Overview
This lecture demonstrates how to solve Pitocin (oxytocin) maternity dosage calculations using the "desired over have" formula method, including unit conversions and stepwise problem-solving.
Key Metric Conversions
- 1 unit (U) of Pitocin = 1,000 milliunits (mU).
- Pitocin is usually ordered in mU/min and supplied in U.
Desired Over Have Formula Method
- Desired dose / Have dose × Quantity (volume) = X (solved value, e.g., mL/hour).
- Always check that units match before solving; convert if needed.
Example Problem 1: Calculating mL per Hour
- Patient ordered 6 mU/min; IV bag has 10 U/1,000 mL.
- Convert 6 mU to U: 6 ÷ 1,000 = 0.006 U.
- Plug into formula: 0.006 U/min ÷ 10 U × 1,000 mL = 0.6 mL/min.
- Convert to mL/hour: 0.6 × 60 = 36 mL/hour.
Example Problem 2: Calculating mU per Minute
- Patient receives 12 mL/hour; IV bag has 20 U/1,000 mL.
- Convert 20 U to mU: 20 × 1,000 = 20,000 mU.
- Formula: 12 mL/hour ÷ 1,000 mL × 20,000 mU = 240 mU/hour.
- Convert to mU/min: 240 ÷ 60 = 4 mU/min.
Example Problem 3: New Infusion Rate after Titration
- Increased rate to 4 mU/min; bag has 30 U/500 mL.
- Convert 4 mU to U: 4 ÷ 1,000 = 0.004 U.
- Formula: 0.004 U/min ÷ 30 U × 500 mL = 0.066... mL/min.
- Convert to mL/hour: 0.066... × 60 ≈ 4 mL/hour.
Key Terms & Definitions
- Unit (U) — Standard amount of drug supplied in the IV bag.
- Milliunit (mU) — One-thousandth of a unit, used for dosing.
- Desired Over Have Formula — Method: (desired dose ÷ have dose) × quantity = amount to administer.
- Piggyback Infusion — Secondary IV medication added to the primary fluid line.
Action Items / Next Steps
- Practice additional dosage calculation problems using the provided worksheet or online quiz.
- Memorize key metric conversions for reliable problem-solving.