Sterilizing Unwrapped Instruments

Flash sterilization is a method for sterilizing unwrapped patient-care items for immediate use. The time required depends on the type of sterilizer and the type of instrument (i.e., porous or nonporous) to be sterilized (Table 3). The unwrapped cycle in tabletop sterilizers is preprogrammed by the manufacturer to a specific time and temperature setting and can include a drying phase at the end to produce a dry instrument with much of the heat dissipated.

Table 3. Examples of drying time required for flash steam sterilization parameters.3
Type of sterilizerLoad typeTemperatureDrying time
Gravity displacement
  • Nonporous items only
    • e.g., metal instruments without lumens
270˚F (132˚C) 3 min.
  • Nonporous and porous items
    • e.g., rubber or plastic items, items with lumens sterilized together
270˚F (132˚C) 10 min.
High-speed prevacuum
  • Nonporous items only
    • e.g., metal instruments without lumens
270˚F (132˚C) 3 min.
  • Nonporous and porous items
    • e.g., rubber or plastic items, items with lumens sterilized together
270˚F (132˚C) 4 min.

If the drying phase requirements are unclear, the operation manual or manufacturer of the sterilizer should be consulted. If the unwrapped sterilization cycle in a steam sterilizer does not include a drying phase or has only a minimal drying phase the items retrieved from the sterilizer will be hot and wet making aseptic transport to the point of use more difficult. For dry-heat and chemical-vapor sterilizers, a drying phase is not required.

Unwrapped sterilization method must meet four criteria: (1) the instruments must be thoroughly cleaned and dried prior to the cycle; (2) mechanical indicators must be checked and, at a minimum, a chemical indicator must be placed with the items to be sterilized; (3) care should be taken to avoid thermal injury to OHCP or patients; and (4) items must be transported aseptically to the point of use. Unwrapped or flash sterilization of implantable items is not recommended.

Unwrapped sterile instruments and other devices exposed to air can become contaminated with dust, airborne organisms, and other contaminants before use on a patient and should never be stored. Critical items sterilized unwrapped must be transferred from the sterilizer to the point of use by an aseptic method for immediate use. Semi-critical items must be handled in a similar manner and should be used within a short time of sterilization.2,3