What is the recommended approach for intravenous (IV) rescue hydration?

IV Rescue Hydration: Evidence-Based Approach

For IV rescue hydration in critically ill patients, balanced crystalloid solutions are recommended over 0.9% NaCl as first-line fluid therapy to reduce mortality and adverse renal events, particularly when large volumes are required. 1

Choice of Fluid

• Balanced crystalloid solutions (such as Ringer's Lactate or Plasmalyte) are preferred over 0.9% NaCl, especially when high volumes are needed, as they are associated with better acid-base balance and potentially lower mortality 1
• Isotonic crystalloids are the recommended fluid type for resuscitation in most clinical scenarios 2, 3
• Hypertonic saline solutions (3% or 7.5%) are not recommended as first-line treatment for rescue hydration as they show no mortality benefit 1
• Synthetic colloids are not recommended due to increased risk of renal failure and haemostasis disorders 1
• Albumin is generally not recommended for routine rescue hydration due to higher cost without demonstrated benefit over crystalloids 1

Fluid Administration Rate

• Non-aggressive fluid resuscitation at a rate of 1.5 ml/kg/hr following an initial bolus of 10 ml/kg (if hypovolemic) is recommended, resulting in lower mortality and fewer fluid-related complications 2
• For sepsis-induced hypoperfusion, at least 30 ml/kg of IV crystalloid fluid should be given within the first 3 hours 1
• Goal-directed therapy with frequent reassessment of hemodynamic status to guide additional fluid administration is essential to prevent fluid overload 1, 2
• Dynamic variables (such as pulse pressure variation, stroke volume variation) should be used over static variables (like central venous pressure) to predict fluid responsiveness where available 1

Monitoring Response

• Reassessment should include thorough clinical examination and evaluation of physiologic variables (heart rate, blood pressure, arterial oxygen saturation, respiratory rate, temperature, urine output) 1, 2
• Laboratory markers including hematocrit, blood urea nitrogen, creatinine, and lactate levels should be monitored as indicators of adequate tissue perfusion 2
• An initial target mean arterial pressure of 65 mmHg is recommended in patients requiring vasopressors 1
• Normalization of lactate levels should be a resuscitation goal in patients with elevated lactate as a marker of tissue hypoperfusion 1

Special Considerations

• In patients with traumatic brain injury and focal neurological signs, a bolus of hypertonic saline may be beneficial due to its osmotic effect, despite not being recommended for routine use 1
• In patients with cirrhosis, albumin may be preferred over crystalloids 3
• Total crystalloid fluid administration should generally be less than 4000 ml in the first 24 hours to avoid fluid overload 2, 4
• Restrictive fluid therapy prevents complications seen with liberal, large-volume therapy, even though restrictive fluid loading may not demonstrate large hemodynamic effects in surgical or septic patients 5

Common Pitfalls

• Avoid fluid overload, which is associated with worse outcomes and increased mortality 2, 4
• Do not rely solely on central venous pressure to guide fluid administration, as it is an unreliable parameter of volume status or fluid responsiveness 4
• Avoid waiting for hemodynamic worsening before initiating fluid resuscitation 2
• Consider patient-specific factors such as age, weight, and pre-existing renal and/or cardiac conditions when determining fluid volume 2
• Monitor for electrolyte disorders, particularly hypokalemia, which can occur with certain IV fluid choices 6