What are the pH and sodium content of Lactated Ringer's (Lactated Ringer's solution) versus Plasma-Lyte (multiple electrolyte solution) intravenous (IV) fluids?

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Last updated: May 10, 2025View editorial policy

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From the Guidelines

Lactated Ringer's solution has a pH of approximately 6-7.5 and contains about 130 mmol/L of sodium, while Plasmalyte has a pH of approximately 6-8 and contains about 140 mmol/L of sodium, as shown in a recent study published in the BMJ in 2020 1. The differences in pH and sodium content between these two crystalloid IV fluids are crucial when choosing the most appropriate fluid for various patient conditions.

  • The pH of Lactated Ringer's solution is slightly acidic due to its lactate content, which the body metabolizes to bicarbonate, helping correct metabolic acidosis.
  • Plasmalyte's pH is closer to physiologic blood pH, making it potentially more suitable for patients with acid-base disturbances.
  • The sodium content in both fluids approximates normal plasma levels (135-145 mmol/L), with Plasmalyte being slightly higher and closer to normal physiologic range. When selecting between these fluids, consider the patient's acid-base status, electrolyte needs, and clinical condition, as recommended by recent guidelines 1.
  • Lactated Ringer's may be preferred in patients with hyperkalemia due to its lower potassium content.
  • Plasmalyte might be better for patients with metabolic acidosis who cannot tolerate additional lactate load, as its composition is closer to normal plasma levels and has a more neutral pH.

From the Research

Comparison of Lactated Ringer's and Plasmalyte IV Fluids

  • Lactated Ringer's solution has a pH of approximately 6.5 2
  • The sodium content of Lactated Ringer's solution is not explicitly stated in the provided studies, but it is known to contain 130 mEq/L of sodium
  • Plasmalyte IV fluid is not directly mentioned in the provided studies, but it is known to have a pH of approximately 7.4 and a sodium content of 140 mEq/L
  • A study comparing Ringer's lactate with a pH of 6.5 and 7.4 found no significant differences in resuscitation outcomes 2
  • The use of IV fluids with different pH and sodium content can have varying effects on acid-base balance and electrolyte status, with potential implications for patient outcomes 3, 4, 5, 6
  • Lactated Ringer's solution can cause a metabolic acidosis with hyperchloremia, whereas Plasmalyte IV fluid may have a more neutral effect on acid-base balance 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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