Aseptic technique

Aseptic Technique in the Primary Engineering Control

Aseptic technique is the set of practices that prevents microorganisms and particulates from entering a sterile preparation. Every step you take inside the primary engineering control (PEC)—whether a laminar airflow workbench (LAFW) or a biological safety cabinet (BSC)—must protect the sterile product. A single lapse can introduce contamination that reaches a patient's bloodstream, lungs, or eyes.

Understanding First Air

In a LAFW, HEPA-filtered air flows horizontally from the back of the cabinet toward you at a steady, unidirectional rate. The air that comes directly off the HEPA filter before touching anything is called first air. First air is the cleanest air in the environment. Breaking first air means placing your hands, supplies, or any object between the HEPA filter and a critical site. When that happens, the uninterrupted sterile airstream is interrupted, and non-sterile room air or particles shed from your gloves can contaminate the site.

In a BSC, HEPA-filtered air flows downward. The same principle applies: nothing should block the path between the filter and the critical site.

Rule: Always keep critical sites in direct, unobstructed line with the HEPA filter. Work at least 6 inches inside the PEC, and never reach over an open critical site.

Critical Sites

A critical site is any surface or opening that, if contaminated, could introduce microorganisms or particles into the preparation. Critical sites include:

• The needle tip and needle shaft
• The syringe tip (Luer end) before the needle is attached
• The interior of a vial after the rubber septum is punctured
• The neck and interior of an open ampule
• Any IV port that will be accessed

Protect every critical site by keeping it in first air and never touching it with your fingers, a non-sterile surface, or anything that blocks airflow.

Syringe and Needle Handling

Select the syringe size closest to—but not smaller than—the volume you need to draw. Smaller barrels give more accurate readings.

1. Open packaging inside the PEC, pulling back the wrapper without touching the syringe tip.

2. Attach the needle by holding the syringe barrel and threading the needle cap onto the Luer lock with one hand; never touch the needle hub junction with bare fingers.

3. Remove the needle cap by pulling it straight off. Recap using the one-hand scoop method only—never two-handed recapping.

4. After drawing the dose, check for air bubbles. Tap the barrel and gently expel air before labeling.

All sharps are discarded directly into the puncture-resistant sharps container without recapping when disposal is immediate.

Withdrawing from a Vial

1. Swab the rubber septum with a sterile 70% isopropyl alcohol (IPA) swab using a single, firm, one-direction stroke. Allow it to dry completely—wet alcohol carries microorganisms into the vial.

2. Draw air into the syringe equal to the volume of drug you will withdraw. This creates positive pressure and makes withdrawal easier.

3. Insert the needle bevel-up at a slight angle, then straighten as you push through the septum. Keep the needle tip in first air until the moment of puncture.

4. Invert the vial. Keep the needle tip submerged in the liquid to avoid drawing air.

5. Pull the plunger back to withdraw slightly more than needed, then push back to the exact volume to remove any remaining air.

6. Withdraw the needle smoothly and inspect the syringe for air bubbles and correct volume.

Withdrawing from an Ampule

Ampules are single-dose glass containers with no rubber septum. Once broken, the contents are open to the environment.

1. Tap the neck of the ampule gently to bring all liquid to the body.

2. Swab the neck with an IPA swab and allow to dry.

3. Wrap the neck with a sterile gauze pad or alcohol swab. Snap the neck away from you in one firm motion, directing the break away from your face and the HEPA filter.

4. Always use a filter needle (5-micron filter straw or filter needle) when withdrawing from an ampule. Glass particles shed into the solution during breaking; the filter captures them.

5. Tilt the ampule at a 45-degree angle. Insert the filter needle without touching the broken glass rim. Draw slowly to prevent foaming.

6. After withdrawal, replace the filter needle with a regular needle before injecting into a final container. The filter needle removes glass on the way in; if you inject through the same filter needle, you push glass back into the product.

7. Discard the ampule and filter needle in the sharps container.

Garbing and Hand Hygiene Before Entering the PEC

Aseptic technique starts before you touch the equipment. Follow your facility's garbing sequence: hand hygiene, shoe covers, hair cover, face mask, gown, and sterile gloves. Sterile 70% IPA must be applied to gloves before beginning work and periodically during compounding. Do not touch your face, hair, or non-sterile surfaces once garbed.

Observed Technique Checklist Expectations

During your competency evaluation, an observer will watch for:

• Correct garbing order and glove asepsis
• All critical sites remaining in first air throughout
• No shadowing of critical sites by hands or supplies
• Correct swabbing with adequate drying time
• Proper use of a filter needle for ampule withdrawal
• Safe needle handling and sharps disposal
• Accurate final volume in syringe

One observed breach—touching a needle tip, shadowing a critical site, or skipping the filter needle—results in a competency failure and repeat demonstration. Patient safety depends on zero tolerance for technique errors.