Which filter removes particulate matter and bacteria that may be introduced during epidural preparation?

Which filter removes particulate matter and bacteria that may be introduced during epidural preparation?

• A. 0.22 micron filter
• B. 5 micron filter
• C. 0.45 micron filter
• D. 1 micron filter

Answer: (A)

Filtering for epidural preparation aims to remove both particulates and bacteria by using a pore size small enough to trap microorganisms. Most bacteria range from about 0.5 to 1.0 micrometers in size, so a filter with a 0.22-micrometer pore size acts as a sterilizing-grade filter that blocks bacteria and also captures fine particulates. Larger-pore filters, such as 5, 1, or 0.45 micrometers, may remove bigger debris but won’t reliably retain bacteria, increasing the risk of contamination. Therefore, the 0.22-micrometer filter is the best choice to ensure sterility during epidural preparation.

Filtering for epidural preparation aims to remove both particulates and bacteria by using a pore size small enough to trap microorganisms. Most bacteria range from about 0.5 to 1.0 micrometers in size, so a filter with a 0.22-micrometer pore size acts as a sterilizing-grade filter that blocks bacteria and also captures fine particulates. Larger-pore filters, such as 5, 1, or 0.45 micrometers, may remove bigger debris but won’t reliably retain bacteria, increasing the risk of contamination. Therefore, the 0.22-micrometer filter is the best choice to ensure sterility during epidural preparation.