Phagocytic reticuloendothelial function after hemorrhage and resuscitation: modulation by different fluids

Although the efficacy of colloid resuscitation fluids in restoring cardiovascular status in hemorrhagic shock is accepted, the effect they have on the activity of the reticuloendothelial system (RES) is less clear. As interaction with the RES may be important in determining susceptibility to infections after resuscitation the effects of three such fluids, hydroxyethyl starch, Haemaccel, and fresh autologous blood on RES function after a 40% hemorrhage have been investigated in BALB/C mice. The mice, anesthetized with isoflurane, were bled over a 10 min period, left hypovolemic for 30 min, and then resuscitated with their shed blood or the same volume of asanguineous fluid. Normothermia was maintained throughout the experiments. Whole body phagocytic activity was assessed at 1, 6, 24, 48, and 72 h after the end of hemorrhage by measuring the clearance rate (K) of intravenously injected 51Cr-labeled sheep red blood cells. No significant change in K was found at any time in animals resuscitated with shed blood. However, significant increases in K were found 48 h after resuscitation with Haemaccel. Hepatic uptake of sheep red blood cells was significantly increased at 48 and 72 h in Haemaccel-resuscitated animals compared with hydroxyethyl starch or shed blood resuscitation, whereas spleen uptake decreased at 72 h. Lung uptake was not affected at any time with any fluid. The same volume of Haemaccel had no significant effect either on K or on organ uptake when given to normovolemic animals. The changes in organ uptake after hemorrhage and resuscitation with Haemaccel were partially prevented if animals were resuscitated with Haemaccel plus autologous red cells.