Although the latest guidelines recommend crystalloids as the first choice for the patients' fluid resuscitation, it still remains controversial that which crystalloid solution is the best choice. It is reported that balanced crystalloid can result in better outcomes than saline for critically ill patients. However, there are few studies conducted between different crystalloid solutions.~Lactated ringer's solution is the longest-used crystalloid solution. Compared with lactated ringer's solution whose anion is lactate, the anion of bicarbonate ringer's solution is bicarbonate. And lactate needs to be metabolized into bicarbonate through the mitochondria of the liver before it can play an alkalization role. Therefore, in theory, bicarbonate ringer's solution does not need to rely on liver metabolism, the onset time to maintain acid-base balance is shorter, and it may be more suitable for patients with severe acidosis. In patients with septic shock, the incidence of moderate to severe metabolic is increased. Bicarbonate ringer's solution can directly supplement the concentration of bicarbonate, while lactated ringer's solution needs to take time and be metabolized in the liver. Thus, we hypothesize that bicarbonate ringer's solution is more effective for patients with shock and metabolic acidosis than lactated ringer's solution.
In this prospective randomized controlled trial, investigators aim to study the effects and safety of bicarbonated Ringer's solution in patients with septic shock compared with lactated ringer's solution, and provide evidence for current fluid resuscitation strategies for septic shock.