Effects of colloidal resuscitation fluids on reticuloendothelial function and resistance to infection after hemorrhage

Abstract

The effects of three resuscitation fluids, hydroxyethyl starch (HES), Haemaccel, and fresh autologous blood, on reticuloendothelial system phagocytic and catabolic functions and resistance to infection after 40% hemorrhages in BALB/c mice were studied. 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. The uptake and catabolism of intravenously injected double-labelled sheep erythrocytes (51Cr-125I-SRBC) in liver and spleen were determined at 1 and 48 h after hemorrhage. No significant changes in the uptake or catabolism of SRBC in liver or spleen were found at 1 h after hemorrhage and resuscitation with any of the fluids. However, at 48 h a significant increase in liver uptake of SRBC was seen in animals resuscitated with either Haemaccel or HES compared to that in animals resuscitated with shed blood or in animals subjected to a sham operation. The increase in liver uptake was accompanied by a small decrease in spleen uptake in animals resuscitated with Haemaccel but not with HES. No great changes in catabolic activity were seen at 48 h, although activity levels tended to be higher in animals resuscitated with Haemaccel. Separate groups of animals were challenged by an intraperitoneal injection with live Escherichia coli at 1 or 48 h after hemorrhage and resuscitation. Sixty-four percent of the animals resuscitated with shed blood survived the challenge with E. coli at 1 h after hemorrhage, whereas only 10 and 0% survival was seen for animals resuscitated with Haemaccel and HES, respectively. At 48 h survival was 80% for shed-blood-resuscitated animals and 60 and 70% for Haemaccel- and HES-resuscitated animals, respectively.

FIG. 1

Mortality of hemorrhaged mice resuscitated with shed blood and injected with E. coli O18:K1 intraperitoneally (i.p.). LD₅₀ was calculated by using allosteric Hill kinetics and an adaptation of the method of Reed and Muench (33) and was found to be 6.8 × 10⁵ CFU.

FIG. 2

Changes in radioactivity, expressed as percentages of the total injected dose (ID), in liver (a), spleen (b), and kidney (c) following the intravenous injection of ⁵¹Cr-¹²⁵I-labelled SRBC into control animals. Results are shown as means ± SEM. n = 3 at each time point.

FIG. 3

Survival of mice after an intraperitoneal injection with E. coli O18:K1 at 1 (a) and 48 (b) h after hemorrhage and resuscitation. n = 10 or 11 in each group.