES in the supine positions. NMES was applied to the gluteus maximus (frequency, 50 Hz; pulse width, 300 μs) with sufficient stimulus intensity to induce muscle contraction. Sacral maximum pressure was determined as peak pressure index (PPI) by averaging the values from the central nine sensors of the maximum pressure zone. The effect of NMES on pressure gradient and the influence of sex difference were also explored.

Results: Sacral PPI was significantly lower after NMES implementation in both the F position and the 30 HE position when compared with conditions without NMES (P <0.001). The pressure gradient was also significantly decreased with NMES (P <0.001). Analysis of sex difference in subjects treated with NMES revealed a significantly greater effect on maximum sacral pressure in males than in females.

Conclusions: Application of NMES to the gluteus maximus helps to disperse sacral pressure in supine positions. NMES on the gluteus maximus can be a clinical means to manage interfacial pressure in supine positions.