Anaesthetic circuit valve positions?

RE: Anaesthetic circuit valve positions?

jojofruits — Tue, 16 Jan 2018 10:15:37 GMT

this thread is brilliant, and has made me adjust what I'm doing in practice, thank you guys!

RE: Anaesthetic circuit valve positions?

Meow1950 — Sat, 13 Jan 2018 16:51:29 GMT

[quote user="Susanna Taylor"]

When ventilating with a T piece, if the valve is too closed the FiCO2 will go up (above 0). The FiCO2 will also go up if FGF is too low with any non-rebreathing system, ventilating or not

For circles, valve position will not directly effect FiCO2 as this should be being removed by the absorber granules. If the pressure in the circle is too high, because the valve is too closed and the FGF too high, you will first see changes to the capnoGRAM such as shark fins, and then slowly increases to ETCO2. OR, possibly low ETCO2 with 'small hills' if the pressure is so high the patient can barely exhale.

Hope makes some sense and helps?

[/quote]

Amazing! Thanks

RE: Anaesthetic circuit valve positions?

Susanna Taylor — Sat, 13 Jan 2018 13:09:58 GMT

When ventilating with a T piece, if the valve is too closed the FiCO2 will go up (above 0). The FiCO2 will also go up if FGF is too low with any non-rebreathing system, ventilating or not

Hope makes some sense and helps?

RE: Anaesthetic circuit valve positions?

Meow1950 — Sat, 13 Jan 2018 12:48:00 GMT

[quote user="Susanna Taylor"]

Agree with general consensus:

IF you have the benefit of capnography, it allows you to be much more confident trying different settings, as you will see within moments if you do something wrong.

[/quote]

Are there any specific reading that correlate with the valve position? Or do you just mean in general, like if it’s closed too much the ETCO2 will be higher etc.

Hope you know what I mean by that question, couldn’t think of a better way to word it lol

RE: Anaesthetic circuit valve positions?

Susanna Taylor — Fri, 12 Jan 2018 13:37:11 GMT

Agree with general consensus:

T piece always open, unless ventilating. (it is worth mentioning that you can ventilate with the T-piece valve partially closed, and not move it - just squeeze the bag. I would recommend using capnography to ensure no rebreathing, but I have never encountered it at suitable flow rates (MV x 2.5). Fully closing the valve as you ventilate comes with a high risk of very high inspiratory pressures, and i would avoid unless you have a pressure gauge/spirometry. A middle ground it to partially close the valve for each breath, then open it. You know when you have closed it enough because the resistance changes as you inflate the chest rather than the scavenging system). Alwasy watch the chest, not the bag). I digress..

Circle system - valve fully open to denitrogenise for 10min and then drop flow rates to low flow (1-1.5L generally), watch the bag here, if stays plump leave valve open, if bag goes a bit flat looking, close the valve partially until bag is plump but not expanding continuously.

IF you have the benefit of capnography, it allows you to be much more confident trying different settings, as you will see within moments if you do something wrong.

RE: Anaesthetic circuit valve positions?

Kirsty RVN — Thu, 11 Jan 2018 22:34:34 GMT

Yeah I always have the valves fully open and was taught this and only close them for leak testing and IPPV and than fully open them again!

RE: Anaesthetic circuit valve positions?

James Colver Cert. Ed, RVN — Thu, 11 Jan 2018 18:38:11 GMT

Should be fully open when you first connect patient, and FGF at 2-4 litres/min - this is to enable the 'room air' to leave the circuit quickly - priming the circuit if you like. THEN the valve can be closed a little bit which can enable FGF to be turned down a bit - or you can leave it fully open.

RE: Anaesthetic circuit valve positions?

Robyn — Thu, 11 Jan 2018 17:54:43 GMT

I was always taught to have my circle circuit half open - I take it there's no point to this anymore and I should start having it fully open?

RE: Anaesthetic circuit valve positions?

James Colver Cert. Ed, RVN — Thu, 11 Jan 2018 17:30:44 GMT

Yes. The tighter the valve is closed, the more pressure inside the circuit - the more pressure inside the circuit, the greater the risk of barotrauma.

The old T pieces didn't even used to have a valve - i.e. they were always fully open. If we wanted to close them, for IPPV then we had to pinch the outflow end of the bag closed with thumb and forefinger!

RE: Anaesthetic circuit valve positions?

Meow1950 — Thu, 11 Jan 2018 10:53:03 GMT

Thanks everyone!

So consensus is fully open for T-piece and almost fully open/fully open for circle?

RE: Anaesthetic circuit valve positions?

molladog — Thu, 11 Jan 2018 08:10:10 GMT

APL valve on T Piece always fully open unless ventilating.

RE: Anaesthetic circuit valve positions?

Nick Shackleton — Wed, 10 Jan 2018 20:53:56 GMT

Fully open here too. Only closing the valve to ventilate then opening it again

RE: Anaesthetic circuit valve positions?

Tania Ford — Wed, 10 Jan 2018 20:49:15 GMT

I always have the valves fully open, unless ventilating

RE: Anaesthetic circuit valve positions?

James Colver Cert. Ed, RVN — Wed, 10 Jan 2018 19:37:12 GMT

Certainly for an ATP I would keep the valve fully open - Apart from leak testing and performing IPPV I cannot see any reason to close the valve either partially or fully.

As said above, closing the valve a little bit in the circle circuit can help to increase the pressure in the circuit if need be, but usually I would have the valve almost fully open.

RE: Anaesthetic circuit valve positions?

jojofruits — Wed, 10 Jan 2018 15:54:40 GMT

I open my valves one and a half turns

If the bag is looking like its under too much pressure then I adjust accordingly.