What are the principles of fluid stewardship in clinical practice?

Principles of Fluid Stewardship in Clinical Practice

Fluid stewardship requires dynamic assessment of fluid responsiveness rather than static measurements, with initial fluid resuscitation of 30 mL/kg crystalloid in sepsis followed by ongoing reassessment using functional hemodynamic measurements to guide further therapy. 1

Core Principles of Fluid Stewardship

1. Initial Assessment and Ongoing Reevaluation

• Thorough clinical examination and evaluation of physiologic variables (heart rate, blood pressure, arterial oxygen saturation, respiratory rate, temperature, urine output) 1
• Echocardiography for detailed assessment of hemodynamic issues 1
• Regular reassessment of response to treatment is critical for appropriate fluid management 1

2. Dynamic vs. Static Measurements

• The use of central venous pressure (CVP) alone to guide fluid resuscitation is no longer justified 1
• Dynamic measures show better diagnostic accuracy for predicting fluid responsiveness:
  • Passive leg raises
  • Fluid challenges with stroke volume measurements
  • Variations in systolic pressure, pulse pressure, or stroke volume in response to changes in intrathoracic pressure during mechanical ventilation 1
• Pulse pressure variation has demonstrated sensitivity of 0.72 and specificity of 0.91 for predicting fluid responsiveness 1

3. Fluid Selection and Administration

• Initial fluid resuscitation in sepsis begins with 30 mL/kg of crystalloid within first 3 hours 1
• Balanced crystalloids (e.g., lactated Ringer's) are preferred over 0.9% saline due to fewer biochemical abnormalities and adverse clinical outcomes 1
• Further fluid administration should be guided by functional hemodynamic measurements 1
• Consider context-specific approaches:
  • Goal-directed protocols may benefit perioperative patients but have shown no benefit in early septic shock 1

4. Timing and Context-Specific Considerations

• Fluid administration should be guided by hemodynamic assessment for specific indications and contraindications 1
• Consider clinical context and history, including timing of the insult 1
• Balance indications for fluid administration against conditions requiring caution 1
• Earlier use of vasoactive medications may be appropriate for some patients with hypotension rather than excessive fluid administration 1

5. Monitoring and Targets

• Target mean arterial pressure (MAP) of 65 mmHg in septic shock requiring vasopressors 1
• Consider normalizing lactate in patients with elevated levels as a marker of tissue hypoperfusion 1
• Regular monitoring of electrolytes, especially sodium, is essential 2

Special Considerations

Terminology and Classification

• Avoid classifying AKI as "pre-renal," "renal," and "post-renal" as these terms can be unhelpful 1
• The term "pre-renal" is often misinterpreted as "hypovolemic" and may encourage indiscriminate fluid administration 1
• Instead, distinguish between conditions that:
  • Reduce glomerular function
  • Result in injury of tubules and/or glomeruli
  • Do both 1

Pediatric Fluid Management

• Use isotonic balanced solutions with appropriate dextrose and potassium for maintenance IV fluids in children 2
• Calculate maintenance fluids using the Holliday-Segar formula:
  • First 10 kg: 100 ml/kg/day
  • Second 10 kg: 50 ml/kg/day
  • Each additional kg: 25 ml/kg/day 2
• Restrict maintenance fluid volume to 65-80% in acutely ill children at risk of increased ADH secretion 2
• Restrict to 50-60% in children with edematous states (heart failure, renal failure, hepatic failure) 2

Common Pitfalls to Avoid

• Relying solely on static measurements like CVP to guide fluid therapy 1
• Failing to reassess fluid status regularly after initial resuscitation 1
• Indiscriminate fluid administration without considering potential harms 1
• Not considering "fluid creep" from all sources of fluid intake, including IV medications and line flushes 2
• Using lactate buffer solutions in patients with liver dysfunction 2
• Administering free water intravenously without caution, increasing risk of hyponatremia 2

By following these principles of fluid stewardship, clinicians can optimize fluid management to improve patient outcomes while minimizing complications associated with inappropriate fluid administration.