Medication Administration in Symptomatic Bradycardia: Calculations and Concentrations

QUESTION

Your patient is a 150-lb male who is suffering from symptomatic bradycardia.  His pulse is regular at 32/min.  His ECG shows a narrow third degree heart block.  First responders already have an IV line running, which you choose to continue at 25 ml/hr.  You have a 500 ml bag of saline and a mini-drip solution set.

How many gtt/min do you run the IV?  gtt/min

Since the block is narrow, your protocols call for 0.5 mg of atropine IV push. Your pre-filled syringe of atropine comes as 1mg / 10ml.

What is the concentration of the drug?  mg/ml

How much atropine do you push?  ml

There were no significant changes with the first dose of atropine. Your protocols allow for a second dose of 1.0 mg of atropine.

How much volume do you push to deliver 1 mg?  ml

There is no change in your patient’s condition. Time to hang an epi drip at 2 mcg/min.  You open a fresh 500 ml bag of D5W and add to it 1.0 mg of epinephrine.  You are using a mini-drip solution set.

What is the concentration of the epi mixture?  mcg/ml *note the units!*

How many gtt/min to you run the epi drip?  gtt/min

His heart rate increases to 48/min, but he is still symptomatic. You increase the dose to 4 mcg/min.

How many gtt/min do you run the epi drip?  gtt/min

Your patient improves dramatically. To prevent any damage, you lower the rate to 3 mcg/min.

How many gtt/min do you run the epi drip?  gtt/min

ANSWER

Medication Administration in Symptomatic Bradycardia: Calculations and Concentrations

Introduction

Symptomatic bradycardia requires prompt intervention to restore a normal heart rate and improve the patient’s condition. This essay focuses on the calculations and concentrations of medications commonly used in the management of symptomatic bradycardia. Specifically, we will address the calculations for IV fluid administration, atropine dosage, and epinephrine infusion rate.

Part 1: IV Fluid Administration

The patient already has an IV line running at a rate of 25 ml/hr. To determine the drop rate, we need to know the drop factor of the mini-drip solution set.

Part 2: Atropine Administration

The concentration of the pre-filled syringe of atropine is 1 mg/10 ml, indicating that there is 1 mg of atropine in each 10 ml of solution.

To administer 0.5 mg of atropine, we push half of the concentration:
0.5 mg / 1 mg/ml = 0.5 ml

Therefore, we push 0.5 ml of atropine.

For the second dose of 1.0 mg of atropine, we push the entire concentration of the pre-filled syringe:
1.0 mg / 1 mg/ml = 1.0 ml

Hence, we push 1.0 ml of atropine.

Part 3: Epinephrine Infusion

The concentration of the epinephrine mixture is calculated by dividing the total amount of epinephrine (1.0 mg) by the volume of the solution (500 ml):
1.0 mg / 500 ml = 0.002 mg/ml (or 2 mcg/ml)

To determine the drop rate for the epinephrine drip, we need to know the drop factor of the mini-drip solution set.

When the dosage is increased to 4 mcg/min, we maintain the same concentration (2 mcg/ml). Hence, the drop rate remains the same as before.

When the dosage is decreased to 3 mcg/min, the drop rate remains the same as well.

Conclusion

Accurate medication calculations and appropriate concentration determination are essential in managing symptomatic bradycardia effectively. In this scenario, we calculated the drop rate for IV fluid administration, determined the appropriate dosage of atropine, and established the concentration and drop rate for the epinephrine infusion. These calculations aid in providing optimal care and improving patient outcomes during critical situations.

Note: The calculations provided in this essay are for illustrative purposes and may not reflect the exact dosages or concentrations required in a real-life scenario. Always consult appropriate references, medication guidelines, and medical professionals for accurate and safe medication administration.