Page 54 - Journal of Special Operations Medicine - Spring 2014

are large and difficult to insert into the 8 to 11mm space anterior tracheal rings, the bougie usually distinguishes
between the cricoid and thyroid cartilages. Standard between tracheal and esophagus placement based on
tracheal tubes are intended for oral and nasal intuba- depth of insertion. When inserted into the trachea, the
tion and are much too long for insertion below the vocal device stops as the leading edge gets wedged into smaller
cords. The distance from the vocal cords to the carina and smaller bronchi; conversely, this holdup should not
averages only 11cm, while standard tubes are approxi- occur if passing into the esophagus and stomach.
mately 30cm long (i.e., they can easily wind up in the
mainstem bronchi, ventilating only one lung). Standard Palpation of the tracheal rings is not guaranteed when
tubes are also not easily secured to the neck (at the right using the bougie through a cricothyrotomy incision,
depth) after insertion. Mainstem intubation is common however. The angle of insertion is very steep and the
after emergent surgical airways performed with stan- tip may not make contact with the rings. Confirma-
dard tracheal tubes. 4 tion in the trachea can usually be confirmed based on
depth of insertion (it stops on reaching smaller bronchi).
A common error when performing cricothyrotomy is Disadvantages of using the bougie when performing a
losing the hole after entering the trachea, and subsequent cricothyrotomy include its long length, adding a step be-
placement of the tube into the subcutaneous space. 2,4,7 tween the incision and tube placement, and the potential
Some authors have advocated use of a finger in the hole to create a false passage on insertion.
or placing the handle of a scalpel in the hole to prevent
loss of the trachea. An inadequately sized incision and ™
4
blood pooling in the hole make correct insertion into the The Cric-Key
trachea challenging. Inserting a finger or scalpel handle The Cric-Key was invented to verify tracheal location
into the hole after the incision is not a guaranteed solu- during surgical airway procedures—without the need
tion, because such techniques still involve a transition for visualization, aspiration of air, or reliance on clini-
where there is nothing in the hole. Placement of a fin- cians’ fine motor skills. It incorporates a short curvilin-
ger, the scalpel handle, or a bougie into the hole is not ear introducer and an overlying cricothyrotomy tube.
instantaneous, and it is easy to create a false passage The verification of placement in the trachea is by palpa-
under the skin but above the trachea. tion of the tracheal rings, similar to a bougie during oral
intubation, but it has a special shape, overall length, and
The bougie-aided cricothyrotomy, as described by rigidity specifically for cricothyrotomy.
Braude and others, involves initial placement of a bou-
gie through the neck incision (and the trachea), followed The Cric-Key has been developed over 4 years of cadav-
by railroading a tracheal tube over the device and into eric testing and product engineering since the initial pro-
the trachea. 4,7 totype. The initial device was formed from a 5mm steel
rod of uniform shape with a shaped handle (from the
The bougie was conceived as a solution for tracheal same rod). Its final version has a semirigid, smooth plas-
tube insertion by Macintosh to aid visualization during tic introducer and overlying cuffed 5.2mm silicone tube
orotracheal intubation. After Macintosh’s original de- (Figure 1). The curvature of the device is allows insertion
8
scription, it was developed by Smiths Medical (Portex
®
[www.smiths-medical.com/brands/portex/]) and given Figure 1 Cric-Key and overlying silicone, short, cuffed tube.
an up-turned or Coude tip to aid tracheal ring palpa- The distal tip is rounded and deflected upward for interaction
tion. Although the bougie has visualization advantages with the tracheal rings. The flattened, bend section just
in situations of difficult laryngoscopy, it does not pref- proximal to the distal tip allows the device to “unbend”
erentially insert into the trachea over than the esopha- on insertion into the trachea.
gus when landmarks are not visually identifiable. It is
long (60cm), and when holding the proximal end of the
device, it is difficult to intuit the orientation of the dis-
tal up-turned tip. Placement in the tracheal is usually
confirmed by tactile feedback of the tip bouncing off
the tracheal rings, but this does not occur if the tip has
rotated posteriorly (i.e., sliding along the smooth wall of
the membranous trachea abutting the esophagus). The
tracheal rings are only are present on the anterior two-
thirds of the trachea. The rings are usually palpable dur-
ing oral intubation because of the angle of the trachea
(descending into the thorax) and the angle of bougie
insertion via the mouth. In addition to palpation of the

46 Journal of Special Operations Medicine Volume 14, Edition 1/Spring 2014