Help! I don't "get" vents!!!

  1. 3
    Hey everyone!

    Very recently I left MedSurg after 7 years for critical care. Thank goodness I have years of experience and knowledge of what "normal" assessments are. So far things are going very well. Titrating pressors, measuring CVP, working with A-lines, etc. are still very foreign to me but I understand what I'm doing and just need practice.

    However...

    I don't understand vent settings. I feel like when people try to explain them to me, they are speaking Bulgarian. I feel like a total moron because all I comprehend is FiO2. I write down the settings and pass them along, but I don't know what they mean!

    Disclaimer...I've only had seven days in the unit and I'm still with a preceptor, of course, so I don't want anyone to think I'm caring for these patients on my own.

    I just need someone to explain to me, in layman's terms even, what the heck the different vent settings mean. (AC? PSV? PEEP? PIP? IDK my BFF Jill?)

    Thanks!
    Joe V, siRNita, and Esme12 like this.

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  2. 25 Comments...

  3. 15
    My advice to you is to find a friendly RT to 'splain it to you. And don't try to eat the elephant all in one sitting. The next time you are in the room with a vent patient, and the RT comes in start with "Can you give me a 5 minute inservice on SIMV and how it's different from PRVC mode?" or "Why did we just increase this patient's PEEP- what are we wanting to accomplish?" A skilled RT who likes to teach can be your best friend in learning vents inside and out. They have been mine for the past 30+ years!
    melby, Nccity2002, mcmgal, and 12 others like this.
  4. 2
    Quote from meanmaryjean
    And don't try to eat the elephant all in one sitting.
    But it's sooo delicious!

    Right now I'm doing ECCO and it tries to cram all of the vent stuff in one module, so I feel like I should be able to have elephant for an appetizer, then blue whale for a main course!

    Thanks for your help, Mary Jean!
    poppycat and Esme12 like this.
  5. 2
    One suggestion I would have would involve an experienced RT or nurse who could demonstrate some basic concepts with a anesthesia bag or flow-inflating ambu bag. That's what vents were originally, was just a machine to replace a person squeezing an ambu bag.

    With a flow-inflating bag, you may get something from feeling the action attached to each concept. . . Squeeze the bag half-way versus fully, that's a lower tidal volume versus a higher one. Squeeze the bag more forcefully, that's a higher inspiratory pressure (pressure support). The flow-inflating bag is great to demo PEEP/CPAP.

    Work on those concepts first, then worry about learning about assist-control, SIMV and so on.
    miasmom and DeLanaHarvickWannabe like this.
  6. 2
    Quote from DeLanaHarvickWannabe
    But it's sooo delicious!

    Right now I'm doing ECCO and it tries to cram all of the vent stuff in one module, so I feel like I should be able to have elephant for an appetizer, then blue whale for a main course!

    Thanks for your help, Mary Jean!
    check out this site.......http://www.ccmtutorials.com/rs/index.htm and .......icufaq's.org
  7. 1
    Quote from meanmaryjean
    My advice to you is to find a friendly RT to 'splain it to you. And don't try to eat the elephant all in one sitting. The next time you are in the room with a vent patient, and the RT comes in start with "Can you give me a 5 minute inservice on SIMV and how it's different from PRVC mode?" or "Why did we just increase this patient's PEEP- what are we wanting to accomplish?" A skilled RT who likes to teach can be your best friend in learning vents inside and out. They have been mine for the past 30+ years!

    This is what I did with interpreting ABGs. I'd get the report and ask the RT if the pt was in metabolic
    acidosis, alkalosis, etc. It helped my knowledge and it established good rapport with the RTs. Generally, people love to be treated like a mentor or good resource person.
    DeLanaHarvickWannabe likes this.
  8. 2
    Some of my best friends in ICU were RT guys. Awesome resource.
  9. 1
    Find a sympathetic RT. I was lucky in that I worked often with one of the most-experienced, friendly RT who loved to teach and did a lot of precepting new staff in his department. He taught me lots.
    Part of our ICU orientation did involve a vent, a mouthpiece and feeling what the different vent settings are like. Sometimes there is nothing like a good demonstration to speed learning.
    Good luck!
    DeLanaHarvickWannabe likes this.
  10. 1
    Go here...index and click on "Vents and ABGs." This site was always my best friend; in fact, I purchased it in book form.
    It's easy to read and even humorous.
    DeLanaHarvickWannabe likes this.
  11. 14
    Quote from DeLanaHarvickWannabe
    Hey everyone!

    I just need someone to explain to me, in layman's terms even, what the heck the different vent settings mean. (AC? PSV? PEEP? PIP? IDK my BFF Jill?)

    Thanks!
    One of the settings on a vent determines the size of breaths that will be delivered (tidal volume aka Vt). Tidal volumes can be achieved by telling the vent to deliver either a set volume (volume control aka VC) or a set pressure (pressure control aka PC).

    When the vent delivers a breath to achieve a set volume, the pressure required to deliver the breath can vary from breath to breath. This is the PIP (aka peak inspiratory pressure) - the vent's measurement of the pressure required to deliver the breath. Conditions that effect lung compliance, like need for suctioning, atelectasis, or pleural effusions (to name a few) influence how much pressure is required to deliver a set tidal volume.

    When the vent delivers a breath to achieve a set pressure, the PIP will be consistent from breath to breath, but the size of the breath (the tidal volume) will vary from breath to breath. This variation is also due to lung compliance. For example, conditions that decrease lung compliance will decrease the volume of the breath because the vent is set to stop delivering the breath once the set pressure has been achieved (regardless of how big or small the breath is).

    AC - "Assist Control" mode. When AC mode is being used, the ventilator is set to deliver breaths (whether the set rate on the vent or a patient initiated breath above the set rate) to achieve either a set tidal volume (volume control aka VC) or a set pressure (pressure control aka PC). Breaths are relatively consistent from one to the next because even when the patient initiates a breath above the set vent rate, the vent will "take over" once the breath is initiated and deliver a breath that achieves either the set tidal volume or the set pressure.

    SIMV - "Synchronized Intermittent Mandatory Ventilation" mode. In SIMV mode, like AC mode, the vent will deliver tidal volumes at either the set volume or the set pressure for the number of breaths that are SET on the vent. Any patient initiated breaths can be of whatever size the patient wishes - they can take little breaths, they can take large "sigh" breaths - whatever they want.

    PSV - "Pressure Support". Pressure support is used when the vent is in a mode that allows the patient to take variable sized spontaneous breaths, like in SIMV mode. Pressure support is used like the name implies, to help 'support the pressure' required to take a breath. It is normally used to assist the patient to overcome all the extra work of breathing through all of the external apparatus required to use a ventilator - ETT, filters, and the like.

    PEEP - "Positive End Expiratory Pressure" (you may hear this term used interchangeably with CPAP or "Continuous Positive Airway Pressure" - lets ignore the differences for now). This is the set pressure that the ventilator keeps in the lungs at the end of an exhaled breath. It is used at different amounts of pressure for a variety of reasons, but the goal is always to create a little "back pressure" in the lungs. You can easily experiment with this idea - make a loose fist with one of your hands, press your lips against the round end of your fist at your pointer finger and thumb and exhale through it. Now tighten your fist a bit and do the same. Feel the difference? This is creating different levels of back pressure in your lungs. This is the very reason that we teach patients with COPD (for example) to practice "pursed lip breathing" - to create a little back pressure in their own lungs.
    A couple of the common goals of using PEEP on a ventilator are to prevent atelectasis (a little bit of back pressure can prevent floppy, fragile little alveolar air sacs from collapsing at the end of an exhalation), or to force pulmonary edema out of the airways and alveoli back into the capillaries. PEEP is also commonly used to improve oxygenation. Let me use an example of how that works - atmospheric oxygen pressures are different at different elevations because it is under more or less pressure in the environment - think of oxygen at the summit of Mt Everest vs Sea Level - the more atmospheric pressure oxygen is under, the more help it receives in diffusing into the capillaries. Using a vent and PEEP allows you to artificially change the "atmospheric pressure" inside the lungs - increasing the pressure helping oxygen to diffuse into the capillaries.

    Just a little Vent 101 from your friendly neighborhood RT (who is transitioning to nursing). I benefit on a daily basis from trolling the boards and gleaning valuable insight and information from the contributors here. Hope I have finally been able to give something back, lol.


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