Effect of lymphatic outflow pressure on lymphatic albumin transport in humans.

The effects of posture on the lymphatic outflow pressure and lymphatic return of albumin were examined in 10 volunteers. Lymph flow was stimulated with a bolus infusion of isotonic saline (0.9%, 12.6 ml/kg body wt) under four separate conditions: upright rest (Up), upright rest with lower body positive pressure (LBPP), supine rest (Sup), and supine rest with lower body negative pressure (LBNP). The increase in plasma albumin content (ΔAlb) during the 2 h after bolus saline infusion was greater in Up than in LBPP: 82.9 ± 18.5 vs. −28.4 mg/kg body wt. ΔAlb was greater in LBNP than in Sup: 92.6 vs. −22.5 ± 18.9 mg/kg body wt (P < 0.05). The greater ΔAlb in Up and Sup with LBNP were associated with a lower estimated lymphatic outflow pressure on the basis of the difference in central venous pressure (ΔCVP). During LBPP, CVP was increased compared with Up: 3.8 ± 1.4 vs. −1.2 ± 1.2 mmHg. During LBNP, CVP was reduced compared with Sup: −3.0 ± 2.2 vs. 1.7 ± 1.0 mmHg. The translocation of protein into the vascular...