What is the preferred fluid for resuscitation in a patient with acute kidney injury (AKI) due to urologic sepsis in the prehospital setting, normal saline (NS) or Hartmann's solution?

Hartmann's Solution (Balanced Crystalloid) Over Normal Saline for Urologic Sepsis with AKI in the Prehospital Setting

Use Hartmann's solution (or another balanced crystalloid like lactated Ringer's) rather than normal saline for initial fluid resuscitation in urologic sepsis with AKI, even in the prehospital setting. 1

Primary Recommendation

• Balanced crystalloids (Hartmann's solution/lactated Ringer's) should be preferred over normal saline to reduce the risk of hyperchloremic metabolic acidosis and further kidney injury, which is particularly critical when AKI is already present 1, 2
• Administer at least 30 mL/kg of balanced crystalloid within the first 3 hours of sepsis recognition, beginning immediately in the prehospital setting 1, 3

Why Hartmann's Over Normal Saline

Evidence Against Normal Saline in AKI

• Normal saline causes hyperchloremic metabolic acidosis and is associated with increased risk of acute kidney injury progression 4, 5
• In patients with pre-existing AKI from urologic sepsis, normal saline can worsen renal function through chloride-mediated renal vasoconstriction and tubular injury 5, 6
• Large volume normal saline resuscitation induces abnormal fluid, electrolyte, and acid-base disturbances that complicate the clinical course 4

Evidence Supporting Balanced Crystalloids

• Balanced crystalloids demonstrate better outcomes including decreased mortality and improved acid-base status in septic patients 7, 5
• Hartmann's solution improves pH, bicarbonate levels, and lactate clearance compared to normal saline in septic patients with metabolic acidosis 8
• The 6S Trial showed that even Ringer's acetate (a balanced solution) had lower mortality compared to other resuscitation fluids in septic patients 4

Practical Implementation in Prehospital Setting

Initial Fluid Bolus

• Begin with 30 mL/kg of Hartmann's solution (approximately 2-3 liters for average adult) as rapidly as possible 1, 3
• Continue fluid administration as long as hemodynamic parameters improve (blood pressure, heart rate, mental status, peripheral perfusion) 1

Monitoring During Transport

• Reassess after each 500-1000 mL bolus for signs of improvement or fluid overload 2
• Stop fluid administration if: no improvement in tissue perfusion occurs, signs of fluid overload develop (crackles, increased work of breathing), or hemodynamic parameters stabilize 2

Special Considerations for AKI

• Patients with AKI have impaired ability to excrete excess fluid, making balanced crystalloids even more important to avoid additional metabolic derangements 2
• Earlier consideration for vasopressor support (norepinephrine) may be warranted if hypotension persists despite initial fluid bolus, to maintain perfusion while limiting excessive fluid administration 2, 3

What to Avoid

• Do not use hydroxyethyl starches - they increase mortality and worsen acute kidney injury, particularly dangerous in patients with pre-existing AKI 4, 3, 6
• Do not delay resuscitation due to concerns about worsening kidney function - delayed resuscitation increases mortality more than the risks of fluid administration 1
• Do not use low-dose dopamine for "renal protection" - it is completely ineffective 4, 1

Common Pitfall

The most critical error is using normal saline "because it's available" in the prehospital setting. Hartmann's solution should be stocked in prehospital units specifically for sepsis cases, as the chloride load from normal saline can directly worsen kidney injury through renal vasoconstriction and tubular damage 5, 6. In urologic sepsis with existing AKI, this harm is magnified and potentially irreversible.