Overview
This lecture covers IV flow rate dosage calculations, focusing on solving for hourly rates (mL/hr), total volumes, and drops per minute using standard formulas.
Calculating Hourly IV Flow Rate (mL/hr)
- Use the formula: Hourly Rate (mL/hr) = Total Volume (mL) ÷ Total Time (hours).
- Example: 500 mL over 8 hours = 500 ÷ 8 = 62.5, rounded to 63 mL/hr.
- Convert units when needed (e.g., 2 L = 2000 mL).
- Round to the nearest whole number when calculating rates.
Converting Units
- 1 liter (L) = 1000 milliliters (mL).
- Always convert volume to mL before calculation.
Calculating Total IV Volume
- Use the formula: Total Volume (mL) = Hourly Rate (mL/hr) × Total Time (hours).
- Example: 167 mL/hr for 12 hours = 167 × 12 = 2004 mL.
Drops per Minute Calculation (IV Drip Rate)
- Use the formula:
- (Total Volume (mL) ÷ Total Time (min)) × Drop Factor (gtts/mL) = Drops per Minute.
- Total Time (min) = Hours × 60.
- Example: 1000 mL over 6 hours using a 15 gtts/mL drop factor:
- 6 hours × 60 = 360 min.
- (1000 ÷ 360) × 15 = 41.66, round to 42 drops/min.
- Alternate method: Use hourly rate (mL/hr) instead of total volume; (mL/hr ÷ 60) × Drop Factor.
Drop Factors
- Drop factor (gtts/mL) is provided on IV tubing packaging.
- It indicates the number of drops required to equal 1 mL of solution.
Key Terms & Definitions
- Hourly Rate (mL/hr) — Amount of fluid delivered per hour.
- Total Volume (mL) — Complete volume of fluid to be infused.
- Drop Factor (gtts/mL) — Number of drops per milliliter, determined by IV tubing.
- Drops per Minute — Number of drops delivered each minute.
Action Items / Next Steps
- Practice similar calculation problems using provided formulas.
- Review drop factor information on IV tubing before calculations.
- Take the suggested online quiz for additional practice.