Mistakes when loading instruments into an autoclave
— Equipo JP Selecta
A seemingly simple load can become the weak point of the entire sterilisation process. The autoclave may complete the programme without alarms and still leave areas of a load without the necessary steam conditions. That is why preparing and arranging the material is not an ancillary step: it determines whether the treatment reaches every surface, cavity or pack.
The risk is not limited to a poor technical result. A badly planned load can force the cycle to be repeated, damage the material or, most importantly, compromise the safety of subsequent work. Checking cleanliness, load type and arrangement before closing the door helps to avoid incidents that are not always visible when the programme ends.
The cycle cannot make up for a badly prepared load
The control system of the autoclave monitors the cycle conditions in the chamber and confirms that the programmed parameters have been reached. However, that confirmation does not replace the correct preparation of each item. If air remains trapped (in pre-vacuum autoclaves, the autoclave's air removal efficiency is checked with the Bowie-Dick test), the packaging is unsuitable or the materials are too close together, the steam may not come into uniform contact with the load.
Prior cleaning, programme selection and orderly placement are all part of the same process.
At J.P. Selecta we design solutions with air removal, programming and drying options adapted to different applications, but the autoclave must be used with a compatible, correctly prepared load.
A completed cycle is evidence that the programme has run; load conformity also requires following the validated procedure for that material.
The most common autoclave loading mistakes
Loading errors tend to recur because they are easy to normalise in day-to-day work: a full tray, a closed container or a programme chosen out of habit. Identifying them makes it possible to set clear criteria for each type of material and reduce the need to reprocess loads.
Loading instruments without cleaning them first
Sterilisation does not replace cleaning. Residues of blood, culture media, oils or organic matter can prevent direct contact between the steam and the surface. In addition, heat can fix certain residues, which makes them harder to remove later and affects the condition of the instruments.
Before sterilisation, material must be washed, rinsed and dried in accordance with its usage procedure. Joints, serrations, lumens and hard-to-reach areas should be inspected with particular care.
This sequence reduces the soil load and allows the steam cycle to act on a properly prepared surface.
Overloading the chamber or stacking materials without leaving room for steam
Steam must circulate freely around the items and displace the air from the spaces occupied by the load.
When trays are overfilled, instruments overlap or pouches rest on top of one another, areas that are difficult to penetrate are created. The chamber may reach the programme temperature while certain points of the load receive insufficient treatment.
Material should be distributed on trays without compressing it, keeping space between items and avoiding continuous contact between packs or with the chamber walls. Hinged instruments are sterilised open, and items made of different materials are separated when the procedure requires it.
The aim is to be able to see each item and to preserve pathways for the steam.
Not adapting the packaging or the cycle to the load type
Not all loads behave in the same way. Unwrapped instruments, packs, textiles, tubing and liquids require configurations compatible with their geometry and the way they exchange heat. Our autoclaves for liquid sterilisation are adapted to liquid cycles. One example is the Steril Pres GMP - 80, which features PLC control, a counter-pressure system and fractionated vacuum air removal to adapt the process to different needs.
It is also necessary to check that plastics, pouches and wraps are suitable for the sterilisation conditions.
Pouches must be placed without folds that block the passage of steam, and tubing must not be kinked in a way that obstructs its interior.
To seal pouches uniformly, at J.P. Selecta we recommend using automatic pouch sealers such as the Seal-Com 3.
You should also avoid mixing loads that require different parameters in the same cycle. To do this, select the validated programme for the specific load and consult the instructions of the material's manufacturer.
Sealing containers hermetically before the cycle
Except in autoclaves with a counter-pressure system and with containers suitable for it, a hermetically sealed container can build up a pressure difference relative to the chamber during heating and depressurisation. This increases the risk of glass breakage, deformed closures or spillage of the contents.
In the case of liquids, improper handling can also cause splashing when the autoclave is opened.
Use containers suitable for the working temperature and pressure, place them on trays to contain any spills and apply the closure specified in the load procedure.
Liquid media are processed in semi-closed containers when the programme specifies this.
It is important not to improvise the fill level or the type of cap: both must be defined according to the container, the volume and the validated method.
Not using control indicators in the load
The autoclave's cycle record provides valuable information about the programme that was run, but it does not replace the controls defined for the load. Chemical indicators make it possible to check exposure to the conditions specified by their manufacturer, while biological indicators are used to verify microbiological efficacy within the applicable control plan.
Placement is as important as the indicator chosen. Indicators must be placed inside the packs and the results must be recorded together with the cycle data. The frequency and type of control depend on the quality system, the risk and the requirements of the sector and must therefore be documented and consistent with the process validation.
Removing the load before drying has finished
Opening the autoclave or removing the material before drying is complete leaves wet packs or packs with condensation. Moisture can encourage contaminants to enter through the wrapping and reduce the ability to maintain sterility during storage.
It can also damage labels, packaging or sensitive instruments.
It is therefore essential to respect the drying time set for the programme and to let the load stabilise.
In applications that require wrapped material, the drying function and, where applicable, the post-cycle vacuum help to obtain dry packs. If moisture is detected, the load must be handled in accordance with the internal procedure rather than being automatically released as fit for use.
These errors rarely correct themselves and do not always trigger an alarm. For this reason, the most effective measure is to define a protocol for each load type:
- Which material is accepted?
- How is it cleaned?
- How is it packaged?
- Which programme is used?
- Where are the controls placed?
- When can the load be released?
Staff training and systematic record-keeping turn these guidelines into a repeatable practice.
Checking the load before starting the cycle takes just a few minutes and prevents consequences that may appear much later, during a microbiological check, an audit or the use of the material.
Reliable sterilisation begins before the start button is pressed.