RT Clinic: Basics of Plateau Pressure and Static Compliance, Early Indicators of ARDS

[@justinebest4776]

I’ve been studying mechanical ventilation for the past 8 weeks in quarantine and this video just made all of the information from the last 8 weeks make TOTAL SENSE. THANK YOU for this video 🙏 Please keep them coming!

[@donnajacinto354]

Great videos..:) Thank you Sir..

[@tgaskill]

Great explanation! Thanks!

[@bkang7175]

Yeah, it makes sense that when Cstat falls below 30, it means the lung compliance is low; hence, the lungs are stiffer. Thanks.

[@brianimdieke5580]

Great vid, could you speak to ventilators that display Cstat breath to breath. Could one optimize peep levels based whether the Cstat goes up or down?

[@rtclinic]

Good question! I've not used static comp to look at optimal peep, but I'm going to give it a try

[@ameelgajjo8097]

For the tidal volume used for Cstat and Cdyn calculations, are you using the the set tidal volume in volume control or the outcome tidal volume the patient is giving? Thank you

[@rtclinic]

They should be similar, but I always use exhaled Vt over inhaled Vt.

[@ameelgajjo8097]

@@rtclinic Thank you

[@ameelgajjo8097]

@@rtclinic Thank you

[@aqilaalalawi8257]

Hi,thanks for this good video,can we measure the plateau pressure on pressure if we can ,i try inspiratory hold but doesn’t appear??in servo i ventilator or we can make inspiratory pause 0.5 second please answer my questions??

[@rtclinic]

I've used a servo-i ventilator in the past. It was used as a transport vent, so I'm not sure if it has the advanced capabilities to read plateau pressures. I would put the scalar pressure vs time waveform on the screen, perform the insp hold, and estimate the height of the plateau based upon the y-axis.

[@ashleyharmon3158]

I was trying to see if you had anything on here I didn’t see it, what are your thoughts on train of four,being paralyzed and static compliance? Do you see an increase in compliance if patients aren’t paralyzed properly? I know you can see a breath initiated, but I’ve read without a great deal of detail that it will show in the ventilator compliance.

[@rtclinic]

Thanks for the question, Ashley! Static compliance can most accurately be measured if the patient is paralyzed. Dynamic compliance (PIP-PEEP) might improve when the patient is initializing their own breaths. I'm not as interested in Dynamic compliance because it has many variables that can be remedied by bronchodilators and mucous removal. I hope this helps.

[@bkang7175]

What happens to Pplat if you held the inspiratory hold button for longer than 3 seconds? Would that affect its accuracy?

[@rtclinic]

It shouldn't affect accuracy. I've held it for 5 to 10 sec to get a stable reading because the more was a small leak.

[@lizl.6874]

This is done if the setting is volume-controlled right? If it is in pressure-controlled ventilation no need to get the plateau pressure?

[@rtclinic]

Great question. Plateau needs to be checked on both Pressure control and volume control. The inspiratory pressure on pressure control is the measured PIP. The plateau could be the same, but will likely be less than the PIP. A breath hold is used to evaluate it .

[@derekbailey4151]

@@rtclinic Will all (ICU level) ventilators allow an inspiratory hold during PC and/or PRVC ventilation?

[@sandieo2739]

At what point do you perform an inspiratory hold? Is it when the vent begins to deliver a breath or is a breath triggered and held when you press inspiratory hold? I'm confused. Thank you!

[@rtclinic]

Thanks for the question Sandie. It is best to wait until the patient initiates a breath. The main objective is to make sure the flow waveform has come back to baseline before doing the breath hold. This will decrease air trapping.

[@bkang7175]

For a highly compliant lung, what would be the Cstat value? Would it be safe to assume it's above 100, since you gave a normal range of 50-100cmH2O?

[@rtclinic]

I'm not sure. Just running some numbers it takes a 1000ml tidal volume with 10 cm h2o between plat and PEEP to cause a c stat of 100. More than that is crazy.