How to manage sepsis-induced low urine output?

Management of Sepsis-Induced Low Urine Output

Initial fluid resuscitation with 30 mL/kg of crystalloid within the first 3 hours is the cornerstone of managing sepsis-induced low urine output, followed by dynamic assessment of fluid responsiveness and vasopressor therapy if needed. 1

Initial Assessment and Fluid Resuscitation

• Definition of low urine output in sepsis: Acute oliguria defined as urine output ≤0.5 mL/kg/h or ≤45 mL/h for at least 2 hours despite adequate fluid resuscitation 1

• First-line intervention:

  • Administer at least 30 mL/kg of crystalloid within the first 3 hours 1
  • Balanced/buffered crystalloids are preferred over normal saline 2
  • Many patients will require more fluid; further fluid should be given according to functional hemodynamic measurements 1

• Monitoring response to fluid resuscitation:

  • A positive response can be considered as:
    • ≥10% increase of systolic/mean arterial blood pressure
    • ≥10% reduction of heart rate
    • Improvement of mental state, peripheral perfusion and/or urine output 1

Dynamic Assessment of Fluid Responsiveness

• Static measures like CVP alone are no longer recommended to guide fluid resuscitation 1

• Dynamic measures to assess fluid responsiveness are preferred:

  • Passive leg raises
  • Fluid challenges against stroke volume measurements
  • Variations in systolic pressure, pulse pressure, or stroke volume in response to mechanical ventilation 1
  • These techniques have better diagnostic accuracy (sensitivity 0.72, specificity 0.91) in predicting patients who will respond to fluid challenge 1

Mean Arterial Pressure (MAP) Targets

• Target MAP ≥65 mmHg as the driving pressure for tissue perfusion 1, 2
• Below this threshold, tissue perfusion becomes linearly dependent on arterial pressure 1

Vasopressor Therapy

• Initiate vasopressors if fluid resuscitation fails to restore adequate MAP and urine output
• Norepinephrine is the first-choice vasopressor 2
• Epinephrine can be considered as a second agent when needed 2
• Vasopressin (0.03 U/min) can be added to norepinephrine, but not as the initial vasopressor 2

Ongoing Reassessment

• Re-evaluate patients every 30 minutes to 1 hour initially 2
• Continue monitoring urine output as a key indicator of tissue perfusion and kidney function
• Repeat lactate measurement within 6 hours if initially elevated 2

Special Considerations for Diuretics

• Furosemide should not be used as first-line therapy for sepsis-induced low urine output
• Consider diuretics only after adequate fluid resuscitation and hemodynamic stabilization
• Monitor for adverse effects including dehydration, blood volume reduction, hypotension, and electrolyte imbalances 3

Cautions and Pitfalls

• Avoid fluid overload: Development of crepitations indicates fluid overload or impaired cardiac function 1
• Stop fluid resuscitation when no improvement of tissue perfusion occurs in response to volume loading 1
• Consider patient-specific factors: Some patients may require several liters of fluids during the first 24-48 hours 1
• Monitor for complications: Aggressive fluid resuscitation can lead to respiratory impairment 1

Algorithm for Managing Sepsis-Induced Low Urine Output

1. Initial resuscitation: 30 mL/kg crystalloid within first 3 hours
2. Assess response: Monitor urine output, MAP, heart rate, mental status, peripheral perfusion
3. If inadequate response:
   • Perform dynamic assessment of fluid responsiveness
   • If fluid responsive: Give additional fluid boluses
   • If not fluid responsive: Start vasopressors (norepinephrine first)
4. Target MAP ≥65 mmHg
5. Continuous monitoring: Reassess every 30-60 minutes initially
6. If persistent oliguria despite above measures:
   • Consider additional hemodynamic monitoring
   • Evaluate for other causes of acute kidney injury
   • Consider renal replacement therapy if indicated

By following this evidence-based approach, you can effectively manage sepsis-induced low urine output while minimizing the risks of both under-resuscitation and fluid overload.