What is a normal lactated Ringer (LR) rate post-operatively?

Normal Post-Operative Lactated Ringer's Rate

For post-operative patients, the normal lactated Ringer's solution rate should be 1.5-3 mL/kg/hour, with intravenous fluids ideally discontinued by postoperative day 1 unless specific indications exist for continued fluid therapy. 1

Initial Post-Operative Fluid Management

• Postoperatively, intravenous fluids should be discontinued at the latest during day 1, with patients encouraged to drink when fully recovered and offered an oral diet within 4 hours after abdominal/pelvic surgery 1
• If intravenous fluids need to be continued postoperatively, a hypotonic crystalloid with 70-100 mmol/day of sodium and up to 1 mmol/kg/day of potassium should be used 1
• Any ongoing losses (diarrhea, vomiting) need to be replaced with a balanced solution such as lactated Ringer's as required, whereas 0.9% saline solutions should be avoided 1

Specific Fluid Rate Recommendations

• For non-aggressive fluid management post-operatively, lactated Ringer's solution should be administered at a rate lower than 10 mL/kg/hour 1
• More specifically, a rate of 1.5 mL/kg/hour in the first 24 hours is considered appropriate for non-aggressive fluid management 1
• For patients requiring continued fluid therapy, the standard rate for lactated Ringer's solution is approximately 1.5-3 mL/kg/hour 1

Special Considerations

• For patients with significant fluid losses or hemodynamic instability, higher rates may be temporarily required, with up to 5-10 mL/kg in the first 5 minutes for adults with significant volume depletion 1
• Patients with congestive heart failure or chronic renal disease should receive more cautious fluid administration to prevent volume overload 1
• Oliguria should not automatically trigger increased fluid therapy as low urine output is a normal physiological response during surgery and anesthesia 1

Monitoring and Adjustment

• Fluid balance should aim for "near zero" to avoid both over and under hydration, which can cause complications 1
• The goal of intravenous fluids is to maintain intravascular volume to ensure adequate tissue and organ perfusion and avoid electrolyte imbalances 1
• For patients with borderline hypotension, perform a passive leg raise test to assess fluid responsiveness before administering additional fluids 2

Pitfalls to Avoid

• Do not automatically treat hypotension with fluid boluses without assessing fluid responsiveness, as approximately 50% of hypotensive postoperative patients are not fluid responsive 2
• Avoid 0.9% saline due to the risk of salt and fluid overload and potential metabolic acidosis 1
• Do not continue intravenous fluids unnecessarily beyond postoperative day 1, as this contradicts enhanced recovery principles 1