Predicting a difficult airway is darn near impossible

[Carlos Danger]

I've seen other studies that said essentially the same thing, but I don't recall coming across this large (almost 190,000 cases) analysis from a few years back.

Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database

We retrieved a cohort of 188,064 cases from the Danish Anaesthesia Database, and investigated the diagnostic accuracy of the anaesthesiologists’ predictions of difficult tracheal intubation and difficult mask ventilation. Of 3391 difficult intubations, 3154 (93%) were unanticipated. When difficult intubation was anticipated, 229 of 929 (25%) had an actual difficult intubation. Likewise, difficult mask ventilation was unanticipated in 808 of 857 (94%) cases, and when anticipated (218 cases), difficult mask ventilation actually occurred in 49 (22%) cases.

 

[StCEMT]

I by no means have near enough experience to be an expert, but I've found a system that has consistently worked well for me. My last airway I couldn't intubate was a failure of troubleshooting on my part, not a truly difficult airway. When I think back to other misses, that has typically been the cause as well. Maybe the hospital is different with your intubation volume being significantly higher, but I feel like that is most often the case for EMS.

I don't typically use LEMONS or any other airway acronym. The biggest factor that I believe has helped has been proper positioning, a bougie technique I have confidence in, using the McGrath, and having troubleshooting techniques mentally rehearsed for working through issues before they arise.

Now I'm not trying to take away from the airways that truly are ones that should have an experienced ED or even Anesthesia doc being in charge of. I've transported them. But more often than not they tend to be pretty average in my day to day. Not consistently using LEMONS etc. hasn't hurt me, but doing the 4 things above has significantly improved my first pass success.

 

[E tank]

Hasn't been my experience at all. The difficult DL's/intubations I've had were due to a rushed/abbreviated (poor) airway assessment. Mid DL, the issues declare themselves pretty clearly and they're almost always discoverable with a thorough exam, which most people do not do. There are about eleven points of a really good exam, some of which you hit with a glance at the patient, but by and large I bet most people just hit the big three...oral aperture, neck extension and prognath. 99% of the time, they're enough. Even when I do sometimes have a positive finding on exam, I can tend to blow it off, assuming I can power through it.

Very unusual for an unexpected difficult DL not to be my fault.

 

[Peak]

I've definitely had patients who we thought were going to be near impossible to tube (typically extreme morbid obesity or HAE cases) who had such clinical deterioration that we could wait, and ended up being pretty easy tubes.

I've also had the opposite where we thought the patient was low risk and had adventitious anatomy only to struggle to secure their airway.

I think the takeaway should be that we should approach every attempt as it might not be successful and to have a bailout ready. I've seen far too many clinicians across too many areas of care (from EMS to ENT) in too many systems who don't seem to give a second to the thought that they might not be successful.

Depending on the environment I don't always have fancy tools at my disposal, but I'll always have backup plans.

 

[E tank]

this guy is one one of the reasons why I can be a little cavalier with airways...for better or for worse....

 

[E tank]

I've definitely had patients who we thought were going to be near impossible to tube (typically extreme morbid obesity or HAE cases) who had such clinical deterioration that we could wait, and ended up being pretty easy tubes.

I've also had the opposite where we thought the patient was low risk and had adventitious anatomy only to struggle to secure their airway.

I think the takeaway should be that we should approach every attempt as it might not be successful and to have a bailout ready. I've seen far too many clinicians across too many areas of care (from EMS to ENT) in too many systems who don't seem to give a second to the thought that they might not be successful.

Depending on the environment I don't always have fancy tools at my disposal, but I'll always have backup plans.

Backup is mandatory....agree....but I bet if you look back on the cases you might have thought could be difficult, given a little time to assess, you would not have thought so....super morbid obesity alone is not an indicator of difficult DL....

 

[Peak]

I think that how long you can assess for is a huge difference between EMS/ED and Anesthesia/critical care. We absolutely need to make a good assessment, but it also needs to be balanced with the clinical urgency of the situation. If we can bridge with bipap or HHF while getting resources and better controlling the environment that is great, but sometimes immediate intervention is mandatory. The ability to get a medical history from the acutely failing patient can often be a struggle at best as well.

At a certain point the amount of tissue challenges my ability to position the patient's anatomy adequately, and when I can no longer identify the relevant anatomy for a cric/trach/retrograde intubation it freaks me out.

 

[E tank]

I think that how long you can assess for is a huge difference between EMS/ED and Anesthesia/critical care. We absolutely need to make a good assessment, but it also needs to be balanced with the clinical urgency of the situation. If we can bridge with bipap or HHF while getting resources and better controlling the environment that is great, but sometimes immediate intervention is mandatory. The ability to get a medical history from the acutely failing patient can often be a struggle at best as well.

At a certain point the amount of tissue challenges my ability to position the patient's anatomy adequately, and when I can no longer identify the relevant anatomy for a cric/trach/retrograde intubation it freaks me out.

The best airway management is the least airway management...

 

[CWATT]

In retrospect, my testing in Paramedic school was almost entirely on predicting difficult aiways (i.e., LEMON) and almost no discussion about troubleshooting beyond ‘change something’. If this article is accurate, perhaps schools should focus on troubleshooting methodology rather than emphasize predicting difficult airways. I myself had an unanticipated ‘difficult’ airway during my OR rotations (significnaly more inferior and anterior than expected but easily resolved with some ELM) but I attributed it to a lack of experience at the time. Now I’m thinking perhaps it was a combination of both experience and low accuracy of difficult airway assesments. In any respect, it’s certainly enough for me to consider how we are instructing new Paramedics.

Side note: has anyone attended airway programs like Rich Levitan’s Practical Emergency Airway Course or George Kovac’s AIME Airway?

 

[Tommerag]

I've definitely had patients who we thought were going to be near impossible to tube (typically extreme morbid obesity or HAE cases) who had such clinical deterioration that we could wait, and ended up being pretty easy tubes.

I've also had the opposite where we thought the patient was low risk and had adventitious anatomy only to struggle to secure their airway.

I think the takeaway should be that we should approach every attempt as it might not be successful and to have a bailout ready. I've seen far too many clinicians across too many areas of care (from EMS to ENT) in too many systems who don't seem to give a second to the thought that they might not be successful.

Depending on the environment I don't always have fancy tools at my disposal, but I'll always have backup plans.

I had a similar experience a few weeks ago when I got called in (was at home sleeping) to the ER to RSI a patient. When I first arrived and saw the patient I thought for sure he was going to be very difficult to intubate. 140+ kg, no neck, tongue was swollen from biting it during a seizure. Surprisingly the pt was a very easy intubation. Caught me by surprise.

Completely agree with you about not being successful. I have the same setup when I intubate in the ER. I still use the good 'ole blade and handle for my first attempt. I always have the Glidescope setup and ready to go right next to me in the event first attempt is unsuccessful. I also have an I-Gel out and ready to go in case I can't get the tube. Now in the field it is a different story and depends on the situation so setup verys. I find having the same exact setup routine helps me quite abit.

 

[Carlos Danger]

It's worth pointing out that this study is not the first one to come to the conclusion that we are, collectively, not very good at predicting the degree of difficulty of either intubation or mask ventilation. There have been at least a few others than showed essentially the same thing.

IIRC, the only elements of an airway exam that have shown to have any real prognostic utility for intubation difficulty are the Malllampati score, mouth opening, PLUS jaw translocation (bite test), but they only work reliably when used together, and even then they aren't all that good. Mallampati by itself tells you very little because it doesn't have anything to do with neck mobility or the ability to displace the tongue and tissues with your blade, which is how you align the oral, pharyngeal, and laryngeal axes.

It isn't uncommon at all for me to find an airway easier than I expected it to be. I think that's probably partly because of the skill that I've developed though experience, but mostly because I'm generally pretty conservative in my approach to airway management, so I take any indicator of difficulty at face value. I always assess neck mobility, Mallampati, and bite test. If there's a smaller than normal mouth opening or a larger than normal tongue or some other anatomic oddity, that's usually apparent without specifically assessing for it.

A truly, objectively difficult airway (CI/CV) is statistically pretty rare, which makes it harder to study this type of thing, as does the fact that everyone assesses airways differently.

 

[DrParasite]

I had a similar experience a few weeks ago when I got called in (was at home sleeping) to the ER to RSI a patient. When I first arrived and saw the patient I thought for sure he was going to be very difficult to intubate. 140+ kg, no neck, tongue was swollen from biting it during a seizure. Surprisingly the pt was a very easy intubation. Caught me by surprise.

Random aside, but they called a paramedic in from home to RSI a patient? they didn't have a doctor who could do it? assuming it was a small hospital with no anesthesia doctors (which I could see), I am not sure if it's impressive that they use paramedics in this manner or worrysome that the ER doctors aren't comfortable RSIing a patient in the ER.

Completely agree with you about not being successful. I have the same setup when I intubate in the ER. I still use the good 'ole blade and handle for my first attempt. I always have the Glidescope setup and ready to go right next to me in the event first attempt is unsuccessful. I also have an I-Gel out and ready to go in case I can't get the tube. Now in the field it is a different story and depends on the situation so setup verys. I find having the same exact setup routine helps me quite abit.

honest question: if the glidescope is a fiber optic camera (and they were being put on the trucks as I was getting off the trucks), and allows for better visibility and higher success rates, why even use the blade, other than "well, that's what we have always used?"

 

[Tommerag]

I figured I might get some questions like yours from my comments (especially the part about not using Glidescope first). Which is completely understandable.

Random aside, but they called a paramedic in from home to RSI a patient? they didn't have a doctor who could do it? assuming it was a small hospital with no anesthesia doctors (which I could see), I am not sure if it's impressive that they use paramedics in this manner or worrysome that the ER doctors aren't comfortable RSIing a patient in the ER.

So you are correct in assuming that it is a small hospital that I work at (Ambulance is run by the hospital). We're a Level IV Trauma (Certified as such by both South Dakota and North Dakota) CAH. 6 bed ER with a separate trauma area that is open with 3 additional beds. We are the biggest hospital in 100 miles to our North, South, and East. Going west there isn't a bigger hospital for over 200+ miles.

We do actually have two full time CRNA's, but only 1 is ever on at a time as they work 1 month on and 1 month off. They are only ever there during the day time hours and are usually at home at night on call. We also have a general surgeon as well. We do not have any ER physicians, all of our docs are either Internal Medicine, or Family Practice. The docs are only on call in the ER for Traumas, or OB patients (3 of our docs also do OB and have 1 midwife/NP. The primary ER provider is either a NP, or PA, with the docs available for back up for them if there is an admission, have questions or want a second opinion, or if it gets extremely busy they might get called to come help.

So when I was called in I was actually doing back up call for 911's as we had 2 transfers out so the day medics weren't in house. There was a CRNA in house at that time, but she was down in OB with a pt in active labor and pushing (hospital policy is a CRNA is in the room for all deliverys, if they are in surgery, or otherwise unavailable for one reason, or another then a Medic has to be there) and she also had a epidural place in the pt. Since she couldn't leave it was either I do the RSI, or I go replace her in OB. I took option 1 (very strongly dislike OB and avoid it when possible).

honest question: if the glidescope is a fiber optic camera (and they were being put on the trucks as I was getting off the trucks), and allows for better visibility and higher success rates, why even use the blade, other than "well, that's what we have always used?"

I actually don't use the blade because that's how it's always been and it irks me when people use that a reason why something is done a certain way. I completely agree with you about the Glidescope give you much better visibility and studies have shown that videolaryngoscopy has higher success rates. The question I'll pose is "What happens if, or when the Glidescope fails?". The Glidescope does not have/need the same technique as a blade. There's no need, with the camera, to actually visualize anything looking in through the mouth like the blade. My thoughts are that if you don't keep up the skill of using a blade and the camera fails when you go to intubate someone it could be more difficult from being out of practice with the blade.

Sorry this reply ended up way longer then I meant.

Edit: Forgot to add

Also as I said earlier I only use the blade for the first attempt. If first attempt fails then I switch to the Glidescope which I already have setup next to me ready to go.

 

[Peak]

honest question: if the glidescope is a fiber optic camera (and they were being put on the trucks as I was getting off the trucks), and allows for better visibility and higher success rates, why even use the blade, other than "well, that's what we have always used?"

It depends on the glidescope model, but the new lopro blades are all digital (as well as some of the older adult setups), but that isn't really the point.

I think that for many providers resistance to using video laryngoscopy is an ego thing. It isn't even a 'I've always done it this way' but more of a macho 'I don't need a crutch' type thing.

I do think that it is almost always easier for me to manipulate and visualize the airway on neos, infants, and peds with direct laryngoscopy with a Miller blade than using a glidescope but that certainly isn't the majority of intubations by any means. I find that often the greatest challenge of intubating kids is in advancing an adequate size ET tube without causing trauma, especially in kids with anatomical upper airway disease.

I'd also point out that not all ambulances and certainly not all pre hospital ALS providers will have video laryngoscopy at their disposal. I've never had access to video laryngoscopy in the field either when I started or to this , although the latter is more a function be being in resource limited environments.

I do think that regardless of the presence or absence of video laryngoscopy clinicians should be skilled in a variety of bailouts. Whether it is a surgical airway (even if it is just bridging with a transtracheal jet), supraglottic airway, digital intubation, or even things as simple as the skilled use of a bougie (though I hesitate to consider this a bailout). It also may be appropriate to place a OG, OPA, and just bag it into a higher resource center.

 

[Tigger]

Random aside, but they called a paramedic in from home to RSI a patient? they didn't have a doctor who could do it? assuming it was a small hospital with no anesthesia doctors (which I could see), I am not sure if it's impressive that they use paramedics in this manner or worrysome that the ER doctors aren't comfortable RSIing a patient in the ER. honest question: if the glidescope is a fiber optic camera (and they were being put on the trucks as I was getting off the trucks), and allows for better visibility and higher success rates, why even use the blade, other than "well, that's what we have always used?"

My old job would get phone calls from the little critical access hospital for help managing airways. They'd rather call us before the on call CRNA, probably because they didn't have to pay us and then we could just transfer the patient. Sometimes things were fine, other times it was easier to bring our bags in and do everything else, to include bringing our McGrath, which I am much more comfortable with than a glidescope.

Speaking of which, I love the McGrath for many things, to include that if the camera becomes obscured with ickiness, it can just be used as a regular mac blade. Sadly the new job does not have video, so I think I'm just going to go back to using the bougie every time. Positioning is the number one way to set yourself up, but even then, if you end up with a crap DL view, the bougie is what I am comfortable with. I am not comfortable ever saying "that'll be an easy one" so for me it's bougie 100% of the time. If I don't need it, it's not too big of a deal, I preload the tube on it. I'd have to put a stylet in anyway, the bougie just seems more versatile for me and I have never been able to get good at using just a tube straight from the packaging.

 

[Carlos Danger]

So you are correct in assuming that it is a small hospital that I work at (Ambulance is run by the hospital). We're a Level IV Trauma (Certified as such by both South Dakota and North Dakota) CAH.

A CMS designated Critical Access Hospital, AND a Level IV trauma resource? A trauma resource with that not only doesn't staff an EM physician, but has NO ONE in-house who can manage an airway?

Anesthesia has to be in the room for all deliveries - WTF? Paramedics are used interchangeably with CRNA's - to the point that the paramedic can elect to take on the expected difficult airway while the anesthesia provider sits on her hands watching OB nurses catch a baby?

It sounds like the medical twilight zone.

Please tell me exactly where this is, because I want to make sure I'm never, ever in that area.

 

[Tommerag]

A CMS designated Critical Access Hospital, AND a Level IV trauma resource? A trauma resource with that not only doesn't staff an EM physician, but has NO ONE in-house who can manage an airway?

Anesthesia has to be in the room for all deliveries - WTF? Paramedics are used interchangeably with CRNA's - to the point that the paramedic can elect to take on the expected difficult airway while the anesthesia provider sits on her hands watching OB nurses catch a baby?

It sounds like the medical twilight zone.

Please tell me exactly where this is, because I want to make sure I'm never, ever in that area.

It is what it is, but welcome to extremely rural healthcare. I can say I've never worked, or been to a CAH that staffs actual ER physicians. For level IV trauma in ND and SD the requirements having a MD/DO on call for trauma, all ER providers must have taken ATLS and passed, and have a general surgeon available 90% of the year. Regardless if we had the trauma designation, or not, we would still receive the same trauma patients that we are already seeing as there is no other option.

Well technically you should probably just assume that all airways will be difficult and be prepared for that. As for the CRNA in the room for OB it makes sense for here due to the amount of OB pt's that drop in in labor with no prenatal care and high and meth, or other drugs.

And no it's not a medical twilight zone, it's rural healthcare. In the 6 years I've worked here we've never had an issue with it. Our mid-levels and docs can intubate and have seen them do it, but usually they would prefer someone else do it so they can continue/start arranging transfers and get that going quicker.

I can see how this sounds crazy and would sound the same to me if I hadn't been working in this environment for the last 6 years.

 

[Carlos Danger]

It is what it is, but welcome to extremely rural healthcare. I can say I've never worked, or been to a CAH that staffs actual ER physicians. For level IV trauma in ND and SD the requirements having a MD/DO on call for trauma, all ER providers must have taken ATLS and passed, and have a general surgeon available 90% of the year. Regardless if we had the trauma designation, or not, we would still receive the same trauma patients that we are already seeing as there is no other option.

Well technically you should probably just assume that all airways will be difficult and be prepared for that. As for the CRNA in the room for OB it makes sense for here due to the amount of OB pt's that drop in in labor with no prenatal care and high and meth, or other drugs.

And no it's not a medical twilight zone, it's rural healthcare. In the 6 years I've worked here we've never had an issue with it. Our mid-levels and docs can intubate and have seen them do it, but usually they would prefer someone else do it so they can continue/start arranging transfers and get that going quicker.

I can see how this sounds crazy and would sound the same to me if I hadn't been working in this environment for the last 6 years.

I do rural anesthesia myself (including OB), so I'm familiar with the challenges. There are plenty of times that I'm the only provider in the building outside of the ED doc, who is busy with his own patient load. And I can tell you that meth or not, prenatal care or not, having a CRNA in the room for every delivery is not a standard per any professional organization's guideline, and is an incredible waste and completely unnecessary. In-house, maybe, in case a section is called. But in the room, doing nothing? When there's a difficult intubation somewhere in house? That is simply absurd and that kind of practice is going to get a patient hurt someday and when (not if) it does, that place will get sued for every asset they own, and the CRNA will be named as well, if they knew that they were needed somewhere and didn't respond.

Sorry if I sound like a ****, but it is what it is.

 

[TXmed]

Thats not super uncommon in the very rural parts of texas. If there is a physician in the small ER then he probably isnt board certified and it will be known to him that the local medics or flight crews will be more experienced at airways than him. Plus they will end up taking the patient out anyways as these hospitals typically dont have ICU capabilities.

 

[Tommerag]

I know. Like i said hospital policy. How long ago it was implemented I couldnt tell you. Youre points are valid as well and i dont disagree with them either.

On a side note i forgothow much i like this forum and actually being able to have civil disucssions.