Temporary arterial shunts to maintain limb perfusion after arterial injury: An animal study

Background: Temporary shunt placement can quickly restore perfusion after e xtremity arterial injury. This study examined the adequacy of limb blood fl ow with shunt use, non-heparin-bonded shunt patency over prolonged periods, and the safety of this technique. Methods: Common iliac arteries were divided and 4.0-mm Silastic Sundt shunt s placed in 16 anesthetized pigs, Eight (group I) had shunts placed immedia tely; eight others (group II) mere shunted after an hour of limb ischemia a nd hemorrhagic shock. Physiologic parameters and femoral artery blood flow in both hindlimbs were continuously monitored. Limb lactic acid generation, oxygen utilization, and hematologic and metabolic effects were serially ev aluated for 24 hours. Results: Shunts remained patent in 13 of 16 pigs, Shunts thrombosed in two group I animals because of technical errors, but functioned well after thro mbectomy and repositioning. Patency could not be maintained in one animal t hat died from shock. Flow in group I shunted limbs was 57 (+/-11 SD) % of c ontrol. For group II animals in shock, shunted limb flow initially averaged 46 +/- 15% of control, but 4 hours after shunt placement, the mean limb bl ood flow was the same as in group I. Increased oxygen extraction compensate d for the lower flow. Lactic acid production mas not increased in compariso n to cont ol limbs. Conclusion: Shunts provided adequate flow in this model of extremity trauma . Correctly placed shunts stayed patent for 24 hours, without anticoagulati on, if shunt placement followed resuscitation.