Page 569 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 45: Airway Management 389

Usually patients can be successfully intubated with topical anesthesia in attempts to use the first one, the second one can be used without delay.
alone. Most patients will benefit from treatment with 0.2 mg of glyco- Those who desire to vasoconstrict the nasal mucosa prior to manipulating
pyrrolate as a drying agent, and topical anesthesia using a combination it can do so with 0.5% phenylephrine spray. Topical anesthesia such as
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of lidocaine spray (4%) and jelly (2%-5%). Topical anesthesia usually 4% lidocaine can then be sprayed into both nostrils. Following this step, a
begins with spraying the oropharynx with lidocaine, obtaining as much nasal trumpet lubricated with 2% lidocaine jelly is introduced into one of
coverage of the oro- and hypopharynx as possible to obliterate the gag the nares. Successful introduction of the trumpet confirms the presence
reflex. An appropriately sized oral airway (9 mm is a good default) is of a patent passage adequate to allow an ETT to be passed. If the operator
then covered with lidocaine ointment or jelly and inserted into the encounters any difficulty in passing the nasal trumpet, the attempt to intu-
pharynx. The patient is instructed to suck on the airway. Lidocaine can bate the trachea through that nostril should be abandoned. Once the trum-
also be sprayed through the oral airway directly toward the larynx. The pet is successfully inserted, lidocaine is then sprayed through the trumpet
importance of the oral airway as a mechanism to administer topical lido- onto the vocal cords. It is best to use ETTs intended for use in the nose
caine requires emphasis, as it is the quality of the hypopharyngeal anes- (such as the Endotrol™ tube) when performing nasal tracheal intubation, as
thesia that allows direct laryngoscopy to be performed. An adequately conventional tubes may be too short and too rigid to be used safely for this
prepared patient will permit placement of a laryngoscope blade or even purpose. The ETT is lubricated with 2% lidocaine jelly and passed into the
a more uncomfortable device such as an intubating LMA. Once the nasopharynx. If any resistance is encountered as the tube is advanced,
operator is assured that the airway has been adequately prepared, laryn- the operator should stop immediately. Attempts to advance the tube past
goscopy (direct or fiberoptic) is performed, and intubation is attempted. substantial resistance are associated with mucosal tears, polypectomies,
Direct laryngoscopy in adults is usually performed using a Macintosh turbinatectomies, crushed and perforated nasal septa, and tunneling of the
no. 3 or 4 blade, although straight blade designs (such as the Miller) are ETT underneath the mucosa, all of which can be associated with exuberant
popular with some operators. The curved blades are generally easier to bleeding and other major complications. If fiberoptic intubation is planned,
use, but the straight blades may be more useful in the event of difficulty the bronchoscope is introduced through the tube into the nasopharynx
obtaining an adequate view. It is desirable for those who manage airways and is advanced into the trachea. The bronchoscope is used as a stylet to
in the ICU to be comfortable with both designs. Although circumstances advance the ETT into the trachea. Tracheal intubation can be confirmed by
are frequently less than ideal, the operator should do everything possible observing the carina and presence of tracheal rings beyond the tip of the
to ensure successful laryngoscopy. If possible, the headboard of the bed ETT. If the plan is to perform nasal intubation under direct laryngeal visu-
should be removed, and the bed moved away from the wall. The patient alization with a rigid laryngoscope, the oropharynx should be anesthetized
should be positioned in the sniffing position using pillows and rolled concurrently with the nose. Direct laryngoscopy is then performed, and a
blankets as necessary. Failure to adequately position the patient is a Magill forceps may be used to guide the tube into the trachea. If blind nasal
common cause of repeated intubation attempts in the ICU setting. Once intubation is planned, then the ETT is advanced slowly, with inspiration,
the patient has been intubated, it is imperative that the airway manager while the operator listens at the end of the tube for breath sounds. As the
holds the tube firmly in place until the tube has been secured. Oral end of the tube gets close to the glottis, the breath sounds become louder.
ETTs must be secured at least with tape; they may be wired to secure The tube is advanced into the trachea while the patient is instructed to take
teeth in circumstances in which the use of tape is undesirable or impos- a deep breath. The sensation of the tube popping through the cords fol-
sible. Importantly, the pressure in the cuff of the tracheal tube should be lowed by efforts at a cough by the patient suggest successful introduction of
maintained at 20 to 22 cm H O from the time it is inserted to minimize the tube into the trachea. The disappearance of breath sounds suggests that
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the risk of VAP. 24 the esophagus has been intubated. If this occurs, the tube should be with-
Successful tracheal intubation can be confirmed by a variety of tech- drawn until breath sounds are heard again. The patient’s head should then
niques in the spontaneously breathing patient, including the appearance be repositioned and another attempt made to pass the ETT. If an Endotrol™
of humidified gases in the tube, audible breath sounds at the end of tube is being used, tension should be applied to the ring to redirect the tip
the tube, breath sounds synchronous with Ambu bag ventilation, and of the tube more anteriorly before another attempt is made.
carbon dioxide detected via capnography or capnometry. ■
■ NASOTRACHEAL INTUBATION Fiberoptic tracheal intubation is increasingly performed in critical care
FIBEROPTIC INTUBATION
The disadvantages of nasal intubation are the increased risk of associated units. There are a variety of explanations for this, including the prolif-
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purulent sinusitis, VAP, and bleeding. 25,26 Advantages of nasal intuba- eration of fiberoptic bronchoscopes, increased familiarity and comfort
tion include ease of securing the tube, free access to the mouth, greater with their use, and increased recognition of their utility as the technique
stability relative to oral intubation, and absence of biting-associated of first choice in the patient with an anticipated difficult airway. Because
obstruction. Nasal intubation can be accomplished with the head in a the technique can be made difficult or impossible by the presence of
neutral position (or in traction) and with the patient sitting upright in blood or secretions, it requires meticulous preparation of the airway with
bed. Nasally intubated patients are less likely to self-extubate than orally drying agents, suctioning of secretions, and careful avoidance of any
intubated patients. 27,28 Blind nasal and fiberoptic nasal intubation are trauma, which might cause bleeding. The technique is most successfully
readily accomplished in spontaneously breathing patients with air hunger. performed in awake patients, because their airway muscle tone maintains
Besides the risks of sinusitis, VAP, and bleeding other disadvantages airway patency, which is important for good viewing conditions. 31
include the greater length of the ETT and trauma to the nasal mucosa, Preparation for performing fiberoptic intubation consists of warming
septum, and turbinates. Relative contraindications to nasal intubation the ETT, if possible, to soften it and make it easier to advance through the
include coagulopathy, compromised immune function, and suspected or vocal cords. The ETT is then placed on the fiberoptic scope in position to
known skull-base trauma. be slid forward when the scope is advanced into the trachea. The airway
Nasal intubation can be performed blindly, with direct laryngoscopy, is prepared with topical anesthesia as discussed previously. Specialized
or fiberoptically. Larger-bore tubes, such as 8.0 mm ETTs, should be oral airways, such as the Ovassapian airway are very useful, as they keep
used in nasal intubation, as they can be inserted as readily as smaller the tube midline, displace the tongue anteriorly, and prevent biting on the
tubes in most patients, present substantially less resistance to air move- bronchoscope (Fig. 45-1). For optimal viewing conditions, it is imperative
ment than do smaller tubes, and are large enough to allow fiberoptic that a competent assistant either provide a vigorous jaw thrust or pull on
bronchoscopy to be performed. 29 the tongue, delivering it anteriorly. The fiberoptic bronchoscope is then
Nasal intubation can be successfully performed without sedation, pro- passed through the vocal cords and down to the level of the midtrachea.
vided that adequate topical anesthesia is used. Many experienced operators The tube is then threaded into the trachea, over the scope with a smooth
prepare both nares simultaneously, so if an anatomic complication arises twisting motion. Tracheal intubation is confirmed with the bronchoscope

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