What is the recommended approach for IV fluid resuscitation in a patient with hypovolemic shock?

IV Fluid Resuscitation in Hypovolemic Shock

Immediately administer 20 mL/kg boluses of isotonic crystalloid (normal saline or lactated Ringer's solution) rapidly over 5-10 minutes in children, or 500-1000 mL boluses over 15-30 minutes in adults, with repeat dosing up to 60 mL/kg in the first hour for children and 30 mL/kg within 3 hours for adults. 1

Initial Fluid Selection and Bolus Strategy

• Crystalloids are the fluid of choice for initial resuscitation, with isotonic saline (0.9% sodium chloride) or lactated Ringer's solution as first-line therapy 2, 1
• Balanced crystalloids are generally preferred over normal saline to reduce the risk of hyperchloremic metabolic acidosis, though isotonic saline remains acceptable 2
• Establish IV or intraosseous (IO) access immediately, using IO if IV cannot be rapidly obtained 1

Specific Dosing by Age Group

Adults:

• Initial bolus: 500-1000 mL over 15-30 minutes 1
• Target minimum: 30 mL/kg within the first 3 hours 1
• May repeat boluses if perfusion does not normalize 1

Children:

• Initial bolus: 20 mL/kg over 5-10 minutes 1
• May repeat up to 60 mL/kg in the first hour if perfusion does not normalize 1
• Maximum total volume: up to 200 mL/kg if signs of fluid overload are absent 1

Reassessment After Each Bolus

Reassess immediately after each fluid bolus to determine need for additional fluid versus transition to vasopressors 2, 1. Evaluate the following parameters:

• Capillary refill time (target ≤2 seconds) 1
• Heart rate (normal for age) 1
• Blood pressure (MAP ≥65 mmHg in adults, normal for age in children) 1
• Extremity temperature and pulse quality (warm extremities with strong peripheral pulses equal to central pulses) 1
• Mental status (normal alertness) 1
• Urine output (target >1 mL/kg/hour in children or >0.5 mL/kg/hour in adults) 2, 1
• Serum lactate levels (aim for 20% reduction if elevated) 2

Critical Stopping Points for Fluid Administration

Stop or slow fluid administration immediately if any signs of fluid overload develop: 1

• Hepatomegaly 1
• Pulmonary rales/crackles 1
• Gallop rhythm on cardiac auscultation 1
• Increased work of breathing 1
• Decreased oxygen saturation 1
• Increased jugular venous pressure in adults 1

Vasopressor Initiation

Initiate norepinephrine if shock persists after 40-60 mL/kg in children or 30 mL/kg in adults, targeting MAP of 65 mmHg 1, 3. This is a critical decision point—do not delay vasopressor initiation beyond these fluid volumes in fluid-refractory shock 1.

• Norepinephrine is the first-line vasopressor 1, 3
• Epinephrine serves as an alternative when necessary 1

Role of Colloids

While crystalloids remain first-line, colloids may have a limited role in specific circumstances:

• Albumin 25% (hyperoncotic) may offer therapeutic advantages in oncotic deficits or long-standing shock where treatment has been delayed, but additional crystalloids must be given if the patient is dehydrated 4
• Albumin expands plasma volume by 3-4 times the volume administered by withdrawing fluid from interstitial spaces 4
• Avoid hydroxyethyl starches due to increased risk of acute kidney injury and mortality 2
• Evidence does not show colloids are superior to crystalloids for mortality outcomes, and colloids are significantly more expensive 2

Special Considerations by Etiology

Traumatic Brain Injury:

• Use isotonic saline exclusively, avoiding hypotonic solutions 1
• Maintain adequate systolic blood pressure for age 1

Burns:

• Give 20 mL/kg within the first hour for adults with ≥15% TBSA or children with ≥10% TBSA 1
• Use balanced crystalloids (Ringer's Lactate) as first-line treatment 1

Hemorrhagic Shock:

• Blood products should be administered separately from crystalloids 3
• Use vasopressors cautiously 3

Critical Pitfalls to Avoid

• Do not use hypotonic fluids for shock resuscitation in any age group 1
• Do not rely solely on blood pressure to guide therapy—assess comprehensive perfusion parameters including capillary refill, mental status, and urine output 1
• Do not continue aggressive fluid without reassessment for overload after each bolus 1
• Do not delay vasopressor initiation in fluid-refractory shock beyond 40-60 mL/kg in children or 30 mL/kg in adults 1
• Do not use etomidate for intubation in pediatric patients with septic shock due to associated higher mortality 1

Dynamic Assessment Over Static Measures

• Use dynamic measures of fluid responsiveness (such as pulse pressure variation, stroke volume variation) rather than static measures like CVP alone when available 2
• Frequent reassessment should include thorough clinical examination and evaluation of all available physiologic variables 5