We are very happy to have a contribution from Dr. Hulbert Silver MD, CCFP, FAWM. Dr. Silver is an Emergency Medicine physician, wilderness medicine practitioner, firefighter, paramedic and exactly the guy you want helping you on a tough airway in a remote location.
Wilderness Airway Kits
I have been spending some time lately trying to put together the smallest, most complete, airway kit possible. Like most docs who want to be able to do everything in the wilderness I do in the ED I am obsessed with having all the toys for every contingency. Like most people who have hiked/marched days at a time with every piece of kit they own digging a separate divot in my back I am obsessed with humping as little gear as possible.
I want to share with you some ideas for the ideal airway kit – constructive Feedback encouraged!
Skill Levels of Users
First, like any kit or cart the most important part is the skill set of the user. All the toys in the world aren’t going to help you if you have not invested the time in becoming proficient with them. Conversely the more proficient one becomes with one tool, the less one tends to need other tools.
So here are some skills I am trying to become proficient at:
Digital Intubation [1,2]
http://www.youtube.com/watch?v=prSjvfPrP1o
Bougie-Aided Cricothyrotomy
If you watch these videos I think will be obvious how these skills would be invaluable to the minimalist doc. Dispensing with the laryngoscope allows you to intubate with just an ET tube and a way to inflate the cuff. The Bougie method dispenses with dilators, haemostats , etc and goes straight to the 6.0 ET tube instead of a Shiley, that you may not otherwise have a use for.
The Kit
With these skills in our armamentarium I suggest that the following kit represents an excellent balance between size and function (I will discuss my reasons for each item after the list):
- 1 Size 7.0mm ET tube
- 1 Size 6.0mm ET tube
- 1 #10 Scalpel
- 1 Pocket Bougie
- 1 14GA 1.75IN (2.1×45 mm) IV catheter or 6.0Fr x 7.5 cm transtracheal catheter
- 1 3mL Syringe
- Skin Prep
(NB: you can take the ET tubes out of the packaging and wrap them in plastic wrap if you want to save even more space. Ditto the syringe, but I like to keep my syringe sterile in case I need to use it to inject meds)
Nice-to-have’s include:
- One way valve from pocket mask or Bag Valve Mask
- Stethoscope
- CO2 detector or esophageal detector
- Manual suction device
- Sterile gloves
- Sterile water or saline
- J wire
- #11 Scalpel
- Industrial Sharpie
- Tape or Tie to hold tube once placed
- Safety pin
Rationale
Why these specific choices? The size 7.0 ET tube is an adequate size for intubating an adult… I can hear the controversy from this side of the page… I understand that bigger is better, but consider the following:
1) the 7 you get is better than the 8 you miss
2) perfect is the enemy of good
3) in an extreme environment the tube that does the greatest good for the widest range of patients is the most useful.
You can adequately ventilate and protect the airway of any patient from an 11 or 12 year old to a full grown man with a 7.0, at least until you get them to a more controlled environment. The added advantage of a 7.0 is that the connector (removed from the tube) fits neatly into the barrel of the 3mL syringe, more on this later.
The 6.0 ET tube (for those who didn’t watch the video) is for the bougie assisted cricothyrotomy. I’m not sure if you could use the 7.0 here, I suspect you could make it fit, (the youtube video by Dr. Scott Weingart recommends a 6.5) but not being an expert I am not going to recommend anything that hasn’t at least got the backing of ‘Expert Opinion’. Also it’s not so bad to have another size tube on hand, if nothing else it extends your intubating ability down to the 7 or 8 year olds.
The scalpel and bougie are also for the bougie assisted cric. The pocket bougie is a useful space saving device. It can be coiled up and stored in smaller spaces than its straight cousin. It can be used in the usual manner for direct laryngoscopy, and has the advantage in video laryngoscopy of being able to bend around in a tighter arc for some of the video laryngoscopes which don’t allow good direct visualization of the larynx (e.g. the Glidescope). Of course if you don’t have a laryngoscope or videoscope in the wilderness, these are not going to be top concerns. You could just get a standard bougie and coil it up.
The IV catheter or transtracheal catheter is for needle cricothyrotomy (http://www.youtube.com/watch?v=aPiQA2XKkcs).
The advantage of the IV cath is that it can also be used for starting IV’s. The advantage of the transtracheal catheter is that it is much longer (7.5cm (3.0 inches) compared to 4.5cm (1.8 inches) for the IV cath) this comes in handy if you want to use it for needle decompression of a tension pneumothorax in a patient with a lot of muscle, or (more realistically) fat, around the thorax. The internal diameters of each are about the same (6.0 Fr is equivalent to 14.4 Guage, or 2 mm internal diameter) and you can put your average size J wire down either of them.
The 3mL syringe is used in the needle cric to draw back as you insert the catheter. If you have some saline or sterile water (from the nice-to-have list) you can put some in the syringe first, and when you see bubbles you know you’re in. It can also be used to inflate the cuff of the ET tube. It will take a few of strokes, but you should get good pressure in a reasonable time. The advantage of a 3mL syringe over a 10mL is that once you have performed the needle cric, removed the trocar from the catheter, and attached the syringe to the cath, you can remove the plunger of the syringe and the connector of the 7.0mm ET tube fits neatly into the lumen of the barrel. You can then attach a BVM or one way valve from a pocket mask to the ET tube connector and ventilate the patient.
On the Nice-to-have list I have put the one way valve from a pocket mask. There is some variation from one pocket mask to another, you just want to be sure it will fit on the ET tube connectors. The Laerdal style ones work well. This is just for protection in case you are worried about disease transmission from respiratory secretions or blood in the airway, but as long as you are in the trachea you shouldn’t have to worry about stomach contents coming up that tube. Obviously a BVM is preferable, but that alone will double or triple the space your kit takes up.
Stethoscope
A stethoscope is an obvious nice to have for many reasons, one of which being you should confirm tube placement somehow. I also added the CO2 or esophageal detector for the same reason. Keep in mind that if you are using air from your lungs (rather than a BVM) to ventilate, the CO2 detector will not be very useful. Esophageal detectors are antiquated (I have never used one) and may be hard to find. So realistically I think tube placement confirmation may be limited to observing chest expansion, seeing condensation in the tube, auscultating the chest (with stethoscope or ear against the chest), feeling the tracheal rings with the bougie, and feeling the tube go between the cords (if using the manual intubation method).
Suction
There are several hand powered suction devices on the market, and they vary in their size and durability. A nice-to-have for obvious reasons, but even the smallest will take up more room than it may be worth.
PPE
Sterile gloves are nice to have if you are cutting the neck, although realistically if you’re doing a surgical airway in the wilderness skin infection is way down on the list of things you need to worry about. The IV/transtracheal catheter, scalpel and gloves are the only things that benefit from being sterile, remember the trachea is not a sterile space so bugs are going to get into the wound from that direction anyway (unless you stick a povadone swab down the patient’s trachea before you start!)
I mentioned the use of the water or saline above; a little in the syringe during the needle cric helps you confirm you are in the airway. Technically I suppose you could use potable (not sterile) water, as you aren’t actually injecting it. You might want to draw it up into the syringe before you put the catheter on though.
Surgical Airway Tips
I put a J wire and #11 scalpel on the list in case you want to start with a needle cric and then do a surgical one by cutting down the wire. This would be a good way to temporize a can’t-intubate-can’t-ventilate situation. You could probably get the needle in way faster (at least if you have as little surgical airway experience as I do) and once the patient is better oxygenated you have a few minutes to do the surgical technique. If you didn’t have either of these items you could always leave the trocar in the cath and cut down the side of it with the #10 scalpel. Careful though, you don’t want to put the needle through the posterior of the trachea or shave off bits of the catheter into the incision. A wire can also be used to do a retrograde intubation in case your digital technique is not yet perfected. (http://www.youtube.com/watch?v=JYMwy1-MwMU). Also note that the wire does not need to be sterile for these procedures. I have one I rescued from a central line kit that got opened by mistake. I just keep it in a Ziploc bag. I promise it won’t go in anyone’s IJ!
Marking and Securing
The industrial Sharpie is another tool with many uses, but one is that you can indelibly mark skin, even after it’s been sterilized, without contaminating it. The manufacture says you shouldn’t, because they don’t want the liability of suggesting this use, but there is at least one good study suggesting the ink is safe and sterile for this application. [3]
As far as tape or a tie to secure the tube, I put this low on the nice-to-have list because I can’t imagine anyone would go into the wilderness if they didn’t have something they could improvise a tube tie with. If you really can’t count on your resourcefulness, I guess you should bring a commercially made one, or a length of duct tape.
No Oral Airway Adjunct, No Problem
I just remembered reading in an old survivalist First Aid manual a method of keeping the tongue out of the oropharynx by sticking a safety pin in the centre and then tying the safety pin off to the clothing, thus pulling the tongue forward. I’ve never seen this done. My literature search (at which I am terrible) came up with one reference from Auerbach[4] which describes a two pin technique referred to as ‘Tongue Traction’. I do not challenge the venerable authority of the author, but personally I would elect for a single central pin, like a tongue ring, avoiding as much as possible the edges of the tongue, where the blood vessels are. Do you really want to risk an oral bleed in a patient with an uncontrolled airway? The problem with my single pin method may be that it could be more likely to pull through, but if you use a large enough gauge pin it seems unlikely. Again, I have never done any cadaver tests or anything, but I saw a guy suspend a cinder block from a tongue ring once, so I suspect a half pound or so of traction is unlikely to tear the tongue.
So I believe that this represents a fairly comprehensive yet elegantly minimalist advanced airway kit. More useful than the Tom Mix knife and pen combo the M*A*S*H fans fantasize about using, less cumbersome than the airway carts I see some gear pigs hauling around to every family day at the beach. Because it’s not just what you can do with it… size does matter!
References
- Stewart, RD. Tactile orotracheal intubation. Ann Emerg Med. 1984 Mar;13(3):175–178.
- Roberts J, Hedges J, editors. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, PA: Elsevier, Inc; 2010
- Burton C, et al. Can Skin Marker Pens, Used Preoperatively to Prevent Wrong Site Surgeries, Transfer Bacteria? Infection Control and Hospital Epidemiology. 2010 Feb; 31(2): 192-194
