Small volume hypertonic hydroxyethyl starch reduces acute microvascular dysfunction after closed soft-tissue trauma

Abstract

A major pathway of closed soft-tissue injury is failure of microvascular perfusion combined with a persistently enhanced inflammatory response. We therefore tested the hypothesis that hypertonic hydroxyethyl starch (HS/HES) effectively restores microcirculation and reduces leukocyte adherence after closed soft-tissue injury. We induced closed soft-tissue injury in the hindlimbs of 14 male isoflurane-anaesthetised rats. Seven traumatised animals received 7.5% sodium chloride-6% HS/HES and seven isovolaemic 0.9% saline (NS). Six non-injured animals did not receive any additional fluid and acted as a control group. The microcirculation of the extensor digitorum longus muscle (EDL) was quantitatively analysed two hours after trauma using intravital microscopy and laser Doppler flowmetry, i.e. erythrocyte flux. Oedema was assessed by the wet-to-dry-weight ratio of the EDL. In NS-treated animals closed soft-tissue injury resulted in massive reduction of functional capillary density (FCD) and a marked increase in microvascular permeability and leukocyte-endothelial cell interaction as compared with the control group. By contrast, HS/HES was effective in restoring the FCD to 94% of values found in the control group. In addition, leukocyte rolling decreased almost to control levels and leukocyte adherence was found to be reduced by approximately 50%. Erythrocyte flux in NS-treated animals decreased to 90 +/- 8% (mean SEM), whereas values in the HS/HES group significantly increased to 137 +/- 3% compared with the baseline flux. Oedema in the HS/HES group (1.06 +/- 0.02) was significantly decreased compared with the NS-group (1.12 +/- 0.01). HS/HES effectively restores nutritive perfusion, decreases leukocyte adherence, improves endothelial integrity and attenuates oedema, thereby restricting tissue damage evolving secondary to closed soft-tissue injury. It appears to be an effective intervention, supporting nutritional blood flow by reducing trauma-induced microvascular dysfunction.

Antithrombin Reduces Inflammation and Microcirculatory Perfusion Failure in Closed Soft-Tissue Injury and Endotoxemia

“…For quantitative offline analysis, a computer-assisted microcirculation image analysis system was used (CapImage v7.4, Zeintl, Heidelberg, Germany). As previously described (9,13,14), functional capillary density was defined as the total length of red blood cell-perfused capillaries per observation area and given in cm/cm 2 . With use of densitometric techniques, macromolecular leakage was assessed in several fields per image and expressed as the ratio of fluorescence intensity selected from the perivascular area to the corresponding intravascular area (plasma gaps in the microvessels between erythrocytes [15]).…”

Erythropoietin improves functional and histological recovery of traumatized skeletal muscle tissue

“…Upon a 20-min stabilization period after completion of surgery, in vivo microscopy of the soleus muscle was performed, as previously described for the EDL. [14][15][16][17] To consider the heterogeneous morphology of the traumatized muscle, a classification system, as recently published by our group 18 was used, considering three zones. Zone 1 (z1) was defined as the central muscle area with entrance of the neurovascular structures.…”

Experimental models to study microcirculatory dysfunction in muscle ischemia?reperfusion and osteomyocutaneous flap transfer

“…This preparation also allows (1) the study of patho-mechanisms of ischemia-reperfusion [65] and low flow perfusion [66], and, in particular, (2) the analysis of the microvascular consequences of closed, soft tissue trauma [67,68].…”