INFLUENCE OF BODY POSTURE ON TRANS-CAPILLARY PRESSURES IN HUMAN SUBCUTANEOUS TISSUE

  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (2) , 131-138
Abstract
Capillary pressure in the human circulation varies within a wide range, depending on the height difference between the capillary and heart. To study the influence of body posture on transcapillary pressures in subcutaneous tissue, 28 healthy volunteers were examined. Interstitial colloid osmotic pressure (IIi) was measured in fluid collected by implantation of multifilamentous nylon wicks. Interstitial fluid hydrostatic pressure (Pi) was measured by a wick-in-needle method. Samples for determination of plasma colloid osmotic pressure (IIp) were obtained by venipuncture. In the upright position, IIi was 15.2 (SD 2.1) mm Hg on the thorax and 10.4 (SD 2.1) mm Hg at the ankle. Similar values were obtained in subjects examined after 2 h in a horizontal position. During sustained rest in bed (40 h), IIi on thorax was practically unchanged, while IIi at the ankle rose from 10.1 (SD 2.9) to 12.2 (SD 2.8) mm Hg. Pi averaged -1.3 (SD 1.6) mm Hg on the thorax and -0.4 (SD 2.5) mm Hg at the ankle, but the difference was not statistically significant. The body posture-dependent variations in IIi ands Pi are small and can compensate for only a fraction of the changes in capillary pressure. [The involvement of body position in edema is discussed.].