hi everyone and welcome to abc's of anesthesia my name is lahiru and for this episode of anesthesia
worst case scenarios we're going to go through the anterior meter-style mass as it relates to
the anaesthetist and as always i'll make this for youtube but also make it available on our abcs of
anesthesia podcast channel as well depending on which medium you want to view it in now the
anterior media style mask there's obviously a really high risk situation high risk lesion but
also something that we're not going to see a lot of in our careers most of our anesthesia careers
and so a lot of this really really important information i've gained not from my own experience
but from the experience of other colleagues of mine as well as this really fantastic article
from 2007 called management of the patient with a large anterior mediastinal mass recurring myths
by slinging carsley now you know taking the experience of those experts in the field i
thought it's just really worthwhile to try and translate that into this kind of viva format
we'll go through some questions go through a lot of exam technique as well uh for this answer exam
so let's get started now this won't obviously be seen on the podcast but what i've brought up here
is a chest x-ray for you to describe so describe this chest x-ray now what i'll try to do is i'll
describe it and describe my strategy as best as i can so this chest x-ray looks pretty normal
now in the face of a normal chest x-ray or normal investigation or something where i'm unsure what's
going on i just try a very systematic approach and the systematic approach for any investigation
is first of all identifying the name the date and time and the actual the actual investigation
itself so this will be this person this date this time and this looks like a pa chest x-ray now the
form for chest x-rays is often a b c d so looking at the airways looking at the bony structures
c for looking at the cardiovascular structures and then d for the diaphragm so just going
through this it looks like the trick here is normal there's no deviation the lung fields
look normal as well looking at the bony landmarks the ribs look normal as well really all everything
looks normal the cardiovascular contours the size looks normal as well and the diaphragmatic borders
look normal so the cost of bringing angles look normal so essentially there's a normal chest x-ray
and in this particular in this particular fiber i'm pretty much saying that it is normal i give
another chest x-ray again this is normal because i'm trying to prove a point that
people really need to have a system when they go through this now this one it's actually not
a chest x-ray it's a ct scan with the um with the sample of what it would look like as a chest
x-ray and it shows an obvious deformity here um so for this in this particular circumstance
it almost seemed to be unusual for you to go through everything systematically when there's
such an obvious problem with this chest x-ray so for the podcast listeners this shows you
know market deviation of the trick here as well as narrowing of the trick here so when there's such a
marked lesion i go straight to the point i say look there's an obvious deformity looks like
there's a structure that's deviating trickier to the right side and now causing narrowing of the
trigger itself and this could be a meter cylinder so i say state facts first and maybe if i if i
want to have a go i say what it could be now at that point the examiner might want to move on
because you've got you know you hit the nail straight on the head other times it might be
that you're you aren't giving enough information and then i go back to my structure in more detail
so i say this is what's most grossly abnormal but in more detail this is this patient this time this
date this is a chest x-ray or whatever scan it is um and starting from the top airway looks
like this there is that marker deformity bones b for bones c for cardiovascular structures and d
for diaphragm okay now the viva goes on to give a situation you're called to assist in ct you have a
35 year old female no past history no medications and no known drug allergies and then apparently
this patient has an undiagnosed anterior media style mass for a ct scan the patient cannot
lie flat and they would like you to give the patient a bit of quick sedation what do you do
now in this circumstance there's obviously a lot that you need to go into and the point of this is
that someone with positional symptoms um because they cannot lie flat in this example it'd be very
very dangerous to for you to proceed down sedation or general analysis your pathway so what do you do
i'd say look i need more information i'd do a full assessment but essentially i wouldn't be
happy to give sedation or ga so this would be a critical error in this circumstance to go ahead
and just give a bit of quick sedation because that can have dramatically bad consequences
for the patient so i might also offer that the fact that the scan can be done
in a different way so for example you don't need to do this with sedation if the patient's
positional symptoms because first of all the scan can be done in many different positions
semi-recumbent um lateral even prone and also can be done very quickly so scan can be done
very effectively in 20 seconds without affecting scan quality so it's very important that you
know this information because you don't want to rush into doing sedation or general anesthetic
for a patient with anterior mediastinal mass and severe or any positional symptoms so that's
really the point of this question i want to see that you don't rush into that so what are the
causes of of is what are the cause of mediastinal mass and we talk about their forties a terrible
lymphoma thymoma germ cell tumor or teratoma and thyroid tumor but there's also others another
good way of really categorizing this would be to think of the structures in the mediastinum
so what is the treatment now in this question there's no reason for you to really know all
the detail of treatments for you know these these kind of pathologies it's not really your
job as an anaesthetist but there's something really important about this so what i'd say if
this question is really where i try to get the candidate to think about the fact that you have
surgical and medical treatment so you wouldn't want to rush into surgery for something that's
so dire and so risky when there could be medical treatment so really the point of this is the fact
that lymphoma is non-surgical um you know you only really have surgery for complications of lymphoma
such as pericardial effusion tan tamponade or pleural fusions but really lymphoma is for
medical management but then there's other tumors like mesenchymal tumors ectopic endocrine tumors
as well as thyroid tumors and thymus that might need surgical management
so let's say they still have no diagnosis after doing the ct scan you go ahead with the ct scan
you alter the position and you still don't have it diagnosis and the surgeon wishes to go to theater
fest anatomy what do you want to know about the patient's workout now this is probably a bit of
an artificial situation but i'm trying to prove a point here in in with this particular question
the fact that you don't have a diagnosis is a really big deal and you really need to get that
diagnosis so i'd want to know everything about the patient's workup have they had everything possible
to make sure that the diagnosis has been attempted for example not only have they had the full blood
panel you know history examination but also investigations and biopsies that are seen like
ct guided biopsies mediastinoscopy anything else for a tissue sample to get a diagnosis
just to repeat once you have a diagnosis you can know whether this is for medical management or
for surgical management that's really vital in real life the other specialists around you the
surgeon the oncologist the physician they will know so much more about this condition than the
anaesthetist than most nieces would and so it is unlikely to happen in real life that you'd go
straight to theater first anonymity without doing all the proper investigations but again this is
just to prove a point that diagnosis is really important and also the diagnosis can be done
without going to theater first anatomy so the next question really is you know what what could you do
to get a diagnosis and there's many things you can do so awake ct guided needle biopsy awake anterior
mediastinoscopy or diagnostic thoracocentesis so what we're doing here is we can use ct guided
techniques with local and minimal sedation awake anterior metastasis with just local anesthetic
anesthesia as well as taking samples from peripheral sites for example imagine you do have
a lymphoma that like a lymphoblastic lymphoma has a high incidence of pleural effusions and so you
could sample that pleural fluid and maybe get a diagnosis therefore not going to theater now we're
ready for medical management or maybe there's a peripheral lymph node that you could biopsy
and again get a diagnosis and not have to go to surgery just for diagnosis or for no reason at all
especially if it's a high risk high-risk anaesthetic so diagnosis does not require a ga
so summary diagnosis can be made in almost all cases without a general anaesthetic rushing to
do a general anaesthetic can be a critical error now moving on with this exam question
the patient presents to the pre-admission clinic for work up prioritised anatomy
what do you want to know an assessment would be the question so again i talk about the point of
difference or the you know the critical issues about this patient so there's a whole bunch of
routine anesthetic assessments that you could go through but what i try to do is try to get to the
point straight away in addition to my routine anesthetic assessment i'm really concerned
about specific things i'm worried about you know tracheal bronchial compression or the respiratory
structures and then all the cardiovascular structures so superior vena caval compression
atrial compression and palmary vessel compression so really any of the low pressure structures i'm
also concerned because it's cancer i'm now using my framework of the five m's so i'm thinking of
you know the mass effect which i've already talked about respiratory and cardiovascular
structure compression any metastases or meths any medication the patient's on any metabolic
consequences of this tumor and also the mental state of the patient and this is all in addition
to my routine assessment so if the examiner wasn't happy with that i could always say in more detail
i'd go through passage of any anesthesia ponv history family history of any problems etc etc
so in history and examination this is again where i think it's really good to have a structure
i like to divide this into tracheal bronchial symptoms cardiovascular symptoms
and then the positional nature of any of these symptoms and the rapidity of progression
the trachea bronchial symptoms would include stridor cough hoarseness of voice and dyspnea
and the cardiovascular symptoms could be those a superior vena caval obstruction like pemberton
sign flushing venous engorgement you know edema in the upper upper limbs or syncope or top near
decreased exercise tolerance anything like that and again to reinforce i really want to know you
know if there's any particular positions that are better for the patient if it has any positional
symptoms and the degree of that as well as knowing the repetitive progression because this might
make us want to go a bit quicker with um rebooking the surgery
so let's say in this example the patient has tracheal compression
what exactly do you want to know and when i when i think about this i really want to know
all the mechanics of how i'm going to ventilate this patient with an endotracheal tube so really
i want to know how narrow this is you know what size tube can i pass through the lesion so
aperture size the length of the problem the length of the constriction and also is any distance below
the lesion so any you know how far from the constriction in the trachea down to the karina
it's a it will be a really big problem if there's any loss of cross-sectional area that's greater
than 50 that's a really bad sign as well as if there's any compression at the carina level or
bronchial compression so again really big problem but in summary i'm trying to think of where
i can pass this tube this the aperture size the constriction amount
how long that constriction is and if there's any distance below the constriction
now in the article they talk about you know beware the pediatric case anaesthetic deaths have mainly
been reported in children and children with trachea bronchial compression of greater than 50
cannot be safely given a ga so safe awake techniques are really not possible
so what's your choice of anesthetic now this is obviously a really complicated area and
it you know take planning a multidisciplinary approach and really you'd want to have a lot of
information before you go ahead now one of the one of my consultants at my training hospital
gave me a really what i thought was a really practical way of handling this situation so
basically three groups of patients the first group is probably the safest group so no symptoms and no
cardiovascular or airway obstruction on imaging the second group minimal symptoms but imaging
does show compression of the cardiovascular or airway structures and they're not you know
that bad they're not that severe finally the worst group is severe positional symptoms due to airway
or cardiovascular system compression so three groups the first two can be safe but the final
group is very very dangerous so for the first and second group what i'd say is you really
want to have a very cautious approach so all your usual preparation but increase your monitoring you
have an art line maybe a cvc maybe even a cardiac output monitor now if there's any flow issues from
you know venous congestion or constriction of the superior indicator you would want to have your eye
intravenous line in the lower limb i also make mention that i want the surgeons in
the room prepped and draped for stenotomy or rigid bronchoscopy as well now the technique most of the
time we talk about the spontaneous ventilation technique so this is an inhalational induction
and then i have various plants depending on what is going on so if there's tracheal obstruction
maybe i could do an awake fiber optic positioning the tube past the obstruction um the spawn venting
induction could be with siever fluorine or whatever intravenous mixture that you
know you're familiar with and then think about this once you've got the patient spawn venting
and everything is tolerated you can gradually give positive pressure to take over ventilation
and at that point if the positive pressure causes a drop in preload and drop in blood pressure you
can always recover from that so you can check if it's tolerated go slowly and only then give muscle
relaxant again cautiously knowing that you may have to do your emergency techniques at any time
so if life-threatening airway or vascular compression occurs then this gets a bit trickier
so overall each of these has all the problems of you know if there's threatened airway
or severe cardiovascular compromise you've got all your normal causes of cardiovascular compromise
and airway problems in any in an anesthetic but also all the problems that occur from
the mass effect so you really have to be solving both problems at once so as a
really basic plan firstly you may need to wake the patient rapidly to explore other options
you've already discovered the patient's least symptomatic position so having a team ready
to reposition whether it's lateral or somehow prone or semi-prone whatever it is you need to
be able to do that very quickly so having the team ready to do that on induction would be necessary
if there's lethal airway compression rigid bronchoscopy could be useful and for lethal
cardiovascular compression stenotomy and surgical elevation of the mass off the great vessels or
whatever cardiovascular structures are causing the problem so let's talk about some details
when is rigid bronchosphere unlikely be helpful so you know we think of rigid bronch as the savior
of this situation of airway compromise but really it can be difficult in certain situations imagine
c-spine and mobility or imagine difficult upper airway anatomy so always plan for airway loss
and have that discussion with the surgeon maybe the surgeon's not familiar not as expert at this
technique and you really need to clarify all these details when you talk about the surgical issues
so let's say we put a crisis into this exam you perform a spontaneous induction with sibo fluorine
so let's imagine this patient is a 50 year old large thyroid malignancy
no past history no allergies no positional symptoms but the malignancy is large
and extends retrosternally there's minimal narrowing of the trachea and the patient then
becomes hypertensive with the blood pressure trending down to 70 millimeters mercury
so again i this is such a high risk situation i'd go through my framework so um first of all telling
everyone that this is potentially has a check my reading if it's an outline make sure the
transducer is in the right spot i'd immediately call for help and help would almost always be
standing by this is such a high risk induction i mean then i scan the patient surgery in the
monitors i really want to get an idea of what's going on through other causes as well
so i think about what are the cause of hypertension i'll treat the normal causes so
i'd give a bolus of fluid um as well as uh giving meta amino and or ephedrine depending on what the
what my monitors are saying but then i'll be really concerned about the tamponade effect
of the mediastinal mass so they'll prepare for prepare another team to help solve that problem
so how would i treat this i would use normal measures as i mentioned i'd use volume iron
trips and vasopressor plus i'd mobilize staff to maneuver the patient position them into the
rescue position the least symptomatic position which is probably left lateral right lateral to
start with and then ensure that the surgeons are ready to do a stenomic at that point as
well if that if there's if that failed so again how do you decide the rescue positions and what
are these rescue positions so they're always determined pre-operatively least symptomatic
position is probably where you want the patient to be if things go bad and also think about
the anatomical relationship of the lesion and the structures rescue positions can be anything
really a bit upright seated lateral or prone so there's a question about is standby cardio
palmary bypass useful and when you think about the fact that it takes five to ten minutes at best
to cannulate and establish circulation and oxygenation even with everything ready to
go so this can be quite a long time so really in the situation that the patient is very symptomatic
with you know severe lesions on imaging really it can be such a hazardous thing to go ahead with
the general anesthetic so cardio primary bypass or ecmo is to be done prior to induction according to
this article so the next question why are children more at risk from anesthesia for mediastinal mass
so really children are over represented in the adverse outcomes and it could be due to
a number of factors but maybe due to the more compressible nature of airway and surrounding
structures a small decrease in the lumen a large increase in areas of resistance because the air is
already smaller there could also be difficulties of getting a clear history and symptomatology from
a child so i just want to summarize three groups of patients you've got your first group
no symptoms and no cvs or airway obstruction or imaging and then the second group minimal symptoms
but imaging shows some compression that's not too severe in those two groups you can go ahead with
the genuine state with a very cautious approach again obviously consult your treating team and
experts in this field who've done this before before embarking on this but the mediastinal
mass with severe positional symptoms due to airway or cardiovascular compromise awake echemo
cardiopyramid bypass pry is something you have to consider and is likely the safest technique
for the patient so in summary we've just gone through the most important elements on history
which are quite logical what are the problems with trachea bronchial obstruction or airway
airway obstruction and pressure on vascular structures you need a diagnosis which can be
done with local anesthetic only and don't rush ahead with general anesthesia or deep sedation
you need a diagnosis and that way you can stratify what you need to do severe positional symptoms in
patients can be an absolute disaster we went through a bit of a basic approach three groups
of patients and the most severe patients severe symptoms severe obstruction on imaging need to be
considered for cardio primary bypass or ecmo and the other groups of patients the first and second
group a careful generate seizure plan with all the fail-safe mechanisms and everything in place
thanks so much for watching abc's of anesthesia and the anesthesia worst
case scenarios and for this installment of anterior muscle masses so as always
if you enjoyed this please like and subscribe and thanks very much for watching you