Skin blood flow in seated geriatric patients.

A hard seat was equipped with devices sensing arteriolar pulsatile blood flow volume rate, externally developed pressure, and shear, all taken in lateral proximity to the ischial tuberosities of sitting subjects. Tests of 14 geriatric hospitalized patients and 9 healthy young men indicated the following: (1) No young healthy man demonstrated blood flow occlusion at pressure values less than 120mmHg. Of the geriatric hospitalized subjects, 2 occluded at less than 20mmHg. (2) Average shear values developed by the geriatric hospitalized group were 3 times that of the young healthy group. (3) Average pressure values demonstrated by the geriatric hospitalized subjects were roughly equal to those of the younger subjects (roughly 70mmHg). (4) Tipping the seat backwards through 20 degrees produced major benefits to the hospitalized geriatric group in terms of increased blood flow, lessened pressure, and lower shear. The young, healthy group experienced some increase in blood flow with no significant change in sitting reactions when tested in a tipped attitude.