0:16 all right you guys welcome back to
0:19 another video lesson in this lesson
0:21 we're gonna be taking a look at the
0:23 different basic ventilator modes that
0:25 you're commonly gonna come across these
0:27 are the modes that you're gonna see more
0:29 often than not and it's gonna be
0:31 imperative that you guys have a good
0:33 understanding of these so that in the
0:35 future when we talk about and you also
0:37 come across some other alternative modes
0:39 of ventilation you have this as a
0:41 baseline in which to understand some of
0:44 these other modes and my name is Eddie
0:46 Watson and I welcome you to ICU
0:49 advantage my goal here with ICU
0:51 advantage is to take these complex
0:54 critical care topics and really break
0:56 them down for you and make them easy to
0:58 understand for you guys I hope that I'm
1:00 able to do just that and perhaps by the
1:01 end of this video I'll have learned a
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1:22 another quick shout out to respiratory
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1:26 was super helpful in reading through the
1:28 notes on this lesson and making sure
1:29 that I had all of the key points that I
1:31 really needed to get across to you guys
1:32 if you haven't seen this channel yet
1:34 he's got a bunch of really awesome
1:36 videos on topics related to respiratory
1:38 therapy so make sure you guys head on
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1:42 and subscribe to his channel alright and
1:43 with that said let's go ahead and get
1:45 started here and let's really start this
1:47 lesson off and begin with a quick
1:50 introduction to the topic of our basic
1:52 ventilator modes so in the previous
1:54 lesson which if you haven't watched it
1:56 yet I'm linking to it up above and down
1:58 in the description I provided you guys
2:00 with an introduction into the world of
2:03 invasive mechanical ventilation in that
2:05 lesson I talked about how pretty much
2:07 all of the ventilators that we use today
2:10 are all forms of a positive pressure
2:13 ventilator and within the world of
2:15 positive pressure ventilation there
2:17 really are many different types or modes
2:20 as we call them that our ventilators can
2:22 really operate in in this lesson here
2:24 I'm gonna be covering the basic vent
2:27 modes to try to really give you guys a
2:28 good understanding of the most common
2:31 modes that you're gonna come across in a
2:33 future lesson I am gonna take a look at
2:35 some of the more advanced modes that you
2:38 may very well come across now when we
2:39 take a look at our different vent modes
2:43 there's really two main categories that
2:44 you're really gonna come across the
2:47 first of these is something that we call
2:49 volume control and the other is
2:51 something that we call pressure control
2:53 so first let's take a look at volume
2:55 control here and I'm actually going to
2:57 take a look at some of these modes here
3:00 in just a minute but really the basis of
3:02 this category is that we're gonna be
3:05 setting and controlling the volume of
3:07 air that our patients get and the way
3:09 the vent does this is it delivers this
3:12 volume by providing pressurized air
3:14 causing it to move into the patient's
3:17 lungs now depending on many factors the
3:19 pressure that's required to deliver this
3:22 volume can and certainly will change
3:25 from patient to patient and from breath
3:26 to breath this right here is a very
3:29 important fact for you to remember so
3:31 now if we move over and quickly talk
3:34 about pressure control here the reverse
3:36 is taking place in pressure control
3:38 we're going to be controlling the
3:41 pressure that we deliver to our patients
3:43 and there are many benefits to pressure
3:45 control which we are going to discuss in
3:47 the next lesson on those advanced modes
3:50 but the thinking and understanding of
3:52 these modes is different than our
3:55 natural intuition now similar to like we
3:56 had just talked about with volume
3:59 control depending on many factors the
4:01 volume of air as opposed to the pressure
4:04 of air that is going to be delivered can
4:06 and will change from patient to patient
4:10 and breath to breath once again this is
4:13 going to be a very key point and this
4:15 really summarizes the main difference
4:17 between our volume control and our
4:19 pressure control as I mentioned here
4:21 volume control our volume is constant
4:24 and our pressure is the changing
4:26 variable whereas in pressure control
4:29 our pressure is constant and the volume
4:32 is our changing variable so a very key
4:35 important distinctive concept to know
4:37 now within each of these main categories
4:40 there really are many different modes
4:42 and even some that kind of cross in
4:45 between both of these modes here but for
4:47 the purpose of this lesson we're gonna
4:49 be sticking to just talking about volume
4:51 control so like I said the main
4:53 principle for volume control here is
4:54 that we want to ensure that our patients
4:56 are receiving a set volume of breath
4:59 each minute and like I said within this
5:01 category we have different modes that
5:04 are ultimately play a different role in
5:07 the impact on our patients work of
5:09 breathing in order to understand the
5:11 differences between these modes though
5:13 we really need to talk about some of the
5:15 settings and some of the things that
5:16 we're going to be looking at on our vent
5:18 alright so the first thing that we're
5:19 going to talk about in our settings is
5:22 something that we call our tidal volume
5:25 and this you'll see in the setting VT
5:27 and essentially our tidal volume is the
5:29 volume of air that set to be delivered
5:32 with each breath to our patient all
5:33 right the next setting that I want to
5:34 talk about is something that we call
5:37 frequency also known as our respiratory
5:39 rate and this will no usually find
5:42 abbreviated as either F or RR and this
5:43 one should be pretty self-explanatory
5:46 but it's how many breaths per minute are
5:48 being delivered to our patient now it's
5:50 important understand how this works and
5:52 how this triggers for a breath to be
5:54 given is it will actually take the
5:57 respiratory rate that you set and divide
6:00 that into 60 to figure out the amount of
6:02 time that we should have between each
6:04 individual breath and we'll talk about
6:06 it more here in a minute but when that
6:08 amount of time has elapsed then it
6:10 triggers another breath to be given all
6:11 right the next setting that we're going
6:13 to cover here is going to be our oxygen
6:15 concentration and this is what we refer
6:20 to as our fio2 and fio2 really means our
6:23 fraction of inspired oxygen this is
6:25 important to know because when we are
6:28 referring to our fio2 oftentimes we'll
6:33 say we're on 50% we're on 80% but really
6:35 we need to understand that this number
6:37 is being expressed as a fraction or a
6:40 decimal so when we say we're on
6:42 fifty percent our fio2 setting is
6:44 actually going to be 0.5 if our patients
6:47 on a hundred percent fio2 then we have
6:51 an fio2 of 1.0 so the next setting that
6:52 I want to talk about in the world of
6:55 volume control is a setting called
6:58 positive end expiratory pressure this is
6:59 something that we more commonly referred
7:02 to as peep so thinking back to one of
7:04 our previous lessons where we covered
7:06 non-invasive ventilation think of peep
7:10 as being really similar to CPAP or BiPAP
7:14 on a BiPAP machine essentially this is a
7:16 constant pressure that's going to be
7:19 applied throughout expiration to really
7:23 help an open and keep open alveoli now
7:27 it's peep along with our fio2 which is
7:29 how we really help to improve our
7:31 patient's oxygenation and so for this
7:33 setting it's really important that we
7:35 maintain at least 5 centimeters of water
7:37 to help to provide what we call
7:40 physiological peep and the reason for
7:41 this is because of the ET tube that we
7:43 have in our patient that this can
7:44 actually allow the intrathoracic
7:47 pressure to fall to zero which would not
7:49 be a good thing now the range of
7:50 settings that will usually see for a
7:53 peep is typically in the range of 5 to
7:55 20 and since they didn't mention in a
7:58 minute ago for our fio2 we typically
8:00 aren't going to find that any lower than
8:04 35% or 0.35 and this can obviously go up
8:06 to a hundred percent alright and so the
8:07 final setting that i want to talk about
8:10 here in this world of volume control is
8:11 something that we call pressure support
8:14 this one you'll see abbreviated as PS
8:17 and the best analogy that I can really
8:19 give you for pressure support is if you
8:21 really think about this as a spotter at
8:24 the gym so this is really an extra push
8:27 of air to assist our patients when
8:29 they're taking spontaneous breaths so if
8:31 you think about that spotter is there to
8:33 kind of help provide a little bit of
8:35 pressure and support as you're going
8:37 through doing some sort of exercise
8:39 that's kind of the same thing that's
8:41 happening with our pressure support only
8:43 in this case we're helping our patients
8:45 take a breath so if you really think
8:47 about this the more pressure support
8:50 that we apply the larger the spontaneous
8:52 breath that a patient's going to be able
8:53 to take with Morris's
8:55 our settings usually for pressure
8:57 support you're gonna find in the range
9:00 of five to twenty typically though we're
9:02 gonna keep it at a minimum of anywhere
9:05 from eight to ten and this is really to
9:08 help overcome the resistance of having
9:10 to breathe through that ET tube actually
9:12 out there if you take the time to look
9:14 for it there is a chart that does a
9:17 breakdown based on the ET tube size and
9:19 how much pressure support it really
9:23 requires to overcome that resistance if
9:24 I happen to find it I'll link to it down
9:26 in the description but it's an
9:27 interesting chart and it really drives
9:30 home the point that just because of the
9:32 size and the resistance of that ET tube
9:33 we're already gonna have to give them
9:35 some sort of assistance because if we
9:38 gave them nothing breathing through that
9:39 ET tube would actually be harder to
9:41 breathe through than if they were
9:43 normally breathing alright so those are
9:45 all the settings that you're gonna need
9:46 to know when we're talking about these
9:49 different modes of volume control lastly
9:51 I do want to talk about a couple of the
9:53 different things that we're going to be
9:55 looking for in the monitoring of our
9:57 patients on the vent and I'm gonna go
9:58 through a couple different parameters
10:00 that you're gonna see on your vent but
10:03 just know that these parameters that I'm
10:05 listing here are far from all of the
10:07 parameters that are really important in
10:10 truly understanding how your patient is
10:12 tolerating being on the vent but again
10:14 this is where the respiratory therapist
10:16 comes in because this is their area of
10:19 expertise over time it certainly is
10:20 great to learn about a lot of these
10:23 different settings and different numbers
10:26 that you get on there but for a basic
10:28 understanding I'm gonna give you a
10:29 couple things that are going to be
10:31 really important the first of these is
10:32 going to be something that we call our
10:34 minute ventilation and this you'll see
10:38 abbreviated as ve now this one's
10:39 probably the most important one for you
10:41 to understand and that's because this is
10:43 a measure of the amount of air that's
10:45 being delivered to our patient per
10:47 minute so it's important to know how we
10:50 get this number and really in a perfect
10:53 world our minute ventilation would be
10:56 our tidal volume times our frequency and
10:58 if you really just kind of think about
11:01 that for a minute if we take the volume
11:02 of air that we're delivering with each
11:05 breath and then multiply that by how
11:07 many breaths were giving per minute
11:10 should tell us what our volume of air
11:11 that we delivered to our patient over
11:13 the course of a minute would be now as
11:15 we know we don't live in a perfect world
11:18 so we have to deal with things like
11:21 inefficiencies triggering pressure
11:23 limits and really the patient's own
11:26 response can and do impact the actual
11:28 delivery of air that they get but if you
11:31 do have to increase or decrease your
11:33 patients minute ventilation to do
11:36 something like let's say control our PA
11:39 co2 on an ABG then we're going to be
11:40 looking to adjust our patients minute
11:43 ventilation and again because we should
11:45 be keeping our tidal volume set based
11:48 off our patients ideal body weight then
11:50 really we know that if we need to be
11:51 making changes to our minute ventilation
11:53 we probably want to be adjusting our
11:55 respiratory rate the core concept here
11:56 is if we have more minute ventilation
11:59 we're gonna have more co2 clearance
12:02 hence less minute ventilation less co2
12:04 clearance and the goal for a patient's
12:06 minute ventilation is going to be from 5
12:09 to 10 liters per minute all right the
12:10 next thing I want to talk about it's
12:12 actually going to be the first of two
12:14 different pressures here it's gonna be
12:15 something that we call our peak
12:17 inspiratory pressure and this one you'll
12:20 see abbreviated as our pip now I'm not
12:22 going to go too far into some ventilator
12:24 Theory here but essentially our pip is
12:26 the maximum pressure that's reached
12:29 during inspiration and the goal here for
12:31 our pip is to have this less than 35
12:34 with the goal of preventing lung injury
12:36 now the last setting and the last
12:37 pressure that I actually want to talk
12:39 about here is something that we call our
12:41 plateau pressure and this one's
12:43 abbreviated RP plat and when we talk
12:45 about some of these pressures and volume
12:47 control the plateau pressure is going to
12:49 be probably one of our most important
12:50 ones to keep an eye on because this
12:52 one's going to be an indication of our
12:54 lung compliance so we measure this one
12:57 at the end of inspiration with an
12:59 inspiratory hold or pause maneuver and
13:01 we really want to be shooting to have
13:04 our plateau pressure under 30 and this
13:06 is really to help prevent Barrow trauma
13:08 so important to know plateau pressure
13:11 means lung compliance if we see an
13:14 increasing plateau pressure this can
13:15 signal that there's some sort of problem
13:18 with our patient's lung compliance all
13:20 right so those are the settings and some
13:23 the major important things that we want
13:26 to be monitoring for in terms of numbers
13:28 on the ventilator and so now let's go
13:30 ahead and move on and talk about the
13:33 different volume control modes so I'm
13:35 going to go through and talk about a few
13:36 different modes that we're gonna see
13:38 here and it can really help to think
13:41 about these modes as being from the most
13:44 supportive to the least supportive in
13:46 terms of our patient's work of breathing
13:48 alright so the first of these modes that
13:50 I want to talk about is something that
13:52 we call assist control this is something
13:55 that you'll see abbreviated either AC or
13:58 VC for volume control now you may also
14:03 see people interchange this with CMV but
14:04 there actually is a very important
14:06 distinction and I'll kind of explain
14:07 that difference here in a minute when we
14:09 get to that so when we talk about assist
14:11 control there's a couple settings that
14:13 are going to be really important for
14:15 this mode obviously we're going to have
14:17 because it's a volume control we're
14:19 gonna have a predetermined volume set
14:22 for each breath so a VT or tidal volume
14:24 and we're also going to set the number
14:25 of breaths per minute or the frequency
14:28 for our patients in addition to that
14:31 we're also going to set an fio2 as well
14:35 as a peep important distinction here is
14:37 we are not going to have a pressure
14:40 support now let me try to explain why so
14:42 we know based on our tidal volume and
14:45 our frequency that every so often we're
14:47 gonna give the patient a set volume of
14:49 breath so if we had a tidal volume of
14:52 let's say 500 and a respiratory rate of
14:55 12 we know every five seconds we're
14:58 gonna give this patient a breath of 500
15:01 MLS and this is essentially what CMV or
15:04 control ventilation does whatever the
15:06 set number of breaths are and the volume
15:08 to be delivered the vent just continues
15:11 to pump that out one after another after
15:14 another and there is no derivation from
15:16 that no matter what the patient needs or
15:17 what they're trying to do they're just
15:19 going to continue to get at the same
15:21 frequency the same volume of breath
15:24 where assist control comes in is this
15:26 actually will take into account the
15:28 patient trying to take their own breath
15:30 so what happens here in assist control
15:33 is if a patient attempts to take their
15:34 own breath this is what we call
15:37 spontaneous breath that the ven is gonna
15:39 recognize this breath but it's going to
15:41 deliver the full set tidal volume so the
15:44 vent is either gonna deliver breath to
15:45 the patient when it's time or if the
15:48 patient tries to initiate their own
15:49 breath the vent is going to recognize it
15:52 but say I know you want a breath here
15:54 have the full breath and because of this
15:56 this is why we don't have a pressure
15:59 support because we're not gonna aid the
16:02 patient in taking a spontaneous breath
16:04 we're just going to detect that they
16:05 want a breath and then give them a full
16:08 breath so this sounds wonderful except
16:10 the fact that this can actually lead to
16:13 excessive ventilation especially if our
16:15 patients are too kipnuk for non
16:18 respiratory related reasons so here this
16:21 to Kipp Nia will lead to blowing off too
16:23 much co2 and ultimately lead our patient
16:26 into a respiratory alkalosis if you want
16:28 kind of a review on this I'm gonna link
16:31 to ABG lesson up above as well as down
16:33 in the description but here if you think
16:35 about if your patients in pain if they
16:37 have anxiety or even if they have some
16:39 sort of central nervous system
16:42 dysfunction causing them to have this
16:45 abnormal - Kipp Nia that this can
16:47 ultimately lead to blowing off too much
16:50 co2 when we physiologically normally
16:51 wouldn't want that now often times
16:54 though we will initially use AC when
16:57 we're intubating a patient as we really
16:59 have the full control over our patients
17:02 minute ventilation as well as fully
17:03 taking over their work of breathing
17:06 alright so because of some of these
17:08 problems that we just talked about with
17:11 assist control and also because of a
17:14 desire to want to be able to have a mode
17:16 that can really help with weaning our
17:18 patients down off the ventilator
17:20 another mode was developed and it's
17:22 something that we call synchronized
17:24 intermittent mandatory ventilation
17:28 something that goes by the name simv so
17:31 essentially with simv we're still going
17:34 to determine or mandate hence the name
17:37 mandatory that a patient gets at least a
17:39 set volume and a set number of breaths
17:41 per minute again for this we also will
17:45 set an fio2 and a peep so so far this is
17:48 looking just like a sis control
17:50 the big difference now when we compare
17:53 this to AC is what happens when a
17:55 patient takes their own spontaneous
17:59 breath in simv instead of delivering the
18:01 set volume of air the patient's actually
18:03 going to be allowed to take whatever
18:05 size breath they can and so now the
18:07 breaths that were delivering through the
18:08 vent are actually going to be
18:11 synchronized with the patient's own
18:13 spontaneous breaths to really help to
18:16 increase their vent compliance so
18:17 essentially as long as they take a
18:20 breath in a predefined window between
18:22 each of the two mandatory breaths then
18:24 if they go to initiate that breath then
18:27 whatever breath they take the size the
18:29 volume that they get is what they get if
18:31 they happen to take that breath right
18:32 about the time that another mandatory
18:34 breath is going to come the vent is
18:36 going to recognize this but similar to
18:38 AC is it's then going to go ahead and
18:41 give that full set tidal volume this
18:43 ensures that we're maintaining at least
18:46 that mandatory minimum level of minute
18:48 ventilation so because the fact that our
18:50 patients are able to take their own
18:52 spontaneous breath that this is where we
18:54 actually are going to set a pressure
18:56 support here and again the point of this
18:59 pressure support is to assist them in
19:01 taking their spontaneous breath if we
19:03 notice that our patient is taking too
19:06 small of the spontaneous breath we can
19:08 increase this pressure support to really
19:11 help them achieve a larger spontaneous
19:13 breath so now a quick test of
19:15 understanding here let's say you have a
19:18 patient who has just been intubated and
19:21 they are currently sedated and paralyzed
19:24 still from the intubation if you were to
19:26 put this patient now in to assist
19:28 control or if you were to put this
19:31 patient into simv with all of the same
19:34 settings other than the pressure support
19:35 that you'd set in simv
19:37 what would be the difference that you
19:39 would see in your patient on the vent
19:41 now well hopefully you realize that that
19:42 was a trick question
19:44 because there's going to be no
19:46 difference between these two so if a
19:48 patient is taking no spontaneous breaths
19:51 simv is going to be indistinguishable
19:54 from AC and if you really kind of think
19:56 this one through if they're paralyzed
19:57 and they're not taking their own
19:59 spontaneous breaths we do have a
20:02 frequency and a tidal volume set
20:04 so again if we think of that example of
20:06 a volume of 500 and a frequency at 12
20:08 every five seconds we're gonna give this
20:11 patient 500 tidal volume and this is
20:13 just gonna go over and over and the
20:15 patient doesn't take any spontaneous
20:17 breath that's all that they're gonna get
20:19 well if they were an AC again they're
20:21 gonna still be getting every five
20:23 seconds of volume of 500 and again
20:25 they're not taking any spontaneous
20:26 breaths so that's all that they're gonna
20:28 get as well and these two modes are
20:30 going to be completely indistinguishable
20:32 from one another now simv is really good
20:34 because it can actually allow patients
20:37 to gradually take back over their work
20:39 of breathing over time and so the less
20:40 support that we give them with the
20:42 mandatory breaths the more work of
20:44 breathing that the patient is going to
20:46 need to take on on their own and so like
20:49 I said simv was initially developed with
20:51 the help of really weaning patients from
20:53 the vent but often we find it as one of
20:55 our primary modes of ventilation because
20:57 of the fact that some of the work of
21:00 breathing is on the patient it really
21:02 requires close observation of our
21:05 patients physiologically as well as
21:07 psychologically to see how they're
21:09 responding to this work of breathing now
21:11 our patients may be at risk of becoming
21:14 tachypneic hyperventilating and leading
21:16 themselves into a respiratory alkalosis
21:20 but again because we're relying on them
21:23 for some of the work of breathing if
21:25 they're minute ventilation just isn't
21:27 sufficient for what they need they're
21:29 not taking enough breaths or large
21:31 enough breaths then we can go to the
21:33 other side of things and be retaining
21:35 co2 leading to a respiratory acidosis
21:38 all right so the last mode that i want
21:39 to talk about here is something that we
21:42 call pressure support now oftentimes
21:45 you'll hear this referred to as CPAP let
21:47 me tell you this is not CPAP please
21:50 don't call it that and in talking about
21:52 pressure support this actually
21:54 technically isn't a volume control mode
21:57 of ventilation because in volume control
21:59 we are setting and controlling the
22:01 volume that our patient is getting and
22:03 pressure support is a form of
22:06 spontaneous breathing so for patients in
22:08 this mode we're only going to set an
22:12 fio2 a peep and a pressure support so
22:14 there's not going to be a tidal volume
22:16 or a rate set for the
22:19 patience although that said most vents
22:20 do have a safety mechanism in place
22:23 something that we call backup rate so in
22:25 the event that our patient goes APNIC
22:27 this backup rate is gonna kick in and
22:30 take over until we reset it now here in
22:32 pressure support minute ventilation and
22:35 thus our patients work of breathing will
22:37 be almost entirely dependent on the
22:40 patient's effort with the assistance of
22:41 whatever we set our pressure support at
22:44 so oftentimes you'll see this used as
22:48 our last step or trial before excavating
22:50 patients typically if we do have our
22:53 patients and pressure support and we are
22:55 doing this spontaneous breathing trial
22:57 we usually have them set at 10 over 5
23:00 which is 10 of pressure support and five
23:02 of PEEP or for a very short run
23:05 sometimes we will run them 5 over 5 and
23:07 again this is going to be a short run
23:11 just prior to excavating all right so
23:13 that finishes up our discussion here
23:15 talking about the different vent modes
23:17 hopefully these modes make sense you can
23:19 see that we're looking at some of the
23:22 same settings were functioning very
23:25 similar in terms of volumes that were
23:27 being delivered but where some of the
23:30 key differences come in is how we handle
23:34 a patient's spontaneous breath from CMV
23:37 or control ventilation where we pretty
23:39 much don't acknowledge that at all
23:41 down through recognizing those breaths
23:44 but giving the full breath an AC to simv
23:46 where the patient will determine the
23:48 size of their breath all the way down to
23:50 pressure support where the patient's not
23:51 going to get any mandatory breaths and
23:53 everything's going to be based on their
23:55 own work of breathing like I said it's
23:57 sort of this progression from the most
23:59 amount of support and the most effort
24:02 and the most coverage taking over of our
24:05 patients work of breathing down to the
24:07 least amount all right and with that
24:09 said I do want to thank you guys so much
24:11 for watching if you found this lesson
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