CAPILLARY FILTRATION COEFFICIENT AND URINARY ALBUMIN LEAK AT ALTITUDE

Rapid ascent to altitude risks the development of acute mountain sickn ess, This study demonstrates changes in peripheral capillary filtratio n coefficient and renal protein loss in subjects suffering from variou s degrees of mountain sickness after passive ascent to 4559 m. Capilla ry filtration coefficient of the calf capillary bed, measured by compu ter-based multistep strain gauge plethysmography, increased significan tly after 23.5 h at altitude when symptoms were most severe: 4.45 (2.7 6-6.03) to 6.31 (3.86-11.07) ml min(-1) per 100 g of tissue mmHg(-1), median (range) (P < 0.02). Urinary albumin excretion was increased aft er one night at altitude from 1.1 (0.6-1.5) to 2.45 (1.0-6.8) mg of al bumin per mmol of creatinine (P < 0.05). These results demonstrate sim ultaneous leakage of a peripheral capillary bed to fluid measured by s train gauge plethysmography, and renal albumin leak, and suggest a sys temic process of increased capillary leakage for different-sized molec ules caused by rapid exposure to hypobaric hypoxia.