AAMI: Time, temperature, humidity affecting cleanliness of instruments, medical devices

Editor's Note

Researchers for a long time have expressed concern about how time and temperature might contribute to changes that affect the cleaning and sterilization of instruments. However, there have been few studies examining these claims. A September 2023 study in Biomedical Instrumentation and Technology from the Association for the Advancement of Medical Instrumentation (AAMI), titled "Effects of Time, Temperature, and Humidity on Soil Drying on Medical Devices," aims to correct that.

This study presents the effects of time and environmental conditions on contaminated instrumentation from point of use until the cleaning process begins. According to the findings:

• Soil drying after a period of 8 hours changes the solubility of the soil complex, with a significant change occurring after 72 hours
• Temperature contributes to chemical changes as well; in particular, temperatures greater than 22°C demonstrated a decrease in soil solubility in water
• An increase in humidity prevented the soil from completely drying and prevented the chemical changes affecting solubility from occurring.

Based on the above findings, the authors suggest several best practices for perioperative nursing, including:

• prioritizing point-of-use sterile processing
• decontaminating medical devices 6 to 8 hours after use
• including transportation in total processing times
• accounting for high humidity.