anatomical study of the respiratory air sacs in ostriches. Their major advantage is facilitating and speeding up computer-aided on-line determinations of VD. lineages by overcoming respiratory dead space and reducing mass. The derived equations were tested in experimental situations, showing equality between values of dead space determined by using the algebraic solution and the graphical method. Fowlers Method At end-inspiration of the 100 O2 breath, the anatomical dead space is filled with 100 O2 and the N2 concentration in the alveoli has been. The formulas exactly represent Fowler's graphical method and can be applied to all gases which are applicable in dead space determination. We obtained two algebraic equations for both possible conditions, nonsloping and sloping alveolar plateau, and, as the main result, an even more general third equation that includes both Bohr's and Fowler's solution. Whereas Fowler visually partitioned phase II into two equal areas bordered by F(V), R(V), and VD, in the present paper the area between F(V) and R(V) is set equal to the area of a trapezoid, one side of which is the unknown VD to be determined.

According to Fowler's method, anatomical dead space (VD) can be determined graphically or computer-aided by iteration procedures by which phase III of a fraction-volume expirogram F(V) is back-extrapolated by a straight line R(V). The respiratory anatomic dead space has been measured by the single breath nitrogen washout method of Fowler in 73 normal subjects ranging from 4 to 42.

Fowler anatomical dead space