Effects of Synthetic Versus Natural Colloid Resuscitation on Inducing Dilutional Coagulopathy and Increasing Hemorrhage in Rabbits.

摘要

On the basis of logistic benefits of colloids over crystalloids, the U.S. military selected Hextend for resuscitation of combat casualties in the field. We investigated the effects of resuscitation with this fluid, as well as other colloids, on coagulation and uncontrolled bleeding in rabbits subjected to a splenic injury. Methods: Anesthetized male New Zealand white rabbits (3.3 kg 0.2 kg) were divided into three groups and subjected to hypothermia (35 Degrees C + or - 0.5 Degrees C) and 40% isovolemic blood exchange (hemodilution) with Hextend (H); Dextran70 (D); or 5% human albumin (A) solution (n 8/group). Complete blood count, arterial blood gas, and coagulation values were measured before and after hemodilution. Laparotomy was performed and a standard splenic injury causing uncontrolled hemorrhage was made. Rabbits were resuscitated (25 mL/kg) with the same colloid used for hemodilution to restore baseline blood pressure. Animals were monitored for 2 hours or until death. Blood loss and survival times were measured. Results: There were no differences among groups in pH, Hct, fibrinogen, or platelets before or after hemodilution. Hct, fibrinogen, and platelets were reduced by 45% to 60% in all groups. Prothrombin time (PT) and activated partial thromboplastin time were prolonged in all the rabbits with the greatest increase in A group. Thrombelastograph (TEG) analysis showed longer initial reaction (R) and clotting (K) times, slower clotting rate and lower clot strength in H and D than A diluted blood. R time was faster and K time remained unchanged in A group after hemodilution.