Lactated Ringer's Solution vs .9% Normal Saline
In Memory of Hotmuzz ~ 6-year survivor!

Saline has been used since the advent of modern surgery and trauma medicine because it can be used to quickly restore circulating volume in acute situations such as shock, massive blood loss or during surgery. Since many (if not most) vets are more accustomed to treating trauma victims than chronic diseases they may reach for saline out of habit whenever an IV solution is needed, but for ongoing fluid maintenance therapy a balanced electrolyte solution is essential.

Recent clinical studies in human medicine are beginning to recognize that solutions such as Lactated Ringer's (LRS) are safer and more effective in many of the uses for which saline has always been standard, but it can take time for new knowledge to trickle down into mainstream practice.

Regardless, there are compelling reasons that 0.9% saline should never under any circumstances be used for fluid maintenance of a crf kitty!

  • Saline does not hydrate tissues, in fact it can draw water out of the interstitial space that feeds the cells!
  • Expansion of circulating volume is very likely to increase blood pressure.
  • Lacking potassium, saline tends to disturb electrolyte balance.
  • Saline is unbuffered and its relatively higher chloride concentration can induce metabolic acidosis.
    • Reference Links

    Complete information about LRS. Addresses common misconceptions and explains electrolyte effects such as the tendency to normalize potassium derangements:

    NCBI: Ringer's Lactate

    Recent reviews explaining a trend away from the use of saline in human ER's and ICU's:

  • Balanced Fluids Safer than Saline
  • Data Suggests Lactated Ringer's is Better than Normal Saline

    • The association of saline with hyperchloremic acidosis and hyperkalemia in transplant surgery:

  • Ringer's lactate solution vs normal saline during renal transplantation
  • Randomized double-blind comparison study

    • Coco had a severe mitral valve defect but did quite nicely with stable renal values even on high volumes of LRS (200-250 ml/day for 2 years). It was only after a misguided (though vet-approved) switch to saline to counter a perceived upward trend in serum calcium that she developed the congestive heart failure which led to her death within 3 months.

    Aurora's Hotmuzz at five years old had only relatively mild renal impairment but a vet decided to switch him from LRS to saline because serum potassium levels were almost at the top of norms. Over the following months metabolic acidosis developed as evidenced both by lab tests and clinical signs. After switching Hotmuzz back to Lactated Ringer's he stabilized and enjoyed the love of his family for another five years.