hi everyone this is Lahiru from abc's of anesthesia and today we're going to go through
ultrasound guided intravenous cannulation now this is exactly the technique that you want for
the most difficult veins sometimes your veins are deep sometimes you just don't have many options
and you want to get it right first time so what we're going to go through is the structure
in how i love structures this is going to be pp dfg
and that's the way you get the best settings and the best view of your vein so let's get started
hey everyone let's get started now i've got with me a very helpful volunteer quan and
he's going to help us kind of demonstrate these techniques so let's go through that framework
it's p p d f g and that stands for probe preset depth frequency or focus and gain so we're going
to show you that now so there's a couple of probes you could use a hockey stick probe and a linear
probe now this one is high frequency which means that you're going to have really good resolution
but not that much great depth resolution and then you've got the linear probe and this is
you know slightly less frequency which means you still get a pretty good resolution but a bit more
depth now most of the time you can really use either one of these i pretty much go for this one
most of the time straight straight away but they're both very very useful and very good
so what you find is that the frequency is already preset on these which is which is pretty important
so when you choose the probe sometimes the probe is chosen itself based on the probe that you've
put into the machine other times you might have a button like this which you press and then you
just preset so you can either select one of these for what you're doing so this is the
linear program here and now the next part is presets again presets might be in a different
menu but really what it is is i can choose a whole lot of different presets here based on what i
might need now these presets are maybe different between different ultrasound machines but they
probably represent a pre-set algorithm to optimize your picture for whatever you need whether it's
nerve vascular carotid superficial whatever it is it will optimize that image so let's go for
vascular so that's probe presets the next thing we want to do is depth i'm going to get my very
helpful volunteer here just to put this on and what you see is a number of different markings
on the side there these are kappa centimeter markings so this depth is about four centimeters
generally speaking for ultrasound cannulation i don't need more than two or three centimeters
so i can just decrease that depth as you can see you can see a whole bunch
of structures here including the artery there which i'll show you in a second
the minimum depth is about you know 1.5 centimeters which i rarely use that shallower
depth i usually and the maximum depth is around 28 and again that's definitely not what i need
for this particular ultrasound guided vascular access so let's get it around three centimeters
that's probably perfect that's d for depth next one is f for frequency that's already preset so
some different machines may allow you to alter the frequency just know that higher frequency gives
better resolution but lower frequency gives you more penetration so you can get more definition of
deeper structures so you might want to play around with your settings to get the best view possible
f for focus is this little arrow so there's usually some marking and what you do is you move
the arrow to the structure of interest so because maybe i'm wanting to do an arterial cannulation
i'd move the structure up there and it makes that structure there the best resolution whereas
if i had something deeper i can move that down and it makes that area there better resolution
better quality image so that's frequency and focus finally let's go to gain gain is really how much
information is coming back it makes your signal brighter or darker so increase gain really just
makes the screen brighter decrease gain makes it blacker and obviously you just need somewhere in
between so you can identify structures so it's again a very useful setting to have
okay so i think that's pretty much it we've gone through how to make your presets really
effective that's ppdfg that is probe presets depth frequency and focus and gain and that's all it is
i'm going to show you veins on a live volunteer with ultrasound and so it's going to be really
useful again for the most difficult veins the deepest veins and when you've got a lot
of problems trying to get vascular access the ultrasound is an absolute game changer
in giving us extra success so first of all as always i get all my setup as usual but
what i'm going to do i'm not going to focus on all the details of cannulation
i'm just going to show you the veins so first of all apply a tourniquet
now what this does is it promotes arterial flow it doesn't block the arterial flow to the you know
arm but it does prevent the venous flow going back which increases the pressure in the veins
which means that they stand out and it's much easier than to show you stuff so the first thing
i do is i always check the orientation of the probe so what i do here is i just touch here with
a glove and make sure that i get some interference in the correct side so i know the orientation
of this now what i'm going to do is i'm just going to scan you'll see that veins are generally really
superficial i'm going to show you what we can see i've got a vein here but it's pretty superficial
so i'm just going to decrease the depth and so what you can see is this
hypoechoic structure or black structure and it's you know it's elliptical which means that it's
probably some kind of vessel and it's also very compressible so you'll see them just pressing
down gently and that is also compressing and most importantly it's not pulsatile
if this was an artery it'd be pulsatile now let's compare it to another side over here
okay so i've got another structure it's a bit deeper
and what do you notice about that that's actually pulsating and so that's an artery
now it is compressible but the more you compress it the more it's going to be pulsatile and you'll
really show up there so that's a structure that i don't want to use i definitely don't
want to get vascular access for if i'm trying to do an intravenous cannulation so you've got to be
very careful with that if i was to put doppler on this you'd also see color pulsating through
and that shows you that it's likely to be a pulsatile structure as well beautiful now
interestingly across here we have the median nerve so that little bundle there is a median
nerve so you can see that this whole cubital fossa region is you know there's a lot of things going
on there there's tendons there's muscle bellies to the other side there's this median nerve which
you definitely don't want to damage and there's an artery so when we're going for these cubital fossa
veins like this one here at the top you gotta be really careful that you don't go very deep now
i find that ultrasound cannulation is just such a really useful technique because it's told me
a lot about the structures around and how i need to be careful for example that vein in the cubital
fossa that we'd go for time and time again is really superficial that's a 0.5 centimeter mark
and so this is you know from about one to two millimeters to four millimeters at its maximum
depth so if your cannula is going more than about that you're probably too deep and if you go too
deep guess what you've got the al you've got the artery there and you've got nerves there now
here's another interesting feature here which is really great to see you see these two structures
we've shown you the artery that's pulsatile and i increase pressure and show that but as
i take the pressure off you can see this beautiful big structure here which is a vein
now that vein compresses while the artery next to it is pulsar and doesn't compress as easily and so
very occasionally when i've got the most difficult situations i'll need to be very accurate with my
intravenous cannula to make sure it goes into the vein and not the artery so that's something quite
interesting to know so now when i look down here i've got generally the cephalic veins are on the
lateral side basilics are on the inside and so you know when i was starting out i was probably trying
to aim more for the lateral veins because these ones here don't have as many you know critical
structures like arteries and nerves below it so that's probably a safer one to go for whereas when
i come around here into the medial side you've got your basilic veins and you can see one at the top
just there but again below that is a number of critical structures so i'd see i'd say
this side once you get it more comfortable and you're familiar with your needle and the depth
what we're going to do is a real life ultrasound guided intravenous cannula
on a very helpful volunteer so let's get started so what i'm going to do is all my usual setup
so i'll put on the tourniquet make sure my patient's comfortable
obviously this setup is a bit different because we're using a trolley here
i'll use aseptic non-touch technique for all of my stuff and i'm just using a small 22 gauge cannula
then we clean the surface with a claw head alcohol solution making sure the patient
isn't allergic to these substances and then we'll get started firstly what i do is i just
check my cannula and then just make sure that the tip is loosened
i then just check the ultrasound make sure it's the right orientation which it is there
and just have a look i'm going for the lateral side because there's lots of other structures
inside on the medial side that are a bit dangerous and as you can see there you can
see the vein there it's compressible and it's not pulsatile so here we go sorry client you're good
beautiful you can see on the screen
you can see that tip on the screen that's in the center
and so now i know i'm in the right spot there i'm just going to advance it a little bit
and then thread it through and that's going in nicely i put my ultrasound probe down
loosen the tornique put pressure distally over there and make sure my sharp is nice and safe
and then i put the cap on like so making sure that there's minimal
blood coming back that's gone all really well put the tegaderm on
there we're good to go so what we're going to
do now we're going to flush that and make sure that that's working
thanks very much for watching and tune in for more ultrasound guided vascular access videos