Pulmonary and Extrapulmonary Effects of Increased Colloid Osmotic Pressure During Endotoxemia in Rats: Organ Water Content

Ileum and liver water content was not significantly different in any group (saline solution-treated rats: liver, 72.3 ± 1.0%; ileum, 76.2 ± 0.87). In contrast, however, significant differences were observed for the lung, the kidneys, and the heart among the various groups (Fig 7). Lung water content increased significantly in the endotoxemic rats (group III) and rats that were treated with both endotoxin and albumin (group IV) compared to saline solution-treated rats and albumin-treated rats (controls, 79.82 ± 0.63%; rats with endotoxemia, 80.89 ± 0.81%; and endotoxin-albu-min treated rats, 82.19 ± 0.61). Endotoxin-albumin treatment produced significantly higher levels of pulmonary edema than those with endotoxin treatment alone. The water content of the heart and kidney were significantly higher in both endotoxin-treated and endotoxin-albumin-treated animals compared to the saline solution-treated controls. Albumin treatment alone produced no significant differences in the water content of lung, kidney, and heart when compared to that in the controls (Fig 7).

Discussion
Our data demonstrate that increasing COP by albumin infusion during an early stage of endotox-emia with capillary leak syndrome is associated with significant increases in P(A-a)O2 [Fig 4], as well as reductions in Hb (Fig 2), arterial O2 content (Fig 3), and O2 carrying capacity. Concurrently, systemic and pulmonary hemodynamics become unstable compared with those variables in endotoxemic rats that had not received albumin therapy (Figs 5, 6). The postmortem water content evaluation of multiple organs in endotoxemic rats that had received albumin treatment also shows significant increases in the water content of lung, heart, and kidney (Fig 7). The increase in pulmonary edema associated with albumin treatment in endotoxemic rats confirms the results of Ernest et al, who studied the distribution of normal saline solution and 5% albumin infusions in septic patients. Clinically, fluid resuscitation for circulatory shock (due to hemorrhage or sepsis) is carried out to a physiologic end point such as normotension. This requires using a two to three times higher volume of crystalloid solutions compared to that for colloid solutions.
Fig7
Figure 7. The water content of multiple organs in saline solution-treated and albumin-treated rats (controls) and in endo-toxemic rats with or without albumin treatment. * = p < 0.05 (all groups are compared by one-way analysis ofvariance, followed by Tukey-Kramer multiple comparison test). The increase in the lung water content of endotoxemic rats was significantly higher than that of endotoxemia with albumin treatment.

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