What is the immediate treatment for hypovolemia?

Immediate Treatment for Hypovolemia

The immediate treatment for hypovolemia should be rapid fluid resuscitation with isotonic crystalloid solutions, specifically isotonic saline as the first-choice fluid. 1, 2

Initial Assessment and Fluid Resuscitation

Assessment of Severity

• Determine severity of hypovolemia based on clinical signs:
  • Mild/moderate hypovolemia: Tachycardia, decreased urine output
  • Severe hypovolemia: Hypotension, confusion, poor capillary refill
  • Life-threatening: Postural pulse change ≥30 beats per minute or severe postural dizziness resulting in inability to stand 2
  • In cases of fluid and salt loss (vomiting/diarrhea): Look for at least four of these seven signs: confusion, non-fluent speech, extremity weakness, dry mucous membranes, dry tongue, furrowed tongue, sunken eyes 2

Initial Fluid Administration

• Administer isotonic crystalloid solution (0.9% saline) as first-line therapy 2, 1
• Initial bolus:
  • For severe hypovolemia: 20 mL/kg should be given immediately 2
  • For septic shock: At least 30 mL/kg within the first 3 hours 2
• Rate of administration:
  • The rate must exceed the rate of continued fluid losses (urine output + insensible losses + gastrointestinal losses) 2
  • Continue rapid infusion until clinical signs of hypovolemia improve 2

Monitoring Response and Ongoing Management

Clinical Endpoints

• Monitor for:
  • Improvement in blood pressure (target MAP ≥65 mmHg) 2
  • Decrease in heart rate
  • Improved capillary refill
  • Urine output >0.5 mL/kg/h 2
  • Adequate central venous pressure 2
  • Decreased serum lactate

Fluid Challenge Technique

• Continue fluid administration as long as there is hemodynamic improvement based on dynamic variables (pulse pressure, stroke volume variation) or static variables (arterial pressure, heart rate) 2
• Reassess after each bolus to determine need for additional fluid

Vasopressors and Advanced Management

When to Add Vasopressors

• If fluid resuscitation fails to restore adequate blood pressure and tissue perfusion, vasopressor therapy should be initiated 2
• Important caveat: Norepinephrine should NOT be given to patients who are hypotensive from blood volume deficits except as an emergency measure to maintain coronary and cerebral artery perfusion until blood volume replacement therapy can be completed 3

Vasopressor Administration

• Target MAP of 65 mmHg 2
• Norepinephrine is the preferred agent:
  • Initial dose: 8-12 mcg/minute
  • Maintenance dose: 2-4 mcg/minute 3
  • In previously hypertensive patients, target blood pressure no higher than 40 mmHg below preexisting systolic pressure 3

Special Considerations

Colloids vs. Crystalloids

• Crystalloids are significantly more cost-effective than colloids (1.5 Euro/L vs. 140 Euro/L for albumin) 1
• No evidence that synthetic colloids are superior to crystalloid solutions 2
• Albumin may be considered in specific cases but should not be first-line therapy 2

Hypertonic Solutions

• Not recommended for routine use as they have not been shown to improve survival or neurological outcomes 2

Pitfalls to Avoid

• Do not delay fluid resuscitation in severe hypovolemia
• Avoid administering vasopressors before adequate volume replacement 3
• Do not use diuretics in hypovolemic patients as they could increase hypovolemia and promote thrombosis 2
• In patients with neutropenic enterocolitis, avoid anticholinergic, antidiarrheal, and opioid agents as they may aggravate ileus 2
• Avoid peripherally inserted catheters in children with congenital nephrotic syndrome to preserve vessels for potential future dialysis access 2

By following this structured approach to the immediate treatment of hypovolemia, focusing on prompt isotonic crystalloid administration with careful monitoring of response, clinicians can effectively restore intravascular volume and improve patient outcomes.