Effects of posture on pulmonary diffusion capacity and regional distribution of pulmonary blood flow in normal male and female high altitude dwellers at 3,650 m. (12,200 ft)

Abstract

Abstract. Studies of the distribution of pulmonary blood flow (Q) at the altitude of La Paz (3,650 m) were extended to the left upper (LUZ) and left lower lung zones (LLZ) from those previously reported for the right lung alone. Comparisons between 2 groups of male and female high altitude dwellers (HAD) continue to show that in female HAD little change occurs in mean QLUZ with adoption of the vertical position and corroborates the minor change previously reported in QRUZ of a female HAD. In contrast to female HAD, both QRUZ and QLUZ in male HAD reduce by about 25% with adoption of the vertical position. The distribution patterns of Q with changes in posture in the sexes at altitude were compared with the changes in magnitude observed in the same group during measurements of DLCO in recumbency and in the vertical positions. DLCO was corrected for BSA and HB. In male HAD DLCO became reduced by 19.7% in the vertical position, which is 7.2% below the differences in Q observed with change in posture. Female HAD showed a mean change of only 5.5% in DLCO with adoption of the vertical position and this is 6.4% less than the corresponding change in Q. The vertical DLCO index and the perfusion zones in female HAD are thus significantly larger than those of vertical sea-level women. By contrast, no such difference obtains in respect of vertical DLCO and perfusion zones between vertical males at altitude and sea level.