Your Practice: Expert Advice on Sterile Technique

Q&A: Expert Answers to Common Perioperative Questions from AORN Guidelines Editor-in-Chief

Those of us who’ve been in the perioperative nursing field for a while know that maintaining sterile technique is a science and an art.

While the AORN Guideline for Sterile Technique provides the evidence-based foundation we need as periop professionals, each facility—and every situation—requires clinical judgment to apply that evidence safely.

Sometimes situations come up where it helps to get a little extra expert advice. Through the AORN Member Nurse Consult Line, members can get help and input when questions arise.

Our Editor-in-Chief of AORN’s Guidelines for Perioperative Practice, Erin Kyle, DNP, RN, CNOR, NEA-BC, EBP-C, is back to share her insights on three questions and common sterile technique challenges reported by AORN members. Kyle offers expert advice and discusses how to apply evidence-based practices in complex OR environments.

Q: How can perioperative teams implement air quality management programs to support environmental controls in existing and aging buildings?

Maintaining optimal air quality in perioperative environments is essential for infection prevention. But it can be challenging in existing and aging buildings. Even in aging buildings, perioperative teams can support environmental controls by forming interdisciplinary teams, maintaining and supplementing HVAC systems, optimizing room practices, monitoring air quality, and educating staff.

The following strategies, grounded in the AORN Guideline for Sterile Technique, can help teams develop and sustain effective air quality management programs—even when infrastructure is less than ideal.

1. Form an Interdisciplinary Team

Successful air quality management begins with collaboration. Assemble a team that includes perioperative RNs, infection preventionists, facilities maintenance, HVAC engineers, surgeons, anesthesia professionals, and environmental services leaders. This group should have the authority and expertise to assess, plan, and implement improvements (Recommendation 9.5.1).

2. Assess the Current State

Start by reviewing the types of HVAC systems in use, the maintenance history, and congruence with current standards (e.g., ASHRAE). Collect baseline data on temperature, humidity, pressurization, air changes per hour, and filtration levels. Identify rooms and locations most at risk for airborne contamination, and those where the highest risk procedures are frequently performed.

3. Monitor and Maintain HVAC Systems

Regularly verify that HVAC systems are functioning as intended. Even in older buildings, scheduled maintenance, filter changes (preferably MERV 16 or HEPA), and repairs can make a significant difference. Document any off-cycle maintenance or failures and assess their impact on air quality (Recommendation 9.5.2).

4. Supplement with Portable Air Cleaning Devices

When built-in systems become outdated or insufficient, consider using supplemental air cleaning devices. These devices can reduce particulate and microbial contamination in targeted areas (Recommendation 7.2.5).

5. Optimize Room Practices

Environmental controls go beyond equipment. “Back to basics” actions such as limiting door openings, minimizing room traffic, and positioning instrument tables and the patient within the airflow curtain are essential. When indicated, re-educate perioperative teams on how their movement and behaviors impact air quality and sterile field integrity (Recommendations 6.1–6.3, 9.5.5).

6. Implement Air Quality Monitoring

Establish a method and frequency for air quality sampling that occurs when the room is unoccupied and during procedures. Use particle counters or settle plates to quantify airborne contaminants. Compare results to established benchmarks and use findings to guide process improvements.

7. Educate and Communicate

Provide ongoing education to perioperative personnel about the importance of air quality, how HVAC systems work, and the impact of their actions on air quality. Share air quality data and feedback to engage staff in continuous improvement.

8. Plan for Upgrades

Work with facilities engineering to develop a long-term plan for updating or replacing aging HVAC systems, especially when there is evidence that the systems are not performing as expected. Prioritize upgrades in high-risk areas and use a structured improvement model (e.g., Plan-Do-Check-Act) to guide change.

References: AORN Guideline for Sterile Technique (2025), Recommendations 7.2.5, 9.5–9.5.6.

Q: Can periop teams return unused sterilized instruments sets from closed case carts in the core to storage, or are they contaminated?

In the dynamic environment of the perioperative core, the question often arises: what should be done with sterilized instrument sets transported in a closed case cart, but that ultimately go unused? This scenario is common because often cases are canceled, schedules shift, and sometimes, the same sets are just not needed.

According to the AORN Guideline for Sterile Technique, sterility is event-related and is dictated by the integrity of the packaging and the conditions under which the instrument set is stored and transported. When the instrument set is in the controlled environment of the core, and further protected from contamination in a closed case cart, the contents are considered sterile.

Sometimes handling instrument sets can result in damage to the packaging, even if managed in a closed case cart. So, before returning an unused instrument set to storage, the perioperative team must perform a careful inspection. The packaging should be intact, with no tears, holes, punctures, or evidence of moisture. Seals and locks must be secure, and chemical indicators should reflect that sterilization parameters have been met.

That said, vigilance remains essential. Staff must not return any instrument set to storage if:

• They have concerns about, or suspect compromised packaging;
• They open the case cart in an uncontrolled environment (e.g., in an OR during a procedure in progress);
• There is any suspicion of contamination for any other reason.

In these cases, reprocessing is indicated.

AORN Guideline for Sterile Technique (2025), Recommendations 5.1, 5.2, 5.5.1, 5.6, 7.8.2–7.8.4; Glossary: Event-related sterility.

Q: Our team wants to understand the balance between preparedness and setting up too early. What is best practice or time limit for having an open and counted setup in an OR?

One of the most common dilemmas in perioperative practice is finding the right balance between being prepared for a procedure and the risk of setting up the sterile field too early.

As perioperative professionals, our instinct is to be ready for anything, but the evidence is clear: the longer a sterile field is open before use, the greater the risk for contamination. However, the benefits of having an opened, set up, and counted field ready to go in case of an emergency can sometimes outweigh the risks associated with sterile field contamination, provided the team mitigates these risks effectively.

Best practice is just-in-time setup. The AORN Guideline for Sterile Technique recommends that the sterile field be prepared as close as possible to the time of use. This approach is rooted in the principle that exposure to airborne particulates and environmental contaminants increases with time. Items in sterile packaging remain sterile if the packaging integrity is maintained, but once opened, the risk of contamination rises with every minute the field is exposed.

There is no universally accepted time limit for how long a sterile field can remain open. Instead, the guideline supports an “event-related sterility” model where sterility is maintained as long as the field is protected from contamination and the environment is controlled. Several studies have investigated how quickly an open sterile field can become contaminated:

• Dalstrom et al. (2008) found that opened sterile operating room trays showed significant contamination after just 30 minutes, with contamination rates increasing over time.
• Bible et al. (2013) demonstrated that bacterial contamination of implants and instruments increased the longer they remained exposed on the sterile field.
• Wistrand et al. (2021) reported that time-dependent bacterial air contamination of sterile fields in a controlled operating room environment began as early as 1 hour after opening, with contamination rates rising steadily.
• Uzun et al. (2020) compared covered and uncovered instrument tables, finding that contamination began earlier and was more pronounced in uncovered tables. Covered tables remained sterile for longer, but contamination was still detected after extended periods.

Practical Sterile Field Recommendations for Teams

• Plan for setup to occur immediately before the procedure when possible.
• If the field is not needed immediately, cover the sterile field with a sterile drape using the recommended technique.
• Develop and follow facility-specific protocols that define the maximum allowable time for an open or covered field, based on your environment, knowledge of air quality that is specific to your ORs, the nature of emergency preparedness needs (e.g., the field is needed in case of an emergent transition to an open life-saving procedure) and other workflows.
• Educate staff on the rationale for just-in-time setup and the risks associated with early opening.

Preparedness is essential, but it must be balanced with the imperative to protect the sterile field from contamination.

References: AORN Guideline for Sterile Technique (2025), Recommendations 3.3, 7.1–7.1.4.

Get Expert Guidance Through AORN’s Nurse Consult Line

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