good so let's get on to airway management and this is something that you'll again have so many
really good people teaching you this stuff there's so many good courses out there um
again i'm just trying to give you a really solid framework that most consultants would think of
when they when you're presented with this stuff aim is to have a simple step-by-step approach
a safe approach to any airway and then being able to communicate that effectively with your
colleagues when you come a bit of the incident so you get an idea of what this means incidence wise
airway assessment like a boss plan for the known difficult airway plan for the unknown difficult
airway and then all the measures you can take for these unknown difficult airways all the way up to
a very brief explanation of the front of next axis or surgical axis first i'm going to ask you uh is
this a difficult airway just have a thought now over the next five seconds and why do you think
this is a difficult airway maybe verbalize it to yourselves now i suspect most of you said look
this this person has a beard and that seems like it's a bad thing for airway management which and
you'd be correct now if i was to say this patient has a melon patty too we'll go through that what
all of these mean environmental distance of seven mouth opening of five jaw protrusion
a which means that's a good grade and normal neck extension what do you think now um i would say on
bra first it's like observation you look at him and you think oh he looks like he's got a short
neck he's got a beard he's going to be difficult but then when you do your further examination a
melon patty two's not too bad thyromental distance of seven is normal mouth opening of five is normal
jaw precision is good and normal neck extension so it's probably not going to be as bad
the only thing that might be difficult is getting a seal with the mask because of
the beard which you can navigate with like a goodall or something yeah fantastic so
i like the the area rule number one which you've addressed really well is that
airways should be assessed and managed with respect to the way you assess and manage the
way you manage the airway so i assess and i assess it in with respect to bagmas ventilation laryngeal
mask airway ventilation or lma and intubation so these are the ways i communicate and i think about
it and that really helps me come across logically to my consultant but also keep the patients safe
so how common is this uh these are some of your take a photo of this just because
uh it's not in your workbooks um but yeah like these are not necessarily the most rare events
but just know that cico so can't intubate can't oxygenate is really quite rare you know one to
three in ten thousand cases and it often happens not because of the patient being inherently
kind intubate can oxygenate it's because people have done the wrong thing by persisting at a
failing technique losing sight of the environment and the situational factors and just repeatedly
attempting an intubation and therefore traumatizing the airway so how do you assess
this airway history examination investigations is still the way i want you to you know if you
ever get asked this it shows perspective to give this kind of approach so you know just know that
past history and anesthetic charts letters and cards so previous anaesthetic airway management
is the best predictor of a difficult airway i've put cane did there because that was my you know
med school mnemonic for causes of anything and it actually applies pretty well here congenital
autoimmune neoplastic endocrine drug infection and trauma that's what that was one of those
things to think of all the kind of roundabout causes of any problem i could think of that
realistically i don't need to think of it too much because they're often so obvious when the patient
comes in you know to be reviewed by myself that i don't have to think about too much but if you're
giving an answer to your consultant this is a complete answer examination is what we'll go
through as well and investigations is often if you need an investigation it's a ct mri
nasa endoscopy or lateral neck x-ray you'll hear a lot of different ways of doing airway assessments
and this to me is a very common sense thing and there's a lot of mnemonics out there but i think
you can do this with far more common sense and logic so one of the things that i'll teach time
and time again is don't worry too much about the mnemonics but just do this in a targeted way to
assess each of bag mask ventilation lma and ett and maybe even surgical airway assessment
and we'll go through what i mean with this so we're going to be very very systematic this is
almost pedantic but it'll give you such an amazing structure that i'm actually i'm really glad that
i get to teach you guys this from the very start so the three axis model is something people talk
about and when you think about it oxygenating a patient is pretty much getting oxygen
somehow through the mouth past that almost right angle curve of the oropharynx down through the
trachea into the lungs and the maths doesn't always line up necessarily so you've got the oral
axis going straight back the pharyngeal axis at a certain incline and the tracheal axis at another
incline these don't line up so air is difficult to get past through whatever means you know when you
bag master patient you need to essentially create positive pressure with a seal to get air flowing
around that curve and if the tongue obstructs you can get a good dell to make that better
if you put an lma you're bypassing all of that curvature and again making that work
with intubation you're trying to get a view so you've got to make all those axes line up to get
your view to finally put the tube into the right spot so that's what they'll talk about with the
three axis model of intubation so here's a diagram which we're going to work on as we go through this
exercise think about the predictors of difficult bag mask ventilation using this picture just from
looking at how you'd get oxygen past the mouth through the oropharynx into the trachea what i'm
doing here is i want you to think about what it takes to bag masters patient you need the seal
so a beard is bad maybe they've got lots of you know a lesion on there maybe they've got a floppy
face because they're a bit elderly very hard to create a seal maybe they're edentulous
no teeth means no structure that makes it hard to ventilate as well or maybe they've got something
in this oropharyngeal area osa is probably the most common thing because they've got so much
soft tissue it's hard to bag mask or they've got a tumor there which again would be apparent because
of the surgery you're doing the final thing i think about is you know once you're trying to
ventilate the lungs is there a lot of obstruction or restriction to the lungs making it harder to
ventilate severe restrictive objective disease or obesity so you know i'm thinking of this diagram
think of the anatomy every time i'm doing this so here are my predictors take a photo of that
but again i'm really happy to move on from each of these because i'd like you to watch
the videos and then write this down so you get a second second shot at memorizing these things
the history of past difficulty the seal is a problem with these factors beard no teeth age
oropharyngeal destruction means there's just lots of crowding and that can be from all of
these factors mentioned and then ventilation is hard because of non-compliant lung mechanics
which is you know bmi is a part of that so using that logic same thing just logically try to tell
me now lma ventilation why would that be hard so i guess going purely from a sort of anatomical
schematic starting at the the lips how how widely can this person open their mouth and they suppose
with the teeth as well there's a minimum profile of two centimeters to insert a low profile lma
so two centimeters is a minimum but you know i'd be pretty concerned at two centimeters but that's
great it's a mouth opening i suppose sort of moving back is that much that's because it's also
related with credit of the oropharynx um moving back uh as opposed to the epic lotus um what's the
party score is you know can you clearly see the epiglottis is there crowding at the back of the
mouth is this an emergency is there someone who needs uh who is having epiclotitis or some sort of
emergency airway absolutely pretty much got the main things there can i insert the lma through
there is like the bag mask is there obstructive things in the oropharynx that create a problem
and finally is the patient can be difficult to ventilate so limit history of that difficulty
is a great predictor insertion lma placement kind of obvious things that you'll probably
realize straight away and then ventilation same as bag masking but even but it's slightly better
because a lma provides slightly better seal potentially than a bag mask but similar things
finally for intubation what do you reckon the predictors are so take 30 seconds
think of reasons why you'd have difficulty getting a laryngoscopic view and intubating um
yes yes sure so starting from the front of the mouth you need enough mouth opening to get in a
laryngoscope you can have difficulty which they've got unusual anatomy or permanent teeth going past
that point you need to be able to displace the jaw forward so any issues with the tissue
in the bottom of the mouth can cause problems with that or with the jaw itself i'm thinking burns and
radiotherapy can cause those kind of constrictions which is great or acute things like um infections
in the floor of the mouth i guess as well it's the things to obstruct i guess can also come into that
category probably that's going to be more of an issue at the level of the vocal cords
and epiglottis and that's really great so that's kind of the system i want you to go through which
is fantastic just logically going through what it takes actually the final thing i sorry i didn't
let you finish that the final thing then is the ability for the neck to extend as well which will
you know not allow you to get a laryngoscopy view whereas you might be able to place an
lma or do bag masking reasonably okay so like you mentioned mouth opening overcrowding of the mouth
um difficult view at a larynx laryngoscopy things like you know malum paddy three or four just mean
there's a lot of overcrowding of the mouth um and then exactly laryngeal structures edema pathology
stride or difficulty swallowing secretions and hoarse voice and this is again probably
different to a lot of what you'd be taught to do but you're taught to do the examinations of mouth
opening melon patty thyromental neck extension jaw protrusion straight off but i really need
you to have context to then communicate back the findings not as findings but as look the findings
mean that they've got a difficult this an easy lma the tube looks okay and these are what my findings
are because you then you've synthesized your information you're adding value to your findings
from what i've just said you know lots of nieces might not teach it to you this way so i've got to
teach you the names about things we regularly talk about so mal and patty score is this it's really
what the mouth looks like and the relationship of how much you can see the back of the pharynx
and how much of the uvula you can see one and two show that there's not much crowding so they're
good grades three and four are bad grades showing overcrowding ah that's a that's a qr code for the
mountain pettis going wiki environmental distance just means your mental prominence to your thyroid
prominence and if that's greater than six and a half centimeters six so six and a half centimeters
the evidence was good uh less than six bad and six to six point five equivocal but again
different sized people would mean that you know you wouldn't take that number as a hard number
really like you'd definitely modify that based on the size of the patient so that's your thyroid
prominence thyromental distance qr code and then the mandibular protrusion test so
class a is your lower jaw goes in front of your top jaw and this is a bit weird to ask patients to
do but you can get them to bite their top lip and that's often a good way of seeing if their jaw is
mobile class b is in line and then class c is an overbite and that's a bad grade and that's a code
for the for job protrusion you'll often hear about the cormac lehane laryngoscopic grades
again grade 1 is full view of the chords grade 2 often classifies 2a and 2b so if you can see
most of the chords 2a if you can see just the tip of the chords at the bottom there it's 2b
3 can often be 3a or b again depending on the angle of how much you can get so a grade 3a is you
just can't see the chords but you can still get underneath but three b means that it really isn't
an odd angle and then grade four means you can't see the epic glottis at all just things to know
because that's how often you'll be communicated to uh when you're doing airway assessments and
when you're doing laryngoscopy and that's the comically hand grade qr code for a web link
okay the five second airway exam so literally you think about all those things but this is
practically what i do i take a history make sure that there's no previous indicators i inspect the
age beard bmi obvious malformations trauma all the cane that stuff uh mouth opening with the mouth
open i ask i look at for a melon patty score a large tongue prominent teeth into inside the
distance or the mouth opening and then with the mouth closed i look for jaw protrusion thyromental
distance and neck extension i do that in five seconds and as you get more experience you'll
be able to you know think about all of the other pathways anatomically for good intubation to line
up those three axes just with that examination but this is literally the system i go through
so let's practice the focus airway exam on each other while you're here just um
turn to your partner and tense your body and just do the airway exam
oh the inter incisor distance is literally the the mouth opening so how far from the bottom
of the you know top teeth to the top of the bottom teeth um if that's really uh difficult
if that's really small then everything almost everything will be difficult
you