hi everyone my name is lahiru and welcome to abc's of anesthesia so what i'm going to go through
today is eye blocks and eye anesthesia now this is a really specialist part of anesthesia practice
and i really want to give you guys as much knowledge information and the actual practical
technique of what i do now what we're going to go through today is actual eye regional anesthesia
there's two blocks in common use that's the subtenance block and the peri bubble block now
subtino's box is my preference the fact that it doesn't use a sharp needle it i find it very safe
but it's also so effective it's super fast onset which means that it's a perfect block for a really
fast operating list i'm going to go through some of my techniques which have been passed down to me
from a lot of my seniors above me but i've also tried to do a few modifications to make it less
movements far less trauma to the eye and just really efficient so that's really what i want
to get get over to you guys now one of the main problems with subtenance blocks is that you might
have a bit of chemosis you might have a bit of hemorrhage or bruising of the eye and i want
to show you the minimalist technique that i do to make this far less of an issue and so i want to go
through that with you guys today all you need for subtina's block is a sterile tray sterile gloves
and the appropriate prep and really just a few pieces of equipment including a sub tenons cannula
the more fuels non-tooth forceps and the westcott scissors and these all the equipment you really
need there's very few contraindications except for you know patient allergy or patient refusal
the only real contraindication i've seen is if a patient has a scleral buckle of course if you know
that there's staphylomata around the eye in the particular zone that you're going to be inserting
the subtilions cannula i definitely stay away from that as well and use the ophthalmologist is
a great resource and i'll just ask them exactly what they need from that particular technique
so let's get started ready okay so the first thing i'm going to do is i'm going to clean the eye
now what i use here is aqueous betadine so i just get the normal
betadine that i've got here but i add a few drops say six drops of normal saline to that
first thing i do get the patient to open the eye nice and wide and just put a couple of drops
of the betadine in there close the eye notice i've got the swab on the side just to stop any
run-off then i pour a bit of that berlin around and i'm just trying to cover the whole area
now each time i interact with the eye i always look at the consent to make sure i'm doing the
correct side and we're doing the right side this gentleman here make sure the patient's
eye is about the level with my forearms parallel to the ground that means it's in a really good
operating position i use now about three to four mils of my solution two percent lignicane
with 30 units per ml highlight so i've got that five mil syringe now importantly what i do is
i have the cannula subtenance cannula uncapped curved surface is facing away from the numbers
notice that the numbers are on that side and the slight curve of the cannula
is away from them that just helps my trajectory as i'm going around the eye the next thing is
to open up the eye nicely so what i do is i want to put this lid speculum in the eye
so what that looks like is first i get the patient open the eye i just lower the bottom
eyelid and put the bottom part of the speculum and then raise the top eyelid slightly and then
wedge that speculum into the top eyelid that can be one of the trickiest things when you're
starting out my next two pieces of equipment are the more phil's forceps the non-toothed forceps
and the westcott spring scissors now what i want to do is i want to make sure that i'm about the
first picking up of the conjunctiva is about seven millimeters from the edge of the iris there
i'm in the infra medial quadrant i press down and then lift up i then use these
scissors to go down onto the eyeball make a small incision i don't go all the way with my
scalp scissors like some people do again i want minimal interaction with the eye and that avoids
a lot of trauma i've then got the sub tions cannula syringe and i'm just
using a really shallow angle so i'm going along the surface of the globe in the infra medial plane
note that i'm not going medially i'm not going to inferiorly i really don't want to put that cannula
into any muscle attachments so now i'm vertical and i just press down with my syringe to try and
infiltrate there's a bit of pressure experienced by the patient but this is not too bad sometimes
you get resistance if you get resistance i push into the eyeball and then lift up and then usually
see what happens there that gives a bit of space in the back of the eye as i infiltrate i use
my little finger for balance to make sure that i've got a really steady hand as i'm doing this
and then out it comes sometimes you'll get a bit of swelling medially and that's fine as well i'll
put some pressure now to minimize that one of the most important things i do now i'll get
the patient to close their eyes close your eyes that's great and i just put some pressure medially
if you get any conjunctival edema or swelling i try to minimize that but what i do then is i put
pressure around the eye and that will still give a decent block but you really want to avoid a lot of
swelling of the conjunctiva and of the eye surface so that might hamper attempts at a good operation
i find one of the most important parts of this is leaving that pressure on this is just like
any other wound pressure decreases the amount of bleeding and hemorrhage that you'll have decrease
the amount of bruising and hopefully the patient's more satisfied with that technique if you used
only two mils of this two percent solution it would just take a bit longer for the onset and
if you use more say three four five mils which is probably unnecessary to use that much but if you
use say five mils it would have a very quick onset open your eye the fact that the eye is sluggish so
i'm just trying to check the eye i'll get the patient to open both eyes close your eyes now
open them the fact that one eye is slightly sluggish means this should be working well
i want you to now look to your right look to your left notice that the left has no movement
so that means that it's working really well and then the right word movement look to the right
again that's sluggish and that will become completely a kinetic for a good operation
there's a bit of bruising there with further pressure that would minimize that as well
so first of all when it's the left eye inserting the speculum i do the top lid first
and then the bottom lid use the scissors to depress the iron and that way i get a
really good exposure of the eye push down seven millimeters from the edge of the limbus lifting up
i do a really small incision just because i want to minimize the amount of trauma it all caused
sometimes just explore inside with the scissors but i don't go all the way down minimizing trauma
again a really shallow angle in for immediately with my sub tenons cannula and you feel that
give sometimes that's all gone really well i'm going to get you to open your both your eyes now
again that's a really good sign so the sluggish left eye is a good sign i'm going to open both
eyes to check and i really like this block there's a bit of redness but it's under the lid
so not too visible i'll get you to look to your left and look to your right and there's
pretty much complete akinesis in a couple of minutes that's a fantastic subtenance block
sometimes i can adjust this to get the right aperture down into the infra-medial quadrant
i'm going to open your eye nice and wide just depress the lower lid
with the scissors infra medially grab seven millimeters from the limbus from the edge of
the iris there and then do a small incident make sure you don't go like this flat for the incision
that you go vertically for the incision okay and then i can see a nice little aperture in there
again i'm going really flat against the cornea
using my little finger to stop too much shaking open your eyes and then slow injection
if there's resistance i push up against the eyeball lifting up a little bit
you can see some conjunctival swelling so going a little bit deeper the swelling continues
i limit the amount of anesthetic i give so that was only a few mils there and the pressure that
i apply will then decrease that swelling i'm just going to do a little demonstration now so
imagine my knuckle is the globe if i first get in a very low angle like this
and go vertical sometimes it's very hard there's a lot of resistance so what i do is i'll push
against the globe so i'm pushing in this direction here and then i just do a lifting motion and that
gives me a bit more space at the back of the globe so that's what i'm doing lifting this way and up
and then it gives me a really good purchase a really good loss of resistance i'll get the
patient to open both eyes open both eyes for me good fact that it's closed is a really good sign
i then use my hands to open both eyes just look to your right no movement there look to your
left look to your left over here no moving this that's perfect a kinesis and that was in
literally two minutes after the block so that's all gone really well we'll get you started now
thanks so much for watching i hope that was really helpful for you
please like and subscribe and please share this video with anyone any questions at all
you can post in the comments below or get me at abcs of anesthesia gmail.com thanks a lot
you