A Clean Bill of Health
On the ground floor of the Norfolk and Norwich University Hospital is a large area that patients and staff never see but this vital operation is kept busy 24 hours a day seven days a week.
The Sterile Services Department with its banks of specialist machines has to sterilise every reusable instrument that is used in the hospital. That’s about 600 theatre trays a day, more than 140,000 trays of instruments a year.
The trays full of instruments are bound for the operating theatres at NNUH as well as Cromer Hospital, GP surgeries and health centres.
There is a constant flow of covered trolleys that leave the Day Procedure Unit and the operating theatres upstairs and are wheeled down to this essential area that’s led by operational manager David Scotton.
Used instruments are put into metal baskets on a robot shuttle which passes along a conveyer and stops at one of the seven machines. The shuttle glides fully laden into the space, the door comes down behind it and the washer/ disinfector begins its programme.
This is the first stage and, like the rest of the department “we never stop, not even for Christmas,” said David who is in charge of more than 80 staff.
Each of the machines for the start of the process cost around £50,000 and its job is not only to make the instruments visibly clean but “microscopically clean” explained David.
From being cleaned the instruments move on automatically into the much larger Inspection Assembly Packing room (IAP) where they are prepared for sterilisation. This part of the process is more labour intensive as the instruments are individually checked before being put into each tray according to the operation that needs them.
This packing room is air locked – rather like the space shuttle- so one hatch cannot be opened until the other one is shut, avoiding any chance of contamination.
David explained that the room is a controlled environment with filtered air to avoid any chance of recontamination and staff working in it have to wear gowns and hats to make sure the instruments are protected from any external contamination.
They check the instruments for visible damage with the naked eye and using illuminated magnifiers or microscopes when necessary.
Each completed tray is then wrapped with a list of the contents on the top. The next step is for it to pass through the hatch and go into one of the sterilisers where steam is created under pressure to destroy any remaining living organisms on the instruments.
”We wash, pack and then sterilise at the end of the process. It’s an odd principle which some people outside of the SSD don’t understand” said David.
Each sterilising cycle takes around 45-50 minutes depending on the load, but the actual sterilisation part of the process is just over three minutes as the temperature has to be between 134 and 137 degrees centigrade otherwise it falls outside acceptable parameters.
David explained “The whole cycle takes that long because all the air is sucked out of the chamber first to create a vacuum. That enables the steam to penetrate through the packaging of the trays into every nook and cranny of every instrument.”
The water creating the steam must be very clean and pure. “It’s not like your kettle steam its much drier which is why the paper list and the paper packaging enclosing the trays come out dry. Nothing gets soggy, it’s dry to the touch.”
After sterilising the trays need ten minutes to cool down and then they go onto the racks in the Sterile Store ready for distribution. Theatre lists arrive ready for the next day and the appropriate trays are collected and sent to theatres ready for operations.
In a separate area of the department is one of the biggest Endoscopy decontamination units in the country, installed just over three years ago. Flexible endoscopes are used daily throughout the hospital but they cannot withstand the same high temperatures as the other instruments.
There are eight automated endoscope reprocessors taking four instruments at a time so 32 can be washed and disinfected simultaneously. These machines have rotating spray arms to wash and disinfect the external surfaces of the instruments and a sophisticated system for the endoscopes’ internal channels.
As each instrument goes through Sterile Services it is tracked through every stage by the computer system. Start to finish can take between five hours to a day. In the Sterile Store surrounded by rows of trays wrapped in blue David just presses a couple of buttons on a computer and can tell you the precise history of a single instrument from when it was first used to how many times it has been through the whole sterilisation process and which theatres have used it.
David sums up the busy and very important process he oversees with “Most of the public have no idea what goes on here behind closed doors, its decontamination on an industrial scale.”
Chief Executive Mark Davies said “Sterile Services is one of the many departments whose work goes on behind the scenes and is not only very important in the running of the hospital but also highly valued. Their contributions to safe quality care are immense.”