Now the patient is in the patient is in the correct position for the preliminary ultrasound
of the leg prior to cannulation.
We have put sterile ultrasound gel into a large 60 ml syringe and that makes it very
easy for me in one movement to apply gel along the course of the vein.
So we can dispense the gel very easily – we have found that a very effective method of
dispensing ultrasound gel during the procedure and I would recommend this as a tip to any
vascular specialists who are undertaking this.
Put the ultrasound gel into a large dispenser.
I am very grateful to Ian Lomas of Promed who helped me with with this and who shared
this top tip.
So, we have ultrasound gel on the leg, we are now going to place the probe on the leg
and look at the vein that we are going to cannulate.
I am going to just change some of the settings and already we can see in the thigh – this
is the mid thigh of the leg – we are imaging in transverse section.
I like to see the vein as a circle on the screen.
I know it is a vein because with light pressure it collapses.
So that is not an artery – it’s a vein . It’s collapsible so it is patent, it has
not become occluded by clot.
It is a very large vein – when I last measured it was over 12 millimetres.
So he has got a very large great saphenous vein in the mid thigh and I follow it down
his leg.
We are now at the knee level and we can see that it is still very dilated.
At this point here, just at the knee level, we see a tributary coming off and going superficial
and the great saphenous vein carries on down into the calf.
So we here see the vein at that’s a point where I am going to cannulate.
So we about 4 cm below the knee joint – a tributary has just come off.
We could go further down but it is not necessary – the vein is of normal calibre there and
further down the leg the vein will be very close to the saphenous nerve and it would
be at risk of injury.
So, a convenient point to cannulate in transverse section is just below the knee and I am confirming
it is a vein.
I like to cannulate in transverse section for several reasons: I can see the vein very
accurately, I can see the surrounding structures – any nerves or important structures near
by- and I can perform the procedure with my left hand holding the ultrasound probe and
my right hand holding the cannulating needle.
So that is the vein we are going to treat and that is the point in the leg where we
are going to cannulate the vein.
So I have chosen the point of access.
I am concentrating hard on the patient’s leg but the patient is not being ignored.
Jane is at the top end by the patient’s side and she is chatting away in the background
– you can’t hear her but she is chatting away with the patient confirming that he is
comfortable and monitoring the vital signs.
So I have chosen my point in transvers section.
I am going to apply some local anaesthetic to the area where we are going to cannulate.
I’ve got a small syringe of lidocaine.
It has a 30 gauge needle so it is a very very tiny needle.
A little bit of scratch here we go.
A little bit of a scratch.
So we are putting a little so called bleb of local anaesthetic at the proposed site
of entry.
We are raising a little bleb of local anaesthetic solution just underneath the skin.
And that is at the mid point of the ultrasound probe in transverse section and on the ultrasound
screen if you have a look you can see the vein is in the middle of the ultrasound picture.
So we have the vein in the middle of the picture and we put a bleb of local anaesthetic right
in the middle of the width of the probe.
So there you can see now, there is the gel on the leg and there is the little bleb of
local anaesthetic.
We give that a few minutes to anaesthetise the leg and then I going to make a small little
nick in the skin with a one millimetre dermal punch.
That just makes a little entry point – it’s a very tiny one millimetre nick – I don’t
know if you can see that there and then we are going to cannulate the vein with a 16
gauge cannula.
That’s the point.
Reapply the ultrasound.
I don’t know if you can see what I am doing here on the surface of the leg and if you
can see also on the screen you can see the cannula coming right up against the vein.
As I advance the needle, you can see that it enters and punctures the vein.
There is the tip of the cannula now in the centre of the target vein.
What I am doing at the moment is advancing the cannula and also moving the transducer
– so it is a two-handed exercise.
I move the transducer slightly up the leg to keep the tip of the needle in focus on
there.
And here we are, we have successfully cannulated the vein.
The patient has felt no discomfort.
We have confirmed that we are in the vein by the presence of a little bit of blood which
has come back from the vein into the cannula.
So we have successfully cannulated the vein now.
I am going to put the probe down and we are going to now introduce the guide wire.
This is a so-called Seldinger technique.
We have a guide wire here, with a little introducer.
The guide wire will be advanced gently up inside the vein and then over this guide wire
we will introduce the sheath.
So here’s the guide wire – we are ready to go.
I am going to withdraw the needle part.
I apply a little pressure beyond the cannula so that we don’t get too much back bleeding
and then we introduce the guide wire into the vein - very gently introduce it.
Some people can feel a little sensation as we introduce the wire but in most cases, they
don’t feel anything at all.
In this case, the patient hasn’t felt anything.
So we now have got the cannula inside the vein, the guide wire inside the vein and at
this point, we remove the cannula while leaving the guide wire in place.
Some people feel a little sensation at this time.
There we are.
We have successfully cannulated the vein.
We have got the guide wire inside the vein.
Then over that we can introduce the catheter.
As you can see – very little blood.
This is not a procedure where we get a lot of blood and it is also a procedure where
we get very little discomfort.
The next thing we do before we do anything else is that we apply a little bit of tumescent
local anaesthetic.
Tumescent local anaesthetic is the anaesthetic solution we provide for pain relief.
Tumescent local anaesthetic was invented by a dermatologist in California 20-30 years
ago now, called Jeffrey Klein and this tumescent local anaesthetic solution is sometimes called
Klein’s solution after Jeffrey Klein who first formulated it.
We use one litre of a bag of saline – we will show you that in a moment- one litre
of a bag of normal saline –it’s called normal saline because it is very close to
the amount of saline that is normally in blood – concentration-wise – and to that litre
of normal saline we add we add – or I add!- 50 ml of 2% lidocaine, 10ml of 8.4% bicarbonate
solution and 1milligram of adrenaline.
And that is the so-called tumescent local anaesthetic solution.
So I have put some local anaesthetic solution around the cannula site and I am now looking
with the ultrasound and I am applying a little bit more tumescent local anaesthetic solution
to the vein and the guide wire inside it.
So when I insert the cannula, it is very comfortable for the patient.
As you can see on the screen we have a little white dot which is the wire inside the vein
and I have also put quite a bit of local anaesthetic around, all under ultrasound guidance to make
sure that when we introduce the cannula it is very comfortable for the patient.
So having applied the local anaesthetic around the guide wire, we are now going to introduce
the sheath for the laser.
It has an introducer part (introducer portion) and then it has got the introducer sheath
itself all connected to some tubing and a 3-way tap if you wish to apply any medications
or flush.
So, we put the guide wire into the sheath.
We make sure the guide wire is out and that we make sure that that is not advanced and
introduced too far up the leg and then we gently introduce the sheath over the guide
wire.
A slight rotatory action seems to help introduce the sheath and we gently introduce it.
Sometimes patients feel a little sensation as we do that, sometimes they feel nothing
and there we are.
The introducer is through the skin, into the vein and the guide wire has helped with that,
that’s why it is called a guide wire.
Ok, having done that we take the guide wire out and we take the introducer of the sheath
out.
Then that allows us to very safely introduce the laser fibre.
So that’s how I cannulate the vein.
It is an essential skill of all phlebology of all vein specialists – to be able to
cannulate the vein under local anaesthetic.
Essential points for me are that I do it in transverse section rather than longitudinal.
I have nothing against longitudinal – transverse works better for me and I think it has a number
of advantages.
It can be performed as a single operator without the help of a technician- left hand has the
probe, right hand has the needle.
We have placed the introducer and we are ready to do the procedure.