A filter must be used in which scenario?
a. Using a 1% lidocaine ampule to prepare an injection
b. Using a morphine 10-mg/mL multidose vial to prepare an IV push
c. Using a potassium chloride 40-mEq/mL single-dose vial
d. Using a morphine 10-mg/mL multidose vial to prepare an epidural
The correct answer and explanation is :
Correct Answer: a. Using a 1% lidocaine ampule to prepare an injection
Explanation:
A filter must be used when withdrawing medication from an ampule, and this applies to option a: Using a 1% lidocaine ampule to prepare an injection.
Why a Filter is Needed with Ampules:
Ampules are sealed glass containers that require breaking open to access the medication inside. During the process of snapping the neck of the ampule, tiny glass particles can be introduced into the solution. If these particles are drawn into the syringe and injected into the patient, they can cause:
- Embolism (blockage in blood vessels),
- Inflammation or irritation at the injection site,
- Or even tissue damage, especially when administered intravenously or intrathecally.
To prevent this, a filter needle or filter straw must be used when drawing up medication from an ampule. The filter is designed to trap any microscopic glass shards or contaminants, ensuring the solution is safe for administration.
Other Options Explained:
- b. Morphine 10-mg/mL multidose vial (IV push): Multidose vials do not pose a risk of glass particle contamination; therefore, a filter is not needed.
- c. Potassium chloride 40-mEq/mL single-dose vial: This is a high-alert medication, and while it requires extreme care due to the risk of cardiac toxicity, it is packaged in a vial, not an ampule—so no filter is needed unless otherwise specified.
- d. Morphine 10-mg/mL multidose vial (epidural): Even though epidural administration demands high sterility and caution, filters are not routinely required unless the vial contains preservatives or particulate matter, which would be specified in the guidelines or by institutional policy.
Summary:
Filters are essential when using ampules, due to the risk of glass contamination. This makes option a the correct and safest choice requiring a filter.