Your hospital may have it's own criteria for doing these, but we have come up with a methodology for doing a PEEP study based on the latest knowledge provided by science (which impresses me).
So, that in mind, here is how to do a PEEP study, or how to find optimal PEEP:
- Increase PEEp by 2-3 Q 20 minutes
- If static compliance, P/F Ratio &/or SpO2 increase, you know it's working.
- Stop when P/F Ratio is equal or > 200, or when static compliance decreases, and set PEEP at the setting just prior to where the hazzards of PEEP were shown.
- Do not increase PEEP if systolic BP is less than 90
- Also, keep mean airway pressure (MAP) less than 15
- Ideally, static complliance should be between 60-100.
As you note here, the goal of PEEP therapy is to find the optimal PEEP that is needed to maintain an SpO2 of 92% or greater, or as specified by the physician.
When PEEP is too high, it tends to put un-needed pressure on the heart. Thus, it can cause cardiac output to decrease. Good monitors of cardiac output are blood pressure and, as new studies show, an even better indicator is MAP. As MAP starts to rise, this can be an early indicator that CO is about to decrease.
As always, if you guys find that my data here is incorrect, or if you have some RT wisdoms to share, please do so.