Ultrasonic Cleaning Is Not a Machine; It Is a Quality System: Preventing Hidden Bioburden in Surgical Instruments

A sterile tray arrives in the operating room. The packaging is intact. The indicator has changed. The sterilizer printout looks perfect. The team opens the set, and everything appears ready, until someone spots dried residue in a box lock, debris trapped in serrations, or worse, visible soil inside a lumen (Images 1-3). In that moment, sterile processing is no longer a behind-the-scenes function. It has become a patient safety crisis in real time.

Most health care professionals understand sterilization. Many understand disinfection. Yet the reality is that cleaning, especially the cleaning of complex surgical instruments, is where risk is either removed or preserved. Ultrasonic cleaning sits at the center of that reality. It is often discussed as a piece of equipment, a tank in decontamination, or a step in the workflow. However, ultrasonic cleaning should not be viewed as “a machine that runs a cycle.” It should be viewed as a quality system that must be verified, monitored, and continuously managed.

When ultrasonic cleaning fails, the most dangerous outcome is not the visible failure. It is the invisible one.

Why Ultrasonic Cleaning Matters More Than Ever

Surgical instrumentation has evolved dramatically. Devices are increasingly complex, featuring fine serrations, hinges, channels, cannulations, and lumens that are impossible to clean thoroughly with brushing alone. Although manual cleaning remains a frontline step, it is insufficient to address microscopic soil and contamination that can remain trapped in hard-to-reach areas.¹

This is where ultrasonic cleaning plays an important role. Ultrasonic cleaners use sound waves to create cavitation in a cleaning solution.² Cavitation produces microscopic bubbles that expand and implode, releasing energy that disrupts soil on instrument surfaces and in complex features.² The result is a cleaning mechanism that can reach areas that traditional brushing and rinsing cannot reliably address.²

Ultrasonics are especially valuable for lumened devices, where internal surfaces create the perfect environment for retained bioburden. Some ultrasonic systems include flow or sonic irrigation, allowing lumens to be actively flushed while cavitation occurs. In these cases, ultrasonic cleaning becomes one of the strongest tools sterile processing has for reducing contamination risk before instruments ever reach the washer/disinfector or sterilizer.²

But effectiveness is not automatic. It depends on whether the system is being managed correctly.

The Blind Spot: Clean Is Not Always Visible

The greatest challenge in instrument cleaning is that “clean” is often assumed rather than verified. Sterile processing professionals know that lumens, box locks, hinges, and fine instrument surfaces can trap debris that is invisible to the naked eye. Even with strong training and experience, a technician cannot always confirm internal cleanliness without objective evidence.

This is what makes ultrasonic cleaning both powerful and dangerous. It can be a strong solution for complex instrumentation, but if it is not functioning properly, the organization may believe instruments are being cleaned effectively when they are not.

An AORN Journal article by Anderson and colleagues makes this point clearly: Ultrasonic cleaners must demonstrate adequate cavitation, soil removal, and lumen perfusion. In other words, the process must be proved, not assumed.³

If your ultrasonic process is not verified, you may be introducing risk into the workflow.

The Lifecycle Perspective: What Many Leaders Don’t See

The sterile processing department (SPD) is often misunderstood, even by highly experienced clinicians. In their review, A Day in the Life of a Surgical Instrument, George and colleagues outline the full life cycle of an instrument, from point-of-use cleaning and transport to decontamination, ultrasonic cleaning, automated washing, assembly, inspection, sterilization, and storage.⁴

Their review emphasizes something infection preventionists and perioperative leaders should take seriously: Instrument reprocessing is not a single step; it is a chain of dependent steps. If early cleaning steps are missed, downstream processes become less effective.

For example, point-of-use pretreatment prevents bioburden from drying onto instruments. If dried soil reaches the SPD, it increases cleaning difficulty and delays turnover.⁴ This affects ultrasonic cleaning performance, because cavitation and chemistry work best when gross debris has already been removed, and soil has not hardened into crevices.

Ultrasonic cleaning does not exist in isolation. It exists in a system where each step affects the next.

Ultrasonic Cleaning Must Be Managed Like a Quality System

The central message is simple: Ultrasonic cleaning is not just a tank. It is a controlled process that must be managed like sterilization. This means it requires standardized workflow, validated parameters, routine monitoring, documentation, maintenance, and staff competency.

Anderson et al describe how facilities should incorporate installation qualification, operational qualification, and performance qualification (PQ) testing into their ultrasonic cleaning programs.³ This mirrors the same mindset used for sterilizers and washer/disinfectors. The concept is straightforward: Health care organizations must demonstrate that equipment is installed correctly, operates as intended, and performs effectively under real working conditions.

Without PQ testing, ultrasonic cleaning is based on trust. And in infection prevention, trust is not a control measure.

The 3 Things Every Facility Must Verify

A strong ultrasonic cleaning quality system should verify 3 core performance components.

1 Cavitation performance

Cavitation is the foundation of ultrasonic cleaning. If cavitation is weak, inconsistent, or inhibited, cleaning outcomes decline. Cavitation can be affected by improper water level, poor degassing, incorrect temperature, overloading, and incompatible detergents.² Facilities should use objective cavitation monitoring tools. Cavitation indicators provide measurable evidence that the unit is producing adequate ultrasonic energy. Without routine cavitation verification, departments may continue running cycles even when performance has degraded.

If you are not testing cavitation, you are not measuring performance; you are only measuring hope.

2 Soil removal effectiveness

The goal of cleaning is not simply “running the cycle.” The goal is soil removal. Soil testing indicators provide a realistic challenge using synthetic soils that mimic blood and tissue. These tools help confirm whether cleaning outcomes are being achieved.²

PQ testing is not theoretical. It is a practical method for demonstrating that the ultrasonic cleaner can remove soils under expected conditions.³ Ultrasonic cleaners may appear to be functioning normally even when performance is compromised.

3 Lumen perfusion and flushing

Lumened instruments are among the highest-risk categories in sterile processing. Internal channels are difficult to visually inspect and to clean manually. Ultrasonic systems with lumen irrigation ports offer a major advantage, but only if the lumens are properly connected, the adapters are correct, the tubing is not kinked, and the flow is adequate.²

Lumen perfusion testing is a core component of PQ.³ If lumens are not effectively flushed, retained debris may remain even when external surfaces appear clean. Infection preventionists (IPs) should pay special attention to lumen processing because failures are often silent until they appear as soiled instruments in the operating department or unexplained infection concerns.

Water Quality: The Silent Variable Infection Preventionists Should Own

One of the most overlooked influences on ultrasonic performance is water quality. Water is not just a utility; it is a core variable in the cleaning process. Leach notes that water hardness, endotoxin levels, temperature, sedimentation, ion levels, and microbial contamination can affect the effectiveness of ultrasonic cleaning. Hard water can contribute to the formation of residues and corrosion.1 Poor water quality can interfere with detergents and reduce cleaning action.¹ Endotoxin presence raises significant concerns for patient safety, especially when cleaning is incomplete.

From a practical standpoint, IPs should consider ultrasonic washers as part of the facility’s water management program. This requires collaboration with facilities management, sterile processing leadership, and clinical engineering. It also means that water monitoring should not be treated as an engineering-only responsibility. Water quality directly affects patient outcomes and should be treated as a shared infection-prevention priority.¹

If an ultrasonic cleaner is running with compromised water quality, even the best staff performance may not overcome that limitation.

What Can Go Wrong (and Why It Happens)

Ultrasonic cleaning failures often stem from predictable breakdowns in process control. Common issues include the following:

• Instruments overloaded or exceeding weight limits
• Hinged instruments placed closed rather than open
• Insufficient degassing of solution
• Improper detergent selection or excessive foaming chemistry
• Poor solution change practices and tank contamination
• Lumen devices improperly connected to irrigation ports
• Kinked tubing or incorrect adapters
• Failure to separate metals appropriately, contributing to instrument damage
• Lack of routine maintenance or calibration
• Inconsistent training and competency validation^1,2

These issues are not rare. They are operational realities. The solution is not to blame the staff, but to implement process controls that prevent these failures from becoming routine.

The Practical Audit: 7 Questions Infection Preventionists Should Ask

During SPD rounds, infection preventionists and quality leaders should ask questions to determine whether ultrasonic cleaning is managed as a system.

1. Do we have written ultrasonic cleaning policies aligned to equipment and device instructions for use?
2. How often do we verify cavitation performance and document results?
3. Are lumen devices consistently connected to irrigation ports correctly?
4. Are soil removal indicators used, and are failures trended?
5. What is the corrective action process when tests fail?
6. What type of water is used, and how is water quality monitored?
7. Is preventive maintenance performed and documented on schedule?

These questions shift the focus from “Do we have an ultrasonic cleaner?” to “Are we managing ultrasonic cleaning as a validated patient safety process?”

Ultrasonics as Risk Reduction and Trust-Building

Sterile processing is not simply a support service; it is a clinical safety function. And ultrasonic cleaning is not just a machine; it is a quality system that must be designed and managed with the same rigor as sterilization.

The life cycle of an instrument is complex, and the consequences of cleaning failures are immediate, visible, and costly. Residual soil leads to operating room delays, tray recalls, damaged departmental relationships, and increased infection risk. In contrast, strong ultrasonic cleaning programs improve workflow reliability, enhance compliance, and build trust between SPD and the perioperative team.⁴

The most effective organizations do not treat ultrasonic cleaning as a checkbox. They treat it as a controlled process with measurable performance. They validate cavitation. They confirm soil removal. They verify lumen perfusion. They monitor water quality. They train staff. They document results. They take corrective action when outcomes fall short.

Because in infection prevention, the most dangerous failures are the ones you cannot see.

References

1. Leach R. How ultrasonic cleaning enhances patient safety. Infection Control Today. March 11, 2025. Accessed February 7, 2026. https://www.infectioncontroltoday.com/view/how-ultrasonic-cleaning-enhances-patient-safety
2. Guide to ultrasonic cleaning of medical devices: how ultrasonics work and more. STERIS. April 12, 2024. Accessed February 7, 2026. https://www.steris.com/healthcare/knowledge-center/sterile-processing/guide-to-ultrasonic-cleaning?srsltid=AfmBOopQq_MBSTUc1netAK8ZWAgF86fK9VfzhVUwLoFF7EknNH2WQFV6
3. Anderson K, Drosnock MA, Kovach SM, Zitek T. Performance qualification testing improves processing of lumened surgical instruments in ultrasonic cleaners. AORN J. 2023;118(2):79-86. doi:10.1002/aorn.13967
4. George RE, Bay CC, Shaffrey EC, Wirth PJ, Rao VK. A day in the life of a surgical instrument: the cycle of sterilization. Ann Surg Open. 2024;5(1):e381. doi:10.1097/AS9.0000000000000381