Comparison of 90 degrees and 30 degrees laterally inclined positions in the prevention of pressure ulcers using transcutaneous oxygen and carbon dioxide pressures.

Although proper positioning is an important measure in pressure ulcer prevention, few objective measurements have been reported of the effects of different positions on oxygen supply to the skin area in direct contact with the mattress. This study compared the effects of 30 degree and 90 degree laterally inclined positions on the cutaneous oxygen supply to the skin through the measurement of transcutaneous oxygen pressure (TCPO2) and transcutaneous carbon dioxide pressure (TCPCO2) on the trochanteric (T) and the retro-trochanteric (R) areas in 20 healthy volunteers. Resting values were TCPO2 (T) 69.4 mm Hg (SD = 10.4), TCPCO2 (T) 36.3 mm Hg (SD = 5.1), and TCPO2 (R) 69.9 mm Hg (SD = 9.2). In the 90 degree laterally inclined position, the TCPO2 (R) value (68.2 mm Hg [SD = 9.9]) did not differ significantly from the resting value. These results show a dramatic impairment of oxygen supply to the skin in the 90 degree laterally inclined position but not in the 30 degree laterally inclined position. Additional studies of patients immobilized for long periods are needed to confirm the best positioning to prevent pressure ulcers.