FLUID DISTRIBUTION AND TISSUE THICKNESS CHANGES IN 29 MEN DURING 1 WEEK AT MODERATE ALTITUDE (2,315 M)

To quantify fluid distribution at a moderate altitude (2,315 m) 29 mal e subjects were studied with respect to tissue thickness changes [fron t (forehead), sternum, tibia], changes of total body water, changes of plasma volume, total protein concentrations (TPC), colloid osmotic pr essure (COP), and electrolytes. Tissue thickness at the forehead showe d a significant increase from 4.14 mm to 4.41 mm 48 h after ascent to the Rudolfshuette (2,315 m) (P < 0.05). At 96 h after ascent the tissu e thickness at the tibia was decreased to 1.33 mm compared to the cont rol value of 1.59 mm (P < 0.01). Body mass increased from 75.5 kg (con trol) to 76.2 kg on the last day (P < 0.05) and body water from 44.21 to 45.01 during the week (P < 0.01). The accumulation fluid in the upp er part of the body was paralleled by a decrease in TPC and COP. At 48 h after the ascent COP dropped from 29.5 mmHg to 27.5 mmHg (P < 0.01) . After 96 h at moderate altitude COP was still significantly decrease d compared to the control level. At 1.5 h after the return from the Ru dolfshuette in Saalfelden (744m) COP was back to the control values. T he TPC also showed an initial drop from 7.75 g.dl(-1) to 7.48 g.dl(-1) after 48 h at altitude and remained below the control value during th e whole week(P < 0.01). It seems from our study that even with exposur e to moderate altitude measurable fluid shifts to the upper part of th e body occurred which were detected by our ultrasound method.