Inverse ratio ventilation

[putmetosleep]

I know what this is (a longer inspiratory cycle and shorter expiratory cycle), but can somebody explain to me when this is used and what the rationale is? I've never seen it used and it's not clicking for me...

Any dangers/things to watch for (besides auto-PEEP)?

Thanks

[RNperdiem, RN]

When I was in orientation, they have us mouthpieces to hook up to a vent to get a feel for the various settings.

This is inverse ratio.

1. Breathe in deep

2. Exhale just a little

3. Breathe in deep again

4. Exhale only a little.

5. Repeat

This is a very unnatural way to breathe. Your patient will require lots of sedation and maybe paralytics not to fight the vent.

I have rarely seen this used except on patients who desperately need oxygenation and are not getting it on more conventional settings.

[PageRespiratory!]

IRV is (rarely) used to recruit atelectasized alveoli, typically in ARDS Pt's. It's really used as an oxygenation tool, without the use of excessive pressure. By prolonging the inspiratory phase, we can increase mean airway pressure, without nessecarily increasing peak airway pressure. IRV is really a last ditch effort, because of the risks previously mentioned (Pt - vent asynchrony, auto peep, ect.) There is no real evidence stating any benefit, I can say I've only seen IRV used once. Unsuccessfully.