EBME Forums Forums Management Equipment Libraries HFOV

Hi all.
Does anybody out there use scavenging on the 3100B HFO Ventilator. If so, could you describe it and how it fits to standard and filtered circuits. Our ITU is looking at options for treating infectious patients (TB, legionnaires etc) on it and whilst Viasys can supply parts, they don't seem to have the background info on their use.
Also HFOV is contraindicated for TB, does anyone know why? I spent ages trawling the net to no avail.
Any info greatly appreciated!
Thanks
Topper

We use the SensorMedic 3100A, pretty much the same beast!!
Ive emailed a couple of images showing the "adaptor" for scavenging.

Yes, but why the contra-indication for TB? I've also had a quick look on-line, and have yet to find (or think of) an answer to that one. Would it be that compliance (lack of) of a TB lung just couldn't handle the rapid oscillations? Does the TB lung "harden"? Or put another way, does (or would) HFOV damage the TB lung? Come on somebody, I need to know!

I cannot find any reference or contraindication against HFOV for a patient with TB. Where did you see the containdication Topper?

I was told by nurses on two occasions the Vent was put on TB Pats. I have a locally produced guide titled Clinical Management Strategies for Adults CCU NX Wolves which i think was collated by our consultants and it states "at present it is advisable not to use HFOV in cases of smear positive Tubercolosis, SARS, pandemic flu etc." This is however under the heading Scavenging and Infection Control.
Topper

Yes, that's it. It would be for reasons of cross-infection prevention, rather than a clinical prohibition. Are these units difficult to clean?

I don't think they are Geoff as the circuits expiratory path vents to the room and not back to the vent but this is why there are the infection issues mentioned above especially regarding exposure of staff etc.
Topper

... hence your original post about scavenging! Got it now. So, it seems that HFOV could very well be beneficial in TB cases (as I had imagined), but the issue is now getting rid of the expired "gases". Not an issue restricted to this ventilator only, then.

How's it done ... collection cannisters, passive, active, a special pump? Do we now need theatre-type active scavenging in ITU's (ICU's)? Surely this sort of thing has:-

a) Cropped up before
b) Is likely to be needed more and more

... especially in the present climate of Health and Safety "awareness". It's an interesting issue. But one that should be adequately dealt with by a decent number of room air-changes per hour anyway (ie, the building HVAC system), I would have thought. What about all the other stuff floating around in the polluted air of the ITU (ICU)?

From what I remember there is not that much which comes into contact with potential biohazard, the circuit itself is entirely disposable and all gases are exhausted via the exhaust port into the room. So unless the atmosphere itself is dangerous then the HFOV should be reasonably well isolated.

The HFOV would be useful clinically for someone with poor lung compliance as the method used to recruit aveoli is very effective and should lead to improved compliance as more atelectic aveoli are recruited.

As previous posters have mentioned the HFOV would not be suitable for infective "open" TB as the exhaust gas is routed directly into the room, there is no bacterial filter in the expiratory phase

The scavanger used to be fitted to the expiratory port on the 3100B circuit and was then attached, I believe, to the vacuum point in the wall. The scavenger itself was originally designed for the removal of Nitric Oxide from the exhaust gas. It is not perfect as it does not form a air tight seal around the expiratory port, but it is certainly better then nothing.
The newer circuit does have a anti-bac filter in the expiratory limb but I think it needs changing every 24 hours, which pretty much renders it useless as you would need to change the circuit, not the filter, every 24 hours and then you would need to start recruiting the lung again.
If only someone else sold a oscillator with a proper filter which would be suitable for this
Mark