Abstract
Military literature has demonstrated the utility and safety of tourniquets in preventing mortality for some time, paving the way for increased use of tourniquets in civilian settings, including perioperatively to provide a bloodless surgical field. However, tourniquet use is not without risk and the subsequent effects of tissue ischemia can impede downstream rehabilitative efforts to regenerate and salvage nerve, muscle, tissue and bone in the limb. Limb ischemia studies in both the mouse and pig models have indicated not only that there is residual flow past the tourniquet by means of microcirculation, but also that recovery from tissue ischemia is dependent upon this microcirculation. Here we expand upon these previous studies using portable Near-Infrared Imaging to quantify residual plasma flow distal to the tourniquet in mice, pigs, and humans and leverage this flow to show that plasma can be supersaturated with oxygen to reduce intracellular hypoxia and promote tissue salvage following tourniquet placement. Our findings provide a mechanism of delivery for the application of oxygen, tissue preservation solutions, and anti-microbial agents prior to tourniquet release to improve postoperative recovery. In the current environment of increased tourniquet use, techniques which promote distal tissue preservation and limb salvage rates are crucial.