Abstract
INTRODUCTION: Based on the potential interest in sodium lactate as an energy substrate and resuscitative fluid, we investigated the effects of hypertonic sodium lactate in a porcine endotoxic shock. METHODS: Fifteen anesthetized, mechanically ventilated pigs were challenged with intravenous infusion of E. coli endotoxin. Three groups of five animals were randomly assigned to receive 5 mL/kg/h of different fluids: a treatment group received hypertonic sodium lactate 11.2% (HSL group); an isotonic control group receiving 0.9% NaCl (NC group); a hypertonic control group with the same amount of osmoles and sodium than HSL group receiving hypertonic sodium bicarbonate 8.4% (HSB group). Hemodynamic and oxygenation variables, urine output and fluid balance were measured at baseline and at 30, 60, 120, 210 and 300 min. Skin microvascular blood flow at rest and during reactive hyperemia was obtained using a laser Doppler flowmetry technique. Results were given as median with interquartile ranges. RESULTS: Endotoxin infusion resulted in hypodynamic shock. At 300 min, hemodynamics and oxygenation were significantly enhanced in HSL group: mean arterial pressure (103 [81-120] mmHg vs. 49 [41-62] in NC group vs. 71 [60-78] in HSB group), cardiac index (1.6 [1.2-1.8] L/min/m2 vs. 0.9 [0.5-1.1] in NC group vs. 1.3 [0.9-1.6] in HSB group) and partial pressure of oxygen (366 [308-392] mmHg vs. 166 [130-206] in NC group vs. 277 [189-303] in HSB group). At the same time, microvascular reactivity was significantly better in HSL group with a lower venoarterial CO2 tension difference (5.5 [4-10] mmHg vs. 17 [14-25] in NC group vs. 14 [12-15] in HSB group). The cumulative fluid balance was lower in HSL group (-325 [-655; -150] mL) compared to NC (+560 [+230; +900] mL, p = 0.008) and HSB (+185 [-110; +645] mL, p = 0.03) groups. CONCLUSIONS: In our hypodynamic model of endotoxic shock, infusion of hypertonic sodium lactate improves hemodynamic and microvascular reactivity with a negative fluid balance and a better oxygenation.