Sterile Instrument Storage in an Austere Environment: Are Sterile Peel Packaging and Cellulose Wrapping Equivalent?

Background: Recommendations for optimal temperature and humidity for sterile instrument storage vary according to different sources. Furthermore, there are limited data comparing methods of packing smaller, lightweight, low-profile instruments. The purpose of this study was to compare sterile peel packaging and sterile cellulose wrapping for sterile instrument storage in an austere environment characterized by elevated temperature and humidity.

Methods: Stainless steel screws were sterilized and stored in either sterile peel packaging, sterile cellulose wrapping, or no packaging. Four groups were evaluated. Group 1 consisted of four screws in a sterile peelpack envelope and served as a time-zero control. Group 2 consisted of two groups of five screws, each packaged with blue sterilization cellulose wrap. Group 3 consisted of two groups of five screws, each packaged in sterile peel-pack envelopes. Group 4 consisted of 10 non-sterile unpackaged screws, which served as controls. Screws from groups 2, 3, and 4 were then cultured for 6 and 12 weeks. Temperature and humidity values were recorded in the instrument storage area.

Results: Average temperature was 21.3°C (SD 1.2°C; range 18.9°C-27.2°C) and average humidity was 51.7% (SD 3.9%; range 39%- 70%). Groups 1 (time-zero control) and 2 (sterile cellulose wrapping) demonstrated no growth. After 6 and 12 weeks, groups 3 (sterile peel packaging) and 4 (control) demonstrated bacterial growth.

Conclusion: The most common culture isolates were gram-positive rods and two common nosocomial Staphylococcius species. Sterile peel packaging was not found to be equivalent to sterile cellulose wrapping in austere environmental conditions.