Table 3.
Medians and interquartile ranges of skin structure parameters on sacral and right heel skin areas (n = 15)
| Sacral skin area | Right heel | |||||||
|---|---|---|---|---|---|---|---|---|
| Baseline | After 2 h | After 2 h and 20 min | Difference 2 h—baseline | Baseline | After 2 h | After 2 h and 20 min | Difference 2 h—baseline | |
| Extensibility—Uf in mm | ||||||||
| Air | 0.32 (0.31‐0.35) | 0.34 (0.32‐0.40) | 0.33 (0.30‐0.38) | 0.03 (−0.01‐0.07) | 0.08 (0.07‐0.12) | 0.10 (0.08‐0.12) | 0.08 (0.07‐0.12) | 0.01 (−0.01‐0.02) |
| Gel | 0.29 (0.26‐0.33) | 0.32 (0.28‐0.37) | 0.31 (0.27‐0.35) | 0.03 (0.01‐0.05) | 0.08 (0.06‐0.10) | 0.10 (0.10‐0.12) | 0.09 (0.06‐0.11) | 0.03 (−0.01‐0.04) |
| Foam | 0.32 (0.28‐0.34) | 0.35 (0.32‐0.37) | 0.32 (0.30‐0.37) | 0.03 (0.01‐0.05) | 0.09 (0.07‐0.10) | 0.10 (0.08‐0.12) | 0.10 (0.08‐0.12) | 0.02 (−0.01‐0.04) |
| P‐value | — | — | — | 0.819 | — | — | — | 0.819 |
| Elastic function—Ur/Ue in % | ||||||||
| Air | 0.79 (0.54‐0.90) | 0.81 (0.65‐0.87) | 0.75 (0.56‐0.92) | −0.01 (−0.06‐0.04) | 0.67 (0.64‐0.77) | 0.66 (0.58‐0.79) | 0.67 (0.61‐0.79) | −0.02 (−0.10‐0.05) |
| Gel | 0.78 (0.65‐0.96) | 0.70 (0.63‐0.93) | 0.66 (0.57‐0.97) | −0.03 (−0.11‐0.03) | 0.68 (0.63‐0.98) | 0.70 (0.62‐0.83) | 0.67 (0.64‐0.74) | −0.06 (−0.20‐0.02) |
| Foam | 0.80 (0.67‐0.97) | 0.65 (0.56‐0.90) | 0.72 (0.59‐0.80) | −0.10 (−0.15‐0.02) | 0.68 (0.62‐0.85) | 0.70 (0.62‐0.81) | 0.67 (0.61‐0.75) | −0.02 (−0.17‐0.15) |
| P‐value | — | — | — | 0.282 | — | — | — | 0.766 |
| Elastic recovery—Ur/Uf in % | ||||||||
| Air | 0.55 (0.42‐0.64) | 0.55 (0.42‐0.65) | 0.52 (0.41‐0.68) | 0.01 (−0.06‐0.03) | 0.36 (0.32‐0.42) | 0.35 (0.30‐0.37) | 0.34 (0.32‐0.38) | −0.01 (−0.05‐0.01) |
| Gel | 0.52 (0.46‐0.64) | 0.50 (0.42‐0.66) | 0.45 (0.37‐0.66) | 0.01 (−0.04‐0.03) | 0.35 (0.33‐0.39) | 0.36 (0.32‐0.40) | 0.36 (0.33‐0.38) | −0.01 (−0.06‐0.04) |
| Foam | 0.57 (0.43‐0.66) | 0.44 (0.42‐0.64) | 0.51 (0.44‐0.64) | −0.03 (−0.11‐0.01) | 0.35 (0.33‐0.43) | 0.38 (0.32‐0.42) | 0.35 (0.32‐0.37) | −0.03 (−0.04‐0.06) |
| P‐value | — | — | — | 0.127 | — | — | — | 0.627 |
| Skin maximum roughness—Rmax in μm | ||||||||
| Air | 51.0 (42.5‐56.0) | 51.0 (45.5‐59.0) | 57.0 (49.5‐63.5) | 2.0 (−1.5‐8.0) | 63.5 (44.0‐93.0) | 67.5 (59.0‐83.0) | 71.5 (61.5‐94.5) | 1.5 (−10.0‐9.5) |
| Gel | 47.5 (42.8‐57.0) | 50.0 (46.0‐57.5) | 52.5 (45.5‐65.0) | 1.0 (−3.8‐9.1) | 63.8 (46.6‐79.5) | 73.5 (57.0‐100.5) | 81.5 (69.0‐110.5) | 5.3 (−3.8‐13.6) |
| Foam | 46.5 (38.5‐53.5) | 52.0 (43.5‐58.5) | 52.0 (47.5‐61.0) | 2.5 (−1.5‐8.5) | 70.0 (44.5‐91.0) | 67.5 (52.0‐93.0) | 70.0 (54.0‐81.5) | −8.0 (−11.0‐9.5) |
| P‐value | — | — | — | 0.849 | — | — | — | 0.424 |
| Mean roughness depth—Rz in μm | ||||||||
| Air | 39.5 (33.5‐41.0) | 39.0 (36.0‐43.5) | 43.0 (38.5‐50.5) | 2.5 (−2.0‐6.0) | 48.5 (32.0‐68.0) | 50.5 (43.5‐63.5) | 52.5 (46.0‐73.0) | 2.0 (−9.5‐9.5) |
| Gel | 35.5 (33.3‐44.6) | 40.0 (37.0‐43.5) | 40.5 (36.0‐49.0) | 1.8 (−2.0‐6.9) | 48.3 (36.1‐59.4) | 51.5 (45.0‐72.0) | 59.5 (53.0‐88.0) | 4.0 (−4.5‐9.1) |
| Foam | 34.0 (32.0‐41.5) | 39.5 (34.0‐44.0) | 42.5 (37.0‐46.0) | 2.5 (−2.5‐5.0) | 51.5 (34.5‐72.0) | 51.0 (39.5‐70.5) | 55.0 (40.0‐58.5) | −8.5 (−10.5‐5.5) |
| P‐value | — | — | — | 0.708 | — | — | — | 0.223 |
| Arithmetical mean roughness value—Ra in μm | ||||||||
| Air | 9.0 (8.0‐10.0) | 9.0 (8.0‐11.5) | 10.0 (8.5‐12.0) | <0.001 (−1.0‐1.0) | 9.0 (7.5‐13.5) | 10.0 (7.5‐12.0) | 10.5 (8.5‐14.0) | < 0.001 (−1.5‐1.0) |
| Gel | 8.3 (6.9‐10.1) | 9.0 (8.5‐10.0) | 9.5 (8.5‐10.0) | 0.8 (−0.6‐1.5) | 9.8 (7.9‐12.0) | 10.0 (9.0‐12.0) | 11.5 (9.5‐17.0) | −0.3 (−1.0‐1.0) |
| Foam | 8.0 (7.5‐10.0) | 8.5 (7.5‐10.0) | 9.0 (8.0‐11.0) | 1.0 (−1.0‐1.5) | 9.5 (7.0‐15.5) | 8.5 (7.5‐13.0) | 9.0 (8.0‐11.5) | −1.5 (−3.0‐0.5) |
| P‐value | — | — | — | 0.673 | — | — | — | 0.180 |