Normal Saline VS Ringer’s Lactate

While saline and lactated Ringer’s solution have a few similarities, they also have differences. This can make the use of one more suitable than the other depending on the situation.

When do we need them?

Intravenous fluid of choice for aggressive fluid resuscitation is isotonic crystalloid solution (eg, normal saline, lactated Ringer solution [LR]), to maintain tissue perfusion and reduce mortality.

Isotonic crystalloid solutions have similar osmolality as that of blood ( –288mOsm/kg H2O), making them effective agent to expand the plasma volume without much altering the osmolality of the plasma.

How Normal Saline and Ringer’s Lactate are different?

Although these agents are equally effective at plasma volume expansion, LR, a balanced fluid, is preferred for resuscitation in burn victims. It contains near-physiologic levels of chloride, potassium, and calcium and includes sodium lactate, a buffer that is hepatically metabolized to bicarbonate, which helps correct acidosis and maintain normal blood pH. ==> This is the reason why LR is preferred fluid for patient with trauma or septic shock (Both have associated Lactic acidosis)

Normal saline is considered an unbalanced fluid because its chloride concentration is supraphysiologic (154 vs 103 mmol/L) and can cause a hyperchloremic metabolic acidosis. It has also been associated with hypocoagulability. (Since this is associated with hypocoagulability, beware of giving this in hemorrhagic fever like Dengue)

Please note that if neurological injury is suspected, Plasmalyte is the preferred fluid.

Fluid Resuscitation

Patients who are in hypovolemic shock require rapid fluid infusions in the form of fluid challenges to maintain intravascular volume.

  1. Rapid infusion of a 500–1000 mL bolus  of normal (isotonic) saline (NS) or lactated Ringer’s solution (RL) within 15 minutes 
  2. Observe the patient for a clinical response
  3. Repeat the fluid bolus infusion if the clinical response is inadequate.
    • An inadequate response to fluid resuscitation is characterized by:
      • Low urine output (< 0.5 mL/kg/hr; best indicator)
      • Increased heart rate
      • Low blood pressure
      • Low CVP (central venous pressure)
  4. If the patient does not respond to multiple fluid challenges:
    • Consider the use of vasopressors and/or inotropes
    • Consider other causes of shock besides hypovolemia (e.g., cardiogenic shock, sepsis).


  1. 1.Kasper DL, Fauci AS, Hauser SL, Longo DL, Lameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. New York, NY: McGraw-Hill Education; 20152.
  2. Procter LD. Intravenous Fluid Resuscitation. Updated: January 1, 2018. Accessed: February 15, 2018.


Apurva Popat

Apurva Popat

Dr Apurva Popat has been teaching Medical science since he was in his medical school and has helped many students to master medical and spiritual knowledge.

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