In practice it is claimed that load characteristics influence a surface steam sterilization process. To the best of our knowledge, no information on this topic has been found in the literature. The purpose of this study was to find if a load influences the duration and related characteristics of a surface steam sterilization process. In a case study, every load monitoring using an objective, quantifying steam penetration test was performed during 30 days. This resulted in 98 production processes with load monitoring. The acquired data were analyzed. A relation between the weight of a load and the duration of a surface steam sterilization process has been found. In this case study, it is demonstrated that the process time increases with the weight of the sterilizer load. Additionally, it is concluded that when the duration of a process is longer, diffusion will have a greater effect and steam penetration increases.LAY ABSTRACT: Steam sterilization is applied in most health-care facilities that reprocess medical devices, in pharmaceutical industries, and in labs where specific instrumentation and equipment have to be sterile. Steam sterilization is still not fully understood, as demonstrated in the literature. Our manuscript contributes to understanding the surface steam sterilization process. The information shared in our manuscript demonstrates by a case study that relations exist between the weight of the load which is steam sterilized, the duration of a process, and the steam penetration in a process. A quantitative relation can be used to predict the duration of a process and the steam penetration. It is likely that for other steam sterilizers these relations can be found as well. This is of interest for institutes researching decontamination and sterilization, health-care facilities, developers and manufacturers of medical devices, and committees addressing standards for steam sterilization.

BACKGROUND: Steam sterilization is an essential part of infection prevention. The literature shows that sterilization of medical instruments containing channels is not trivial. Phaco hand pieces have a simple configuration: a device contains a channel with a constant radius. No literature was found indicating whether the sterilization conditions on the inner surface of a phaco hand piece are influenced by the orientation of the hand piece.
OBJECTIVE: To determine whether the orientation of a phaco hand piece influences the results of a sterilization process of this device.
METHODS: A qualitative case study, including experiments, is performed with a protocolled combination of steam sterilizer, process, phaco hand piece, orientation of the phaco hand piece, and wrapping.
RESULTS: In this specific case, the orientation of the hand piece influenced the result of the steam sterilization process; in vertically (upright) oriented phaco hand pieces with free water drainage, sterilization conditions are reproducibly established. In the same process, in horizontally oriented or vertically oriented hand pieces without free drainage, these conditions are not established in a reproducible way.
CONCLUSIONS: In the investigated combination of sterilizer, process, load, loading pattern and wrapping, phaco hand pieces have to be oriented vertically (upright) with free water drainage to obtain steam sterilization conditions on the inner surface. It is likely that instruments with comparable configuration and dimensions will yield comparable results. It is therefore recommended that this issue is considered during the development of medical instruments and during performance qualifications of such instruments.