Permissive Hypotension Strategies for the Far-Forward Fluid Resuscitation of Significant Hemorrhage

摘要

Acute hemorrhage accounts for about 50% of the deaths on the battlefield in conventional warfare. In addition, hemorrhage is the primary cause of death in 30% of injured soldiers who die from wounds. With future combat strategies focused around the Objective Force Warrior, greater dispersal of troops and fighting in urban settings and on non-linear battlefields, the likelihood of longer evacuation times for combat casualties is suggested. As a consequence of these conditions and the logistic limitations of weight and cube, fluid resuscitation research within the Army's Combat Casualty Care Research Program is focused to investigate limited- or small-volume fluid resuscitation strategies, including permissive hypotension, in far forward areas for the treatment of severe hemorrhage. The goals are to improve battlefield survival and to reduce or prevent early and late deleterious sequelae. Utilizing both anesthetized and conscious large (swine) and small (rodent) animal models, current efforts are focused on evaluating available crystalloid and colloid fluids such as lactated Ringer s, Hespan and Hextend. In addition, other studies are evaluating hemoglobin therapeutics as well as hypertonic/hyperoncotic fluids. Preliminary data suggest that colloid containing fluids offer volume sparing effects over standard isotonic crystalloids, but under these animal model conditions, no obvious advantage of an oxygen-carrying fluid has been observed. Studies to evaluate limitations of hypertonic fluids under these conditions are currently in progress. As there are little data available on the consequences of permissive hypotension coupled with longer evacuation times for the military, these studies have important implications towards the development of optimal fluid resuscitation strategies for stabilization of the combat casualty.