IPPV

RE: IPPV

Nicola Smith — Sat, 23 May 2020 14:41:26 GMT

Hi, you would need much higher oxygen flow rates if you have the valve fully open otherwise your bag will deflate, you would then be removing the big advantage of circles, lower oxygen costs and less risk.of hypothermia due to reuse of pre warmed gases.

If you are doing IPPV with valve fully closed and Very little fresh oxygen the risk would be that if you do not have the correct monitoring in place your patient could be rebreathing C02 leading to hypercapnia your soda lime would need to be functioning really effectively to ensure your patient wasn't rebreathing.

If you are doing IPPV and not closing the valve down the risk is that you are not ventilating patient enough as gas could just be emptying straight into the scavenge. It's the fine balance between ventilating enough without over inflation. If you work out what your patients tidal volume that might give some indicator as you can compare how much is in your bag versus how much your patient needs, and observe chest movement to look for normal inflation. A capnograph is very useful when doing IPPV as I think we do also have a tendency to give too many breaths per min as we get carried away!!

RE: IPPV

E13 — Sat, 23 May 2020 01:54:36 GMT

Thank you! Just to clarify (sorry) is a circle ever used with valve fully open? What is the difference between the two methods of IPPV - closing the valve and reopening it every time, or leaving it half open and not touching it? I understand the risk of barotrauma if you give too big a breath with the former, but is there anything else?

Thank you :)

RE: IPPV

Nicola Smith — Thu, 21 May 2020 05:59:17 GMT

Most people choose to run their circle semi open with valve partly open. Strictly speaking a circle is classified as a closed circuit so can be run with valve fully closed and Very low oxygen, just enough to replace metabolic need. In practice people usually choose not to run this way for safety as you need to be 100% happy with your skills and monitoring equipment to run this way- ideally using capnography and blood gas analysis as you need to be certain patient is ventilating effectively and that your soda lime is working properly.

Using IPPV is same, if you are 100% happy with everything it could be done but also bear in mind the risk of baro trauma to the lungs as well with leaving the valve completely closed and oxygen running. In standard first opinion practice without access to an anaesthetist and lots of equipment I would always be running a circle as semi closed and therefore doing the same with IPPV to ensure I have enough 02 to my patient.