From the Guidelines
Lactated Ringer's (LR) is generally preferred over Normal Saline for most fluid resuscitation scenarios, particularly in large volume resuscitation, due to its balanced electrolyte composition and lower risk of hyperchloremic metabolic acidosis and acute kidney injury (AKI) 1. When deciding between Normal Saline and Lactated Ringer's, several factors should be considered:
- Normal Saline is preferred for patients with hyperkalemia, severe metabolic alkalosis, or those receiving blood transfusions, as lactated Ringer's contains potassium and can convert to bicarbonate.
- Normal Saline is also the better choice for patients with traumatic brain injury or at risk for cerebral edema, as it has a slightly higher osmolarity.
- Lactated Ringer's is especially beneficial in patients with metabolic acidosis (including diabetic ketoacidosis after initial resuscitation), hypovolemic shock, trauma, burns, and pancreatitis. The reason LR is often superior is that normal saline can cause hyperchloremic metabolic acidosis when given in large volumes due to its high chloride content (154 mEq/L compared to plasma's 95-105 mEq/L) 1. Key points to consider when choosing between Normal Saline and Lactated Ringer's include:
- The risk of hyperchloremic metabolic acidosis and AKI associated with Normal Saline, particularly in large volume resuscitation 1.
- The balanced electrolyte composition of Lactated Ringer's, which more closely resembles human plasma.
- The potential benefits of Lactated Ringer's in patients with metabolic acidosis, hypovolemic shock, trauma, burns, and pancreatitis.
From the Research
Normal Saline vs Lactated Ringer's
- Normal saline is often associated with the development of hyperchloremic metabolic acidosis and renal vasoconstriction 2
- Lactated Ringer's is proposed as the infusate of choice, but should not be given in patients with severe metabolic alkalosis, lactic acidosis with decreased lactate clearance, or severe hyperkalemia, and in patients with traumatic brain injury or at risk of increased intracranial pressure 2
Specific Situations
- In diabetic ketoacidosis (DKA), balanced fluids (such as Lactated Ringer's) may be preferred over normal saline for initial fluid resuscitation, as they can reduce the risk of hyperchloremic metabolic acidosis and improve clinical outcomes 3, 4
- In patients with DKA, large-volume resuscitation with normal saline is associated with prolonged ICU length of stay, increased time on insulin infusion, and higher rates of non-anion gap metabolic acidosis 4
- In patients with severe metabolic acidosis, sodium bicarbonate administration should be individualized, and considered in patients with moderately severe acidemia (pH<7.20 and plasma bicarbonate level < 12mmol/L) who are at risk for worsening acidemia, particularly if hemodynamically unstable 5, 6
Guidance for Clinicians
- The optimal choice of infusate should be guided by the cause of hypovolemia, the cardiovascular state of the patient, the renal function, as well as the serum osmolality and the coexisting acid-base and electrolyte disorders 2
- Clinicians should be aware of any coexisting disorders in patients with hypovolemia and guide their choice of infusate treatment based on the overall picture of their patients 2