Problems with self seal sterilisation pouches

Re: Problems with self seal sterilisation pouches

Sal the 1st — Mon, 12 Oct 2009 23:28:38 GMT

thank you for coming on here and keeping us all up to date . its nice to know that companies and manufacturers care about our comments

Re: Problems with self seal sterilisation pouches

Andy Hardie — Mon, 12 Oct 2009 16:51:41 GMT

Hello!

I'm a rep for Millpledge - We did have a problem a while ago with our pouches so I understand your troubles...

The issue was twofold. Firstly, the film was too brittle once the pouch had undergone the sterilisation process and tore too easily but this was not helped by the second problem - strong glue. This made the weakest point in the pouch the imaginary 'line' down the centre of the film, rather then at the point where the paper met the film, in turn leading to the problem you describe.

I believe the problem has been rectified now, but if anyone else experiences this problem PLEASE get in touch with us to let us know!

Many thanks,

Andy Hardie

Re: Problems with self seal sterilisation pouches

sisterscope1 — Thu, 23 Jul 2009 21:33:32 GMT

No problem Freckle, glad to be of help.

Millpledge acknowledge that there have been quality issues with their pouches and are currently trying to resolve the issue.

Re: Problems with self seal sterilisation pouches

scubamoo — Wed, 22 Jul 2009 09:03:48 GMT

Hi There

We order ours from centaur and they are flowmed ones.... they don't seem to split.

Re: Problems with self seal sterilisation pouches

Freckle — Tue, 21 Jul 2009 22:42:25 GMT

bloody fantastic post thankyou! bit too tired to properly digest it all atm, but will be coming back to it tomorrow ;)

incidentally, i have scoured all my nursing books this evening for more info on this, and couldn't find anything anywhere near as informative as your post - and i have a fair stack of vet nursing books!

Re: Problems with self seal sterilisation pouches

sisterscope1 — Tue, 21 Jul 2009 22:19:10 GMT

Sure Freckle, will do my best. So...

A packaging material must fulfil the following criteria to be considered for terminal sterilisation of supplies, ie those that are sterilised and stored for use at a later date.

Permit the removal of air from the package and allow subsequent penetration by the sterilant (e.g steam). Residual air creates "cold spots" and prevents steam condensing onto the surfaces of the items to be sterilised - resulting in a non-sterile item.

Permit removal of the steriliant - if it traps steam it will condense to water within the package once cooled.

Provide a barrier to microbial penetration - essentially act as a filter to the air which moves in and out as the package is handled/stored. Must remove 99.999% to be considered sterile barrier.

Should be tear and puncture resistant without shedding fibres in order to maintain sterility.

Should allow for aseptic presentation of the contents onto the sterile field. i.e you need to be able to get it out again without contaminating it or the sterile area it is being placed onto. If you have to violently shake it out of a bag with your hands directly over the sterile trolley, it isn't working!

So, nylon film - rubbish. Air can't come out, steam can't get in - except via the tape seal. Difficult to remove items once packaged without compromising sterile field - you have to "milk" them out or place your hands directly over sterile field

Peel pouch - v good. Air/steam moves ONLY through paper side - make sure load autoclave paper to plastic and stack on edge. Allows for steam penetration and improved drying - condensate during the drying phase will run off rather than sit on. Any item which falls over the seal during presentation is considered non-sterile.

Tray wrap - non-woven disposable sheets used to wrap trays, gowns etc, provides barrier by providing tortuous pathway for microbial migration - bacteria can't move through wrap if dry and also because of the way it is folded around the items to be sterilised. Usual to have 1-2" margin of sterility around the edges to allow for opening/presentation.

Re-usable textiles - rubbish. As with re-usable drapes, not a barrier wet or dry.

Rigid containers (NOT Schimmelbush drums) - excellent! Solid container body with a seperately fitted lid which once sealed in place provides an excellent protective barrier. A special filter in the lid permits the removal of air and penetration of steam and facilitates drying (in porous load autoclaves). Lids locked with disposable locks, removed in theatre and sterile person reaches in without touching container to retrieve sterile items - normally arranged in a special tray inside. Expensive but cost effective in long run as minimal disposables or waste.

Problem with wet loads - if the package is wet then it will allow for microbial penetration, as bacteria can gain acces to the contents by capillary action (wicking). I always think of this as follows - if you put some powder paint on a surface and cover it in a dry cloth, does the paint come through? No. If you wet the cloth, paint travels through by capillary action and you get a funky coloured tea towel. If you dry the cloth, does the paint stay on the cloth or move out again? So drying wet items out of the autoclave is a no no, they are considered contaminated. Remember, as hot items cool down when they are removed from the autoclave, they will pull a partial vacuum - ie as the warm air inside cools down, it contracts - sucking in air from the outside. If the barrier is dry and intact, this isn't a problem. If wet, well you've a Picasso on your hands.

Why are they wet? What type of autoclave do you have? Shouldn't use packaging materials in gravity displacement autoclaves UNLESS you can adjust the sterilisation times to counteract the poor steam penetration. Drying is usually by passive means, ie sitting in a warm chamber, this only removes some moisture. As soon as you open the door and it mixes with cold air, residual steam will rapidly condense to water and you're left with wet packages. It's not ideal, but if you can open the door slightly and keep the chamber hot, it will help drying. In porous load or vacuum assisted autoclaves, pulling a vacuum in the chamber aids drying - steam occurs and sub-atmospheric pressures and is easily removed from the package. Loading - don't put heavy items on shelves above pouched items, they dry at different rates and water is more likely to drip down. Stack pouches on edge rather than on top of one another. I think in small autoclaves you can get something which resembles a toast rack for that purpose. Don't overcrowd autoclave, if you've poor drying, chances are you had poor steam penetration in the first place. In large porous load autoclaves with dynamic air removal, wet loads are usually a problem with steam quality.

Blimey, gone on a bit - sorry!

Re: Problems with self seal sterilisation pouches

Caroline Boothroyd — Mon, 20 Jul 2009 22:58:45 GMT

we used to use ones direct from NVS but swapped a few months ago to Millpledge and have has no probs with them so far! we double bag everything and anything sharp had a cover on.

we did get a few from the Rep last year and they were crap, but we put it down to old pouches sitting in the car for years! all our new stock has been fine and seem better and thicker than the NVS lot

Re: Problems with self seal sterilisation pouches

Freckle — Mon, 20 Jul 2009 22:48:14 GMT

thankyou for your reply - as I said its an area I'm really interested in, and want to do well in practice - I think its such an important aspect of the job (as is cleaning - don't get me started on the number of vets/vn's i have worked with who couldn't care less about dilution rates and contact times grr)

We do use the pouches, but don't currently have any large enough to take gowns. If you don't mind me asking, could you explain a bit more about how the whole sterilisation by autoclave works with respect to the packaging... as I said, haven't done 2nd year yet, and I will google it, but we all know that google aint always that accurate We do also get stuff that comes out the autoclave with wet packaging (with the pouches) on a fairly regular basis... I always place it 'paper side up' to dry... I presume after reading your post that they cannot actually be considered sterile?

Re: Problems with self seal sterilisation pouches

sisterscope1 — Mon, 20 Jul 2009 15:02:20 GMT

Freckle, sterilisation packaging materials are not designed to be airtight - if they were, they would fail. A sterilisation package provides a barrier, so after sterilisation in storage/handling etc., air is "filtered" through the barrier material and microbes can't penetrate (unless wet - which is why anything wet after being sterilised in steam cannot be considered sterile or packages that become wet in storage.)

Can you use an alternative packaging material? Peel pouches or wraps? I'd definitely ditch the nylon film, apart from being rubbish as a sterilisation packaging material, it's really difficult to remove the items from without contaminating them or compromising the sterile field.

Re: Problems with self seal sterilisation pouches

Freckle — Fri, 17 Jul 2009 21:58:34 GMT

wow!

thanks for your reply!

so whats the best way to pack stuff with nylon film and indicator tape? coz i have always been told in practice (not done 2nd year.. yet) to make it airtight..

sorry if my reply is a bit ott, but i LOVE the 'ensuring sterility' part of nursing, incl contact times, dilution rates etc, so am rather gutted that i had such a 'wrong' view on the whole nylon film/indicator tape thing :( boooo!

please help me to be better at sterility!

Re: Problems with self seal sterilisation pouches

sisterscope1 — Thu, 16 Jul 2009 17:06:28 GMT

Thanks for replies.

Have sourced some different ones and they seem fine, so maybe just a problem with Millpledge?

The pouches are stacked on edge in loading baskets and are a good few inches from the chamber walls (our autoclave is 16 cubic feet, so quite large!) so I don't think this was the problem.

Freckle, when you say "packet on a roll", do you mean nylon film? Plastic on both sides and you make a "bag" with tape? If so, remember it is not permeable to steam/air through the plastic, so air/steam can only move through the seal. If you're making them 'airtight' then air cannot be removed and steam cannot enter, so they're not sterile if they survive without popping. They pop because residual air inside the packs heats up and expands in the autoclave and causes the tape to rip open. Nylon film isn't ideal as a sterilisation packaging material for this reason, in fact it's useless. When we used to use reusable gown, they were wrapped in sterilisation paper using an envelope method, kept the packs nice and compact and easy to store. The wrap is really cheap too.

Re: Problems with self seal sterilisation pouches

Freckle — Thu, 16 Jul 2009 07:37:04 GMT

slightly off topic but i find that when i use the old packet on a roll & indicator tape to pack up gowns, that they always pop open! It only seems to happen with mine lol, but i am the only person who makes sure they are 100% airtight before autoclaving them... could this be the problem, and if so, how can I rectify it without compromising sterility?

thanks

Re: Problems with self seal sterilisation pouches

chris beasley — Wed, 15 Jul 2009 16:17:35 GMT

We use "selfseal" from NVS. Only time we ever had a problem was when the autoclave over heated and the plastic stuck to the drapes!

We are still tring to remove the last of it!

Re: Problems with self seal sterilisation pouches

Fiona Leathers — Wed, 15 Jul 2009 14:39:25 GMT

Is it the Millpledge ones you are using? cos we have this problem sometimes, occasionally I think its how the autoclave has been packed, too full and it stores heat up too much, as the air is flowing around the packs. But that's just my theory......don't hold me to it!

Re: Problems with self seal sterilisation pouches

loobylou — Tue, 14 Jul 2009 22:28:18 GMT

We use self seal pouches and don't have any problems. Not sure what brand they are, we get them form NVS. We also tend to double bag a lot of items so if they get damaged in storage we still have an inner wrapper.

Re: Problems with self seal sterilisation pouches

Sal the 1st — Tue, 14 Jul 2009 22:23:29 GMT

have come across this problem some time ago - never got to the bottom of it, it was almost as if the plastic was 'brittle' but started ordering through NVS instead - theirs are made by ?flowmed

Re: Problems with self seal sterilisation pouches

sisterscope1 — Tue, 14 Jul 2009 22:20:49 GMT

Sorry, just to be clear - not problem with items perforating through, such as sharp instruments, but rather the pouch splitting on the plastic side. You start to peel open and before you know it, it's split up the middle.

Thanks Nick

Re: Problems with self seal sterilisation pouches

Nick Shackleton — Tue, 14 Jul 2009 22:17:03 GMT

We used to have them but have recently changed! Not sure what make they are thou as not in charge of that! Will check on Thurs and get back to you. Not had any probs with the new ones, we also use them plastic caps you can put over sharp instruments, such as IM pins, stifle distractors etc.....