Ultrasonic Cleaning Is Not a Machine; It Is a Quality System: Preventing Hidden Bioburden in Surgical Instruments
Summary: Published in the March 2026 issue of Infection Control Today (Vol. 30, No. 1), this article by Marjorie Wall, EDBA, CRCST, CIS, CHL, CSSBB, argues compellingly that ultrasonic cleaning in the sterile processing department (SPD) must be conceptualized and managed not as a piece of equipment but as a validated patient safety quality system — with the same rigor applied to sterilizers and washer/disinfectors. The core argument is that while ultrasonic cleaning is the most effective available tool for removing microscopic soil from complex surgical instruments — using cavitation (imploding microscopic bubbles generated by high-frequency sound waves) to dislodge debris from serrations, hinges, box locks, cannulations, and lumens that manual brushing cannot reliably address — its effectiveness is entirely dependent on whether the system is correctly managed, monitored, and maintained. The article identifies the central patient safety risk: ultrasonic cleaning can fail silently. Instruments may appear clean, packaging may be intact, and sterilization indicators may have changed — yet retained bioburden can remain trapped in lumens and complex features. This invisible failure can lead to surgical site infections, operating room tray recalls, and medico-legal exposure without any obvious proximate cause. Drawing on Anderson et al. (AORN Journal, 2023), Wall identifies three core performance components that every facility must continuously verify: (1) cavitation performance — using objective cavitation indicators to confirm adequate ultrasonic energy generation (not simply “running the cycle”); (2) soil removal effectiveness — using synthetic soil challenge tests that mimic blood and tissue to confirm cleaning under real working conditions; and (3) lumen perfusion — confirming that lumened devices are correctly connected to irrigation ports and that internal surfaces are actually being flushed, not just externally exposed to cavitation. Water quality is addressed as a frequently overlooked but critical variable: water hardness, endotoxin levels, temperature, ion content, and microbial load all affect detergent performance and cleaning efficacy, and Wall advocates for including ultrasonic washers in facility water management programs as a shared infection prevention priority. The article concludes with a seven-question IP audit framework for SPD rounds and a discussion of how strong ultrasonic programs build trust between SPD and the perioperative team.
Key Highlights:
- Ultrasonic cleaning must be managed as a validated quality system — installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) testing required, mirroring sterilizer validation standards
- Three verifiable performance components: (1) cavitation — use objective cavitation indicators, not visual inspection; (2) soil removal — use synthetic soil challenge tests simulating blood and tissue; (3) lumen perfusion — confirm irrigation port connection, adapter compatibility, tubing integrity, and flow adequacy
- Most dangerous failure mode is the invisible one: instruments that appear clean may still harbour retained bioburden in lumens, serrations, and box locks — risking SSI, OR delays, and tray recalls without obvious proximate cause
- Water quality as a shared infection-prevention priority: hard water, elevated endotoxins, and microbial contamination reduce cavitation effectiveness and detergent performance — facilities should include ultrasonic washers in water management programs, requiring collaboration across SPD, facilities management, and clinical engineering
- Common operational failures: overloading tanks, instruments closed rather than open, inadequate degassing, improper detergent selection, poor solution change practices, kinked or misconnected lumen tubing, lack of preventive maintenance, inconsistent staff competency validation
- Seven-question IP audit: written IFU-aligned policies; cavitation verification frequency and documentation; consistent lumen port connection; soil indicator use and trend tracking; corrective action process for failed tests; water type and quality monitoring; preventive maintenance schedule documentation
Keywords: sterile processing wound care, surgical instrument bioburden, ultrasonic cleaning instruments, infection prevention surgical instruments, sterile processing quality system, surgical site infection prevention