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What Gas Plasma Sterilization is, and How it Works.

Gas plasma sterilization is a low temperature and low pressure alternative to sterilizing with autoclaves (steam sterilization).  It’s really simple and cool.  The ingredients are only hydrogen peroxide and electricity in the machine.

In sterile processing departments, hydrogen peroxide plasma is used to sterilize flexible endoscopes and cameras mainly.

Sterrad by ASP and Thierry systems are the main plasma sterilization technologies in the market.  These machines are expensive, but necessary to protect fragile gear.

I’ve seen quite a few questions about plasma being used for sterilization.  It is a simple and fascinating technology that was really fun to research.  I hope to make all of you reading this a subject matter expert!  Here are the main questions.

What is Gas Sterilization Used for?

Certain items are too delicate for the high pressure and temperatures of steam sterilization.  In the OR, it was mainly fragile cameras and scopes for endoscopic surgeries.

The optical lenses and electronic parts are fragile and precise.  Heat or pressure can warp or crack parts.  A small defect in internal optics is magnified and can put a scope down for repairs.  Cameras and scopes must be in perfect condition for surgery in the body.

Broken scopes and cameras were the scourge of the operating room in my Surgical Tech career.  Facilities have a limited number of cameras and scopes since they’re expensive as hell!

We would have to quickly turn around cameras in a Steris or delay surgeries sometimes.  That isn’t fun for anybody in the OR. That is what makes plasma sterilizers vital ones for certain sterile departments.

How Does Plasma Sterilization Work?

The plasma machine needs a special box and wrapping for the instruments.  Then, they are taped and placed inside.  The cycle is started and an air pump removes the atmosphere from inside the chamber.

Next, a specific amount of liquid hydrogen peroxide is injected into the chamber.  Under the vacuum, the liquid immediately turns to hydrogen peroxide vapor.  This is sometimes called the diffusion phase.

The vapor touches all surface areas in the chamber.  Because hydrogen peroxide is antiseptic, this vapor starts killing the microorganisms.  The chamber pressure is then lowered further.  An electromagnetic current energizes this vapor and forms the plasma.

What is a gas plasma?

A plasma is the fourth state of matter.  It is not solid, liquid, or gas.  In the case of Sterrad plasma sterilization, hydrogen peroxide, H2O2, is used.  When the chamber pressure is lowered, the peroxide goes from liquid to a gas vapor as it is injected.

An electric current breaks apart the chemical bonds in the vapor and it transforms into a highly charged plasma.  The hydrogen and oxygen atoms become too energetic to maintain their bonds as H2O2.  The plasma creates UV light and free radicals.

The charged plasma cloud kills the microorganisms and destroys their reproductive abilities.  Their DNA is destroyed in this process.

The radio frequency to the chamber is then turned off.  The plasma recombines to form oxygen, water, and other products that are all non toxic.

The entire cycle is run one more time in the Sterrad 50 and 100 machines.  The vent phase is the final step for sterilization.  Filtered air draws into the chamber to equalize the negative pressure.

Plasma sterilizers are low temperature, so there’s no cool down time.  You can use the instruments right after being processed!  How cool is that?

Also, What is a Sterrad sterilizer?

Sterrad is the leading producer of plasma sterilization machines.  They are the industry standard and are used by thousands of facilities.

To recap, plasma sterilizers use lower temperature technology to decontaminate items.  Certain instruments and optical gear are too delicate for high pressure and temperature steam.

I think gas plasma sterilization is a really cool technology.  There are so many harsh chemicals used in the health industry today.  It’s nice to see something that only vents oxygen and water vapor.  I hope this type of clean tech keeps expanding.