Bolus Fluid Rate Calculator
Calculate total bolus volume, infusion rate (mL/hr), and drip rates for fluid resuscitation.
Calculation Results
Total Bolus Volume: mL
Pump Infusion Rate: mL/hr
Gravity Drip Rate: drops/min
Understanding Bolus Fluid Rate Calculations
A fluid bolus is a rapid administration of a specific volume of intravenous (IV) fluid, typically used to treat hypotension, dehydration, or shock. Calculating the correct rate is critical to ensuring the patient receives the volume within the clinically indicated timeframe without causing fluid overload.
The Core Formulas
To determine the bolus parameters, healthcare professionals use three primary calculations:
- Total Volume (mL): Patient Weight (kg) × Prescribed Dose (mL/kg).
- Infusion Rate (mL/hr): (Total Volume ÷ Time in Minutes) × 60.
- Drip Rate (gtt/min): (Total Volume × Drop Factor) ÷ Time in Minutes.
Step-by-Step Example
If a physician orders a 20 mL/kg bolus for a patient weighing 25 kg to be delivered over 30 minutes using a 15 gtt/mL drip set:
- Step 1: 25 kg × 20 mL/kg = 500 mL (Total Volume).
- Step 2: (500 mL ÷ 30 min) × 60 = 1,000 mL/hr (Pump Setting).
- Step 3: (500 mL × 15 gtt/mL) ÷ 30 min = 250 gtt/min (Manual Drip Rate).
Clinical Considerations
When administering a fluid bolus, always monitor for signs of fluid responsiveness or fluid intolerance, such as changes in heart rate, blood pressure, and lung sounds (checking for rales/crackles). In pediatric and geriatric patients, boluses are typically administered more cautiously, often in increments of 10 mL/kg to avoid cardiovascular strain.