What does "Ao" stand for?

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So no idea what "Ao" (That's big A, little letter o) stands for, and neither does anybody I've asked.

It's sensor is attached to the the vent's tubing right before it hooks to the ett. It's a mostly flat line that has upward deflection in regards to breathing. We use it to determine where to average the CVP.

I figured the descriptors would help incase it's not referred to "Ao" elsewhere. I must have my curiosity satisfied! Thanks in advance :)

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Specializes in NICU, PICU, PCVICU and peds oncology.

"Ao" usually refers to the aorta. The description of the sensor you've given is most likely the end-tidal CO2 sensor, which will give you a waveform on your monitor. Other than that I have no idea what else it could be.

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Definitely not end-tidal co2. Yeah, everybody just always says "a-oh" and nobody seems to know what it means. Somebody ventured the guess airway output, but that seemed a bit far fetched. *shrug*

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Don't quote me on this, but I thought it meant pressure at the airway opening. Similar to PAW.

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I'd say also 'aorta'.

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Specializes in ICU.

Got any biomechanical engineers on call or that work the unit? Lead RT? Pulmonologist you could ask?

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Specializes in MICU for 4 years, now PICU for 3 years!.

At my hospital, we use the Ao pressure line for our abdominal pressures... not sure what it would mean in relation to your vent, sorry...

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Specializes in Cath Lab/ ICU.

In my dept, it means Aortic pressure...

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Specializes in CTICU.

The "Ao" is just the label on the monitor for the waveform (and actually means "aortic" pressure). The actual tracing you're seeing is an airway pressure (Paw). The purpose of it is so that you can see where end-expiration is in order to accurately assess end-expiratory central pressures ie CVP or PCWP. The thought is that if you can pinpoint end-expiration from the airway waveform, people won't be just looking at the CVP waveform and guesstimating end-expiration, as it has been demonstrated that there is significant interobserver variation when people guess. I attached some info.

Paw and CVP.pdf

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Great pdf!! Thank you

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