Volume replacement with Ringer-lactate is detrimental in severe hemorrhagic shock but protective in moderate hemorrhagic shock : studies in a rat model
Introduction: To date, there are insufficient data demonstrating the benefits of preclinically administered Ringer-lactate (RL) for the treatment of hemorrhagic shock following trauma. Recent animal experiments have shown that lactate tends to have toxic effects in severe hemorrhagic shock. This study aimed to compare the effects of RL administered in a rat model of severe hemorrhagic shock (mean arterial blood pressure (MAP): 25 to 30 mmHg) and moderate hemorrhagic shock (MAP: 40 to 45 mmHg). Methods: Four experimental groups of eight male Wistar rats each (moderate shock with Ringer-saline (RS), moderate shock with RL, severe shock with RS, severe shock with RL) were established. After achieving the specified depth of shock, animals were maintained under the shock conditions for 60 minutes. Subsequently, reperfusion with RS or RL was performed for 30 minutes, and the animals were observed for an additional 150 minutes. Results: All animals with moderate shock that received RL survived the entire study period, while six animals with moderate shock that received RS died before the end of the experiment. Furthermore, animals with moderate shock that received RL exhibited considerable improvements in their acid-base parameters and reduced organ damage. In contrast, in animals with severe shock, only two of the animals receiving RS survived but all of the animals receiving RL died early, before the end of the study period. Moreover, the severe shock animals that were treated with RL exhibited considerably worsened acid-base and metabolic parameters. Conclusions: The preclinical use of RL for volume replacement has different effects depending on the severity of hemorrhagic shock. RL exhibits detrimental effects in cases of severe shock, whereas it has pronounced protective effects in cases of moderate shock.