3% NaCl adenosine, lidocaine, Mg2+ (ALM) bolus and 4 hours "drip" infusion reduces noncompressible hemorrhage by 60% in a rat model.

Abstract

Noncompressible torso hemorrhage is the leading cause of potentially survivable trauma in far-forward combat environments. Our aim was to examine the effect of small-volume 3% NaCl adenosine, lidocaine, and Mg (ALM) bolus and 0.9% NaCl/ALM "drip" on survivability and cardiac/gut/kidney function in a rat model of hepatic hemorrhage and shock. Male Sprague-Dawley rats (428 ± 4 g) were anesthetized and randomly assigned to one of five groups (n = 16): (1) Sham, (2) No treatment, (3) Saline controls, (4) ALM therapy, and (5) Hextend. Animals were ventilated, instrumented with single or double laparotomy for tissue probe insertion, and hemorrhage induced by liver resection. After 15 minutes, a single 3% NaCl ± ALM bolus (0.7 ml/kg) was injected IV (phase 1) and after 60 minutes, 4 hours 0.9% NaCl ± ALM stabilization "drip" (0.5 ml/kg/h) was administered (phase 2), with 1-hour monitoring. Mortality for Shams (no resection) was 0% (25%); No treatment, 87.5% (100%); Saline controls, 37.5% (75%); ALM therapy, 0% (25%), and Hextend, 87.5% (100%) (double laparotomy in parentheses). Hextend-treated animals died during the first 20 minutes of phase 2. A single ALM bolus during phase 1 led to a 2.4-fold higher cardiac output and improved hemodynamics. 3% NaCl ALM bolus increased tissue pO2 and flow in gut and kidney during phase 1 and, during ALM "drip" in phase 2, tissue pO2 decreased but flow continued to rise, indicating increased tissue O2 extraction and delivery. During phase 2, CO, ejection fraction, and fractional shortening decreased and were erratic in all groups except ALM treatment. ALM therapy led to up to 60% less bleeding over 6 hours compared to Saline controls and 75% less bleeding than Hextend. Small-volume ALM therapy significantly reduced mortality and internal bleeding compared to Saline controls or Hextend-treated rats. Hextend increased mortality, severe bleeding, and microvascular-organ injury.