Episode 40: OR Vent modes

In this episode, episode 40, I go over the basics of Vent modes and settings in the operating room and how they differ from the ICU.  I also discuss a few common special cases and how to adjust the vent to deal with them.

7 Replies to “Episode 40: OR Vent modes”

  1. Thanks Jed! Another volume status question related to the vent.
    How do you do the end exploratory occlusion test? I have read the description but still don’t get it. Do you clamp the circuit at the end of expiration?
    Also what are your feelings on a bump in end tidal CO2 indicating volume responsiveness?
    Thanks!
    Josh

    1. Hi Josh,

      The end expiratory occlusion test is done simply by stopping the ventilator after expiration in a patient who isn’t taking spontaneous breaths. This will mean that instead of getting another breath when they normally would, they will remain apneic for the 15 seconds of the test. Normally, inspiration (on a vent) will cause increased intrathoracic pressure and therefore decreased preload and decreased cardiac output. If you prevent inspiration, you prevent that decrease in preload. Preventing a decrease in preload is kind of like giving more preload (double negative equals a positive) and so it is like giving a fluid bolus. If you see a response to that “bolus” it an predict fluid responsiveness. This has limited utility because it only works in patients who won’t take a breath during that 15 seconds.

      As for an increase in ETC02 the idea is to do something like a passive leg raise and then see if you get a bump in your ETC02. If you do, the idea is that the “bolus” from the passive leg raise MUST have increased cardiac output for the ETC02 to increase so it indicates volume responsiveness. I’m not aware of great evidence to support this and clinically I think we rarely see it, probably because in a patient who is really volume down there are so many things going on that you can’t isolate JUST the passive leg raise and watch the CO2 if that makes sense.

      Best,
      Jed

  2. I just want to comment on how much I appreciate your podcast! Your explanations and examples truly turn on the light bulb to some of the topics I can’t understand.

    By chance will you be doing a podcast on just NMBs? I think you went over them briefly in another lecture but just wondering.

    Thanks so much!
    Brenna

    1. Hi Brenna,

      I’m glad you’re enjoying the podcast. I will put your idea on the list for a future episode.

      If you haven’t already please take the survey at accrac.com/survey and leave a comment and rating on iTunes. It helps others find the show.

      Thanks so much.

      Best,
      Jed

  3. Thank you so much for all the great podcasts! I’m in CRNA school and it comes extremely helpful to review topics , refresh content, and learn new things! I’ve shared your work with several colleagues! I think it excellent!

    1. Thanks so much Barbara. I’m glad you’re enjoying the podcast! Best of luck with your ongoing training.

      Best,
      Jed

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