Lactated Ringer’s is Superior to Normal Saline in the Resuscitation of Uncontrolled Hemorrhagic Shock Presented by intern 陳姝蓉 S. Rob Todd, MD et al, Journal of TRAUMA Injury, Infection, and Critical Care, March 2007

Introduction Treatment of hemorrhage: hemostasis & volume resuscitation Normal saline (NS) & lactated Ringer’s solution (LR): often used for resuscitation of hemorrhagic shock Purpose: analyze effects of NS and LR on the resuscitation of uncontrolled hemorrhagic shock in a swine model Hypothesis: similar effects between NS & LR

Materials and Methods Prospective, randomized controlled trial N = 20 (Yorksire crossbred pigs) underwent invasive line placement, midline celiotomy, and splenectomy Splenectomy: prevent variation in amounts of sequestered blood Grade V liver injury (central hepatic v.) created 15 min after stabilization Resuscitation delayed for 30 minutes to allow the animals to reach their nadir blood pressure Blindly randomized swine to receive NS or LR resuscitation at 165 mL/min to achieve and maintain baseline MAP for 90 min postinjury Post 2-hour study period blood analysis: lactate level, ABG, chemistry panel, CBC, PT/PTT, fibrinogen, D-dimer

Results

NS vs. LR (p=0.02) (p=0.04) (p=0.54) (p=0.34)

Mean Arterial pressure (MAP) MAP: No significant differences between the curves (p=0.87)

Lab data Significant hypernatremia and hypercholremia in NS group Persistent hyperchloremia metabolic acidosis in NS group Dilutional coagulopathy in NS group

Discussion Plasma chloride concentration was significantly greater in the NS group  persistent acidosis Adverse effects of acidosis:  Myocardial contractility (↓), peripheral vascular resistance(↓), inotropic response to catecholamines (↓)  Arrhythmias, platelet dysfunction, and overall coagulation cascade dysfunction Swafford et al.: LR might prolong lactic acid load caused by hemorrhage in intoxicated individuals White et al.:  Lactate metabolized by gluconeogenesis (30%) or oxidation(70%)  OH - excess  pH(↑) Hypothesis: increased volume requirement in NS group was the result of the significant diuresis

Discussion Dilutional coagulopathy  Dependent on type and volume of fluid utilized  In NS animals: fibrinogen (↓), lower platelet count, prolonged PT Hypothermia :  Slowing enzymatic reactions of coagulation cascade & altering platelet function  Our model: prevented by active warming technique LR resuscitation: serum lactate (↑) without an associated acidosis

Summary NS resuscitation:  Requires greater volume & increased urine output  Hyperchloremic metabolic acidosis & coagulopathy LR is superior to NS for the resuscitation of uncontrolled hemorrhagic shock in swine

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