The thing about performing an awake fiberoptic intubation is sometimes they just don't go as smoothly as we'd like. There's also a perception that they eat up valuable OR time (link, they don't). And while we should be frank with patients that being intubated fiberoptically while awake won't be "fun" (fun is eating ice cream or riding your bike), the choice to omit an awake fiberoptic despite concerning risk factors (link to DA algorithm) has high potential to be life threatening, will definitely eat up OR time, and is most certainly not "fun". When I know an awake fiberoptic intubation is the safest option for a patient, I'll tell them so. "I just can't risk your life by putting you to sleep and hoping that I can 'breath for you'. You're too important and my most important job is to keep you safe."

Sometimes surgeons may disagree with your choice. That's fine. I usually just shrug and reply that I'm not a gambler. Despite these occasional oversteps by a colleague, I try to be direct yet sincere in all of my communications. These may not be your responses. And you don't even need one. All you need is the knowledge that you are here to keep your patient safe, and in this arena, you know best.

The next thing you can do is get really good at what you do.

This 'how to' aims to help streamline your approach to awake fiberoptic intubations, making the entire process more efficient and more comfortable for the patient, and also for you.

Happy fibering!

Awake Fiberoptic Intubations: A Nuts & Bolts 'How-To'

1. Patient Buy-in

2. The Right "Stuff" - Your Equipment

3. Do or Do Not, but it'd better be dry - Glycopyrrolate

4. Comfortably Numb - Some topicalization and lidocaine administration options that work well for me

5. LAST call - How much is too much?

6. Got some nerve - what are we even numbing?

7. I Wanna Be Sedated - sedation options

8. It's a set-up - How to set up your tower and equipment

9. Just do it - Grab your fiber and intubate that patient

10. Final Tips & Tricks

11. Nasal fiberoptic considerations

12. When fiberoptics fail

13. Extubating the difficult airway

    
    

1. Patient Buy-In

At the end of the day, if your patient isn't on board with your plan, this just isn't going to work. Assuming your patient has decision making capacity, they need to understand why you think they need to be intubated awake.

In case you're wondering that yourself, the simple answer is because their life is not worth risking.

The next thing patients benefit from understanding is what the procedure will be like and what steps they can expect. This certainly doesn't have to be overly detailed. Depending on the patient and situation, I might say something like this,

"To make sure we keep you safe, we are going to use a small, flexible camera to guide a breathing tube into your windpipe while you are still awake and breathing on your own. To make sure this is comfortable for you, we will coat the back of your throat and windpipe with numbing medicine, similar to what is used at the dentist. We will also give you a medication that will make your mouth feel very dry. This medicine will help the numbing medicine to work better than it otherwise would. Many people notice their heart beats faster with this medication. That is completely normal and is an expected side effect of the drying medicine. Once your mouth is very dry (I know, it doesn't feel awesome), I'm going to use some soft cotton gauze to put numbing paste in the back of your mouth. I'll remind you to try to not swallow it, because its best if the medicine sits in the back of your throat for a while".

"Once we are done with that, we will go to the operating room and get you comfortable on the OR bed and place our monitors. We will be giving you small amounts of relaxing medicine as needed but not too much because it is very important you don't get too sleepy, as that could be dangerous. While we are getting you settled, we will also be giving you more numbing medicine for the lower, harder to reach parts of your mouth, windpipe and vocal cords. We won't rush any of this buts it's also important we don't waste time either, as the numbing medicine can start to wear off rather quickly. Once you feel nice and numb, we will give you a small 'oral airway' for you to place into your mouth. After that, we will use our camera to look at your vocal cords. We will likely spray additional numbing medicine onto your vocal cords. Some people will cough immediately after this and that's ok. We will remove our camera, and you can remove the oral airway until the coughing stops. After that, you can place the oral airway back into your mouth and we will use our camera again to look at your vocal cords. Then, we will drive our camera through your vocal cords and into your windpipe, which will all be numb. It can still be normal to feel a pressure-like sensation and to cough again at this point. That means that the procedure is almost done, and the breathing tube is close to being where it needs to be. As soon as we confirm that the tube is in the right place, we will immediately give you medicine for you to go completely to sleep. We will talk you through each step and will be with you the entire time. Do you have any questions?"

As time permits in emergent situations, and certainly routinely in elective cases, a full explanation for the reasoning behind and steps involved in an awake intubation should be provided to the patient. A caring and direct approach to this entire discussion is, in my opinion, the most impactful step in ensuring that the procedure goes smoothly. This is scary stuff for the patient. Don't forget how much power you have to help them feel safe simply by talking with them.

2. The Right Stuff - Your Equipment

All necessary equipment should be prepared and at the ready prior to beginning the procedure, including topicalization. Remind all providers in the room that the procedure requires both calm and quiet.

Your patient will be taking their cues both from you and the others in the room. That being said, try to project a sense of calm confidence. Remind any trainees assisting you to do the same.

Ideally, awake fiberoptic intubations will take place in the operating room, to take advantage of greater space as well as immediate surgical assistance and easier access to equipment.

What equipment will I typically need? Here's a photo of the basic setup you'll need when performing an awake fiberoptic intubation.

Does it matter what size scope I use? YES. The larger the scope the better. Imaging and suction capabilities will be better because a larger scope means more fiberoptic cables and a larger working channel (the working channel is the internal lumen within the bronchoscope).

BUT THE MOST IMPORTANT FACTOR WHEN IT COMES TO BRONCH SIZE IS GOOD SIZE MATCHUP WITH THE ETT. What you DO NOT want is a skinny bronch and a large ETT. This significantly increases the difficulty and failure rate of the procedure due primarily to impingement (i.e. when you go to railroad your ETT off of the bronch and into the trachea, the ETT is more likely to get STUCK on tissue as you try to railroad it down the bronch and through the glottis).

So what size bronchoscope should I use? Here's the short answer. For the average sized adult use the Olympus "adult scope" (aka. the "5-0", so named because its external diameter = 5.0mm). Use the 5-0 in combination with the 6-0 or 7-0 ETT (either fits fine). I do not recommend using an 8-0 ETT with the 5-0 bronchoscope. Reason being is that the 8-0 ETT (so named because its internal diameter is 8.0mm) is a bit too large for the 5-0 bronchoscope. Using this combination results in 3.0mm of excess space within the ETT, allowing for too much "wobble" of the ETT around the scope, risking impingement, and the ETT getting caught up on tissue and failure of the procedure.

What is the smallest ETT I can use? So long as the bronchoscope is undamaged and lightly lubricated, only 0.5mm of wiggle room within the ETT is necessary. That means you can use a 5.5 ETT with the 5-0 bronchoscope. If a patient's airway pathology (tracheal stenosis, etc) requires a smaller ETT, you can size down to the Olympus "Intermediate scope" (aka. the "4-0", again, so named because its external diameter is 4.0mm).

What about the disposable Verathon glidescope bronchospes? For the most part, I think these scopes work just fine. Their dexterity feels inferior, however, and for a scary looking airway I usually request the Olympus tower, if available.

Are the disposable scopes sized the same? No, they aren't. But their sizing is printed in large letters on each scopes packaging, making it very easy to pick the right one. The available sizes are 2.8, 3.8, 5.0, and 5.8 mm. Again, select the largest bronchoscope that will fit into the ETT you will be using (i.e. the 5.8 will be preferable for most cases when a 7-0 ETT will be used).

Lubricant - In preparing your equipment, spray a fine mist through the proximal end of your ETT. Then, take the ETT and load it onto your bronchoscope. To evenly disperse the silicone lubricant along the apposing surfaces of your ETT and scope, simply run the ETT up and down the scope a couple of times. That's all you need to do.

Defogger - Apply some to the tip of your bronchoscope and make sure additional defogger remains somewhere within easy each. I usually just apply some to the green sponge that comes with the defogger in the packaging and stick it directly onto the OR table, right next to where the patient's head will be on the donut.

Positioning - There are certain advantages to this positioning. Many patients may be more comfortable with the head of the bed elevated, especially those with significant airway pathology. Elevating the head of the bed and facing the patient during the intubation also takes advantage of gravity's forces, encouraging movement of lidocaine into the lower and more distal airways. Facing the patient may simply be helpful for many patients, as it allows for more impactful communication and eye contact between provider and patient. Standing behind a supine patient, however, may be a more familiar positioning orientation for many providers.

What type of ETT should I use? Traditional PVC ETT's are reasonable, however, some research has proven parker flex-tip ETT's and Fastrach ETT's to be superior in terms of ease of intubation, railroading, and decreased incidence of laryngeal impingement (BJA 78-86). Additionally, positioning the bevel of the tracheal tube posteriorly is recommended (80,82, 86).

Monitors, do I need them? Yes, standard ASA monitors should be used during the procedure as sedation and topicalization agents can both impact cardiac rhythm and blood pressure, and sedation can cause airway obstruction or hypoventilation. Continuous capnography monitoring may at times be challenging but is accomplished via integrated monitoring with nasal prongs.

Should I give oxygen during the procedure? Yes, at the very least, administer oxygen via nasal prongs before beginning and throughout the entirety of the procedure.

3. Do or do not, but it'd better be dry - Glycopyrrolate

Why is it needed?

The main reason is because without secretions on the mucous membranes, lidocaine is MUCH more effective. Yes, secretions can also obscure your view with the fiberoptic and increase the risk of coughing or laryngospasm, but they also are a barrier and dilutent to your topical anesthetics. So always, always use a drying agent before trying to topicalize. (Dry before you try)

I'm still not convinced.

Glycopyrrolate pretreatment also extends the DURATION of airway anesthesia, with orally applied lidocaine anesthesia doubling from 20 minutes to 40 minutes in the treatment group (42).

Can I use another anti-sialagogue?

Sure. Atropine and scopolamine are both effective, anticholinergic drying agents. However, glycopyrrolate is more commonly used and has less tachycardia than atropine. It also does not cross the blood brain barrier and therefore has no central nervous system effect while scopolamine and atropine can both produce sedation, amnesia as well as delirium.

When should I give it?

You should use it for every awake fiberoptic intubation. Use it early, prior to topicalization. Glycopyrrolate itself begins working at the receptor level rather quickly to slow or halt secretion formation. Time is still needed for existing secretions to dry out. Healthy volunteers described a drying sensation within 7 minutes of glycopyrrolate administration and a significant drying effect was noted after 15 minutes (42). IM doses have a slower onset of 20 minutes with peak effect at 30 to 45 minutes (180). Either way, the medication will need just a bit of time to work, so bring it with you on your way to meet the patient and give it immediately after you obtain consent.

Will I need to redose glycopyrrolate?

No, drying effect persists for up to 7 hours.

I hate waiting and I'm feeling rushed.

I get it. Sometimes, I'll administer glycopyrrolate then manually dry the patient's mouth with a few cotton gauze 4x4's so that I may start topicalizing the glossopharyngeal nerve. By the time I've finished and wheeled the patient to the OR, the rest of the airway will be dry and ready for topicalization.

How much can I give?

2-4 mcg/kg (max dose 400 mcg). For an average sized female, I'll typically give 1.5 mL's (0.3mg). Average sized males? About 0.4mg.

My patient is already tachycardic. Should I omit the glycopyrrolate?

That really depends. My take is that the glycopyrrolate is so beneficial and the risks of moving forward without it are so high (failed topicalization leading to failed awake FOI intubation in a difficult airway, inadequate topicalization necessitating over administration of lidocaine and increasing risk of toxicity) that I would be hard pressed to find a reason not to use it. I'd opt to use glycopyrrolate with an esmolol drip if necessary. Alternatively, IM glycopyrrolate produces minimal heart rate changes compared to IV administration (182).

Summary

• 2-4 mcg/kg (max dose 400 mcg)

• Does not cross the blood brain barrier (no confusion)

• Does not work instantaneously

Bonus Tip - O2 flow through the suction port of scope will also aid in eliminating secretions from of view

4. LAST call - How much is too much?

What's LAST?

Local Anesthetic Systemic Toxicity, affecting the cardiovascular and central nervous system. Dangerous and potentially fatal in any patient, the ramifications of LAST in a patient with a difficult airway are even more critical.

What is the therapeutic serum concentration of lidocaine when the drug is used as an antiarrhythmic?

This is usually considered to be 1.5 to 5 mcg/mL

What is considered the toxic plasma concentration of lidocaine?

5 mcg/mL (which is also the approximate upper limit of the antiarrhythmic therapeutic range)

What are the symptoms at this range?

Lightheadedness, tinnitus, metallic taste in the mouth, circumoral and tongue numbness can occur (55).

At what serum concentration are seizures frequently seen?

8 to 10 mcg/mL, although they have been documented at serum levels of 6 mcg/mL (47)! Seizures can be proceeded by visual changes and muscle twitches.

At what levels can cardiorespiratory arrest occur?

20 to 25 mcg/mL

So how much lidocaine can I give? 

The truth is the maximum dose is not known and recommendations for maximum topical lidocaine doses vary widely across the literature (from 4.5mg/kg up to 9mg/kg) partially because systemic absorption of lidocaine is so variable and dependent on numerous and complex factors.

Can I find recommendations from the ASA?

The ASA makes no specific recommendations for maximum dosing. The following chart reflects FDA recommendations for infiltration and nerve block administration:

*FDA lidocaine dosage recommendations for normal healthy adults

Are there airway specific recommendations for maximum lidocaine dosing?

Some international airway societies have put out recommendations. In 2001 the British Thoracic Society recommended that the dose of lidocaine used for bronchoscopy be limited to 8.2 mg/kg and that extra care be used in the elderly or those with liver or cardiac impairment (97). This maximum dosage recommendation appears to apply to all techniques, and the method of topicalization does not seem to have been taken into consideration. The Thoracic Society of Australia and New Zealand, also in 2001, recommended that the total dose of lidocaine used for bronchoscopy not exceed 4 to 5 mg/kg (98).

It should be noted that toxic local anesthetic levels have been reached using far less than these recommended max doses, highlighting the significance of thoughtful and patient specific dosing with the minimum dosage necessary to achieve desired effects.

Ok, so how does the maximum lidocaine allowance change based on how it is given?

The systemic absorption of lidocaine varies based on many factors and the above dosing guidelines will not be a perfect fit for every patient. Broadly speaking, the extent of systemic absorption is widely variable and depends on the site and technique of application, tissue vascularity, the total dose administered (46,47) the state of the mucosa, the concomitant use of drying agents (42,48) the amount of mucous present, the rate and depth of respiration, the state of the circulation, the patient’s disease state (49,50) and individual variation (49,50).

Does lidocaine absorption vary based on where it is applied in the respiratory tract?

Yes, though lidocaine is rapidly absorbed through mucosa, absorption is slower in the more proximal parts of the respiratory tracts and more rapid in lower parts of the airway, including the tracheobronchial tree. Absorption from alveoli approximates IV administration (51). One small study measured serum lidocaine levels following application of 3mL of 10% lidocaine to either the larynx or trachea. The peak lidocaine concentration in the laryngeal group ranged from only 0.4 to 2.5 mcg/mL while the tracheal group ranged from 1.9 to 8.2 mcg/mL (80).

Ok, but seriously, how much lidocaine can I use? 

What patient factors increase the risk of LAST?

Patient-dependent risk factors include organ dysfunction, low serum levels of the binding proteins, and extremes of age. Preexisting cardiac disease increases susceptibility to the arrhythmogenic and myocardial depressant effects of local anesthetics. Special care should be taken in cases of decompensated heart failure, severe valvular pathology, or reduced ventricular function. Liver or kidney dysfunction can lead to reduced drug metabolism and clearance, resulting in higher drug levels in circulation. Hepatic or renal dysfunction can result in decreased metabolism and clearance and a higher level of circulating drug. In addition, liver/kidney failure, malnutrition, or any other disease process that results in a decreased serum level of albumin can indirectly increase the level of the free drug for a given dose.

Patients at the extremes of age are more susceptible to toxicity. The geriatric patient population are more likely to have organ dysfunction, which will contribute to toxicity. Further, both elderly and pediatric patients may have diminished muscle mass and, as such, are more likely to receive a higher dose of drug for their weight. Skeletal muscle acts as a depot for systemically absorbed LA.

Are there other possible life-threatening reactions to lidocaine which can occur?

Yes, rarely, hypersensitivity reactions have been documented as well as methemoglobinemia without associated benzocaine or prilocaine use (12 events in a 2007 literature review 64).

Can you tell me more about the systemic absorption of lidocaine when using a typical nebulizer?

One factor affecting absorption is droplet size. Higher oxygen flow rates through nebulizers create smaller droplets (<30 mm) that travel further distally into the bronchial tree and increase the rate of absorption (41). Droplets larger than 60 mm are preferable for airway anesthesia as they remain somewhat localized to the proximal airways and do not deposit in the lower, distal airways where local anesthesia is simply not necessary (41).

Of note, up to 50% of nebulized lidocaine is lost to the environment with continuous nebulization, and this application method has been reported to produce low peak plasma concentrations as compared to other techniques (47,48,58,72,73). In healthy volunteers, lidocaine doses of 6 mg/kg produced a peak concentration of lidocaine of only 0.45 mcg/mL (48). Another study measured peak plasma levels of 0.95 mcg/mL following administration of 10 mL of 4% lidocaine (73).

Can you tell me more about the systemic absorption of lidocaine when using a typical atomizer?

Peak plasma levels of lidocaine following tracheal spraying were equivalent or lower than intravenous administration, despite the tracheal group receiving a dose 3X larger (3.3 mg/kg of 4% lidocaine) than that of the IV group (1 mg/kg of 2% lidocaine). After tracheal spraying, maximum plasma lidocaine levels of 2.0 to 5.6 mcg/mL were recorded at 15 to 20 minutes. Following IV administration, peak concentrations of 5.0 to 6.85 mcg/mL were reached within 12 minutes (75).

What patients are at high risk for LAST?

A grand mal seizure was reported in a 30-year-old, 48-kg woman with renal failure, congestive heart failure, cardiomyopathy, and abnormal liver function tests. following application of 4% lidocaine laryngeal spray and 1% tracheal and oropharyngeal viscous lidocaine (total dose 300 mg). The plasma lidocaine level shortly after the seizure was 12 mg/mL.

How long does the anesthetic effect of topical lidocaine last?

How do I calculate the maximum dose of lidocaine for my patient?

Maximum dosage should be calculated based on a patient's lean body weight (LBW link to calculator).

LBW = Total body weight - fat weight

LBW decreases with age, is lower in females and increases with obesity.

Is it ok if my patient swallows some lidocaine?

Try to discourage it as doing so can cause nausea and adds to the cumulative lidocaine dose without benefit to the patient. After first pass metabolism, about 35% of an oral dose does reach the systemic circulation (36).

Do you have any other studies for me to sift through?

One study, delivering up to 380 mg of 1% lidocaine solution almost entirely through the bronchoscope reported blood levels less than 2.48 mcg/mL, with the exception of one patient with abnormal liver function who had a plasma concentration of 18.2 mcg/mL, reportedly without symptoms. Peak concentration typically occured between 5 and 30 minutes. (87).

Another 52 patient, randomized, and double-blinded study compared 2% and 4% lidocaine administered via a spray-as-you-go technique prior to bronchoscopic intubation (35). Mean lidocaine dose was 3.4 ± 0.6 mg/kg in the 2% group and 7.1 ± 2.1 mg/kg in the 4% group. The highest lidocaine concentration measured in the 2% group was 2.0 mcg/mL, and in the 4% group was 3.6 mcg/mL with peak lidocaine concentration at 20 to 30 minutes following administration. Again, significant individual variation in plasma levels was noted.

41 patients undergoing topical airway anesthesia before fiberoptic bronchoscopy received an average dose of 9.3 ± 0.5 mg/kg lidocaine via combination of 10% nasal and oropharyngeal spray + 4% SAYG lidocaine to the oropharynx, 1% tracheobronchial spray and 2% nasopharyngeal gel. The average peak plasma concentration occurred around 45n minutes and was 2.9 ± 0.5 mcg/mL. Two patients had plasma levels above 5 mcg/mL but demonstrated no clinical evidence of toxicity.

In a second study of 10 healthy volunteers, lidocaine plasma concentrations following 4% lidocaine gargle and swallow was compared with 10% oropharyngeal spray. Dose for each group was 6.8 mg/kg. The gargle produced a peak concentration of 2.4 mcg/mL, whereas the spray produced a peak concentration of 1.9 mg/mL at 50 minutes (46).

Serum concentrations of lidocaine were measured in 25 participants in a bronchoscopy training course. Participants received lidocaine via a combination of 4% nebulized lidocaine, 5% nasal spray with phenylephrine, 10% oropharyngeal spray, and 4% bronchoscopic spray. The average calculated dose administered was 8.8 mg/kg though 75% of the nebulized dose was excluded from calculation. Duration of sampling ranged from 100-120 minutes. The highest recorded lidocaine concentration was 4.5 mcg/mL. Though multiple symptoms of lidocaine toxicity were reported by the subjects including lightheadedness, dysphoria, nausea, and shivering (54).

When do peak plasma concentrations typically occur?

A reasonable estimate is probably about 30 to 90 minutes from the start of airway local anesthesia administration (53).

In summary, the maximum safe dose of lidocaine that can be topically applied to the mucous membrane of the airway is difficult to determine and must take into account the method of topicalization employed as well as the time course of administration. Traditional dosage guidelines may be excessively conservative when some or the entire dose is administered by aerosol, based on the available evidence with respect to serum levels and toxicity occurrences. Caution must be exercised however and a precalculated dose should not be exceeded. In clinical practice, the smallest amount of anesthetic sufficient to achieve the desired effect should be used, and in general, for awake bronchoscopic intubation, the use of large doses is unnecessary. As always, clinical judgment is required and meticulous attention to detail should be employed when lidocaine is applied to the airway such that effective anesthesia is achieved without producing toxicity.

Can topical lidocaine application to the upper airway cause obstruction?

In healthy volunteers, some PFT studies have demonstrated sudden yet reversible reductions in inspiration (decreased peak inspiratory flow, decreased forced inspiratory flow between 25% and 75% of maximum inhaled volume) yet preserved gas flow with expiration. In others, volunteers have noted subjective sensations of obstruction during deep inspiration along with impaired abilities to swallow and temporary voice changes. Transnasal fiberlaryngoscopy has noted glottic obstruction related to incomplete obstruction produced by medialized vocal cords during quiet inspiration and occasionally complete obstruction related to movement of the epiglottis into the vocal cords during maximal inspiratory efforts. (103). Volunteers with asthma also demonstrated measurable decreases in FEV1 by 15 to 35%, lasting up to 60 minutes and somewhat mitigated by pre-administration of salbutamol inhalation prior to airway topicalization. (104, 105, 106). In practice, case reports echo this possibility with 3 patients developing complete airway obstruction following airway topicalization with sedation, two of which required emergent surgical airways. One patient with a history of recurrent neck carcinoma following radiotherapy and presenting with hoarseness and stridor developed complete airway obstruction following laryngeal topicalization and suctioning.

Preexisting airway compromise, topical anesthesia, airway instrumentation, and sedation may all contribute to sudden and unexpected total airway obstruction, transforming a planned awake fiberoptic intubation into a critical emergency. This possibility highlights the importance of emergency preparedness, including immediate availability emergent surgical airway equipment and staff. Further, precarious airways, including those with significant stridor or bleeding, and respiratory distress are cause for due consideration to elective awake tracheostomies under local anesthesia. (111-113)

5. Comfortably Numb - Some topicalization and lidocaine administration options that work well for me

When applied to the airway mucosa, how long does it take for topically applied lidocaine to work?

About 1 to 2 minutes with a peak effect within 2 to 5 minutes (24, 39, 43).

How long does topically applied lidocaine last following application to the mucous membranes?

Duration is said to be anywhere from 14 to 40 minutes depending on which study you read (31, 41, 40, 43).

I like the spray as you go technique

The latent period (up to 2 minutes) has a profound significance when fiberoptic intubation is performed using a spray-as-you-go technique and suggests that a significant risk of insufficient anesthesia may exist when instrumentation precedes anesthetic effect .43

What concentration of lidocaine should I use when applying topically?

Concentrations of lidocaine of 1% to 10% (10% not available in the US) have been used for topical anesthesia of the airway. Excellent topical anesthesia of the airway in the adult can be produced by 4% lidocaine, but at 2% (20 mg/mL) concentration, topical anesthesia may be inadequate, and 1% lidocaine has been found to be insufficient for airway instrumentation.44

Do higher concentrations of lidocaine last longer?

Increasing the concentration beyond the optimum level does not affect the latent period or duration of action (39).

What if I add epinephrine to my lidocaine solution?

Traditionally speaking, lidocaine with epinephrine increases the maximum per kilogram dosing allowance to 7 mg/kg. However, topical epinephrine penetrates mucous membranes poorly, has no significant local effect, does not prolong the duration of topical local anesthesia,31 and will not slow the rate of anesthetic absorption.45

5. Got some nerve - what are we even numbing?

   Glossopharyngeal nerve

   Gag reflex

   Supplies sensation to posterior third of the tongue, the vallecula, the anterior surface of the epiglottis, the tonsils and pharyngeal wall.

   The glossopharyngeal nerve descends between the internal jugular vein and internal carotid artery before eventually curving anteriorly at the level of the middle pharyngeal constrictor muscle to supply branches to the palatine tonsil, tongue base, and serous glands of the mouth.

   
   

   The glossopharyngeal nerve sits within the submucosa posterior to the lingual tonsil. Of note, the space just lateral to the injection site is occupied by important vascular structures, including the internal carotid artery.

   
   

   “Survival Tips”

   · Improve patient comfort with intraoral approach - Prior topicalization applied to the tongue base (via atomizer, lidocaine “lollipop” etc) mitigates the gag reflex and improves visualization for a posterior tonsillar pillar injection

   · Oropharyngeal discomfort following intraoral needle blockade has been reported as lasting more than 24 hours in 91% who received the block of 5 cc bilaterally. [5] Discomfort may be minimized with lower volumes.

   · For poor mouth opening, coagulopathy or contraindication to needle blockade, adequate anesthesia can be achieved via application of soaked pledgets to mucosa of the posterior tonsillar pillar.

Numb that nerve! My go to for numbing CN IX is simple.

Good visualization of the tonsils?

1. Apply small lidocaine soaked pledgets to the base of one tonsil for about 2 minutes

2. Then, I apply the lidocaine soaked pledget to the contralateral tonsil base for 2 minutes.

3. Remind the patient to try to not swallow, rather just let the lidocaine sit in the back of the mouth which will all help with the numbing process.

4. One inch of 5% lidocaine paste contains approximately 100mg of lidocaine (usually about 1/2 inch per tonsil works fine)

Poor mouth opening or visualization of the tonsils?

1. Using the atomizer, I'll direct the nozzle in the direction of the tonsils

2. Remind the patient to let the lidocaine sit in the back of their mouth (holding their tongue lightly with a cotton 4x4 gently discourages swallowing)

The payoff for a needle block here seems to be negligible or absent with equivocal results in terms of patient numbing, some studies reporting prolonged oropharyngeal pain/discomfort for >24 hours following needle blockade and other studies demonstrating higher lidocaine serum levels following needle block versus topical application of lidocaine. An exception may be in cases of an exceptionally pronounced gag reflex. Onset time of the block has been noted to be about 1 minute169 and the duration of the block to be 45 to 60 minutes.

Glossopharyngeal Nerve Block

The glossopharyngeal nerve can be blocked using a posterior approach as it runs about 1 cm deep to the mucosa behind the midpoint of the palatopharyngeal fold (see Figure 3-30).37,118,120,165,167-169 A 23-gauge angled tonsillar needle with 1 cm exposed shaft at the tip can be inserted 0.5 cm behind the midpoint of the palatopharyngeal fold, directed laterally and slightly posteriorly to a depth of about 1 cm.165,169 Following a negative aspiration test, 2 mL of 2% lidocaine127 or 3 to 5 mL of 1% lidocaine167,169 can be injected. Mouth opening must be sufficient to permit visualization of the palatopharyngeal fold (posterior tonsillar pillar),70 and adequate topical anesthesia of the tongue and adjacent pharyngeal mucosa is necessary to permit exposure of the tonsillar pillar with a tongue blade or laryngoscope.

 Superior laryngeal nerve blocks were also performed and supplemental anesthetic was administered through the bronchoscope. An inadequate block occurred in 10 patients. Blood was aspirated in six patients requiring needle repositioning and four additional patients complained of headache thought to have been due to partial intra-arterial injection of the local anesthetic. Two patients had a seizure during the endoscopy and five developed an arrhythmia following the block. The overall complication rate secondary to the glossopharyngeal nerve block was reported to be 2%.167 Complications in addition to those noted above include local infection and hematoma formation.118 Contraindications include coagulopathy and local pathology.

Alternatively, the lingual branch of the glossopharyngeal nerve can be blocked as it runs deep to the mucosa of the palatoglossal fold (anterior tonsillar pillar) (see Figure 3-31).118,166,168,170 Although the lingual branch of the nerve supplying the posterior third of the tongue is blocked primarily, in some cases retrograde submucosal tracking of the local anesthetic has been shown to occur, with blockade of the pharyngeal and tonsillar branches.118,171 A 22- to 27-gauge needle is inserted in the floor of the mouth, 0.5 cm lateral to the lateral aspect of the base of the tongue at the palatoglossal fold (see Figure 3-31).118,168,170 The needle is inserted to a depth of about 0.5 cm,168,170 and following a negative aspiration test, 2 mL of 2% lidocaine166,168 or 2 to 5 mL of 1% lidocaine118,170 can be injected. If blood is aspirated, the needle should be redirected medially.118 If air is aspirated, the needle has passed through the palatoglossal fold to enter the oropharynx and should be withdrawn until no air is aspirated.118 Woods and Landers reported 34 anterior approach glossopharyngeal nerve blocks and noted a duration of action of 15 to 20 minutes with plain lidocaine and 60 minutes with lidocaine and epinephrine.168,130 The blocks were performed with a minimum of patient discomfort.168 The gag reflex was not completely obliterated in “a number of patients.”168 Sitzman et al reported a prospective, randomized, single-blinded crossover study of airway anesthesia for direct laryngoscopy on 11 anesthesiologist volunteers which compared 2% viscous lidocaine swish and gargle (S&G), S&G combined with 10% lidocaine spray, and S&G combined with bilateral anterior glossopharyngeal nerve blocks.170 There was no significant difference between the S&G/spray and S&G/block groups with respect to discomfort during direct laryngoscopy; however, the S&G group did experience significantly more discomfort than the other two groups. A trend toward less coughing and gagging with S&G/spray compared with S&G/block was noted, although the difference was not significant. Oropharyngeal discomfort lasting 24 hours or more occurred in 91% of the participants in the block group, and four participants had discomfort lasting more than 3 days. The study was stopped due to this oropharyngeal discomfort. The study used 5 mL of 1% plain lidocaine bilaterally, and the authors suggest that the discomfort may have been related to the volume of solution injected.170,132 Contraindications include coagulopathy and local pathology. Potential complications include intra-arterial injection, patient discomfort, hematoma formation, and anatomic distortion. In addition, local anesthetic injected into the floor of the mouth anterior to the palatoglossal fold may produce bilateral hypoglossal nerve block and impair the ability to swallow.168 The block is considered to be acceptable in the presence of a full stomach.157

Superior Laryngeal Nerve (Vagus Nerve Branch - CN X)

Sensation to (supplied by internal branch)

Supraglottic larynx

Motor to (supplied by external branch)

Cricothyroid muscle

1. Blockade of which is inconsequential for successful ATI

2. Controls vocal cord tension and thus voice pitch

3. Plays no role in vocal cord abduction or adduction

Basic Anatomy

The SLN originates from the vagus nerve (cranial nerve X), dividing into the internal and external branches beneath the internal carotid artery. The internal branch pierces the thyrohyoid membrane 2 to 4 mm below the greater cornu of the hyoid bone, where it runs submucosally within the pyriform recess and ramifies, sending sensory branches to the tongue base, epiglottis and mucosa of the supraglottic larynx

Numb that nerve!

Needle Blockade?

A) Regionalist may stand ipsilateral to target nerve with ultrasound positioned to patient’s contralateral shoulder B) Needle is inserted just lateral to inferior edge of hypoid bone and walked off caudally following contact prior to aspiration and injection

Landmark-Guided Blockade Technique

1. Neck gently extended to allow for superficial palpation of glottic structures

2. Hyoid bone palpated slightly cranial to superior edge of thyroid cartilage

3. Gently displace the hyoid bone toward the point of needle entry (to facilitate landmark identification), inserting a 22 to 25-gauge needle off lateral side of the neck, with needle tip directed towards greater cornu.

4. Once bone is contacted, walk inferiorly off hyoid. [6]

5. Following negative aspiration, inject 2-3 mLs of 2% lidocaine, with an additional ml administered as the needle is withdrawn. [7]

i. An isolated blockade of the internal branch of the SLN (and thus exclusion of external branch blockade) can be achieved by a small, millimeter advancement through the thyrohyoid membrane

SLN block can provide effective analgesia for 60 to 180 minutes.[9) This is in contrast to local spray techniques for which sometimes incomplete and always shorter block durations of 8 to 14 minutes [10]

· Ultrasound-guided SLN blockade exhibits a high success rate and rare incidence of complications when the greater horn of the hyoid is used as a sonographic landmark.[6]

Ultrasound-Guided Blockade Technique

1. Place linear transducer in the transverse plane to identify the hyoid bone in the midline (hyperechoic, triangular structure).

Move probe laterally to identify the greater cornu of the hyoid bone, just medial to the superior laryngeal artery (Fig 7).

The greater cornu of the hyoid bone, just medial to the superior laryngeal artery B) which runs alongside the internal branch of the SLN and can be used as a simple means of approximating nerve location. [6&8]

3. Using an in-plane technique, pass needle perpendicular to the skin, aiming immediately below the greater cornu (Fig 8) and inject 1-2 mL of local anesthetic following negative aspiration.

When oxygen flow is delivered into the tubing at about 6 to 8 L·min−1, occlusion of the bleed hole with a fingertip produces a fine spray of local anesthetic from the atomizer nozzle. When held at the nostril, and coordinated with deep breaths on command (“in through the nose and out through the mouth”), the device can produce profound anesthesia of the airway from the nose to the trachea and beyond in about 5 minutes.38,120 The atomized local anesthetic can also be administered through the mouth, although superior gas flow characteristics through the nose may deliver the anesthetic more efficiently to the pharynx, larynx, and trachea.38,120. An excellent block can be achieved with 10 to 12 mL of 3% or 4 % lidocaine.

What concentration of lidocaine is best?

In the study by Wieczorek et al in which either 2% or 4% lidocaine was administered by atomizer to a group of obese patients, the authors concluded that atomized lidocaine for awake intubation was efficacious, rapid, and safe.84 A subsequent study from the same center compared 2% and 1% lidocaine using the same atomization technique and volume of anesthetic.85 The authors concluded that 1% lidocaine provided measurably inferior airway anesthesia

Can I use the nebulizer?

Results are mixed. In my experience, numbing and blockade is simply not consistently dense enough for this to be my sole approach to airway topicalization. If the nebulizer is used, keep these points in mind:

1. Approximately half of the lidocaine is lost to the atmosphere

2. Time to adequate airway anesthesia is approximately 10 to 20 minutes

3. Duration of anesthesia, as in most topical techniques, will be brief (10 minutes)

4. Gag reflex may be obliterated in some patients, but most will need supplementation

5. Most studies reporting on nebulization techniques for airway anesthesia also report combining the nebulizer with other techniques

Nebulized local anesthetic has also been administered by facemask using 4 to 20 mL of 4% lidocaine58,72,74,90 or 6 mg·kg−1 of 10% lidocaine.44 Nebulization by this technique required 10 to 22 minutes.48,58,72,74,90 In a study reported by Kundra et al, 7 of 24 patients required supplemental lidocaine through the fiberoptic bronchoscope after nebulization of 4 mL of 4% lidocaine and administration by mask.72 This study compared nebulization with a combined regional block (CRB) technique consisting of nasal lidocaine-soaked swabs, superior laryngeal nerve block, and transtracheal injection of lidocaine for awake nasotracheal bronchoscopic intubation. The authors reported that the patients in the CRB group were more comfortable during the procedure. Four of five other reports of awake intubation or bronchoscopy using nebulization by mask also used supplemental anesthesia.58,74,90,149,150 Chinn et al reported that only one of five healthy subjects lost the gag reflex following administration of 10 mL of 4% lidocaine by means of a DeVilbiss 35B nebulizer and Hudson oxygen mask.73 No bronchoscopy or intubation was performed.

Recurrent Laryngeal Nerve (Vagus Nerve Branch - CN X)

Sensation to

Subglottic larynx and trachea

Motor to

All intrinsic muscles of the vocal cords

Basic Anatomy

The right and left recurrent laryngeal nerve, branching from their respective vagus nerve, both have slightly different paths as they ascend up to innervate the trachea and vocal cords. The right recurrent laryngeal nerve originates at the level of the right subclavian artery as it loops around the right innominate artery. The left recurrent laryngeal nerve originates as it loops around the aortic arch on the left.

Numb that nerve!

Any blockade of the recurrent laryngeal nerve will occur through topicalization techniques. Even a translaryngeal nerve block technique is a means of delivering lidocaine directly to the tracheal mucosa via injection through the cricothyroid membrane.

Translaryngeal Nerve Blockade

A 21- to 23-gauge needle can be passed posteriorly in the midline immediately cephalad to the cricoid cartilage to enter the larynx (see Figure 3-29).26,38,157 Alternatively, a 20-gauge angiocatheter can be used.118 Directing the needle caudally will direct it away from the vocal cords which are located 1.3 cm cephalad from the transverse plane at the midpoint of the cricothyroid membrane.26 The correct intraluminal position of the needle can be confirmed by the aspiration of air.26,118 Then, 0.5 to 2.0 mL of 4% lidocaine,157,158 3 mL of 4% lidocaine,90 4 mL of 2% to 4% lidocaine,118 or 2 to 3 mL of 2% lidocaine159 can be injected either at end exhalation160 or inhalation.118 Translaryngeal injection predominantly produces anesthesia of the infraglottic mucosa.72 The cough precipitated by the injection facilitates the spread of the anesthetic which has been shown to reach the superior aspect of the true cords in 95% of cases.161 The sensory blockade above the glottis is dependent on the magnitude of the cough response.72 If the goal is to spread anesthetic into the larynx and pharynx then injection at end inspiration seems most logical.

Contraindications to cricothyroid puncture include coagulopathy, local pathology, and an inability to clearly identify the cricothyroid membrane due to obscured landmarks as in the morbidly obese.26,158 Relative contraindications include those circumstances in which vigorous cough could be deleterious, such as raised intracranial pressure or intraocular pressure, open eye injury, or unstable cervical spine injuries.118 The use of translaryngeal anesthesia in the presence of a full stomach is controversial.68 Complications of laryngeal anesthesia, including laryngospasm and soft tissue infection, have been rarely reported.26,157 Potential complications include bleeding, subcutaneous emphysema, pneumomediastinum, pneumothorax, vocal cord damage, and esophageal perforation.118 A review of 17,500 cricothyroid punctures revealed only 8 complications: 2 laryngospasms, 2 broken needles, and 4 soft tissues infections of the neck.26

Spray As You Go Technique (SAYGT)

the time required to produce maximal local anesthesia after bronchoscopic instillation may be as long as 5 minutes, and this technique may provoke unnecessary reflex glottic closure and cough. In the study reported by Xue et al the safety and efficacy of 2% and 4% lidocaine administered by a spray-as-you-go technique for bronchoscopic intubation were compared.35 p. Overall 61.5% to 73.1% of patients displayed grimacing or coughing responses during intubation. The authors reported intubating conditions to be excellent or acceptable in all patients, although a lack of complete anesthesia was reported in both groups.35

7. I Wanna Be Sedated - sedation options

   If adequate local anesthesia of the airway can be achieved, awake intubation can be rapidly and easily accomplished without the use of sedation.  The emphasis should however be placed on the development of regional anesthesia skills, rather than on the use of sedation in an attempt to compensate for poor airway anesthesia.37 As time and circumstances permit, sedation can be used to further minimize discomfort, produce anxiolysis, and attenuate recall,37 although the need for anxiolysis or amnesia is reduced or eliminated if airway anesthesia can be rapidly and skillfully achieved. In the presence of airway compromise or respiratory distress, any additional impairment of the level of consciousness can lead to deterioration in the clinical situation. The goal of sedation during awake intubation is a calm and cooperative patient who remains crisply responsive to command.37,38 During an awake bronchoscopic intubation, the ability of the patient to breathe deeply on command improves visualization of the airway structures, moves the epiglottis anteriorly out of the path of the advancing bronchoscope and endotracheal tube, and by producing maximum abduction of the vocal cords facilitates glottic cannulation. Sedation can therefore make bronchoscopic intubation more difficult.

   
   

Midazolam administered in increments of 0.25 to 0.5 mg to the adult produces anxiolysis and amnesia,189 and titration to a suitable end point without losing patient cooperation is usually achievable,37 although the ability of the patient to briskly respond to command may be impaired. The onset time is 1 to 3 minutes and the duration of action is about 2 hours.37,68 Fentanyl can provide sedation, analgesia, and euphoria, can attenuate laryngeal reflexes, and has an antitussive effect.34,37,64 Respiratory depression can also occur,37 as can bradycardia.150 When used in combination, a synergism between fentanyl and midazolam occurs which potentiates the effects of both drugs.34,64 Hypotension and apnea can occur. However, when administered in low doses and titrated carefully to affect, midazolam and fentanyl in combination can be used to produce satisfactory sedation, and side effects can be avoided.37

Overdose with benzodiazepines or opioids can be reversed with flumazenil and naloxone, respectively.

In the emergency situation, when judicious chemical restraint is required to permit airway management of combative and intoxicated patients, haloperidol, also a butyrophenone, can be immensely helpful.38 Intravenous doses of 2 to 10 mg in the adult can be carefully titrated to effect.33 Ketamine may be particularly useful in the uncooperative patient without IV access who requires chemical restraint.191 Recently, the use of remifentanil for awake bronchoscopic intubation as a single agent and in combination with propofol or midazolam has been reported.192-197

Remifentanil was administered in dosages of 0.1 to 0.5 mg·kg−1·min−1. Both groups received PO midazolam 1 hour preoperatively. Four percent lidocaine spray was administered to the nose, and 4 mL of 4% lidocaine was sprayed through the bronchoscope onto supraglottic and subglottic areas. Patients in the remifentanil group had a significantly reduced response to the nasal passage of the tube and less cough as the larynx was intubated. The investigators felt that remifentanil suppressed laryngeal reflexes significantly better than fentanyl and midazolam and improved intubating conditions.195

Remi

The ester structure of remifentanil is unique among fentanyl congeners and results in very rapid metabolism. The peak effect site concentration of remifentanil occurs within 1 to 2 minutes of bolus injection,193 and the offset is also rapid. The time necessary to reach a 50% decrease in serum concentration after stopping a continuous infusion at steady state is 4 minutes.195 The median dose of remifentanil administered over 2 minutes, required to produce loss of consciousness, has been found to be 12 mg·kg−1, and at doses ≤5 mg·kg−1 no subjects lost consciousness.193,201 It has been recommended that dosing should be calculated on lean body mass and reduced by as much as 50%-70% in the elderly.193 Remifentanil therefore appears to be very easily titrated. Jhaveri et al noted mild muscle rigidity in 40% and moderate rigidity in an additional 40% of a group of elective surgical patients following the administration of 2 mg·kg−1 of remifentanil over 2 minutes.201 No severe muscle rigidity was observed at doses less than or equal to 4 mg·kg−1. Wilhelm et al administered remifentanil by infusion to a group of patients undergoing oocyte removal and did not observe muscle rigidity at doses up to 0.4 mg·kg−1·min−1. 202 Anecdotally, in the author’s experience remifentanil infusion appears to attenuate the gag reflex as well as laryngeal reflexes, and can facilitate airway anesthesia. It may be particularly useful in patients with hyperactive gag reflexes, and in the presence of excess secretions. Remifentanil may prove to be an exception to the general rule that sedatives cannot or should not be used to compensate for poor regional anesthesia of the airwa

Dex

Dexmedetomidine (DEX) is a centrally acting alpha-2- adrenoceptor agonist, which produces sedation, analgesia, anxiolysis, xerostomia, and some degree of amnesia.203-208 The sedation produced by DEX is unique in that patients appear to be asleep but are readily aroused.204 The term “cooperative sedation” has been used191,205 as DEX appears to maintain191,209 or enhance210 patient cooperation, and the ability to follow commands.209 DEX produces minimal204,206,209,211 or no respiratory depression191,203,210 but can produce hypotension, hypertension, tachycardia, and bradycardia.191,203-206 When administered as a continuous IV infusion, however, it is associated with a predictable and stable hemodynamic response.203 Caution is necessary when DEX is administered to patients who are volume depleted, vasoconstricted, or who have severe heart block.203 Contraindications to DEX as listed by Unger include hypovolemia, hypotension, aortic stenosis, idiopathic hypertrophic subaortic stenosis, pulmonary hypertension, and heart block in the absence of a pacemaker.191 The recommended loading dose of DEX is 0.5 to 1.0 ug·kg−1 over 10 to 20 minutes, which can then be followed by a continuous infusion of 0.2 to 0.7 ug·kg−1· h−1. 191,205,206,209-211 The elimination half-life is 2 hours.203 Avitsian et al performed a retrospective review of 19 patients who underwent awake bronchoscopic intubation using DEX for sedation.211 Midazolam and/or fentanyl was also given to all but two patients, and topical anesthesia was utilized. A dose of 1 ug·kg−1 of DEX was administered over 10 to 15 minutes and this was followed by a continuous infusion of 0.2 to 0.7 ug·kg−1·h−1 if required. The intubation was “smooth” in all cases with good patient tolerance and no airway obstruction. Thirteen patients developed hypotension after induction of general anesthesia that was managed with ephedrine or phenylephrine.211 Grant et al reported three cases of awake bronchoscopic intubation in which DEX was used for sedation.206 Local anesthesia was utilized but no other sedatives were administered. Intubating conditions were acceptable in all three patients. No clinically important hypotension or bradycardia was reported. One patient recalled the intubation but was not distressed by that recollection. Abdulmalak et al reported five cases in which DEX was used as the sole sedative for awake bronchoscopic intubation.209 Topical lidocaine was also utilized. The patients remained responsive to command and were all intubated on the first attempt. Four of the five patients had no recall of the intubation. Hypotension required treatment in two cases. The lowest heart rate reported was 48 bpm. Bergese et al reported the use of dexmedetomidine sedation in four patients with difficult airways who underwent successful awake bronchoscopic intubation.210 Two patients also received midazolam. Local anesthesia was used in three patients. Two patients were initially uncooperative, but following the administration of DEX were able to follow command, and excellent intubating conditions were achieved. Hemodynamics remained stable during the procedure in all four cases. Neumann et al and Maroof et al have also reported successful awake bronchoscopic intubations in patients with difficult airways under topical anesthesia and DEX sedation.212,213 Dexmedetomidine infusion in combination with ketamine infusion has also been used for awake bronchoscopic intubation.214 Scher and Gitlin administered a bolus of 1 mg·kg−1 of dexmedetomidine over 10 minutes and followed this with an infusion of 0.7 mg·kg−1·h−1. 160 Upon completion of the dexmedetomidine bolus, 15 mg of ketamine was administered as a bolus, and then followed by an infusion of 20 mg·h−1. The patient remained responsive to command and calm. Regional anesthesia of the airway was then performed “in the usual manner,” and bronchoscopic intubation via a bronchoscopic oral airway was performed.214 Intubating conditions were reported to be excellent and included a secretion-free airway. The patient had no recall of the procedure. Hagberg et al performed a randomized double-blind comparison of remifentinil (R) and dexmedetomidine (DEX) for sedation during awake bronchoscopic intubation in a group of 30 patients.207 All patients were given glycopyrrolate and midazolam and their airways were topicalized with 4% lidocaine. Patients in the remifentinil group were given a bolus of 0.75 ug·kg−1, followed by an infusion of 0.075 ug·kg−1·min−1. Patients in the DEX group received a bolus of 0.4 ug·kg−1 over 10 minutes followed by an infusion of 0.7 ug·kg−1·h−1. All patients were successfully intubated. Thirteen of 17 patients in the R group were intubated on the first attempt, 3 required 2 attempts, and 1 required 3 attempts. In the DEX group, 5 of 13 patients were intubated on the first attempt, 4 required 2 attempts, and 4 required 3 attempts. Minimal hemodynamic instability was observed in both groups. Intraoperative recall was significally lower in the DEX group.

8. Just do it - Grab your fiber and intubate that patient

9. Final Tips & Tricks

   Position yourself in such a way that you can easily hold the scope straight, doing so ensures that any right or left rotation of your hand holding the scope body will translate into a predictable right or left motion of the tip of the scope during the procedure

   Centering your target on your screen translates to centering your target under your scope

   Use some type of oral airway conduit to improve your view, maintain oral airway patency, and protect your scope

   When using an oral airway conduit, ensure that IT STAY MIDLINE. Each time the oral airway pops up and out of the mouth it typically also falls out of the midline, sitting crooked in the oropharynx. Trying to guide your scope into the glottis through a crooked oral airway will be at best frustrating, as once your scope exits the distal end of the airway you'll typically just see pink mucosa or best case scenario you'll see the glottis off at the edge of your screen and impossible to reach.

   Asking your patient to inhale deeply just prior to advancing your scope or ETT through the glottis will help to open the glottis and make these maneuvers less difficult

   Coughing elevates the larynx, so aim your scope for the anterior commissure of the vocal cords

   Gentle jaw thrust during the procedure can improve your view of the vocal cords and also decrease risk of ETT impingement during railroading

   If you do experience impingement during railroading, assuming your ETT is well sized to your bronchoscope, simply withdraw the ETT 1-2 cm and readvance gently while simultaneously rotating the ETT

   Distance between tracheal rings is approximately 0.7 cm, once the ETT is deposited above the carina, counting 5-6 tracheal rings between ETT tip and carina will ensure that it is in a midtracheal position, lowering the risk of accidental main stemming later

   Always use silicone lubricant for airway equipment

   If you simply choose to ignore my sound advice and use water based surgical lubricant instead, often it will dry out and essentially do the opposite of what you want, turning to glue. If the lubricant does desiccate during your procedure, you can dribble a few cc's of normal saline down the tube to release it from the dried out lubricant's hold.

   
   

    lack of patient co-operation, apnoea, and airway obstruction were widely reported complications of afoi contributing to failure: the review panel and lrs considered poorly managed sedation to be a factor in these cases. there were several reports of problems when remifentanil was used in combination with other drugs for sedation. problems noted during these events that may have been due to remifentanil included respiratory depression, apnoea and delayed respiratory arrest. it was the impression of the review panel that remifentanil was more likely than other sedatives to cause these types of events but this remains unclear.

   
   

   Recommendation: fibreoptic intubation is most effective in co-operative patients. airway patency and co-operation may be lost by over-sedation. where complex sedation techniques are to be used strong consideration should be given to delegating the provision of sedation to an anaesthetist not performing the tracheal intubation.

    Recommendation: following awake fibreoptic intubation, general anaesthesia should only be induced after the tracheal tube has been railroaded, its position checked and the cuff inflated to seal the airway. Recommendation: afoi may fail. a back-up plan should always be worked out in advance

11. When fiberoptics fail

     afoi failed due to a number of factors including poor co-operation, inappropriate sedation, bleeding, inability to identify anatomy and airway obstruction. to put this in context nap4 focuses on patient with complications and successful uses of afoi would not be reported to this project. respiratory depression, apnoea and delayed respiratory arrest complicated sedation. it was the impression of the review panel that remifentanil was more likely than other sedatives to cause these types of events but this remains unclear. difficulty in railroading a tube after successful endoscopy is a recognised cause of failed afoi and complications arising from such cases were reported to this project. this was a particular problem with use of the nasal route and consideration should more frequently be given to an oral approach.

    
    

12. Planned Awake Cricothyroidotomy or Surgical Tracheostomy

    The role of preoperative planning, inspection of preoperative imaging as well as preoperative bedside nasendoscopy cannot be overemphasized. There will be circumstances where the initial decision to perform an awake fiberoptic intubation is better off abandoned in favor of an awake surgical airway. Preoperative exam, and specifically a quick bedside nasendoscopy, may reveal poor or completed obstructed view of the glottis, whereby attempts to maneuver a bronchoscope or ETT around such obstruction are very likely or entirely likely to fail. Masses overlying the glottis may appear quite friable as well, hinting at possibilities of significant airway bleeding and subsequent aspiration and/or obstruction following instrumentation attempts. Preoperative imaging is invaluable for estimating airway diameter, whereby severely narrowed airway diameters will preclude the passage of even smaller ETT's, necessitating placement of a surgical airway below the point of narrowing. Contaminated airways, either secondary to the presence of blood or other substances, may again preclude fiberoptic visualization within the airway as well as foil the action of topical local anesthetics. These and other circumstances may indicate necessity for performance of an awake surgical airway, which despite the inherent invasiveness of the procedure itself, can be performed with relative ease and efficiency. As with any awake airway procedure, extreme care should be taken with the administration of any planned sedation during the procedure.

    
    

    Tip

    A patient presenting with stridor indicates a significantly narrowed airway, with a diameter of 4mm or less necessary to achieve such turbulent flow characteristics.

13. Other Options

    Inhalation induction inhalational induction techniques with maintenance of spontaneous ventilation in patients with head and neck pathology can and do fail. Recommendation: when inhalational induction is the primary plan for cases involving head and neck pathology the airway strategy should accept it may fail with loss of the airway. a clear rescue plan, that does not assume the patient will wake, should be in place before anaesthesia starts. Cannula cricothyroidotomy emergency large or small bore cannula cricothyroidotomy, when undertaken in earnest, commonly fails. Recommendation: when emergency cricothyroidotomy is included as part of the airway strategy for cases involving head and neck pathology success should not be assumed. the airway strategy should accept it may fail.

14. Extubating the difficult airway