Airway Skills 1:
Aids to Intubation
Emergency Airway Cart Equipment
Adult Surface and Shelf
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Pediatric Surface and Shelf
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Shared Shelves
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Equipment that is inserted into a patient’s nose or mouth must be kept clean. When the doors of the cart are opened during patient care, all touched equipment must be cleaned or replaced to prevent the spread of infection.
Oral and Nasal Airways
Oral and nasal airways are important and useful. Obtunded patients "swallow their tongues": the flaccid tongue falls back on the posterior pharynx, occluding the airway. An oral airway is placed against the hard palate in backward position as shown. It slides posteriorly against the hard palate. When at the level of the uvula, it is rotated so its curved surface is against the tongue, holding it up and opening the airway.
These airways are called Guedel airways. They come is sizes 0 to 5 with 0 being an infant size and 5 a large adult size. PEDS: Caution: In infants the tongue is especially likely to be pushed by an oral airway, resulting in obstruction.
Nasal airways have the advantage of not stimulating gagging in
semi-conscious patients.
They are placed by sliding them over the superior surface of the
palate, avoiding intracranial placement through a fracture of the
cribriform plate located high in the nasal cavity.
Reference
McGee JP, Vender JS. Nonintubation management of the airway: mask ventilation in Airway management: principles and practice, Benumof JL, Ed. Mosby: St. Louis. 1996;228-254.
Endotracheal Tube Introducer
The endotracheal tube introducer (ETI) is a firm but elastic disposable guide used to intubate the trachea. The ETI is a deceptively simple instrument that is 60 cm long, 15 French. The ETI is often referred to as a bougie* and is available as the Flex-Guide introducer. This device has made the procedure of orotracheal intubation much easier and more often successful than it had been previously.
The Flex-Guide ET tube introducer
PEDS:
A standard ETI
fits through a 5.5 ID ET tube, making it useful in
treating children up to 5 or 6 years old. An 8 French size (made by the
Cook
Co.) fits through a 3.0 ET tube. To use this instrument
correctly, insert the ETI so that you can feel the tip of the ETI’s
“hockey stick” end rattle
over the tracheal rings, confirming correct placement. Even if this
sensation is not
felt, at the carina, the ETI should meet resistance that will cause it
to turn right or
left. If it does not encounter such resistance, the ETI is mistakenly
traveling down the
esophagus. This turning movement is known as the Cheney effect. If an
intubator
preloads an ET tube on the introducer, this sensation will be lost.
Stand or lean back in order to intubate at arm’s length. This “limbo” position allows binocular vision and depth perception. Hold the ETI gently between fingers without bending it. When you can see only the arytenoids or the epiglottis, you can direct the ETI into the trachea by keeping the hockey stick end pointed forward. This technique is also useful when there is edema and cord spasm. After you are convinced that the ETI is in the trachea by feeling the tracheal rings or the Cheney effect, place the ETI to the depth that its black ring is located at the corner of the patient’s mouth, indicating that there is enough length remaining to allow loading an ET tube on it. The ETI will protrude from the proximal end of the ET tube. The black ring is 38 cm from the straight end of the ETI. Do not remove the ETI until the ET tube is in the trachea.
The line of vision through the blade is avoided by placing the ETI from the side
Another “trick of the trade” is to turn the ET tube 90º counter-clockwise (to the left) as the tube moves toward the glottis. An effect called “railroading” is caused by the bevel of the tube getting caught on the arytenoid folds. This can be avoided by the counterclockwise turn.
If it occurs, pull the ET tube back an inch to free the tip before turning it.
If the team member who is performing cricoid pressure presses
too hard,
the ETI may not enter the larynx. If this happens, ask the team member
to ease
up on the pressure. If the ETI has to be inserted blindly or with
bending, leave
your laryngoscope
in place and have an assistant load and advance the ET tube while the
laryngoscope blade holds tissue away from the ETI.
Use the ETI on every intubation to hone your skills in its use. It is definitely not just a simple stylet. It makes intubation much easier but it also requires skill. Obtain this skill before you encounter a difficult intubation.
The ETI is useful as an ET tube exchanger. A caution is that if the ETI is pushed in with too much force, it can penetrate the trachea or bronchus. The black line should be positioned at the corner of the mouth during ET tube insertion.
PEDS: An 8 French pediatric airway exchange catheter (made by the Cook Co.) has the correct characteristics for use as an ETI. It will fit through a size 3.0 ET tube, making it suitable for use in newborns and infants. It is 45 cm long and does not have a hockey stick bend. The order number is C-CAE-8.0-45. Carefully note the depth of insertion and maintain this depth while the ET tube is inserted over it.
The endotracheal tube introducer is an essential tool in airway management. The shorter yellow introducer is for use in children less than about 5 years of age.
References
Viswanathan S, Cambell C, Wood DG, Riopelle JM, Naraghi M. The Eshmann tracheal tube introducer. (Gum elastic bougie.) Anesthesiol Rev. 1992;19:29-34.
Gataure PS, Vaughan RS, Latto IP. Simulated difficult intubation. Comparison of the gum elastic bougie and the stylet. Anaesthesia. 1996;51:935-938.
Dogra S, Falconer R, Latto IP. Successful difficult intubation: Tracheal tube placement over a gum-elastic bougie. Anaesthesia. 1990;45:776-780.
Esophageal Intubation Detector and the CO2 Detector
The esophageal intubation detector (EID) is often called a Wee tester.** The device consists simply of a 60 cc syringe with an adaptor to fit the standard 15 mm connector of an endotracheal tube.
The esophageal intubation detector
If the ET tube is in the esophagus and the syringe plunger is pulled back, the vacuum developed causes the walls of the esophagus to collapse around the end of the endotracheal tube, producing marked resistance to further movement of the plunger. When the endotracheal tube is in the trachea, the plunger moves without resistance because the rigid walls of the trachea do not allow it to collapse enough to obstruct the end of the tube. To use it correctly, pull the plunger back about half-way out. If the ET tube is in the esophagus, the plunger will move back toward the patient.
False results can be obtained under the following circumstances:
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The patient has received positive pressure ventilation through an ET tube located in the esophagus or with a bag-valve-mask. There may be enough air in the esophagus and the stomach to allow aspiration with little resistance. If this is a possibility, repeat the aspiration.
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The patient has severe pulmonary disease resulting in resistance to aspiration. Severe asthma and fulminant congestive heart failure are examples.
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The patient is morbidly obese (400 lbs or more). The trachea can collapse secondary to the weight on the chest wall when suction is applied.
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PEDS: In children less than 1 year, the soft trachea can collapse. Fortunately, these circumstances can be predicted clinically. The EID is accurate > 95% of the time.
An alternative method of confirming correct intubation when the EID may be incorrectly placed is to attach a CO2 detector (Easy Cap, Mallinkrodt, Inc.) to the ET tube. The color of its pH-sensitive paper changes from lavender to yellow, indicating that CO2 is being exhaled and that the ET tube must be in the trachea. If the patient is in cardiac arrest and no blood is flowing, no CO2 will be sensed even though the tube is correctly placed and the color will remain lavender. An intermediate response is tan meaning a less-than-normal amount of CO2 is being sensed. This color change can be produced in esophageal intubation when there is retained CO2 in the esophagus or if there is poor pulmonary perfusion. If the tan color is seen, give 6 breaths and observe again. If not improved to yellow, remove the ET tube or confirm its placement by other means.
CO2 detectors are available in adult and pediatric sizes and work for up to 2 hours during normal ventilation. If there is excessive moisture and secretions in the ET tube, they are disabled in 10 to 15 minutes.
Another means of monitoring CO2 is by the use of capnography. The device measures the level of CO2 being exhaled and transmits the information to a monitor. Capnometers are equipped with alarms that alert staff to abnormally high or low levels. Normal levels vary between 30 and 40. Capnography may be used long term.
References
Wee MYK. The oesophageal detector device. Assessment of a new method to distinguish oesophageal from tracheal intubation. Anaesthesia. 1988;43:27-29.
Zaleski L, Abello D, Gold MI: The esophageal detector device. Does it work? Anesthesiology. 1993;79(2):244-247.
Bozeman WP, Hexter D, Liang HK, Kelen GD: Esophageal detector device versus detection of end-tidal carbon dioxide level in emergency intubation. Ann Emerg Med. 1996;27:595-599.
Securing an ET Tube
There are many good ways to secure an ET tube. Here is a
relatively
simple and inexpensive method: Use a long piece of twill tape. Form a
loop at the
middle of the tape. Pass the loop around the ET tube and pull the tape
through it
to form a "Lark's Head Hitch" as shown. Assure that the hitch will not
slip by
tying a single overhand knot around it as shown. Pass one limb of the
tape around the
patient's neck using a Magill forceps to pull it around without neck
motion then
tie the two limbs together.
When securing a tube at the mouth or nares, pass the twill over the ears and then around the neck.
PEDS: Securing an ET tube in an infant.
Cut a 4
x 4 inch square of protective see-through skin dressing in
half. Cut out a section of the dressing to result in a “pants” shape.
Dry off the
infant’s cheeks and lips and then apply the dressing as shown.
Hold
the ET tube in place by inserting a finger into the infant's mouth
and press the tube against the hard palate in the midline.
Now pucker the
infant's mouth around the ET tube and use strips of
adhesive tape to attach the tube to the protective dressing on both
cheeks.
The
ET tube should stay in the center of the mouth, or it will be
pulled out of the trachea when the head turns.
* Sir Robert Macintosh invented the ETI in the 1940s as the Gum Elastic Bougie.
** Dr. MYK Wee, an Australian anesthesiologist, invented the EID in 1988.