Heat Transfer. Condensation. Revaporization

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Vernon Russell
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1 Objectives Wrapping a Towel Around the Problem of Wet Packs Identify causes of wet packs in steam sterilization Review suggested documentation that can assist in solving wet pack problems Why are Wet Packs a Problem? Potential pathway for microorganisms Contamination possibilities Difficult to identify Involve many players and factors Require investigation of all elements Necessitate process audits Finding / Documenting Wet Pack Occurrences Investigate Clearly document the occurrence Wet pack log Wet Pack Log Events of the Sterilization Process Sterilizer # Gravity or Prevac Date Time of Day Wet Item(s) Location in Load Comments (Nature of wetness) Exposure Time Exposure Temp. Dry Time 1

Potential pathway for microorganisms Contamination possibilities Difficult to identify Involve many players and factors Require investigation of all elements Necessitate

2 Events of the Sterilization Process Heat Transfer HEAT TRANSFER - an energy exchange between the sterilizing agent and the receiver of that heat CONDENSATION - the steam collapses into water, as heat is transferred to the item to be sterilized REVAPORIZATION - evaporation of condensate to dry the load Condensation Revaporization Examining Individual Packs External wetness seen Immediately as packs are removed from sterilizer Internal wetness noticed when Packs opened for use Moisture wicks through wrap Troubleshooting External Moisture Localized moisture Displaced moisture Moisture location Poor steam quality Check valve failure Dispersed moisture Sterilizer malfunction Technique problem 2

Individual Packs External wetness seen Immediately as packs are removed from sterilizer Internal wetness noticed when Packs opened for use Moisture wicks through wrap

3 Moisture Outside of Package Troubleshooting Internal Moisture Poor pack preparation Metal mass Tray too small Entrapment of moisture Instruments wet when packed Inadequate drying phase Absorbed moisture within a pack Check sets when cooled Internal Wet Packs Note location of moisture Inspect item preparation Loading techniques Location on sterilizer cart Textile packs Open them up Internal Wet Packs Shake them out Feel for moisture Hot/warm towels Instrument Set Preparation Standard instrument trays Appropriate size tray NO Cake pan type trays or flat trays Instrument Set Preparation Use appropriate materials Consult container manufacturer Adequate drainage holes 3

Location on sterilizer cart Textile packs Open them up Internal Wet Packs Shake them out Feel for moisture Hot/warm towels Instrument Set Preparation Standard

4 Instrument Set Preparation Instruments must be dry Even instrument distribution Disassemble instruments Alternate heavy handle instruments Use organizing pouches correctly No paper/plastic peel pouches Instrument Set Preparation Instrument set weight Within lbs Avoid exceeding 25 lbs. Ergonomics Difficulty in drying Wrap heavy devices in an absorbent towel AAMI ST 79 Peel Pouch Preparation Incorrect Double pouching paper/plastic peel pouches Slide one pouch into the other Paper to paper Plastic to plastic Correct Inner pouch smaller than outer pouch Do not fold inner pouch 4

lbs. Ergonomics Difficulty in drying Wrap heavy devices in an absorbent towel AAMI ST 79 Peel Pouch Preparation Incorrect Double pouching

5 Basin Set Preparation Maximum weight - 7 lbs. Nested utensils separated with absorbent material Basin Set Preparation Use consistent wrapping / placement technique Curled basin edge Medicine cups peel pouched Hollow surgical light handles Linen Pack Preparation Linen pack density Arrangement of textiles How tight is it wrapped? Consult newer textile manufacturers for Preparation instructions Sterilization parameters Properly wrapped Tightly wrapped Wet Pack Issues Wet packs more prevalent with introduction of: Non-woven disposable wrap New textiles Rigid sterilization containers Follow manufacturer s guidelines Choose wrappers Wrapping Designed and tested for steam sterilization Appropriate size Avoid using wrappers for a dual purpose 5

handles Linen Pack Preparation Linen pack density Arrangement of textiles How tight is it wrapped?

6 Loading the Sterilizer Loading the Sterilizer Absorbent shelf liners Non-woven disposable Nonwrap unacceptable Loading the Sterilizer Basin Sets On Edge Tilted Separate loads if possible Textiles Hard goods When mixing load contents Textiles on top shelves Hard goods below Instrument trays placed flat Basin sets - on edge and tilted Instrument Sets Placed Flat Textile Packs Layers Perpendicular to Shelf 6

Hard goods When mixing load contents Textiles on top shelves Hard goods below Instrument trays placed

7 Paper/Plastic Peel Pouches on Edge Loading the Sterilizer Do not allow items to touch chamber walls Use baskets to contain small items Use sterilizer carts whenever possible Thoroughly cool items on sterilizer carts Loading the Sterilizer Avoid overloading Positioned correctly Efficient air removal Steam penetration Evacuation Selection of Sterilization Parameters AAMI recommendations Steam sterilizer manufacturer recommendations Medical device manufacturer recommendations New extended cycles Add additional shelves if needed Steam Cycle Type:Pre-vacuum Temperature: 132 o C (270 o F) Dwell Time: 4 minutes 7

Steam penetration Evacuation Selection of Sterilization Parameters AAMI recommendations Steam sterilizer manufacturer recommendations Medical device

8 Instrument Cycle Temp. Exposure Time Single & Dual Insert Sets Prevac C 15 min. Single & Dual Insert Sets Prevac C 14 min. Multiple (2-3) Insert Sets Prevac C 40 min. Unloading the Sterilizer Allow items to thoroughly cool on cart Do not place hot or warm items On cold surfaces In boxes / bins Stacked on top of each other Plastic dust covers Other Considerations Use instrument lubricants Follow manufacturer instructions Compatible May leave instruments slippery Other Considerations Sterilizer chamber drain screens Checked and cleaned At least daily Preferably every shift Keep Other Considerations sterilizers and accessories clean Equipment, Process, and Environment Audit Conduct routine audits of: Equipment Process Environment 8

Considerations Use instrument lubricants Follow manufacturer instructions Compatible May leave instruments slippery Other Considerations Sterilizer chamber drain screens Checked and cleaned

9 Check Equipment Audit Dynamic steam pressure from generator: 50-80psi Steam pressure regulated when entering sterilizer Plumbing lines direct as possible Steam lines covered with insulation Equipment Audit Competition for steam Cart washer Multiple washer/disinfectors Cafeteria equipment, e.g., dishwasher New / different sterilizer installed Process Audit New personnel contribution Prep, pack, and load Internal / external departments Linen Changes in wrap material Introduction of rigid sterilization containers Policies and Procedures New medical devices Process Audit Complex tray configurations Multiple layers Metal and plastic combination trays All plastic trays Trays in excess of 25 pounds Heavy metal mass in orthopedic instrument trays Environment Audit Steam generator or plumbing changes Seasonal maintenance Construction Renovation projects 9

, dishwasher New / different sterilizer installed Process Audit New personnel contribution Prep, pack, and load Internal / external departments Linen Changes in wrap material Introduction of rigid

10 Environmental Audit Temperature / humidity consistent from season to season Temperature should remain at F ( C) Relative humidity at 30-60% Environmental Audit Sterilizer cart cooling areas Should be room temperature Not near / under air conditioner vents Summary Source of wet packs extremely difficult to resolve Keep a detailed wet pack log Most common sources of wet packs avoided with: Good pack preparation techniques Sterilizer operation techniques Drying characteristics of packaging materials, etc. References: Association for the Advancement of Medical Instrumentation, Comprehensive guide to steam sterilization and sterility assurance in health care facilities. ANSI/AAMI ST79:2006, Arlington VA Perkins, J., Principles and Methods of Sterilization in Health Sciences, 2 nd edition.. (Springfield, IL: Charles C. Thomas, 1969). Ryan, P. Wet Pack Syndrome: Causes and Cures, Particulate and Microbial Control, 1 (September/October 1982) p.73. STERIS Corporation, Preparing Instruments, Utensils, and Textiles for Sterilization and Wet Pack Problem Solving, Bliley, J., Clement, L., Cracking the Steam Sterilizer Door; Dispelling the Myth HPN, May,

packs avoided with: Good pack preparation techniques Sterilizer operation techniques Drying characteristics of packaging materials, etc.

THE BASICS OF PACKAGING

THE BASICS OF PACKAGING Objectives: Review the regulatory requirements for packaging Present the purpose, function and essential characteristics of packaging Describe packaging options, their use, and