You are asked to prepare a syringe of medication for a nerve block. The CRNA wants 30ml of 0.2% ropivacaine with 1:200,000 epinephrine. You have normal saline, 0.5% ropivocaine and 1:1000 epinephrine. How many mLs of 1:1000 epinephrine do you draw up?

To determine how many milliliters (mL) of 1:1000 epinephrine you need to draw up, we must calculate the appropriate dilution to achieve the desired concentration of 1:200,000 epinephrine in 30 mL of solution.

### Step-by-step solution:

1. **Desired concentration of epinephrine:**  
   The CRNA wants a concentration of 1:200,000 epinephrine. This means 1 gram of epinephrine is dissolved in 200,000 mL of solution.  

2. **Amount of epinephrine needed for 30 mL:**  
   \[
   \text{Amount of epinephrine} = \frac{1}{200,000} \times 30 \, \text{mL}
   = \frac{30}{200,000} \, \text{grams} 
   = 0.00015 \, \text{grams} 
   = 0.15 \, \text{mg}
   \]
   So, 0.15 mg of epinephrine is needed in 30 mL of solution.

3. **Available epinephrine concentration (1:1000):**  
   A 1:1000 concentration of epinephrine means 1 gram of epinephrine is dissolved in 1,000 mL of solution. This is equivalent to 1 mg/mL of epinephrine.

4. **How many mL of 1:1000 epinephrine contain 0.15 mg?**  
   \[
   \text{Volume of 1:1000 epinephrine} = \frac{0.15 \, \text{mg}}{1 \, \text{mg/mL}} = 0.15 \, \text{mL}
   \]

Thus, you need to draw up **0.15 mL** of 1:1000 epinephrine to achieve a concentration of 1:200,000 epinephrine in the 30 mL of solution.

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Would you like further details or clarification?

Here are 5 related questions you might be interested in:
1. How do you prepare the full solution of 0.2% ropivacaine and epinephrine from the given stock solutions?
2. What is the importance of the epinephrine concentration in a nerve block?
3. Can you use other concentrations of ropivacaine or epinephrine for this nerve block?
4. How would the calculation change if you needed a different total volume of solution?
5. How does epinephrine prolong the effect of ropivacaine in nerve blocks?

**Tip:** Always double-check your dilutions when preparing medications, especially when dealing with potent drugs like epinephrine!

You are asked to prepare a syringe of medication for a nerve block. The CRNA wants 30ml of 0.2% ropivacaine with 1:200,000 epinephrine. You have normal saline, 0.5% ropivacaine, and 1:1000 epinephrine. How many mLs of 1:1000 epinephrine do you draw up?

Learn how to calculate the volume of 1:1000 epinephrine needed to prepare a 30 mL syringe with a concentration of 1:200,000 epinephrine. This medical math problem involves concepts of dilution, proportions, and unit conversion. Suitable for students in Grades 10-12 or healthcare professionals.

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