IV Fluid Resuscitation: Volume and Timing
Adults with Hypotension/Shock
For hypotensive adults, administer 500 mL of isotonic crystalloid (0.9% saline or lactated Ringer's) over 15 minutes or less, and repeat boluses based on hemodynamic response, with most patients requiring 30 mL/kg (approximately 2-3 liters) within the first 3 hours. 1
Initial Bolus Strategy
- Volume per bolus: 250-500 mL is the standard range, with 500 mL being most commonly used 1, 2, 3
- Infusion time: Administer each bolus over less than 15 minutes (infusion rate of 25-33 mL/min) 1, 3
- Fluid type: Use isotonic crystalloids (0.9% saline or lactated Ringer's) as first-line therapy 1, 4
Repeat Dosing Protocol
- Reassess after each bolus for hemodynamic improvement: increased blood pressure (≥10 mmHg rise in systolic/MAP), decreased heart rate, improved peripheral perfusion, capillary refill <2 seconds, improved mental status, and urine output >0.5 mL/kg/h 1, 5
- Repeat 500 mL boluses every 15-30 minutes if the patient remains hypotensive and shows signs of fluid responsiveness 1, 3
- Total volume in first hour: Most septic patients require 30 mL/kg (approximately 2-3 liters for a 70 kg adult) within the first 3 hours, though some may need significantly more 1
Defining Fluid Responsiveness
- A positive response is typically defined as a cardiac output/cardiac index increase ≥15% after a fluid bolus 1, 2, 3
- Continue fluid boluses only if the patient demonstrates ongoing fluid responsiveness 1
Critical Stopping Points
Stop fluid administration immediately if any of these develop: 1
- Pulmonary rales/crackles
- New or worsening hepatomegaly
- Jugular venous distension
- Increased work of breathing
- Worsening oxygenation
- Gallop rhythm on cardiac exam
When these signs appear, initiate vasopressor support rather than continuing fluids 1
Maintenance After Resuscitation
- Once hemodynamically stable, transition to maintenance crystalloid at 5-10 mL/kg/h if ongoing fluid needs exist 1
- Monitor closely for signs of fluid overload (increased JVP, crackles, peripheral edema) 1
Pediatric Patients with Hypotension/Shock
For hypotensive children, administer 20 mL/kg of isotonic crystalloid as a rapid bolus over 5-10 minutes, and repeat up to 60 mL/kg in the first hour with mandatory reassessment after each bolus. 1, 5
Initial Bolus Strategy
- Volume per bolus: 20 mL/kg of isotonic crystalloid (0.9% saline or lactated Ringer's) 1, 5
- Infusion time: Administer each bolus over 5-10 minutes (can be pushed or given via pressure bag) 1, 5
- Fluid type: Use only isotonic crystalloids; hypotonic solutions are contraindicated due to high risk of iatrogenic hyponatremia 1, 5
Repeat Dosing Protocol
- Reassess after each 20 mL/kg bolus for: ≥10% rise in blood pressure, ≥10% reduction in heart rate, improved mental status, capillary refill ≤2 seconds, warm extremities, and urine output >1 mL/kg/h 1, 5
- Repeat 20 mL/kg boluses as needed, up to a maximum of 60 mL/kg in the first hour for most conditions 1, 5
- Septic shock exception: Children with septic shock commonly require 40-60 mL/kg in the first hour, and may need up to 200 mL/kg total if they remain fluid-responsive without signs of overload 1, 5
Critical Pediatric Considerations
Do not rely on blood pressure alone to assess shock in children—hypotension is a late finding; use perfusion markers (capillary refill, peripheral pulses, mental status, urine output) instead 1, 5
Stop fluids immediately if these develop: 1, 5
- Hepatomegaly
- Pulmonary rales/crackles
- Increased work of breathing
- Worsening oxygenation
- Gallop rhythm
When these signs appear, initiate inotropic support (dopamine or epinephrine) rather than continuing fluids 1
Special Pediatric Populations
- Severe anemia (malaria, sickle cell): Blood transfusion is superior to crystalloid bolusing in non-hypotensive children; use smaller cautious boluses (10 mL/kg) if fluid resuscitation is needed 1, 6
- Dehydration without shock: Use 50 mL/kg over 2-4 hours for mild dehydration, 100 mL/kg over 2-4 hours for moderate dehydration 5
Maintenance After Resuscitation
Once perfusion normalizes, transition to maintenance fluids using Holliday-Segar formula: 5
- 100 mL/kg/day for first 10 kg
- 50 mL/kg/day for next 10 kg
- 25 mL/kg/day for each additional kg
Use isotonic solutions (0.9% saline or lactated Ringer's) for maintenance, not hypotonic fluids 5
Special Clinical Scenarios
Anaphylaxis
- Adults: 1-2 liters of normal saline at 5-10 mL/kg in first 5 minutes if hypotension persists after epinephrine 1
- Children: Up to 30 mL/kg in the first hour if hypotension persists after epinephrine 1
- Rapid infusion of colloid-containing volume expanders may be necessary if hypotension remains refractory 1
Diabetic Ketoacidosis (DKA)
- Initial bolus: 15-20 mL/kg/h (1-1.5 liters) of 0.9% saline in the first hour 1
- Subsequent rate: 4-14 mL/kg/h of 0.45% saline if corrected sodium is normal/elevated, or 0.9% saline if corrected sodium is low 1
- Goal: Correct estimated deficits within 24 hours; osmolality change should not exceed 3 mOsm/kg/h 1
COVID-19/Viral Pneumonia with ARDS
- Use conservative fluid management for ARDS patients without tissue hypoperfusion 1
- Avoid liberal fluid strategies that may worsen pulmonary edema 1
Common Pitfalls to Avoid
- Do not use hypotonic fluids for acute resuscitation in any age group—they significantly increase hyponatremia risk 1, 5, 4
- Do not delay bolus therapy while awaiting laboratory results in severe hypotension—begin treatment based on clinical assessment 1, 5
- Do not continue fluids beyond 60 mL/kg in children (or 2-3 liters in adults) without reassessment and consideration of vasopressor support 1, 5
- Do not ignore signs of fluid overload—hepatomegaly and rales mandate stopping fluids and starting inotropes/vasopressors 1
- In obese adults, consider using ideal or adjusted body weight rather than actual body weight for the 30 mL/kg calculation to avoid excessive fluid administration 7