VivaCast 1 – Cleaning and Sterilisation for the FRCA Primary Exam

Primary FRCA Viva Question could be…

What are the differences between preparing a laryngoscope blade for reuse, compared with a laparoscope, and a stethoscope?

How are medical instruments cleaned and sterilised?

Medical instruments undergo cleaning to remove debris, followed by sterilisation using methods like autoclaving, chemical agents, or irradiation to eliminate all forms of microbial life, ensuring patient safety.

Cleaning

Soap / detergent, depending on what is being cleaned appropriate ppe may be required. <45 degrees to not coagulate the proteins, making it hard to remove and creating. A realm for bugs.

Eradicating filth is naturally the first step to achieving sterilisation.

Achieving disinfection of Equipment

• Moist heat – ie 100 degrees c water for 10 mins – kills everything but bacterial spores
• Chemical Disinfection – Take time to work – can decay, more quickly in high temps 
• Alcohols, Hypochlorites, Aldehydes
• Pasteurisation – 77 degrees for 30 mins – intermediate level of bug reduction.
• Glutaraldehyde 2% oft used for endoscopes 20 mins

Achieving Sterilisation Of Equipment

• Steam Autoclave
• Steam + Pressure – The Autoclave 134 deg C for 3, or 121degC for 15 mins (Pressurised to increase the temp of the steam)  
• Steam + Formaldehyde – formaldehyde is irritant, eyes/resp/skin
• Hot Air – 160 degc for 2 hours (some kit cant handle that)
• Ethylene Oxide – colourless, inhalationally toxic, kills everything, costly 2-24hs
• Irradiation – can cause kit damage, bulk / industrial process
• Glutaraldehyde is time based exposure depending on nature of equipment

Define or Die

Cleaning

The process that removes contaminants (dust soil, large amounts of micro organisms, general gunk (blood etc)

You cant disinfect and sterilise something that is unclean.

Bioburden 

“the gunk/detritus’

Disinfection 

Reduces the number of micro organisms but not bacterial spores like clostridia) Reduces the quantity of bugs to a sub harmful to health level.

Sterilsation 

Removes/ destroys all microbial life inc spores.

Item risk stratification

Critical / High: –  contact breaks in the skin / mucous membranes – or are being introduced into a normally sterile body compartment – these must be sterile. (needles. Scalpel indwelling devices)

Semi-Critical / Intermediate: those which contact mucus membranes, or might be readily infectious with pathogenic organisms – e.g. laryngoscope blades ET tubes/ endoscopes

Non-Critical / Low: only come in contact with skin – stethoscope etc need to be cleaned / dried 

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Transcript

Gas Gas Gas VivaCast: Sterilisation and Equipment Cleaning

Introduction and Exam Strategy

00:00-00:36

Hello, my fellow Gas, Gas, Gas compatriots. Today is the first VivaCast with my willing victim, Tom.

Whilst it might be tempting to put the viva to the back of your mind and focus on the SBA, the content heavily complements each other as you would expect. So I would thoroughly recommend you have the courage to practise for the viva as well as studying for the exam, bearing in mind I didn’t have the courage.

So Tom, who are you and where are you in your exams?

Meet the Candidate

00:36-01:06

I’m Tom. I’m a CT3 trainee in the North West. I’ve recently passed my written back in September, and I’m waiting to sit the viva in January.

We are going to pile straight into quiz action. Tom has ready and raring post night shift. We’ll then review what we’ve spoken about and try and sharpen things up a little bit.

So, Tom, this is your physics and equipment viva.

Equipment Classification and Sterilisation Requirements

01:06-02:58

Question: What is the difference between preparing a laryngoscope blade for reuse relative to a laparoscope or a stethoscope?

The different levels of preparing equipment are linked to their categorisation as critical, semi-critical or non-critical.

Critical pieces of equipment enter parts of the body that are normally sterile and thus have to be cleaned to the highest degree. Semi-critical equipment makes contact with mucous membranes or broken skin and still has to be cleaned to a high degree than equipment that does not do that. Non-critical equipment contacts intact skin or is just present in clinical areas and can be cleaned to a less high degree.

The levels are divided into sterilisation at one end of the spectrum, disinfection in the middle, and cleaning. Cleaning has a fairly common sense definition really – it’s usually using soap or surfactants to remove contaminants from the outside of an object that can include blood, faeces and things like that.

Disinfection involves bringing microorganisms down to a safer level, but not necessarily destroying them all, and not normally including bacterial spores such as Clostridia, for instance.

Critical equipment that’s going to enter parts of the body that are normally sterile has to be sterilised. Sterilised meaning all living organisms are killed on that object so as to prevent cross infection. There are different techniques for achieving all of these.

Sterilisation Methods

02:58-04:05

We mentioned at the beginning that soap and surfactants can be used for cleaning. At the other end of the spectrum, sterilisation, there are different ways to sterilise equipment:

Firstly, using steam, so primarily utilising heat from heated water essentially. We can use irradiation, so gamma rays being a fairly common technique for killing microorganisms on equipment that requires sterilising. Or we can use pressurised gas to sterilise equipment as well – the name of the gas escapes me just now, but there is one that’s in relatively common use.

In the middle for disinfection we can use solutions such as hypochlorite solutions or alcohols that will kill most living organisms on surfaces when exposed for appropriate amounts of time, but they, as mentioned before, don’t normally remove bacterial spores.

Prior to sterilisation or disinfection, cleaning is an essential first part because you need to remove contaminants from equipment before you can properly disinfect or sterilise them.

Examiner Feedback and Additional Details

04:18-06:02

That was a structured answer where you broke it down into semi-critical, very critical and non-critical stuff, and then broke down the requirement standard of cleanliness or sterilisation relative to that. It might be easier to bullet point things a little bit more.

The pertinent thing to mention with cleaning, beyond just removing debris, is that often it’s done at sub forty-five degree temperatures to stop the alteration of proteins that might make it harder to clean the thing in the first place.

You mentioned chemical disinfection methods, alcohols, hypochlorites, and some aldehydes as well. Or moist heat, i.e. a hundred degrees Celsius water for ten minutes, kills everything except for the bacterial spores you mentioned there, Tom.

The other two things to mention on the disinfection front: There’s pasteurisation. So if you have something at seventy-seven degrees for thirty minutes, it kills off most bugs, but not all. And then glutaraldehyde is probably the chemical to mention of the aldehydes, which is used for cleaning endoscopes.

Is it effective against mycobacteria if given enough time as well? Which I think can be more resistant to some of the other solutions. Yeah, if you cook it for long enough.

And the gas you were trying to think of for achieving sterilisation is ethylene oxide. It’s colourless, it’s inhalationally toxic, it costs a bit and it takes two to twenty-four hours of exposure for it to actually sterilise stuff. So it’s quite expensive to achieve sterile equipment, isn’t it? Lots of equipment, chemicals and various procedures involved.

Key Definitions and Risk Categories

06:02-08:08

The last thing is just to make sure we’re definitely hot on those definitions. Cleaning is the process of removing contaminants, dust, soil, large amounts of microorganisms, blood. But you can’t disinfect or sterilise something until it’s clean. As a term, bio-burden – that’s just the gunk and general detritus that’s on whatever thing you’re trying to clean.

Tom mentioned that disinfection is reducing the number of microorganisms, but not bacterial spores like Clostridia, reducing those bug levels to a sub-harmful level of health. Sterilisation is annihilating everything under the sun that is lurking on that device.

He mentioned stratifying the risk of where you’re going with that device, so a critical or high-risk area is sterile cavities within the body, and anything that goes there also has to be sterile: laparoscope, needle, scalpel, etc.

Semi-critical or intermediate risk is those coming in contact with mucous membranes or broken skin. That would be things like your laryngoscopes, your endoscopes, and maybe your sigmoidoscopes.

And then non-critical or low is stuff that comes into contact with skin. So your stethoscope just needs to be clean and dry. Excellent.

Exam Technique Advice

08:08-09:56

Just thinking about exam technique a little bit as well, the question itself did mention laryngoscopes and endoscopes. So some specific reference to the technique used for those, as you mentioned, talking about aldehyde for endoscopes, will probably pick up some of the marks.

And then you might close out with if you’ve got to the end of that and they’re still asking you questions about irradiation with gamma rays or how stuff might be packaged and taken into theatre, then you’re doing really well because you’ll have answered all the core bulk of questions, but they will just keep asking you questions until that time goes bing and they move you on.

Expect to spend five minutes on each sort of subject area. And really, you want to spend a couple of minutes talking. They might interrupt or try and move you on. Try not to spend the whole five minutes talking and trying to let your examiner in because if you just keep talking, you might talk yourself off topic and they might not get where they want to go. So you’ve got to have some natural pauses where they might think, “Ah, okay, tell me about…”

Candidate Reflection

09:56-10:07

How did you feel that went? Yeah, okay. Maybe a little bit lacking on the detail, but I felt able to structure it, which is half the battle sometimes.

Always have a decent structure, or a fallback structure like pre-op, intra-op, post-op, or bullet point things, and then hang off of that to make it sound like you know what you’re on about, which is half the game.

So, Tom, that was your Physics and Equipment five-minute subsection viva, because that would only be five minutes in the exam.

Closing

10:07-10:42

Hello everyone, that was Tom. I am James. This was the Gas, Gas, Gas VivaCast, and it was the first time that we’ve recorded something over the Internet. We spent quite a lot of time scratching our head and trying to make it work. We are not sound engineers. But if it was useful, email me and let me know. My email address is on the website.

Next time, Tom does physiology, and then I drag him backwards through a hedge, doing pharmacology.