as compression increases cuff volume decreases and cuff pressure increases with the garment pressure constant as is the case illustrated in fig3 it is found that the cuff pressure increases more gradually but in a linear fashion the bias pressure of the cuff against the garment is believed to alter the garment pressure in addition to changing the cuff pressure thus in order to obtain an accurate measure of the garment pressure when there is no bias pressure the linear region of the plot is extrapolated downward to zero bias pressure to determine the theoretical cuff pressure at zero bias pressure if the cuff pressure and bias pressure are plotted on paper by a chart recorder the extrapolation can be done graphically as illustrated by broken line 65 in fig3 which intersects the y or cuff pressure axis at approximately 58 milimeters of mercury alternately the extrapolation can be done analytically by a suitable computer the more gradually sloped linear portion of the plot spaced from the origin i e the portion in the range of twenty to fifty milimeters of mercury is described by the equation pc mpb po where pc is the cuff pressure m is the slope of the linear plot pb is the bias pressure and po is the theoretical cuff pressure existing when pb equals zero thus the computer need merely determine the value of m select any point on the linear curve for values of pc and pb and solve for po in either event after the cuff pressure component due to the garment pressure is determined the cuff is deflated by means of a.