Lecture Notes: Dopamine Calculations

Introduction

• Speaker: Sarah from RegisteredNurseRN.com
• Topic: Solving dopamine calculations.
• Resource: Access a free quiz post-video for practice.

Pharmacology Review: Dopamine

• Dopamine: A beta-adrenergic agonist.
  • Acts as a vasopressor with positive inotropic effects.

Effects of Dopamine

• Vasopressors: Cause vasoconstriction
  • Narrow vessels
  • Increase blood pressure, systemic vascular resistance, and cardiac output.
• Use Cases: For patients in shock with severe hypotension, low cardiac output, or low systemic vascular resistance.
• Contractility: Increases heart's contractility (heart pumps stronger).

Dosage Effects

• Low Doses (0.5 to 3 mcg/min):
  • Causes renal vasodilation
  • Increases kidney perfusion and urinary output
• High Doses (2 to 10 mcg/kg/min):
  • Causes renal vasoconstriction

Administration

• Method: IV, best through a central line.
  • Reason: Prevent tissue ischemia and necrosis from extravasation.
• Treatment for Extravasation: Phentolamine (causes vasodilation).

Monitoring

• Continuous EKG Monitoring: Required.
• Parameters:
  • Heart rate
  • Blood pressure
  • Urinary output
  • IV site condition

Dopamine Calculation Example 1

• Order: IV dopamine drip at 10 mcg/min
• Patient Weight: 55 kg
• Available: 800 mg in 500 mL bag
• Objective: Calculate mL/hour

Calculation Steps

1. Start with Weight: 55 kg
2. Dose: 10 mcg/kg/min, convert to mcg
3. Conversion: 1,000 mcg = 1 mg
4. Available Dose: 800 mg/500 mL
5. Multiply and Divide: Convert units to mL per minute, then to mL/hour
6. Result: 20.6 mL/hour

Dopamine Calculation Example 2

• Order: IV dopamine drip at 5 mcg/kg/min
• Patient Weight: 180 lbs (convert to kg)
• Available: 400 mg in 250 mL bag
• Objective: Calculate mL/hour

Calculation Steps

1. Convert Weight: 180 lbs to kg using 2.2 lbs/kg
2. Plug in Dose: 5 mcg/kg/min
3. Conversion: 1,000 mcg = 1 mg
4. Available Dose: 400 mg/250 mL
5. Multiply and Divide: Convert units to mL per minute, then to mL/hour
6. Result: 15.3 mL/hour

Conclusion

• Reminder: Take the free quiz for practice.
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