Comparison of blood rheological changes in the microcirculation during experimental hemorrhagic and traumatic shock.

OBJECTIVE: The aim of the present study was the analysis of the specific hemorheological disorders during the middle stages of experimental traumatic and hemorrhagic shock. METHODS: The following hemorheological properties were investigated: Red Blood Cell (RBC) aggregability, their deformability, and systemic hematocrit. The RBC aggregability was assessed by using the "Georgian technique". The RBC deformability was determined with the nuclepore membrane filter method of Reid. The hematocrit was measured by blood centrifugation. The results obtained were treated statistically by using the "Two sample T-test". RESULTS: We found that in the animals with traumatic shock the erythrocyte aggregability index increased by mean 181%, while in the hemorrhagic group this index on contrary decreased by mean 68% as compared to control group; The RBC deformability underwent a significant decrease during both traumatic and hemorrhagic shock: by a mean of 52% during the first and 62% during the second one. The systemic hematocrit decreased by a mean of 45% during the traumatic shock and by a mean of 50% during the hemorrhagic shock. CONCLUSION: The data obtained provide evidence that the hemorheological disorders are among the most significant microcirculatory disturbances in the pathogenesis of both the traumatic and the hemorrhagic shock.

Blood rheological abnormalities in the microcirculation during experimental traumatic shock.

OBJECTIVE: To find whether the principal indices of blood rheological disorders related to the microcirculation undergo drastic changes during the traumatic shock. METHODS: RBC aggregability and deformability, as well as the systemic hematocrit, were assessed in white laboratory rats with the techniques that provided us with direct and quantitative data. RESULTS: We found that in the experimental animals the RBC aggregability was sharply increased, the RBC deformability significantly decreased, while the systemic hematocrit underwent considerable lowering during the traumatic shock. CONCLUSION: The blood rheological properties are significantly disordered during development of the traumatic shock.

Hemorheological disorders in the microcirculation following hemorrhage.

We analysed hemorheological disorders in the microcirculation of intestinal mesenterium of adult laboratory rats following massive exsanguinations when the mean arterial pressure dropped and then the hemorrhagic shock developed in the animals. The mesenteric microcirculation was analysed by the Texture Analysis System (Leitz, Wetzlar): (a) diameters of the afferent arterioles, capillaries, and efferent venules; (b) the blood flow velocity; (c) microvascular blood flow changes (during the RBC aggregation); (d) local microvascular hematocrit; and (e) the transformation of capillaries into plasmatic microvessels. During development of the hemorrhagic shock we found that the blood flow velocity decreased in all microvessels, there was an increased RBC aggregation which gradually enhanced in the mesenteric microvessels' lumen causing blood flow slowing down till appearance of stases. A part of the capillaries transformed into plasmatic vessels. Therefore the microcirculation demonstrated a significant decrease, this being related both to the lowered pressure gradient and to specific hemorheological disorders in the capillary networks.