Dear all
We are in process of decomissioning our N2O manifolds and switching to canisters. My colleague Dr Dolphin has been looking into the details of this and we have a question in regard to the xchange in pressure (4 vs 44 bar) between canisters and pipes and whether this will cause the anaesthetic machines to alarm and fail. I am pasting his much more detailed question below in case anyone has any advice please?
Thank you very much!
Jasmine
My question is a rather technical one and the answer might depend on which anaesthetic machines we’re using. We are currently using GE Aisys CS2 anaesthetic machines and will also be adopting the GE Carestation 600 in some theatres soon. I have not been able to get any kind of response from GE on this question.
We are looking to replace the manifold-supplied wall outlets with individual cylinders of nitrous oxide with a Schrader-valve adapter (of the sort shown in the attached picture) that will be brought to theatre for the rare cases when someone really wants to use nitrous oxide. None of our anaesthetic machines have a pin-index nitrous oxide cylinder yoke any more, only O2 and medical air cylinder yokes.
My question is this: when we plug the anaesthetic pipeline into the Schrader valve adapter mounted on the nitrous oxide cylinder, presumably this will deliver around 44 bar of pressure from the cylinder to the pipeline rather than the 4 bar that the manifold wall outlet supplies. Does this cause a problem for the anaesthetic machine? Or does the adapter regulate the pressure down to a more managable number?
The user manual for the Aisys CS2 (attached) suggests that the machine is expecting a pipeline inlet pressure of 280-600kPa (2.8-6 bar) so I don’t know what it would do in terms of self-checking error messages or system over-pressure to be connected to a higher pressure. I am slightly reassured that the manual suggests in section 11-2 that both the pin-index yokes and the pipeline inlets have a pressure regulator between the gas supply and the anaesthetic machine… however I am not any kind of expert on reading pneumatic circuit diagrams!
Any advice from those who have explored this before would be very welcome!
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