Effect of lymphatic outflow pressure on lymphatic albumin transport in humans

Abstract

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 (Delta Alb) 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. Delta Alb was greater in LBNP than in Sup: 92.6 vs. -22.5 +/- 18.9 mg/kg body wt (P < 0.05). The greater Delta Alb 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 (Delta CVP). 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 space after bolus saline infusion reflects lymph return of protein and is higher in Up than in Sup. Modulation of CVP with LBPP or LBNP in Up and Sup, respectively, reversed the impact of posture on lymphatic outflow pressure. Thus posture-dependent changes in lymphatic protein transport are modulated by changes in CVP through its mechanical impact on lymphatic outflow pressure.

Leakage of albumin in major abdominal surgery

“…Exogenous vasopressors such as norepinephrine are associated with plasma volume contraction [ 25 ], and we speculate that physiological stress can also have similar rapid effects. Intermediate effects on P-alb (hours) include compromised lymphatic return of albumin, either by para-aortal resection of lymph glands in major abdominal surgery or by altered lymphatic outflow pressure (i.e., central venous pressure) caused by positive pressure ventilation [ 26 ], the state of hydration, or posture [ 27 ]. Also, the transcapillary escape rate can be increased by overhydration or inflammation [ 4 ].…”

Time course and magnitude of fluid and electrolyte shifts during recovery from high-intensity exercise in Standardbred racehorses

“…A key assumption in calculating the changes in PV and ECFV using plasma protein concentration is that there is no net gain or loss of protein by the vascular compartment during exercise and recovery. However, there is mounting indirect evidence that a net gain of protein by the vascular compartment may occur during exercise and the initial recovery period 21,22 . If this assumption is incorrect and there was a net gain of protein from the lymph, then the exercise-induced decreases in PV and ECFV were overestimated by an amount proportionate to the protein gain.…”

The influence of exercise volume and posture on exercise‐induced plasma volume expansion

“…We used transthoracic impedance ( Z 0 ,) as an indicator of changes in thoracic blood volume (Wu & Mack, 2001). An increase in Z 0 would be associated with a decrease in thoracic blood volume and central venous pressure and thereby promote the lymphatic return of proteins to the vasculature by reducing lymphatic outflow pressure (Brace, 1989; Nagashima et al, 1999; Szabo & Magyar, 1967; Wu & Mack, 2001). In supine subjects, the application of lower body negative pressure reduced Z 0 and lymphatic outflow pressure and subsequently increased lymphatic delivery of albumin to the vascular compartment (Wu & Mack, 2001).…”

“…Based on albumin's ability to increase osmotic pressure, shifts in albumin distribution induced by exercise are thought to play a central role in increasing plasma volume after exercise (Gillen et al, 1991). Albumin dynamics are closely tied to posture both at rest and during exercise (Gillen et al, 1991; Nagashima et al, 1999; Wu & Mack, 2001). Specifically, plasma albumin content increases after upright cycle ergometry training (Convertino et al, 1980) and following a single session of high‐intensity intervals (Gillen et al, 1991, 1994; Nagashima et al, 1999).…”