Chapter 21 Devices for Managing the Difficult Airway Ensuring a patent airway with adequate ventilation and oxygenation is a primary goal in anesthesia and resuscitation. Although death and brain damage from the difficult airway have declined, its management remains a significant problem ( 1 ). The American Society of Anesthesiologists (ASA) has developed an algorithm to help the anesthesia provider recognize and deal with patients who have, or are likely to have, a difficult airway ( 2 , 3 ). If a difficult airway is recognized beforehand, the course is likely to be different from that which occurs if that problem goes unrecognized. Various aspects of airway preservation are dealt with in other chapters, including masks and airways ( Chapter 16 ), tracheal intubation ( Chapter 19 ), and use of the supraglottic airway devices ( Chapter 17 ). When these techniques are unsuccessful, other measures need to be considered. Combitube Description The Combitube (ETC, esophageal-tracheal double lumen airway, ETLDA, esophageal tracheal Combitube) ( Fig. 21.1 ) has two separate lumens that are fused P.662 longitudinally and two inflatable cuffs ( 4 , 5 , 6 ). Each lumen is linked by a short tube to a standard 15-mm connector at the breathing system end. The pharyngeal lumen has an occluded distal end and eight oval-shaped perforations (ventilating eyes) between the cuffs. The tube and connector associated with the pharyngeal lumen may be colored blue. The other (tracheoesophageal, tracheal) lumen has a patent distal end and a clear tube. The smaller distal cuff serves to seal either the esophagus or trachea, depending on its placement. The larger (pharyngeal) cuff (balloon) is above the perforations. It serves to seal the pharynx by filling the space between the base of the tongue and soft palate so that gas cannot escape through the mouth or nose. The pilot balloon for the pharyngeal cuff is colored blue. If the tip is inserted into the trachea, the distal cuff is inflated and the tube is used as a conventional tracheal tube. If the tip is inserted into the esophagus, both cuffs are inflated and ventilation occurs through the holes above the distal cuff.
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Chapter 21 Devices for Managing the Difficult Airway Ensuring a patent ai rway wi th adequate vent i lat ion and oxygenation is a primary
goal in anesthesia and resuscitation . Al though death and brain damage from the
diff icul t ai rway have decl ined, i ts management remains a s ignif icant problem (1).
The American Soc ie ty of Anesthesiologis ts (ASA) has developed an algorithm to
help the anes thesia prov ider recognize and dea l with pat ients who have, or are
l ikely to have, a diff icul t ai rway (2,3). If a diff icul t ai rway is recognized beforehand,
the course is l ikely to be d if fe rent from tha t which occurs if that p roblem goes
unrecognized.
Various aspects of ai rway preservat ion are dealt with in other chapters, inc lud ing
masks and ai rways (Chapter 16), trachea l in tubat ion (Chapter 19), and use of the
supraglo tt ic airway dev ices (Chapter 17). When these techniques are unsuccessful ,
other measures need to be considered.
Combitube
Description The Combitube (ETC, esophagea l-tracheal double lumen airway, ETLDA,
esophageal tracheal Combitube) (Fig. 21.1) has two separate lumens that are fused
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longi tudinally and two inf latable cuffs (4,5,6). Each lumen is l inked by a short tube
to a s tandard 15-mm connector a t the breathing system end. The pharyngeal lumen
has an occluded dis ta l end and e igh t oval-shaped perforat ions (vent i lat ing eyes)
between the cuffs . The tube and connector assoc iated wi th the pharyngeal lumen
may be co lored blue. The other (tracheoesophageal , t rachea l) lumen has a patent
dis tal end and a c lear tube. The smaller distal cuff serves to seal e ither the
esophagus or trachea, depending on i ts placement. The larger (pharyngeal) cuff
(balloon) is above the perfora tions . It serves to seal the pharynx by f i l l ing the space
between the base of the tongue and soft palate so tha t gas cannot escape th rough
the mouth or nose. The pi lot ba lloon for the pharyngeal cuf f is colo red blue . If the
t ip is inserted into the trachea, the distal cuff is inf lated and the tube is used as a
conventiona l tracheal tube. If the t ip is inserted into the esophagus, both cuffs are
inf lated and vent i lat ion occurs through the holes above the distal cuff .
View Figure
Figure 21.1 Combitube. Note the ventilating eyes between the two cuffs. (Courtesy of Sherican Cather Corp.)
The Combitube has a pronounced anterior curve toward the patient end. I t is
marked wi th two black rings a t the machine end that help to indicate the insert ion
depth .
The Combitube is available in two sizes: the regular (41 French [Fr]) for adult
males and the small adul t (SA, 37 Fr) for females and small adul ts . The Combitube
is recommended for patien ts wi th a heigh t greater than 5 fee t (152 cm). The
Combitube SA is recommended for use in pat ients 4 to 6 fee t ta ll (120 to 180 cm)
but has been used in pat ients up to 6-1 /2 feet tall (198 cm) (7,8 ,9). The Combitube
is not recommended for pat ients younger than 12 years of age.
Use I t is important to p rac tice insert ing the Combitube under controlled condi tions
before attempting to use i t on a dif f icul t ai rway. I f a cerv ical col la r is in place, i t
should be removed and the cerv ical spine immobilized manual ly whi le the
Combitube is inserted (10,11,12). Once the ETC has been inserted successful ly ,
the anterior port ion of the collar should be reapplied before re leasing the manual
stabi l ization (6).
The Combitube can be inserted f rom any posi tion . For blind insertion, the head
should be in a neutral posi tion wi th the occiput on the f lat surface on which the
patient is pos it ioned, not the snif fing posit ion tha t is usual ly used for tracheal
intubat ion. Bending the Combitube in the port ion between the bal loons for a few
seconds may fac il i tate insertion (6,13,14,15,16). Suctioning is no t necessary, even
in the presence of b lood or vomitus (4).
The Combitube is inserted wi th one hand, whi le the other hand pul ls the tongue
forward and l if ts the jaw (4,17,18). I t should be passed along the surface of the
tongue, not the pa la te. It is important to keep the Combitube midl ine during
insert ion to avoid bl ind pockets such as the val lecula. The Combitube is advanced
unti l the space between the two black rings l ies be tween the patient 's tee th or gums
or unti l resistance is felt . Temporary release of cricoid pressure (if used) may be
required (19). I f there is diff icul ty advancing the ETC, rotating the tube may be
helpful in some patients (16). The use of a laryngoscope may fac il i ta te successful
placement and lower the number of complicat ions (7 ,20,21,22).
The pharyngeal balloon is inf lated with 100 mL (85 cc for the Combitube SA) of air.
The Combitube of ten moves outward about 1 cm during inf lation (5). The distal cuff
should be inf lated with 5 to 12 mL of ai r (Combitube 37 Fr) o r 5 to 15 cc of a ir
(Combitube 41 Fr). It may be preferable to inf la te the dista l cuff f irs t if the patient is
at r isk fo r aspiration (23). The blue bal loon should not be v isible when look ing into
the pat ient's oral cavi ty (16).
Af ter insertion and ba lloon inf la tion, vent i lation is begun in order to determine
whether the dis tal lumen is in the esophagus or trachea. Since most insert ions
resul t in esophageal placement, venti la tion should be attempted f irs t v ia the blue
lumen. Gas travels down the tube, through the late ral wall perfo rat ions, into the
pharynx, and on in to the trachea. I t is prevented from entering the stomach by the
distal cuff in the esophagus and from escaping through the mouth and nose by the
pharyngea l cuff . If no evidence of venti la tion is detected, a switch should be made
to the c lear lumen wi thout altering the Combitube's posit ion. If venti lation is
sa tisfactory, the device is then used as a tracheal tube. If venti lation continues to
be inadequate, the Combitube should be
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wi thdrawn 1 to 3 cm af ter def lating the cuffs and venti la tion attempted again wi th
the blue lumen (24). I f th is thi rd attempt at venti lat ion is unsatisfac tory, the
Combitube should be removed and vent i lat ion establ ished by using another
technique.
View Figure
Figure 21.2 Combitube in place in the esophagus. (Courtesy of Sherican Cather Corp.)
The esophagea l detector device and the colorimetric carbon d ioxide detector
(Chapter 22) have been used to verify correct posi tion (24,25,26,27,28,29,30,31).
In anesthesia sett ings, capnography can be used.
Af ter s tabi l izing the tube, the amount of ai r in the cuffs shou ld be reduced. I f the
Combitube is inserted into the trachea, inf lation should be to just sealing volume
(32). The volume in the pharyngea l bal loon should be reduced to the minimum
required to fo rm an effec tive seal (7,22,33,34,35,36). If venti lat ion is control led, a
s light posi tive end-expiratory pressure may be present (21,37,38,39).
In the esophageal posi t ion (Fig. 21.2), the unused tracheal lumen can be connected
to suction to asp irate f luids or a gas tric tube can be inserted (22). Epinephrine can
be insti l led th rough the esophagea l lumen (40). The dose should be ten times tha t
administered through a trachea l tube.
The Combitube in the esophageal posit ion may be exchanged for a s tandard
tracheal tube by using a flexible fiberscope, r igid laryngoscope, or retrograde
intubat ion around the Combitube (5,7,9,41,42,43,44).
Indications The Combitube is useful for a irway management in the diff icul t-to -intubate pat ient
(6,25,45,46,47,48,49,50,51,52,53,54,55,56,57). Because it can be placed wi thout
having to v isua lize the la rynx, i t may be especially useful for pa tients with mass ive
ai rway bleeding or regurgi ta tion. I t can be used in pat ients wi th l imited access to
the ai rway and limited mouth opening and fo r pat ients in whom neck movement is
contraindicated. It has been used successfully in patien ts in a halo head frame
(58,59), a pat ien t wi th excessive pharyngeal bleeding (60), a hematoma causing
upper ai rway obstruct ion (61), a pat ient who had a wooden splinter through the
mouth partial ly b locking the pharynx (62), respira tory arres t secondary to an acute
as thmatic exacerbation (63), a pat ient wi th fac ial burns (64), and a patient trapped
in a car (65). It may be useful in entertainers in whom i t is important to avoid vocal
cord damage (18). I t has been used for Cesarean sect ion (66). The ETC has been
used successfully after failu re wi th a laryngeal mask ai rway (LMA) (54 ,59).
The ETC has an establ ished role in cardiopulmonary resusci ta tion in both
prehospi tal and in-hospi tal se tt ings (56,67,68,69,70,71,72,73). It is included in the
Guidel ines for Advanced Cardiac Life Support of the American Heart Association,
Pract ice Guidel ines for Management of the Diff icul t Ai rway o f the ASA, the
Canadian Airway Focus Group, and guidel ines for resuscitat ion of the European
Resusci tation Counci l as a suitable al ternat ive ai rway to tracheal intubation,
especial ly in the “cannot vent ilate, cannot in tubate” s i tuation (2,45,74).
The Combitube has been used successfu lly fo r anes thesia las ting up to 6 hours,
including gyneco logic laparoscopic surgery (5,21,22,38,41,75). Relatively high
ai rway pressures can be used (4,21,22). While it is no t recommended for rou tine
anesthesia, i t may be a v iab le op tion fo r patients in whom it has been placed to
secure a dif ficul t airway (76,77). Using it in elect ive cases may
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increase the anesthesia provider's comfort wi th the dev ice. I t has been used in the
esophageal posi tion wi th mechanica l venti lation for up to 8 hours (38).
The Combitube has been used during percutaneous di latat ional tracheostomy (see
below) (78) but may not be the best choice for ai rway management during this
procedure (79). The trachea is free of any appl iance, but i t does not a llow a
f iberscope to be used during the procedure (80). It has also been used fo r
venti lation during tracheotomy (81).
Contraindications Contraindicat ions to us ing the Combitube inc lude ac tive pharyngea l or laryngeal
ref lexes; known esophageal trauma or patho logy; ingestion of corros ive agents; and
oropharyngea l, pharyngeal, or hypopharyngeal mass . It should not be used in
patients younger than 12 years of age or in those under 4 feet tal l.
Advantages
Compared wi th a tracheal tube, the time needed fo r insertion is s ignif icantly
shorter, and less sk il l is required (82). Because successful use does not require
di rect v isualiza tion, the presence of b lood and/or vomitus does not p revent
successful placement. Once in place, the Combitube provides comparable
venti lation and improved oxygenation compared wi th tracheal in tubation
(37,38,41,48,67,68,71,83). I t can be used by an anesthesia provider who has
l imi ted use of the left a rm (84).
Minimal training is needed before use. The skil ls required to insert a Combitube do
not need to be reinforced as of ten as they do for tracheal intubat ion. The
Combitube can be used successful ly by non-anesthesia personne l both as a f i rs t-
l ine treatment and after failed trachea l in tubat ion (71,72,73,83,85,86,87,88). I t is
of ten used by paramedics.
The Combitube in the esophageal posit ion is wel l tolera ted by the pat ient during
emergence from anes thesia (4). Its use is not associa ted wi th h igh levels of trace
gases (89). There is no danger of bronch ia l in tubation in the esophagea l posit ion.
The pharyngeal balloon anchors the device in p lace, lessening the risk of
accidental extubat ion.
The Combitube prov ides good but not complete protect ion from aspiration
(7,9 ,22 ,48,58,63,72,90,91,92). Gastric dis tent ion can occur wi th i ts use (36).
Disadvantages Tracheal suct ioning or fiberopt ic bronchoscopy is no t possible through the
Combitube in the esophageal posi t ion unless the Combitube is modif ied (93).
I f inserted into the trachea, the result is a tube with a relat ively large outer
diameter bu t smal l internal lumen. The ai rf low resistance wi th a small adul t
Combitube is greater than tha t of a 7-mm tracheal tube but lower than that of a 6-
mm tube (94,95).
A case has been reported where the patient could not be venti lated af te r the
Combitube was placed (96). The tube was found to be so deep that the upper cuff
obstructed the tracheal lumen. Pul l ing the tube backward remedied the problem. In
another case where vent ilation was diff icul t, f lex ible f iberoscopy showed a valvel ike
mechanism by the aryepiglo ttic folds over the perforat ions in the tube (97).
Insertion and removal of the Combitube may be associa ted wi th a higher stress
response than that wi th a tracheal tube or supraglottic ai rway device (22,39).
Insertion takes longer than wi th the LMA (72). The Combitube may be inserted
without mov ing the head or neck, bu t there may be more cerv ical spine motion
during ai rway management wi th a Combitube than with other devices (98,99).
Trauma to the ai rway and esophagus may occur wi th the Combitube
(12,21,36,71,100,101,102,103,104,105). It exerts relatively high pressure on the
tracheal mucosa (106). Sore throat and dysphagia are common after i ts use
(33,100). Trauma may be reduced by using the smal l adult Combitube when
appropriate, gentle insertion, hal ting further advancement in the presence of
resistance, us ing a la ryngoscope to aid insert ion, adequate anesthetic depth , slow
cuff inf la tion, and regular assessment of both cuff pressures .
The prox imal cuff of the Combitube is made of latex, making i t unsui table for use in
a pat ient wi th latex alle rgy (Chapter 15).
The Combitube is expensive compared to other s ingle use devices. Th is makes it
uneconomical to use fo r routine anesthet ics.
Retrograde Intubation Retrograde (translaryngeal-guided, guided b lind) intubation is an elective or
emergency technique for securing a d if f icu lt a irway, either alone or in conjunction
wi th other techniques (107,108,109). It shou ld be considered part of the
armamentarium of every anes thesia provider (2). Retrograde intubation is a useful
option in pa tients who cannot be intubated by using tradi tional techniques
(110,111,112,113,114,115,116,117,118,119). It may not be su itable fo r pat ients
who require immediate intubation and venti lat ion, as the procedure can be expected
to take 5 minutes or more fo r complet ion.
A retrograde in tubation set is shown in Figure 21.3 . After sk in prepara tion, a
ca theter-over-needle dev ice wi th an a ttached syringe is inserted th rough the
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cricothyroid membrane in a cephalad di rec tion (F ig . 21.4). Entering the ai rway
lower in the airway (between the c ricoid cart i lage and the f irs t t rachea l ring or
between the f irs t and second tracheal r ings) a llows more room for advancing the
tube (107,117,120,121,122,123). Free ai r aspiration conf irms the location . Local
anesthesia should be injected through the syringe. The needle and syringe are
removed, and a guide wire is inserted through the catheter (124) (Fig. 21.5).
Another dev ice such as an ep idura l or central venous catheter may be used as a
guide .
View Figure
Figure 21.3 Retrograde intubation set.
The guide is advanced cephalad unt i l i t emerges at the oral cav ity or nares (Fig.
21.5). I t may be necessary to use a spec ia l dev ice to re trieve the guide wire
(123,125,126). If nasotracheal in tubat ion is desired, a catheter can be inserted
nasal ly , brought out through the mouth, and secured to the gu ide wire (127). The
ca theter is then pulled out through the nose, bringing the guide wire with it . The
ca theter at the crico thyroid membrane is removed and the guide clamped a t the
sk in.
View Figure
Figure 21.4 The catheter-over-needle with syringe attached is inserted through the cricothyroid membrane in a cephalad direction. Aspiration of air confirms placement within the airway.
A la rger device such as an ep idural catheter or airway exchange catheter can be
s lid over the guide wire and the tracheal tube advanced over the catheter
(108,123,128,129,130,131,132) (Figs. 21 .6,21 .7,21.8). Al ternately, the tracheal
tube can be threaded over the guide wire , with the guide wire going ei ther th rough
the Murphy eye or main lumen.
The guide should then be put under s l igh t tension. The tracheal tube is advanced
unti l i t reaches the point where the gu ide wire en ters the airway. The guide wire is
removed f rom above and the tracheal tube inserted to the proper depth. If the
tracheal tube cannot be advanced, i t may be he lpful to ro tate it 90 degrees
counterc lockwise, exchange i t for a smalle r tube, relax the tens ion on the guide, or
insert a f iberscope through the tracheal tube (112,123,133). The tracheal tube may
also be pu lled into the trachea by tying the retrograde gu ide to the tracheal tube
(108,117,122,131,134).
Al te rnately, after the guide wire is retrieved through the mouth or nose, i t may be
placed through the channe l of a f lex ible f iberscope wi th a tracheal tube threaded
over i t (108,109,111,114,123,135,136,137,138). The f iberscope is advanced over
the guide and down to the point of ex i t of the guide wire f rom the trachea. At this
point, the guide wire can be loosened and the f iberscope advanced further (139).
Af ter conf i rmation tha t the f iberscope is in the trachea, the guide is removed v ia the
proximal port of the fiberscope. The tracheal tube is then advanced into the
trachea.
Retrograde in tubation is a safe, easy, and dependab le method of intubation (117).
I t may be especially useful in patien ts wi th ai rway trauma or l imited neck mobi l i ty
and in the presence of oropharyngeal bleeding, wh ich
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may obscure the f ield of the f iberscope (108,113,140). I t has been used in infan ts
and children (112,123,135). It has been used to place a double-lumen tube (141).
This method may be a usefu l means for reintubat ion when a tracheal tube is
removed (142). I t has been used to in tubate a pa tient with a Combitube in place
(143). I t is inc luded in the ASA Algori thm for Management of the Diff icul t Airway
(3).
View Figure
Figure 21.5 A: Guide for retrograde intubation. B: The guide is inserted through the catheter and advanced cephalad until it emerges from the mouth.
Compl icat ions of retrograde intubation include sore th roat, t rauma, baro trauma, and
pretracheal abscess (117,119,138,144,145). The tracheal tube may inadvertently
s lip out as i t is advanced (146).
Cricothyrotomy Placing a dev ice through the cricothyroid membrane to gain control of the ai rway is
not a new procedure (147,148,149,150). In recent years, the technique has been
ref ined and is now commonly used by emergency medical serv ices (151,152). It is
part of the ASA and Dif ficul t Ai rway Society diff icult ai rway algori thms (2,3).
Cricothyro tomy equipment shou ld be on every d if ficul t airway cart.
General Considerations The thyroid carti lage is p rominent and easily palpable in most ind iv iduals ,
especial ly in males. I t may be dif f icul t to palpate in obese pat ients and infants . The
rela tively avascular crico thyroid membrane is located approximately 2 to 3 cm
below the thyro id notch in adul ts . This area is usual ly the mos t accessible part of
the respiratory tree below the glott is . Occasional ly , i t may be necessary to choose
a s i te lower in the airway between the second and thi rd tracheal rings (153,154).
Cricothyro tomy can be perfo rmed by plac ing a small needle or catheter (needle
cricothyrotomy), a large cannula specia lly des igned fo r this purpose, or surgical ly
insert ing a cuffed tube (147,155). If time allows , f iberopt ic guidance may decrease
the incidence of malposi t ion (156).
Techniques
Needle Cricothyrotomy
Technique The patient 's head is extended and the crico thyroid membrane ident ified. A needle
or catheter-over-needle un it wi th a syringe a ttached is inserted in
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the midl ine point ing between 30 degrees and 45 degrees in a caudal d irect ion. I f ai r
can be aspira ted f reely into the syringe, the needle is ins ide the ai rway. A th ree-
way s topcock can be placed between the syringe and need le wi th one limb of the
stopcock connec ted to a capnograph (154,157). Aspirat ing carbon dioxide conf i rms
ai rway placement. The cannula is then s lipped off the needle into the trachea and
the need le removed.
View Figure
Figure 21.6 A: Airway exchange catheter. B: Airway exchange catheter has been advanced over the guide wire (after removal of the connection).
Smal l intravenous cannulae are usual ly read ily available but a re easily compressed
and prone to k ink ing (158,159,160). P lac ing a small bend in the end of the catheter
may decrease the inc idence of k inking (159). Some
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intravenous catheters are not sui tab le , because a syringe cannot be a ttached and
many are too short (161).
View Figure
Figure 21.7 The tracheal tube is advanced over the airway exchange catheter.
View Figure
Figure 21.8 The guide wire and airway exchange catheter are removed, and the tracheal tube is advanced into the trachea.
Large-gauge in travenous ca theters have been used successfully (162). Most
authors recommend a 14-gauge or larger catheter fo r adul t pa tients
(147,163,164,165). Use of a catheter with s ide holes may lessen the risk of tracheal
damage (163).
Catheter length is important. If the catheter is too short, i t may come out, and gas
wi l l be injec ted into the subcutaneous neck t issues . However, the longer the
ca theter, the greater the resistance to f low. For the adu lt patien t, the catheter
should be at least 4 cm in length. For the patient wi th a thick neck, a greater length
may be necessary (166).
Other devices used inc lude a Tuohy needle (167,168), the vessel dilator of an
intravenous introducer ki t (169,170), a tr iple -lumen central venous catheter (171),
and a suct ion catheter (172).
To connec t the c ricothyrotomy dev ice to a means of vent i lat ion, either a Luer lock
(Fig . 21.9) or a 15-mm connector is required . Many k i ts p rov ide both . Some have
the Luer lock attachment ins ide a 15-mm connector.
Ventilation Techniques The catheter diameter of ten does not al low an adequate t ida l volume to be
delivered at the pressures prov ided by conventional venti lators. A source of high-
pressure oxygen and robust connect ions are required.
Jet Ventilation Inject ion of high-veloci ty gas in to the ai rway through a narrow cannu la wi thout a
seal is termed je t venti lation . It can be perfo rmed automatical ly o r manua lly. Jet
venti lation is convent ional ly carried out a t rates up to 60 cyc les /minute. Above 60
cycles/ minute, the techn ique is referred to high-frequency jet vent i lat ion (173).
View Figure
Figure 21.9 This device is designed to deliver oxygen at a high flow through a small tubing. The pressure tubing is attached to a 50-psi oxygen source, such as the outlet of a piped oxygen system. The pressure delivered can be adjusted by turning the knob. The pressure is measured by the pressure gauge at left. The flow is controlled by the toggle switch downstream of the knob. The tubing end at the top has a Luer lock connector and is attached to a large-bore needle or catheter placed percutaneously through the cricothyroid membrane.
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A means of jet venti la tion should be avai lable in every anesthet iz ing area (174).
Unfortunately, not a ll locat ions have the equ ipment readi ly avai lable and ready fo r
use (175). During an emergency is no t the time to assemble these dev ices. Al l
connec tions mus t be correct for the mode of venti lat ion ant ic ipa ted and robust
enough to withstand the pressures that wil l be used.
In a small pat ien t, the peak pressure should be reduced to 5 pounds per square
inch (psi ) and then increased in increments of 5 ps i unt i l adequate ches t excurs ions
are observed (166,176,177). In adul ts , the jet vent ilation device should be preset a t
25 psi, then increased or decreased as indicated by the cl inical response (178).
The upper a irway should be made maximally pa tent during jet venti lat ion by putting
the pat ient in an opt imal “sn if f” posi tion , by using bi late ral jaw thrust and
oropharyngea l ai rways, and by avoiding jet venti lation during phonation. If complete
ai rway obstruction pers is ts af te r je t venti la tion is a ttempted, the ai rway needs to be
converted to a tracheostomy as soon as possible.
The pattern of je t venti lation is important (142,162,179). The inspiratory volume
depends on the gas f low rate, injection time, respiratory system compl iance, and
ai rway res is tance. The expiratory volume wi l l depend on the exhalat ion time, elas tic
recoil of the lungs, and airway resistance. Care mus t always be taken not ini tiate
inspiration before the end of exhalat ion . End-t ida l carbon dioxide can be moni to red
by plac ing a sample l ine through the mouth or nose (180). The inspired oxygen
concentration wi l l depend on the amount of ai r that is entrained, which depends on
the ratio of the catheter to the trachea and the structure of the catheter (number of
s ide holes ).
I f too much gas escapes from the trachea th rough the mouth or nose during
inspiration , the patient 's mouth and nose should be c losed or the backflow blocked
wi th a th roat pack (181).
Devices A number of jet venti lat ion devices are commercially avai lable . One is shown in
Figure 21.9. They are connected to a piped oxygen outlet or an oxygen cylinder
wi th a regulator. Some have a means to regulate the de livered pressure and/or an
alarm.
The jet may act as a Venturi and entrain adjacent gas to increase the volume
delivered. The je t's ef fic iency depends on a number of factors (173). The amount o f
gas delivered increases as the driv ing pressure is ra ised.
Automatic Ventilator Automatic venti lators tha t can de liver a jet of gas automatical ly while moni toring
both del ivery pressure and ai rway pressure are avai lable and can be attached to
the crico thyro tomy ca theter (142,169,172,183,184,185,186). Some automatically
pause venti lation when the end-expiratory pressure exceeds a preset l imi t, enabling
detec tion of outlet obstruc tion (171).
Manual Jet Ventilation Device A manually control led jet vent ilat ion device may be attached to the c ricothyrotomy
ca theter and the pat ien t venti la ted by using an in termittent jet of oxygen. T idal
volume, inspired oxygen concentration, and ai rway pressures are not easily
moni tored. A check must be made for complete exha lat ion af ter each delivered tidal
volume.
Flowmeter Many anesthes ia machines have an auxil ia ry (courtesy) f lowmeter. This o r a
f lowmeter attached di rec tly to a piping system outlet can be used as a source of
oxygen (186,187). Noncompliant tubing should be used between the f lowmeter and
the crico thyro tomy ca theter. A three-way s topcock or other device can be used at
the pat ient end to convert the cont inuous f low o f gas to intermit tent bursts, or a
hole can be cut in the tubing and the operator's f inger placed over the hole to
deliver a jet of oxygen.
Oxygen Flush I t may be possible to supp ly oxygen f rom the anesthesia machine by a ttaching
noncompl iant tubing to the common gas outlet and intermit tently act ivating the
oxygen f lush (188,189,190,191). Alternatively, i f there is a port near the patient end
of the tubing, a second person can continuously depress the oxygen f lush button
whi le the anesthesia provider intermit tently occ ludes the port (192).
Not a ll anes thesia machines have a common gas out let tha t can be accessed, and
not all anes thesia machines supply oxygen at a h igh enough pressure to drive the
oxygen through the noncompl iant tubing and a cricothyroid catheter (191,192).
Before relying on this means of vent i lat ion, the anes thesia department should
ascertain what pressure wil l be delivered.
Anesthesia Breathing System The 15-mm connector f rom a c i rc le breathing sys tem can be connected to the
cricothyroid device and the oxygen f lush intermit tently ac tivated. Because the
reservoir bag and tubings absorb mos t of the pressure, the lungs wil l probab ly no t
be effect ively vent i lated by this method a lthough adequate oxygenation may be
achieved (188). Applying pressure to the reservoir bag wil l increase the delivered
pressure .
Manual Resuscitation Bag A manual resusc itator (Chapter 10) or a Mapleson sys tem (Chapter 8) may be
attached to the c ricothyrotomy dev ice. These cannot provide adequate venti lation
unless a very large cannula is used (176,192,197).
Percutaneous Dilatational Cricothyrotomy The elements of a percutaneous crico thyro tomy se t are shown in Figure 21.10. A
number of customized k i ts containing the necessary items are available
(164,175,198,199,200,201,202,203,204,205,206,207,208,209). A need le-over-
cannula or a s imple needle wi th an attached syringe is inserted through the
cricothyroid membrane and ai r asp irated (Fig. 21.11). A gu ide wire is then inserted
through the catheter.
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(Fig . 21.12), and the catheter is then removed. The hole in the skin around the
guide wire is enlarged by us ing a scalpel (Fig. 21 .13). The tract around the gu ide
wi re can be enlarged by using a series of progress ively larger d ilators ( in troducers)
or a curved dilator (Fig. 21.14). The a irway dev ice is then inserted into the trachea
over the wire guide or dilato r, wh ich is then removed (Fig . 21.15). A crico thyrotomy
tube may have a cuff (Fig. 21.16). The insertion assembly may differ (Fig. 21.17).
View Figure
Figure 21.10 Elements of a cricothyrotomy set. At bottom is a syringe with needle. Next is the guide wire, which is advanced through the needle. The small scalpel is used to enlarge the hole in the skin at the site of the guide wire. The dilator is used to enlarge the opening into the airway. The tube is advanced over the dilator. The guide wire and dilator are then removed, and the tube is used to ventilate the patient.
This techn ique is fast and usually easy to perfo rm, even in the patient wi th a short
neck or sp inal inju ry. An advantage is that most anesthesia providers are
experienced in wire-guided techniques (210). Adequate vent i lat ion can be achieved
by using a conventional breathing sys tem if the d iameter of the device is at least 4
mm (147,208). However, i t may resu lt in more compl ications and less chance of
correct posi tioning than a catheter-over-needle technique (211,212).
Surgical Cricothyrotomy In surg ical cricothyrotomy, a transverse sk in inc ision is made at the level o f the
cricothyroid membrane (147,151,198,213,214,215,216). I f the neck is edematous
and the larynx cannot be palpated, the incision shou ld be vert ical and then
deepened unt il the laryngeal cart i lages are identif ied. An inc is ion is then made in
the crico thyro id membrane. A catheter may be placed as a guide. The inc is ion in
the membrane is then spread, and a trachea l or tracheostomy tube is placed
through the opening. A bougie may fac il i tate insert ion of a tracheal tube (217).
Surgical crico thyrotomy is more t ime consuming than the percutaneous methods
and requ ires an experienced surgeon but provides a more def initive ai rway
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than the other methods . However, if speed is particu larly important and/or when
equipment for less invasive techniques is unavai lable, i t can be performed qui te
rapidly.
View Figure
Figure 21.11 The needle-over-catheter is inserted through the cricothyroid membrane in a caudal direction.
View Figure
Figure 21.12 A guide wire is inserted through the catheter.
Indications Upper Airway Obstruction with Inability to Ventilate or
Intubate A prime indication for c ricothyrotomy is the inabi l ity to secure a patent ai rway by
conventiona l techniques (154,170,194,218,219,220,221,222,223). These include
fore ign body aspirat ion and upper ai rway pathology or when a person skil led a t
intubat ion is not avai lable or cannot intubate the pat ient and a supraglott ic device
cannot be inserted .
Anticipated Difficult Intubation Cricothyro tomy may be used as an ad junct to fiberopt ic o r other intubat ion
techniques where it is an tic ipated that intubat ion may be dif f icult to perform
(109,166,174,224,225,226,227). It p rov ides a means to venti late the patien t if the
intubat ion procedure is p rolonged. This may be espec ia lly useful for pat ien ts who
cannot tolerate an awake intubat ion. Je t venti la tion may make subsequent tracheal
intubat ion easier because the high tracheal pressure may open the collapsed
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glottis (154,228,229). Leaving the crico thyro tomy device in place during the
recovery period al lows emergency oxygenation at a time when reintubat ion may be
diff icul t or contraind icated.
View Figure
Figure 21.13 The hole in the skin around the guide wire is enlarged by using a scalpel.
View Figure
Figure 21.14 A: The tract around the guide wire is enlarged by using a curved dilator (introducer). B: The cricothyrotomy tube fits over the introducer and guide wire.
Procedures Involving the Airway Jet vent i la tion th rough a crico thyrotomy device can be used during procedures
involv ing the upper ai rway (168,171,174,182,230). This leaves the ent ire ai rway
f rom the vocal cords to the face access ib le to the surgeon. Since there is no
tracheal tube, there is a reduced likel ihood of f i re (231) (Chapter 32). A
disadvantage is that the ai rway is not p rotec ted f rom contamination by blood and
surgical debris . However, the cont inuous egress of gas from the ai rway helps to
reduce contaminat ion.
Cervical Spine Injury I f cerv ical spine injury has occurred or has not been ruled out, cricothyrotomy may
be a good way to es tab lish an ai rway. Other methods of securing an a irway wi th
minimal neck movement are d iscussed in Chapters 17 and 19.
Contraindications Intrathoracic Airway Obstruction Cricothyro tomy is only useful for obstruct ions above the cricoid carti lage.
Obs truct ions at or below this level may be pushed deeper. For obstruct ions at o r
below the level of the c ricoid, tracheotomy wi l l be necessary.
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View Figure
Figure 21.15 The introducer and guide wire are removed, and the cricothyrotomy tube is left in place.
Inability to Locate the Cricothyroid Membrane This procedure should not be attempted i f there is uncertainty about the loca tion of
the crico thyro id membrane.
Complete Airway Obstruction I f there is complete obstruct ion above the cricothy-rotomy catheter, there wi l l be no
ex it path for exhalat ion. However, if a foreign body obstruction in the mouth or
larynx is p reventing resp iration, there is the possibi l i ty that this could be blown out
and the obs truct ion rel ieved. It may be possib le to adminis te r pressurized oxygen
safely to patients wi th comple te upper ai rway obstruct ion by using a Y-adaptor
attached to the catheter hub (228). Oxygen can be admin is tered through one l imb
whi le the other l imb is used for passive expira tion.
View Figure
Figure 21.16 Cuffed cricothyrotomy tube. (Courtesy of Cook Critical Care.)
Pediatric Patients Cricothyro tomy is technica lly diff icul t in the ped iatric population and shou ld be
performed wi th extreme caution in chi ld ren below 10 years of age (155). Ped iatric
patients have a higher incidence o f complicat ions f rom cricothyro tomy than do
adults (232).
Laryngeal Pathology Cricothyro tomy should not be used in the presence of laryngeal inf lammation or
infect ion .
Decreased Compliance Patients with cond it ions such as emphysema and chronic bronchi tis of ten have
dimin ished compliance tha t may make venti lat ion less effect ive.
Complications Barotrauma I f posit ive pressure is applied below the vocal cords, ai rway pressure may rise to a
hazardous level wi th resul tant barotrauma (175,182,183,228,230,233,234,235).
Carefully moni toring chest movements, l imiting inspiratory pressure and time, and
al lowing adequate t ime for expiration wil l decrease the risk of baro trauma. Airway
pressure monitoring should be perfo rmed, if feasible . Some jet venti lato rs
automatical ly pause when a preset pressure is reached (171,229).
Trauma Placing a cricothyro id device can resul t in in jury. Bleeding, hematoma, laryngea l
cart i lage injury, mucosal ulcera tion, and perfo rat ion of the posterio r trachea and
esophagus have been reported (175,205,213,220,236,237,238,239,240).
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View Figure
Figure 21.17 Cricothyrotomy set with the guide wire attached to the needle and a side tubing through which air can be aspirated.
I f the catheter is incorrect ly placed or s lips out of the trachea or i f there is a hole in
the catheter near the surface of the neck , oxygen may be injected into the tissues,
resul ting in subcutaneous or medias tinal emphysema (183,228,241,242,243).
Subcutaneous emphysema also may occur after decannulation (168,244). The
cricothyrotomy device should be fi rmly secured to prevent dis lodgment. Suturing
the device in place should be cons idered i f t ime permits. Neck movement should be
l imi ted. “Whipping” of the catheter with each breath can be minimiz ing by keeping a
short length wi thin the trachea and using a low driv ing pressure (171).
Late complicat ions include granula tion at the cuff si te, excess ive procedure time,
tracheal s toma s tenosis, persis tent s toma, hemorrhage, subglottic s tenosis ,
aspirat ion of blood, dysphonia, vocal cord paralysis or pares is, voice changes, and
wound infec tion (220,236,239,245,246).
Kinked Catheter I f the catheter kinks , venti la tion may not be possib le (158,168,247). Adding a smal l
curve to the t ip may help prevent k ink ing (159). Precurved catheters are
commercial ly avai lable (248). I f kink ing occurs, i t may be possible to change the
ca theter for one more resistant to kinking by us ing a gu ide wire (168).
Failure to Cannulate the Trachea The reported fai lure rate for successful ly p lac ing catheters in the trachea varies
f rom 0% to 40% (151,200,213,214,219,220,236,238,239,240,249,250,251). Prac tice
wi th the technique during elective cases or a s imulator increases fami liarity wi th
the method and faci l i tates its use in an emergency s ituat ion (156,247,252,253).
Advantages and Disadvantages Cricothyro tomy is re lat ively s imple , safe, easy to learn, and quick. The success rate
is high even in inexperienced hands (151,152,214,219,220,238,239,250).
Percutaneous jet vent i lat ion may fac i l i tate tracheal intubat ion by al lowing
identif icat ion of the glott is opening (154,228). The princ ipa l disadvantage is that i t
does not establ ish a def ini tive ai rway.
Percutaneous Dilatational Tracheostomy Percutaneous di lata tiona l tracheos tomy entai ls insertion of a full -sized
tracheos tomy tube in the subcricoid area (254). I t is an alternat ive to trad it ional
surgical tracheostomy. It may be performed at the bedside in a crit ical care un it .
Many insti tu tions have adopted i t as the technique o f cho ice in crit ically i ll pat ients
who require a tracheostomy (255,256,257). I t is mos t of ten performed elect ively but
can be used in an emergency s ituat ion (258).
Technique Venti la tion can be maintained throughout the procedure by using a tracheal tube
placed above the si te of the proposed tracheostomy, a suprag lo tt ic ai rway dev ice, a
Combitube, a microlaryngea l tube, an a irway exchange catheter, or a flex ible or
The Combitube may not be su itable if the longer lumen is in the trachea (79).
Endoscopy is often used during the procedure to avoid complicat ions
(261,265,275,277,278,279,280,281,282,283). An opt ical s tylet may a lso be used
(284). I t al lows conf irmation of the posi tion of the tracheal tube as wel l as correct
placement of the needle (i .e ., whether i t is midl ine and
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at the correct level), guide wire , di la tor, and f inal ly the tracheostomy tube. More
severe complicat ions occur when endoscopic v isualizat ion is no t used (285). I t also
makes it relat ively easy to perform a therapeutic or diagnost ic bronchoscopy after
the procedure is completed (286,287). Disadvantages of f iberoscopy inc lude an
increase in the t ime needed for the procedure, the need for a separa te sk il led
person, and the potent ial for hypoventi lat ion (288). A l ight wand may be used to
guide the procedure (289,290).
A modif icat ion of this technique is to uti l ize endoscopic guidance during gu ide wire
placement and then to insert an ai rway exchanger catheter (266,291). This
produces less ai rway res is tance, a llows venti lation and adminis tration of oxygen,
and fac i l i tates reintubation, if necessary.
The patient is placed in the supine posi tion wi th the neck extended un less there is
known or suspec ted cerv ical spine ins tab il ity. Ultrasound scanning can be used to
identify blood vessels and the correct level (269,292,293,294,295,296).
I f the patien t is intubated, the trachea l tube should be wi thdrawn to a point above
the in tended s i te of the tracheostomy. A bougie or airway exchange catheter may
be inserted through the tracheal tube to fac il i tate reintubat ion if the tracheal tube is
dislodged (291,297).
A short, sha llow skin incis ion is made over the trachea, between the f i rs t and fourth
cart i lages (259,298). If the s i tuat ion is urgent, the crico thyroid membrane may be
punctured (202). A large gauge needle is then introduced into the tracheal lumen
between two rings (Fig. 21 .18). Posi tion wi thin the trachea is conf i rmed by
aspirat ion of ai r, d irect b ronchoscop ic v isual iza tion (preferred), o r capnography
(299,300). Local anes thetic can be injected in to the lumen of the trachea. A guide
is introduced through the needle into the trachea, and the needle is then removed.
View Figure
Figure 21.18 After the front of the trachea has been exposed, the needle with syringe attached is inserted into the trachea. Entry into the trachea is confirmed by the appearance of air bubbles on aspiration. A guide wire is then inserted through the needle, and the small dilator is inserted.
Different techniques are used to dilate the opening in the anterior tracheal wall
over the guide (301,302,303,304). The f i rs t employs progressively la rger tapered
di lato rs (F ig . 21.19) o r one large tapered or screwl ike d ilator (Fig . 21.20)
introduced over the guide (305,306,307,308,309,310,311,312,313,314). Some
di lato rs have a hydrophi l ic coat ing that helps to en large the entrance si te . Another
technique uses a di lating forceps (315,316,317). This technique is fas ter and may
be
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associated wi th fewer compl ications than sequential d ilatat ion technique (318,319).
Ki ts containing the necessary i tems for each method are available
(254,309,320,321,322).
View Figure
Figure 21.19 Progressively larger dilators can be used to enlarge the hole.
View Figure
Figure 21.20 A large dilator is passed over the guiding catheter, which was passed over the guide wire.
The lubricated tracheostomy tube is inserted over the dilat ing device or guide,
which is then removed (323) (Fig . 21.21). Special t racheal cannulas with obl iquely
cu t tips that faci l i tate insert ion have been developed (259). Capnography should be
used to confi rm correct p lacement (286,324).
Contraindications Relat ive contra indicat ions to percutaneous tracheos-tomy include infect ion a t the
s i te, inabi l ity to extend the neck, anatomical features in terfering wi th ident if icat ion
of anatomic landmarks, tracheomalacia, and severe coagulopathies. Its use in
ch ildren is controvers ia l (259,325,326,327). However, percutaneous dilatational
tracheos tomy has been performed in al l of these subgroups (255).
Advantages and Disadvantages A major advantage of percutaneous tracheostomy is the abil ity to perform the
technique at the bedside. This avoids delays, risks , and logistical problems of
transfer to the operat ing room. Compared wi th a surgical tracheostomy, i t is less
expensive, faster, easier, and associated wi th less blood loss and is less l ikely to
resul t in cosmetic deformity, infect ion, or bacterial contaminat ion of neighboring
term complication rates are less than for operat ive tracheostomy
(316,329,331,334,339,340,341,342,343,344). It can be perfo rmed in most pa tients
who cannot undergo neck extension (345,346) and in morbid ly obese patients
(306,347,348,349,350).
Complications Studies indicate tha t there is a learning curve for percutaneous d ilatat ional
tracheos tomy (351). The compl icat ion rate may be higher in obese pat ien ts (350).
The use of ul trasound should reduce the number of serious complica tions
(295,296).
Incorrect Placement Some studies show that a signif icant number of tubes have been placed in an
improper loca tion, usual ly higher in the airway than in tended (352,353). A tube may
end up moving cephalad rather than cauda lly (354).
View Figure
Figure 21.21 The tracheostomy tube is loaded over a small dilator, which is in turn loaded over a guiding catheter, which is then loaded onto a guide wire. After insertion into the trachea, the dilator, guiding catheter, and guide wire are removed.
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Trauma Trauma resul ting f rom percu taneous tracheostomy can inc lude formation of a false
passage e ither anterior to or beside the trachea, injury to the pos terior tracheal
wal l or tracheal cart i lages, hematoma, hemorrhage, esophageal perforation,