The pentafraction of hydroxyethyl starch inhibits ischemia-induced compartment syndrome

Pentafraction (PF), a solution of biodegradable hydroxyethyl starch macromolecules with molecular weights of 10 to 100 x 10⁴ daltons, has been shown to minimize tissue edema by sealing interendothelial clefts at the capillary level. The effect of PF on ischemia-reperfusion-induced compartment syndrome was studied. Ten rabbits underwent bilateral femoral artery occlusion following ligation of branches from the terminal aorta to the popliteal artery. After 7 hours of ischemia, reperfusion was established with heparinized polyethylene shunts. Experimental animals (n = 5) received PF and control animals (n = 5) received normal saline (NS) as an intravenous infusion (30 mL/kg) for 1 hour, beginning 10 minutes after shunt placement. During reperfusion, anterior compartment pressure was continuously monitored in the left lower extremity. To quantitate oxidative metabolism, triphenyltetrazolium chloride (TTC) reduction (micrograms of TTC per milligram of protein) of tibialis anterior muscle from the right lower extremity was measured at femoral artery occlusion, 7 hours of ischemia, and 2 hours of reperfusion. In the NS group, anterior compartment pressure significantly increased from the end of the ischemic interval, 10.8 ± 4.14 to 36.4 ± 9.9 mm Hg and 44.6 ± 15.4 mm Hg, after 1 and 2 hours of reperfusion (ρ < 0.007) compared with the PF group, which did not change significantly, 10.6 ± 2.6 to 11.4 ± 12.9 mm Hg and 7.4 ± 2.8 mm Hg, after 1 and 2 hours of reperfusion (ρ < 0.67). After 1 hour of reperfusion, the anterior compartment pressure of the NS group was significantly greater than that of the PF group (ρ < 0.009) as well as after 2 hours of reperfusion (ρ < 0.007). The TTC reduction following 2 hours of reperfusion increased significantly to 0.153 ± 9.76 µg/mg in the PF group compared with the NS group, 0.006 ± 1.34 µg/mg (ρ < 0.02). We conclude that the pentafraction of hydroxyethyl starch inhibits the increase in compartment pressure that follows prolonged severe muscle ischemia in this rabbit hindlimb model of skeletal muscle ischemia.