inducing morbid obese

[Patron]

while intubating an obese patient, do you try to see if you can ventilate before giving succ? you dont need to do RSI, my argument is what if you cannot ventilate do you wake the patient up or give succ to relax the cords or stick an LMA? personally I dont think it is necessary to check if you can ventilate before succ because you only loosing FRC O2 reserve. I apprecite your feedback guys

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[sevoflurane]

while intubating an obese patient, do you try to see if you can ventilate before giving succ? you dont need to do RSI, my argument is what if you cannot ventilate do you wake the patient up or give succ to relax the cords or stick an LMA? apprecite your feedback guys

Reverse trendelenburg is your friend.

 

[GasEmDee]

while intubating an obese patient, do you try to see if you can ventilate before giving succ? you dont need to do RSI, my argument is what if you cannot ventilate do you wake the patient up or give succ to relax the cords or stick an LMA? personally I dont think it is necessary to check if you can ventilate before succ because you only loosing FRC O2 reserve. I apprecite your feedback guys

I agree with you. I do not wait before giving sux. In the time you wait to do that, they will exhaust a lotof their FRC. If you have a difficult airway, you need them fully relaxed, so that you can enact your plan (or backup plan). They just won't wake up in time to save themselves.

Ever do these ECT cases, where you give sux? Usually, there is time for a couple shocks (e.g 3 minutes) , before the neuromuscular blockade wears off.

 

[Jeff05]

while intubating an obese patient, do you try to see if you can ventilate before giving succ? you dont need to do RSI, my argument is what if you cannot ventilate do you wake the patient up or give succ to relax the cords or stick an LMA? personally I dont think it is necessary to check if you can ventilate before succ because you only loosing FRC O2 reserve. I apprecite your feedback guys

if you can't ventilate you don't just magically wake the patient. you still have to do something. if you have laryngospasm and can't break with PPV, then you give sux.

the goal of RSI in obese pts is to give you intubating conditions as quickly as possible, as these patients may be difficult to mask ventilate and desaturate quickly. in addition, if you are having trouble intubating or ventilating, they will resume spont respiration in a few minutes.

did a 150kg pt today for gastric bypass. ramp, reverse trend, fully preox, prop 300mg, sux 150mg, tube.

 

[Mman]

We do lots of obese patients (hooray for all the gastric bypasses we do) so this situation is way too familiar.

So long as their mouth opening is wide enough and have some neck mobility giving me reassurance that I can get a glidescope in their mouth, I'll just give the sux without ventilating.

As mentioned above, reverse T-berg and good positioning with a ramp or blankets or whatever is your friend and makes life much easier.

The problem with waiting to ventilate is that they are going to be difficult to ventilate. And then you have to try to fit an airway in (oral or nasal). Clock ticking the whole time and you don't have long until the pulse ox starts dropping.

I say give yourself the best shot with your first shot and have backup plans nearby in case of emergency.

 

[pencan]

We use the troop pillow for our really obese patients and Lap Bands works great and beats wasting blankets. It only costs a few hundred dollars and is washable. they also have disposable ones.

http://www.tmml.com/Catalogue/ProductDescription.asp?c=109446

 

[amyl]

for me its all about the ramp and having the glidescope near by.... just push it

 

[Idiopathic]

just a habit, i always ventilate prior to NMB, unless Im concerned about a full stomach. i find it puts myself and my trainee at ease, especially when they are junior...we are both worried enough about the airway, its nice to know you can bag the patient, or what maneuver you had to do to be able to bag the patient.

if i was by myself, id probably handle it as the above posters have mentioned

 

[sevoflurane]

This debate will go on for ever.

In residency, I had an attending that said he would testify against any anesthesiologist that didn't test for mask ventilation before he paralyzed.

I'm in the other camp. If you induce these whales with 2mg/kg of propi... you might as well give 'em sux. If you induce and can't ventilate, what are you going to do???? Wait for the propofol to wear off and wake them up to do an awake fiberoptic? They will be as blue as papa smurf by then. Obese patients have increase O2 requirements and have much higher cardiac outputs than the 70 kg man (perfusing all that fat increases the work load on the heart and it's O2 requirements/demand). Their FRC is reduced and their closing volume is elevated. You can use all the tricks in the book, but that doesn't change the fact that they have a tendency to desaturate no matter what you do..... So waiting for the propofol to wear off to do an awake fiberoptic is not very popular in my camp. I can honestly say, I've yet to go down that pathway.

I either induce with prop and sux or I do an awake fiberoptic. An alternative is to give enough propofol to get them right over the apneic threshold so they can recover and resume SV more rapidly, but this takes skill and never guarantees you can ventilate once they get oropharengeal hypotonia. As always, previous records are worth their weight in gold in anyone that looks like a difficult AW.

 

[proman]

Spontaneous inhalation induction with CPAP is underappreciated in the morbidly obese but I agree that if you anticipate difficulty masking or intubating an awake approach is best.

Having lost the ability to mask after paralytic before, I don't think it has any value.

 

[Planktonmd]

The vast majority of morbidly obese patients that I see are usually not difficult to intubate if positioned correctly.
They might be difficult to mask ventilate but I never find out since I usually don't attempt to ventilate them before intubation.

 

[doctor712]

Hi All,

Have been wanting to ask about this case discussion. So, I wonder, is this (a good example) of the academic dogma that some of you talk about? Real word versus residency stuff?

For example, when I observed a CT Anesthesiologist and friend for a week, he took me aside and made a point to say: anesthesia starts with making sure you can ventilate. Period. So, I thought it was a takeaway that I'd hang on to as the time between now and medical school/residency passes. i.e. Can you mask ventilate? If not, why induce? Because, if you cannot, and the patient has lost spontaneous resipirations, oh darn.

But then I read a lot of the replies here, Sevo's in particular, and he brings up the discussion and the debate, and the majority of the peeps on this board say, "why bother?" So, I understand this to be: if you induce, and patient cannot be ventilated, you're not going to wait for propofol to wear off (the FRC and desaturation argument) so, you're going to paralyze (make for optimal intubation) and try and intubate anyway. This is what I'm gathering, as Jeff05 said.

So, my question is, understanding the above, why would you induce in the first place without assuring you can mask ventilate by giving it a go? I understand that once you induce, in a theoretical patient that let's say cannot be ventilated or tubed w/o paralytic, you might have to move forward and paralyze and do whatever the heck you have to do to get the tube in, BUT, why not avoid that unknown and mask ventilate? What do you lose?

I guess that then begs the thought, in the perfect world, you induce obese patient and w/o paralytic you stick a tube in. Done. So, when that doesn't happen, and you have chosen to take a known/assumed difficult airway (obese or prior history of) and induce WITHOUT mask ventilating, why, with all my naivete, would someone knowingly burn that bridge? When you don't have to?

I understand that either way, you must ultimately induce, right? But, do you really have to? If you try to mask ventilate, and fail, would you still induce normally? Change things up a bit? Get an emergency airway kit within arms' reach. Chill out and get some support. Awake FOB thoughts start churning, I dunno. If so, and you would not change a thing after failing a mask ventilation, then that answers the question, and I've learned something. But isn't that the point of assuring you can mask ventilate in first place?

Maybe, if I'm lucky, somebody can ask ME a question, or present a scenario is what I mean, so I can clearly see the logic in case X or case Y and how those scenarios change. That would be a NICE exercise... 🙂

Curious,
THANKS IN ADVANCE
D712

 

[Idiopathic]

Hi All,

Have been wanting to ask about this case discussion. So, I wonder, is this (a good example) of the academic dogma that some of you talk about? Real word versus residency stuff?

For example, when I observed a CT Anesthesiologist and friend for a week, he took me aside and made a point to say: anesthesia starts with making sure you can ventilate. Period. So, I thought it was a takeaway that I'd hang on to as the time between now and medical school/residency passes. i.e. Can you mask ventilate? If not, why induce? Because, if you cannot, and the patient has lost spontaneous resipirations, oh darn.

But then I read a lot of the replies here, Sevo's in particular, and he brings up the discussion and the debate, and the majority of the peeps on this board say, "why bother?" So, I understand this to be: if you induce, and patient cannot be ventilated, you're not going to wait for propofol to wear off (the FRC and desaturation argument) so, you're going to paralyze (make for optimal intubation) and try and intubate anyway. This is what I'm gathering, as Jeff05 said.

So, my question is, understanding the above, why would you induce in the first place without assuring you can mask ventilate by giving it a go? I understand that once you induce, in a theoretical patient that let's say cannot be ventilated or tubed w/o paralytic, you might have to move forward and paralyze and do whatever the heck you have to do to get the tube in, BUT, why not avoid that unknown and mask ventilate? What do you lose?

I guess that then begs the thought, in the perfect world, you induce obese patient and w/o paralytic you stick a tube in. Done. So, when that doesn't happen, and you have chosen to take a known/assumed difficult airway (obese or prior history of) and induce WITHOUT mask ventilating, why, with all my naivete, would someone knowingly burn that bridge? When you don't have to?

I understand that either way, you must ultimately induce, right? But, do you really have to? If you try to mask ventilate, and fail, would you still induce normally? Change things up a bit? Get an emergency airway kit within arms' reach. Chill out and get some support. Awake FOB thoughts start churning, I dunno. If so, and you would not change a thing after failing a mask ventilation, then that answers the question, and I've learned something. But isn't that the point of assuring you can mask ventilate in first place?

Maybe, if I'm lucky, somebody can ask ME a question, or present a scenario is what I mean, so I can clearly see the logic in case X or case Y and how those scenarios change. That would be a NICE exercise... 🙂

Curious,
THANKS IN ADVANCE
D712

My point is that if I cant easily mask ventilate then my threshold for taking over an airway from a junior provider is dropped to the floor, if I can I will be much more likely to allow them 2/3 attempts.

I tell everyone who comes through the OR that anyone can get lucky and put a tube in, but mask ventilation is the thing that can truly save someones life. You need to know how to do it on all types of people: small, big, etc. and this is the reason why I do it for everyone (barring a few specific circumstances).

The take home message is: if you are concerned that you may not be able to intubate, then you should follow your ASA algorithm and consider awake procedure. Ultimately, however, the patients in the situation described by the OP are not your true Class IV airways and just tend to desaturate quicker, etc. It is the very rare patient in real life who cannot be tubed or masked and so you should be equally proficient in both.

 

[Mman]

Hi All,


So, my question is, understanding the above, why would you induce in the first place without assuring you can mask ventilate by giving it a go? I understand that once you induce, in a theoretical patient that let's say cannot be ventilated or tubed w/o paralytic, you might have to move forward and paralyze and do whatever the heck you have to do to get the tube in, BUT, why not avoid that unknown and mask ventilate? What do you lose?


I understand that either way, you must ultimately induce, right? But, do you really have to? If you try to mask ventilate, and fail, would you still induce normally?

You cannot attempt to mask ventilate until you induce the patient. An awake patient isn't going to let you do a jaw thrust and might a tight seal with the mask and give them positive pressure ventilation. And even if they do, it isn't really predicting that you could do the same once they are unconscious and apneic.

Essentially, once you induce with an IV agent such as propofol, you have made them apneic and the clock is ticking until they desaturate. But you can't try to mask ventilate until you've already gone down that road. The question is whether or not you give the succinylcholine before attempting to mask ventilate.

I do have one other trick I try if I'm a little nervous, but not quite nervous enough to do an awake FOI. Induce with some ketamine and inhaled sevo and get them pretty deep but breathing spontaneously and try to get a view with the glidescope with them still breathing. Backup plan is to turn off the gas and just wake them up while still breathing spontaneously.

 

[Matty44]

Hi All,

Have been wanting to ask about this case discussion. So, I wonder, is this (a good example) of the academic dogma that some of you talk about? Real word versus residency stuff?

For example, when I observed a CT Anesthesiologist and friend for a week, he took me aside and made a point to say: anesthesia starts with making sure you can ventilate. Period. So, I thought it was a takeaway that I'd hang on to as the time between now and medical school/residency passes. i.e. Can you mask ventilate? If not, why induce? Because, if you cannot, and the patient has lost spontaneous resipirations, oh darn.

But then I read a lot of the replies here, Sevo's in particular, and he brings up the discussion and the debate, and the majority of the peeps on this board say, "why bother?" So, I understand this to be: if you induce, and patient cannot be ventilated, you're not going to wait for propofol to wear off (the FRC and desaturation argument) so, you're going to paralyze (make for optimal intubation) and try and intubate anyway. This is what I'm gathering, as Jeff05 said.

So, my question is, understanding the above, why would you induce in the first place without assuring you can mask ventilate by giving it a go? I understand that once you induce, in a theoretical patient that let's say cannot be ventilated or tubed w/o paralytic, you might have to move forward and paralyze and do whatever the heck you have to do to get the tube in, BUT, why not avoid that unknown and mask ventilate? What do you lose?

I guess that then begs the thought, in the perfect world, you induce obese patient and w/o paralytic you stick a tube in. Done. So, when that doesn't happen, and you have chosen to take a known/assumed difficult airway (obese or prior history of) and induce WITHOUT mask ventilating, why, with all my naivete, would someone knowingly burn that bridge? When you don't have to?

I understand that either way, you must ultimately induce, right? But, do you really have to? If you try to mask ventilate, and fail, would you still induce normally? Change things up a bit? Get an emergency airway kit within arms' reach. Chill out and get some support. Awake FOB thoughts start churning, I dunno. If so, and you would not change a thing after failing a mask ventilation, then that answers the question, and I've learned something. But isn't that the point of assuring you can mask ventilate in first place?

Maybe, if I'm lucky, somebody can ask ME a question, or present a scenario is what I mean, so I can clearly see the logic in case X or case Y and how those scenarios change. That would be a NICE exercise... 🙂

Curious,
THANKS IN ADVANCE
D712

I think the thing that you're missing here is that you can't really mask a patient that's awake. I mean, I suppose you might be able to if they were completely relaxed and they just let you do all the work of breathing for them, but that would probably be uncomfortable for the patient. You check for the ability to mask ventilate AFTER you induce the patient and they go apneic. At that point, you have to create a good seal with the mask and position the patient appropriately, which usually involves a good amount of chin lift/jaw thrusting, which can be very uncomfortable for someone who is not unconscious. So there's really no way to confirm if a pt is impossible to mask ventilate until you actually induce and try it (unless there is and I'm just wrong...if so, forgive me, I'm still a noob🙄)

Edit:Just saw the above post....

 

[doctor712]

Ok, thanks ID and MMan. Understood, so, a quick follow up question, and I think I see the clarification here, why not attempt to mask ventilate (always) before giving paralytic? In your example, MMan, you try Ketamine and Sevo so (I imagine) Ketamine goes away quicker than propofol and Sevo just gets turned off, still spontaneously breathing, problem averted...

Therefore, with propofol, or anything else that won't go away quick enough to allow this patient not to desat, I'm still a little grey on why peeps on this board for example, like my man Plankton, don't attempt to mask ventilate before paralytic - always? Is it because, maybe Planktons induction scenario, they are no longer breathing spontaneously so you simply can't wait until they awake, and well, only shot really now is "Sure, now I'll paralyze..." and do something else if need be?

I guess that uncertainty can still be avoided if you mask ventilate and get that answer before paralytic goes in. Maybe it's just that certain people have had so much experience with being able to mask or tube that it's like (thinking of a BAd analogy here quick, im tired...) you know you have tongs to use on the grill when BBQ-ing, but, so what, you grab the burger/corn/chicken with your fingers really quickly because the last 1000 times you did it, you took a little risk, but lost nothing but a little hair on the old fingers...certainly didn't get flamed out and die... (BAD example, but I think still clear.)

Thanks for the replies both!
D712

note: thanks matty, yeah I was a bit confused with mask ventilating and pre-oxy for a moment... roger that!

 

[proman]

If your fingers could still get burned using tongs, would you still insist on using them?

 

[CecilJacobson]

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

IMO every single time a patient goes under, except for maybe Andrea Bocelli, should get an LMA no questions asked.

I would trade a possible sore throat for better results and recovery (due to perfect O2 sat.) every single time.

Not to mention if something goes wrong...

Then again, I'm no doctor, I'm just a scrub.

-CJ

 

[Arch Guillotti]

Ok, thanks ID and MMan. Understood, so, a quick follow up question, and I think I see the clarification here, why not attempt to mask ventilate (always) before giving paralytic? In your example, MMan, you try Ketamine and Sevo so (I imagine) Ketamine goes away quicker than propofol and Sevo just gets turned off, still spontaneously breathing, problem averted...

Therefore, with propofol, or anything else that won't go away quick enough to allow this patient not to desat, I'm still a little grey on why peeps on this board for example, like my man Plankton, don't attempt to mask ventilate before paralytic - always? Is it because, maybe Planktons induction scenario, they are no longer breathing spontaneously so you simply can't wait until they awake, and well, only shot really now is "Sure, now I'll paralyze..." and do something else if need be?

I guess that uncertainty can still be avoided if you mask ventilate and get that answer before paralytic goes in. Maybe it's just that certain people have had so much experience with being able to mask or tube that it's like (thinking of a BAd analogy here quick, im tired...) you know you have tongs to use on the grill when BBQ-ing, but, so what, you grab the burger/corn/chicken with your fingers really quickly because the last 1000 times you did it, you took a little risk, but lost nothing but a little hair on the old fingers...certainly didn't get flamed out and die... (BAD example, but I think still clear.)

Thanks for the replies both!
D712

note: thanks matty, yeah I was a bit confused with mask ventilating and pre-oxy for a moment... roger that!

I can understand your curiosity with these scenarios but you are in way over your head for a pre-med especially. You can't fully grasp how to approach these scenarios until you have some miles under your belt, have seen how different folks approach things, and experienced all of the above-described scenarios yourself.

With that being said, I almost always push the relaxant right away. I have seen patients become impossible to ventilate after induction/paralytic but it seems as though they always were some messed up ENT patient who had been operated on for head and neck cancer or irradiated. These are the patients that you should be doing awake. Almost everyone becomes easier to ventilate after relaxant and gives you better intubating conditions.

I have never woken a patient up after a failed airway but I know others who have so it isn't unheard of. A long preoxygenation can buy you the time you need to recover as can judicious use of induction agent and sux.

 

[Mman]

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

IMO every single time a patient goes under, except for maybe Andrea Bocelli, should get an LMA no questions asked.

I would trade a possible sore throat for better results and recovery (due to perfect O2 sat.) every single time.

Not to mention if something goes wrong...

Then again, I'm no doctor, I'm just a scrub.

-CJ

I found this post to be quite amusing on multiple levels.

 

[Jeff05]

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

IMO every single time a patient goes under, except for maybe Andrea Bocelli, should get an LMA no questions asked.

I would trade a possible sore throat for better results and recovery (due to perfect O2 sat.) every single time.

Not to mention if something goes wrong...

Then again, I'm no doctor, I'm just a scrub.

-CJ

you have NO idea what you are saying. i wouldn't even know where to start with the idiocy of what is written above.

 

[lord_jeebus]

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

IMO every single time a patient goes under, except for maybe Andrea Bocelli, should get an LMA no questions asked.

I would trade a possible sore throat for better results and recovery (due to perfect O2 sat.) every single time.

Not to mention if something goes wrong...

Then again, I'm no doctor, I'm just a scrub.

-CJ

This post must set some sort of record. Each and every sentence is astonishing. It's the "Plan 9 from Outer Space" of SDN posts - so bad that it's good.

 

[sevoflurane]

Wow... Very civilized comments for the anesthesia SDN.... I guess I expected more.

 

[doctor712]

If your fingers could still get burned using tongs, would you still insist on using them?

I guess... what else is there? Spatula? Nah. Fork? Nah.

(I'll play along!) I don't like the long tongs actually, I like the small ones. Higher risk of getting burned, but better ease of use and more control. And they certainly drop a lot less burgers than sloppy use of spatula - especially with a rolling hot dog near the end of the grill. 🙂 Now I have to figure out what this has to do with anesthesia. 🙂

But thanks for the answers all! Arch, agreed, over my head, but I appreciate the answers! On another note, I think other med students and premeds even would be welcome to chime in on this Anesthesia board every blue moon if they showed some damned curiosity and interest rather than show up, insult, and move on. Not sure of the goal there, but anyhoo.

 

[Mman]

But thanks for the answers all! Arch, agreed, over my head, but I appreciate the answers! On another note, I think other med students and premeds even would be welcome to chime in on this Anesthesia board every blue moon if they showed some damned curiosity and interest rather than show up, insult, and move on. Not sure of the goal there, but anyhoo.

Back to the actual Q/A section of this thread....

I use ketamine plus inhalation induction not because ketamine goes away quicker than propofol, but because it does not depress their ventilatory drive. I guess I could do either straight ketamine or just a straight inhalation induction, but I like to combine it to try to get them very deep so I can have good laryngoscopy conditions, but still maintain spont ventilation so I can bail if I need to.


As to Arch's point about this being over a pre-med's head, it's a valid point. These are very good clinical questions, but as with many things in medicine the correct answer is that "it depends". There isn't one right answer. What you need is a knowledge base and experience to come up with a plan that is safe for the patient in front of you.

My reason for not checking if I can ventilate is that if I can't really ventilate, my first move is going to be to give the succinylcholine anyways. So why not get it in quicker and then I'll have a better shot at getting the tube in and it'll wear off quicker so that we can't intubate and are struggling to ventilate I'll have the option of waking them up faster than if I waited 30-60 seconds to give the sux in the first place.

Complicated (but great) questions and complicated answers.

 

[sevoflurane]

I agree with Mman and his approach. I would also like to add that ventilation is acutally easier once the patient is paralyzed (99.9% of the time).

 

[doctor712]

Back to the actual Q/A section of this thread....

I use ketamine plus inhalation induction not because ketamine goes away quicker than propofol, but because it does not depress their ventilatory drive. I guess I could do either straight ketamine or just a straight inhalation induction, but I like to combine it to try to get them very deep so I can have good laryngoscopy conditions, but still maintain spont ventilation so I can bail if I need to.


As to Arch's point about this being over a pre-med's head, it's a valid point. These are very good clinical questions, but as with many things in medicine the correct answer is that "it depends". There isn't one right answer. What you need is a knowledge base and experience to come up with a plan that is safe for the patient in front of you.

My reason for not checking if I can ventilate is that if I can't really ventilate, my first move is going to be to give the succinylcholine anyways. So why not get it in quicker and then I'll have a better shot at getting the tube in and it'll wear off quicker so that we can't intubate and are struggling to ventilate I'll have the option of waking them up faster than if I waited 30-60 seconds to give the sux in the first place.

Complicated (but great) questions and complicated answers.

Thanks, Mman!

 

[sevoflurane]

Rarely do I give these people 2mg/kg prop. I may give as little as 120mg.... just enough for amnesia (have plenty of it left over in case I need it). I also use a reduced amount of sux (I don't ever give 200mg of sux). If they get tachy/HTNive, I'll shoot them with some esmolol.

Given this way, you don't have to wait nearly as long to resume spontaneous ventilation and are able to achieve good intubating conditions.

 

[GasEmDee]

This is proof that someone can watch something (anesthesia and surgery) being done all day long and yet never gain any insight into the process.

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

IMO every single time a patient goes under, except for maybe Andrea Bocelli, should get an LMA no questions asked.

I would trade a possible sore throat for better results and recovery (due to perfect O2 sat.) every single time.

Not to mention if something goes wrong...

Then again, I'm no doctor, I'm just a scrub.

-CJ

 

[Idiopathic]

so i like to dose my hypnotioc at about 1 per kilo for propofol, turn on some sevo as they start to sleep and try to ventilate them...if i can get one breath in with sevo/N2O then it makes a huge difference to me

all i really want from my hypnotic in most people is to get them where they will let me ventilate them

 

[Arch Guillotti]

so i like to dose my hypnotioc at about 1 per kilo for propofol, turn on some sevo as they start to sleep and try to ventilate them...if i can get one breath in with sevo/N2O then it makes a huge difference to me

What do you do when you can't ventilate?

 

[fakin' the funk]

Spontaneous inhalation induction with CPAP is underappreciated in the morbidly obese

Please elaborate, sir.

 

[fakin' the funk]

ASK AN OMF! (Oral&Maxilla Facial Surgeon)

Those Docs are airway specialists. From my experience I would say they are better than anesthesiologists, because they push so much less drug. One time I watched an anesthesiologist come in to an OMF outpatient surgical practice and push almost ten times the amount the OMF would have used. It took almost two hours for the patient to walk out of the recovery room.

Then again, I'm no doctor, I'm just a scrub.

-CJ

I am tickled pink by the concept that anesthesiologists are walking around pushing TEN TIMES TOO MUCH DRUG and getting the same, or inferior, clinical effect as those pharm-savvy OMFS docs.

"That ******* anesthesiologist gave TWO HUNDRED mg of propofol, and 60mg rocuronium -- I got the same effect from TWENTY mg of propofol and 60mg rocuronium!"

 

[sevoflurane]

so i like to dose my hypnotioc at about 1 per kilo for propofol, turn on some sevo as they start to sleep and try to ventilate them...if i can get one breath in with sevo/N2O then it makes a huge difference to me

all i really want from my hypnotic in most people is to get them where they will let me ventilate them

I would humbly suggest leaving the N20 on the side lines for this patient population. Filling their relatively low FRC with near 100% O2 will give you considerable more time during apnea, especially when you can't ventilate.

Also, these morbidly obese people have a tendency to develop pulmonary HTN with r. ventricular failure. Adding N20 (which itself may increase PVR) to a hypercarbic/hypoxic (increased PVR) morbidly obese patient with pulm. htn may get you into trouble from low FIO2/increased PVR/right ventricular dysfxn. much quicker than some may think.

 

[Idiopathic]

What do you do when you can't ventilate?

Thats patient specific and I believe that you can wake someone up, insert an LMA or proceed with paralytic depending on what your assessment of the situation is.

 

[Idiopathic]

I would humbly suggest leaving the N20 on the side lines for this patient population. Filling their relatively low FRC with near 100% O2 will give you considerable more time during apnea, especially when you can’t ventilate.

Also, these morbidly obese people have a tendency to develop pulmonary HTN with r. ventricular failure. Adding N20 (which itself may increase PVR) to a hypercarbic/hypoxic (increased PVR) morbidly obese patient with pulm. htn may get you into trouble from low FIO2/increased PVR/right ventricular dysfxn. much quicker than some may think.

im not sure that one breath with50% N2O/50% O2 and some sevo is enough to get into trouble, but your points are very well made and should be taken into consideration, I agree

 

[Arch Guillotti]

Spontaneous inhalation induction with CPAP is underappreciated in the morbidly obese but I agree that if you anticipate difficulty masking or intubating an awake approach is best.

One day I did an inhalational induction on a fat person with no IV. That was the last time I did that. Way too sloppy for me.

 

[Arch Guillotti]

Thats patient specific and I believe that you can wake someone up, insert an LMA or proceed with paralytic depending on what your assessment of the situation is.

How many times have you woken somebody up? I doubt it is very many, if any at all because my guess is that you would be doing these folks awake.

So that leaves you with pushing relaxant and putting an LMA in (which can easily be done with relaxant on board).

 

[IlDestriero]

The vast majority of morbidly obese patients that I see are usually not difficult to intubate if positioned correctly.
They might be difficult to mask ventilate but I never find out since I usually don't attempt to ventilate them before intubation.

Plank, you're right on the money.
Reverse trend, troop elevation pillow, good (real) preoxygenation, prop, sux tube. LMA on the machine and a Glidescope in the room, but never needed.
If they actually look like a bad airway due to micrognathia, limited mouth opening, etc. Just do an awake fiber.
The majority of these patients are not difficult to intubate at all.

 

[Idiopathic]

How many times have you woken somebody up? I doubt it is very many, if any at all because my guess is that you would be doing these folks awake.

So that leaves you with pushing relaxant and putting an LMA in (which can easily be done with relaxant on board).

Waking a patient up after can not mask/tube is a perfectly legitimate path down the algorithm. It might save someone a tracheostomy for an elective procedure. Obviously if you give 250 fentanyl and 200 propofol those patients may be tougher to wake up so you may have no choice. Ill argue that there may be a different way to do things.

 

[Idiopathic]

Plank, you're right on the money.
Reverse trend, troop elevation pillow, good (real) preoxygenation, prop, sux tube. LMA on the machine and a Glidescope in the room, but never needed.
If they actually look like a bad airway due to micrognathia, limited mouth opening, etc. Just do an awake fiber.
The majority of these patients are not difficult to intubate at all.

Kind of my point, and in PP or by yourself, no doubt you follow one of these

difficult airway: keep awake

reasonable airway: prop/sux/tube

but with trainees i tend to want to encourage ventilation for their benefit and mine

 

[rsgillmd]

Kind of my point, and in PP or by yourself, no doubt you follow one of these

difficult airway: keep awake

reasonable airway: prop/sux/tube

but with trainees i tend to want to encourage ventilation for their benefit and mine

I'm with you Idio, for the most part. It's one thing when I'm by myself and another when I'm working with a trainee. But this is for non-morbidly obese patients. I treat my morbidly obese patients as full stomachs, so they get RSI.

And someone commented about LMA after relaxant. I don't give muscle relaxant to insert my LMAs. If I'm planning on doing a case under LMA, I'll give my induction agent and maybe 50 mcg of Fentanyl. They return to spontaneous breathing very quickly, and I titrate the rest of the narcotic and gas from that point. In residency I had an attending that would like to always give 10 mg of Roc before inserting an LMA. His argument was that he doesn't want to worry about being bitten. In my opinion if you do a proper induction to begin with, you shouldn't need to worry about being bitten. I realize this is paragraph may risk diverting the thread, which I don't want to do. So I will say no more.

 

[Arch Guillotti]

And someone commented about LMA after relaxant. I don't give muscle relaxant to insert my LMAs. If I'm planning on doing a case under LMA, I'll give my induction agent and maybe 50 mcg of Fentanyl. They return to spontaneous breathing very quickly, and I titrate the rest of the narcotic and gas from that point. In residency I had an attending that would like to always give 10 mg of Roc before inserting an LMA. His argument was that he doesn't want to worry about being bitten. In my opinion if you do a proper induction to begin with, you shouldn't need to worry about being bitten. I realize this is paragraph may risk diverting the thread, which I don't want to do. So I will say no more.

I don't give relaxant for LMA's either. Never really thought about it till now.

 

[dhb]

I do have one other trick I try if I'm a little nervous, but not quite nervous enough to do an awake FOI. Induce with some ketamine and inhaled sevo and get them pretty deep but breathing spontaneously and try to get a view with the glidescope with them still breathing. Backup plan is to turn off the gas and just wake them up while still breathing spontaneously.

Very nice trick, thanks.

 

[pgg]

I am tickled pink by the concept that anesthesiologists are walking around pushing TEN TIMES TOO MUCH DRUG and getting the same, or inferior, clinical effect as those pharm-savvy OMFS docs.

"That ******* anesthesiologist gave TWO HUNDRED mg of propofol, and 60mg rocuronium -- I got the same effect from TWENTY mg of propofol and 60mg rocuronium!"

Yeah, that CecilJacobson character is pretty funny. I thought maybe we were being trolled, but he actually seems sincere.

He's probably still reading this thread, thinking we're all a bunch of *******es.



Anyway, unless I'm deliberately doing a very slow, gentle induction for some reason, I'll almost always flush the propofol in with the muscle relaxant.

Otherwise, I view the induction agent itself as the point when I'm "betting the patient's life on my ability to ventilate." Given how fast obese people desaturate, and how this patient population may be less tolerant of transient hypoxia in the first place, I don't think you can count on the induction agent wearing off in time for them to breathe for themselves. Even if their respiratory DRIVE returns in time, they're still going to be pretty zonked and will likely be obstructed anyway.

I used to "prove" the airway with mask ventilation in everyone before giving the relaxant. But then I found that on the occasions when mask ventilation was difficult, I often ended up giving succ anyway to facilitate securing the airway. Or I'd cram an LMA into them and then relax them.

Particularly these days when we have solid backup options in LMAs and Glidescopes, I usually feel safer giving myself optimal conditions ASAP, and that usually means giving the relaxant up front with the induction agent.


I do a LOT fewer awake FOIs since leaving residency, where it seemed the barest hint of a fat neck, buck teeth, small mouth, etc was an ironclad indication for awake FOI. I don't think I'm cowboying it. I also don't think the difficult airway cart scope has been touched by anyone else here in months.

 

[Mman]

I do a LOT fewer awake FOIs since leaving residency, where it seemed the barest hint of a fat neck, buck teeth, small mouth, etc was an ironclad indication for awake FOI. I don't think I'm cowboying it. I also don't think the difficult airway cart scope has been touched by anyone else here in months.

Agreed. In a busy level 1 trauma center with lots of fat patients, I've only done about 2 or 3 awake FOIs in the last year. And that's supervising up to 4 rooms at a time. Now there still has been once or twice I've had to grab the fiberoptic and do an asleep FOI because nothing else was working, but it is pretty darn rare.

 

[proman]

One day I did an inhalational induction on a fat person with no IV. That was the last time I did that. Way too sloppy for me.

I wouldn't do it without IV access. Central line if needed.

Please elaborate, sir.

Preoxygenate, titrate a little bit of opioid, sevoflurane starting at 0.5% for 3 or 4 breaths, 1% for 3 or 4 breaths, now with assisted tidal volumes but maintaining spontaneous ventilation, 2% for 3 or 4 breaths.

At this point, if the airway obstructs, no more volatile agent will be administered and the little bit that's on board will redistribute and the patient will awake. The end tidal % doesn't accurately reflect how much is on board because equilibrium hasn't been reached. You can continue to deepen the sevo until the point where you think laryngoscopy will be tolerated.

I'm not a fan of single breath inductions in adults.

 

[hoyden]

So, my question is, understanding the above, why would you induce in the first place without assuring you can mask ventilate by giving it a go?

In a non-morbidly obese population the ability to ventilate often improves after a paralytic is given, and you can not assure your ability to mask ventilate before you induce.

I understand that once you induce, in a theoretical patient that let's say cannot be ventilated or tubed w/o paralytic, you might have to move forward and paralyze and do whatever the heck you have to do to get the tube in, BUT, why not avoid that unknown and mask ventilate? What do you lose?

In a morbidly obese population, almost as a rule of thumb, you will not be able to mask ventilate, but your ability to intubate is not that abysmal. Therefore you will proceed to this option fast, given the problems you face.

 

[Arch Guillotti]

Anyway, unless I'm deliberately doing a very slow, gentle induction for some reason, I'll almost always flush the propofol in with the muscle relaxant.

Otherwise, I view the induction agent itself as the point when I'm "betting the patient's life on my ability to ventilate." Given how fast obese people desaturate, and how this patient population may be less tolerant of transient hypoxia in the first place, I don't think you can count on the induction agent wearing off in time for them to breathe for themselves. Even if their respiratory DRIVE returns in time, they're still going to be pretty zonked and will likely be obstructed anyway.

I used to "prove" the airway with mask ventilation in everyone before giving the relaxant. But then I found that on the occasions when mask ventilation was difficult, I often ended up giving succ anyway to facilitate securing the airway. Or I'd cram an LMA into them and then relax them.

Particularly these days when we have solid backup options in LMAs and Glidescopes, I usually feel safer giving myself optimal conditions ASAP, and that usually means giving the relaxant up front with the induction agent.


I do a LOT fewer awake FOIs since leaving residency, where it seemed the barest hint of a fat neck, buck teeth, small mouth, etc was an ironclad indication for awake FOI. I don't think I'm cowboying it. I also don't think the difficult airway cart scope has been touched by anyone else here in months.

Agree 100%. I think "proving" the airway is silly in the vast majority of cases.

Some folks are no brainers for awake intubations. These are pretty few and far between except for the obvious head and neck cancer patients, folks who hand you a difficult airway letter, etc.

I think that in the vast majority of cases the "test ventilation" is bogus.

 

[periopdoc]

In residency, I had an attending that said he would testify against any anesthesiologist that didn't test for mask ventilation before he paralyzed.

With *******s like this, the malpractice attorney's can look forward to long and happy careers.

Why test ventilate. ~80% of the time neuromuscular blockade improves mask ventilation. ~15% of the time there is no difference in mask ventilation after neuromuscular blockade administration. ~5% of the time neuromuscular blockade makes mask ventilation more difficult necessitating the addition of an airway, or the application of my patented one handed jaw thrust/ mask application maneuver.

So what have you gained by test ventilating? Only the knowledge that the patient can or cannot be mask ventilated without neuromuscular blockade on board. How does that knowledge help you? What have you lost? Precious time.



If you induce a MO patient so lightly that waking the patient up without ventilating them is an option, they will be so light that test ventilation will be more difficult and even more meaningless. Your options at that point are to administer neuromuscular blockade, or deepen them to the point that you will never wake them up before they suffer a hypoxic arrest if you can't ventilate them.

If you induce deeply enough to have a test ventilation that is meaningful, they are not going to wake up before suffering a hypoxic arrest should you be unable to ventilate them.

So make your assessment in preop. Can you ventilate this patient. If you believe so, then give a full induction dose followed very shortly thereafter by a full dose of neuromuscular blocker (RSI or MRSI style). If you can ventilate them (>95% of the time I can) great. If not, you are that much closer to definitive airway control and you are maximizing the benefit from your pre-oxygenation efforts.

If you do not believe that you can ventilate them, then intubate them while they are spontaneously breathing. Not necessarily awake, nor necessarily with inhaled agents. There are lots of options for this scenario.

- pod