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Chapter 16 Face Masks and Airways P.444
Face Masks The face mask allows gas administration to the pat ien t from the breathing system
wi thout introducing any apparatus in to the pat ient's mouth. The abi l i ty to hold the
mask and to administer posi tive pressure venti lat ion through the mask is a basic
sk il l that a ll anesthesia prov iders mus t master. In the past, the face mask was often
been used to administe r an ent ire anesthetic . More recently, the introduction of
supraglo tt ic airway dev ices (Chapter 17) has led to a dec rease in this practice .
Whi le some supraglottic ai rway devices have the word mask in their ti tles , they are
very different f rom face masks and are dealt wi th separately in Chapter 17.
The face mask is also used to administer noninvasive posi tive pressure vent ilation
(NPPV) for treatment of respira tory failure (1,2).
Description A face mask may be constructed of a number of substances, inc luding black rubber,
c lear plast ic , an elastomeric material , o r a combinat ion of these. The majori ty of
anesthet ics today employ a disposable plast ic mask. These masks are designed to
f it a wide variety of pat ients and are not as easy to use as many older masks that
were s ized and anatomical ly designed to f i t a narrower range of pa tients.
Body The body (shell, dome) const i tutes the main part of the mask (3). A transparent
body allows observation fo r vomitus, secre tions , blood, l ip color, and exhaled
moisture . A transparent mask may be better accepted by a conscious pat ient (4).
Seal The seal (rim, f lap , edge) is the part of the mask tha t comes in contac t wi th the
face. Two general types are available. One is a pad (cushion) that is inf lated wi th
ai r or f i l led wi th a material that wil l conform to the face when pressure is applied.
The second type is a f lap that is a f lex ible extension of the body that conforms to
the contour of the face. I t is p ressed onto the face to create a seal .
Connector
The connector (orif ice, col la r, mount) is at the opposi te s ide f rom the seal. I t
consists of a th ickened f i tt ing wi th a 22-mm in ternal diameter. A ring wi th hooks
(Fig . 16.1) may be placed around the connector to allow a mask strap to be
attached.
Specific Masks Masks come in a variety of sizes and shapes (F igs . 16.1, 16.2). An assortment
should be kept readily available, because no one wi l l f i t every face we ll .
View Figure
Figure 16.1 Clear, disposable masks. (A, Picture courtesy of Kendall; B, Courtesy of Rusch, Inc.)
P.445
View Figure
Figure 16.2 Black rubber masks. (Courtesy of Sun Med.)
Rendell-Baker-Soucek Mask The Rendell -Baker-Soucek (RBS) mask (Fig. 16.3), which is designed for the
pedia tric pa tient, has a triangular body. I t has a low dead space (5,6). Some of
these masks are scented and may have a pacif ier (F ig. 16.3B). This mask has been
used for the patient with a tracheostomy (7,8,9) and a patient with acromegaly (10).
I t may also be useful when a mask to cover only the nose is needed (11).
Endoscopic Masks An endoscopic mask is designed to al low mask venti lat ion whi le an endoscope is
being used (12,13,14,15). One is shown in F igure 16.4. A port/diaphragm in the
mask body al lows a f iberscope to be inserted in to the nose or mouth. A l ighted
stylet (Chapter 19) may also be used (16). A tracheal tube previously loaded over
the f iberscope or l ighted style t can then be advanced, if desired.
Scented Masks Since face masks are often used for an inha la tion anesthesia induct ion or for
preoxygenation prior to induction , efforts have been made to make this experience
more acceptable by using scents to camouflage the odors of inha la tional agents
(17,18,19,20,21,22,23,24). The scent may be incorporated into the mask by the
manufac turer o r app lied to the mask by the anesthesia provider (Fig. 16 .5). Some
masks are color coded according to the scent. The e thyl alcohol in some appl ied
f rui t f lavors may affect the accuracy of some gas monitors (25 ,26). Pre-scented
masks from the manufacturer do not present this problem (25).
Techniques of Use The face mask shou ld form a tight seal on the patient 's face while f i t ting
comfortably in the user's hand. A proper seal is essential ly for preoxygenation
(27,28). A poor f it requires the anes thesia provider to main tain steady pressure.
This may lead to c ramped hands and ti red muscles and l imits the user's ab il i ty to
perform other tasks. With spontaneous respirat ion, a loose seal wi l l resul t in
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ai r dilu tion. With assisted or controlled venti lation, adequate gas exchange may be
impossib le wi th a poor mask f it . An inadequate seal can be compensated for some
ex tent by increasing the fresh gas f low, bu t th is is wasteful and contaminates the
room with anes thetic gases and vapors.
View Figure
Figure 16.3 Rendell-Baker-Soucek masks. A: Clear plastic version. (Courtesy of Rusch, Inc.) B: With pacifier. (Courtesy of Ohio Medical Products, a division of Airco, Inc.) C: They are also available in black rubber.
View Figure
Figure 16.4 Endoscopic masks. (Pictures courtesy of VBM Medical, Inc.)
Correct mask use starts wi th selec tion of the appropriate s ize and shape. Th is may
require some tr ial and error. The smalles t mask that wi l l do the job is the most
desirable because i t wi l l cause the leas t increase in dead space, usua lly be easiest
to hold, and wi l l be less l ikely to resul t in pressure on the eyes. If a sea l is d if ficult
to establ ish, reshaping the mark 's malleable perimeter, altering the amount of air in
the seal or se lec ting a different mask may be helpful. If there is a leak , the mask
should be checked to make certain there is an adequate sea l between the breathing
system connector and the mask (29).
One-hand Method There are several methods of holding a mask to maintain an open ai rway and a
t igh t sea l. A commonly used method is shown in Figure 16.6. The thumb and index
f inger on the lef t hand are placed on the mask body on opposi te s ides of the
connec tor. These fingers push downward to hold the mask to the face and prevent
leaks . Addi tional downward pressure, if required, can be exerted by the anesthesia
provider's chin pushing down on the mask elbow. The remaining three f ingers are
placed on the mandible or the inferior part of the mask. I t is important that the
applied pressure does not decrease a irway patency. Care should be taken to
prevent pressure on the eyes. In some cases, i t may be necessary to extend the
f ingers to the right s ide of the mask to get a good seal. It may be benef ic ia l to
gather part of the le ft cheek around the lef t base of the mask wi th the palm of the
left hand.
View Figure
Figure 16.5 Adding scent to the face mask may make inhalational inductions more pleasant.
P.447
View Figure
Figure 16.6 Holding the mask with one hand.
Two-handed Method A second method can be used to open any but the most dif f icul t ai rway and obtain a
t igh t fi t (Fig. 16.7). It requires two hands, so a second person is necessary if
assisted or control led resp iration is needed. The thumbs are placed on ei ther side
of the mask body. The index f ingers are placed under the angles of the jaw. The
mandib le is li f ted and the head extended. If a leak is present, downward pressure
on the mask can be inc reased by pressing down on the mask wi th the anesthesia
provider's chin on the mask elbow (Fig.16.7B). If a second person is not availab le,
the anes thesia venti lator can be used to supply posi tive pressure wh ile the ai rway
is held open by both hands (30).
Two-handed Jaw Thrust Another method to open the airway is to have one person stand a t the head of the
patient and perform a jaw th rus t at the ang le of the left mandible whi le the right
hand compresses the reservoir bag (31). The second person s tands at the patient 's
shoulder, fac ing the f irs t person. This second person's right hand covers the lef t
hand of the fi rs t person, and the lef t hand ach ieves righ t-s ided jaw thrust and mask
seal.
Claw Hand Technique The c law hand technique is useful for children undergoing short-durat ion
ophthalmic procedures (32). The anesthesia prov ider stands a t the s ide o f the bed,
P.448
fac ing the chi ld . The face mask is appl ied to the face by using the right hand wi th
the palmer surface fac ing upward. The ring f inger goes under the angle of the jaw,
and the middle f inger is placed under the angle of the jaw on the lef t . The index
f inger and thumb encirc le the body of the mask. The anesthesia provider then
t igh tens the grip on the mask to achieve a good f it . The l i tt le f inger is kept free.
View Figure
Figure 16.7 A: Holding the mask with two hands. Also shown is the Esmarch-Heiberg maneuver, which involves dorsiflexion at the atlanto-occipital joint and protrusion of the mandible anteriorly by exerting a forward thrust on the rami. B: The anesthesiologist's chin on the mask elbow helps to create a better seal between the mask and the patient's face.
Bearded Patient Techniques Achieving a sat isfac tory mask f it is of ten d if f icu lt when the patien t has a beard. One
so lut ion is to shave the beard (33). This is usual ly not acceptab le to the patient.
Another solut ion is to use a supraglottic ai rway device (34).
In some cases, i t may be possible to place the round end of the mask between the
lower l ip and the a lveolar ridge (35). The beard may be covered wi th a c lear
adhesive drape, a def ibri llator pad wi th a ho le cu t in the middle, plastic c ling wrap,
or gel and gauze (36,37,38,39,40,41,42,43). A small mask can be placed over the
nose and the mouth held shut (44).
Mask Ventilation of the Tracheostomy Stoma A Rende ll -Baker-Soucek mask can be used over a tracheotomy stoma to achieve
control led or assis ted vent ilation (8,9). It is placed around the s toma wi th the nasal
port ion poin ting in a caudal di rection so that the mand ibular curve rests on the
tracheal reg ion and the apex on the suprasternal notch.
Difficult Face Mask Ventilation Diff icul t mask vent ilat ion is reported to occur in 5% to 6% of anesthetics (45,46,47).
A varie ty of fac ial charac teris tics (fa t, emaciated, and edentulous faces as wel l as
those wi th prominent nares, burns, f la t noses, receding jaws) or other p rob lems
(dra inage tubes in the nose) wi l l be encountered in c l inical p rac tice. Pred ictors of
diff icul t mask vent ilat ion inc lude male gender, a beard, lack of teeth, age over 55
years , macroglossia , high body mass index, a his tory of snoring , increased
Mal lampati score, and low thyromenta l dis tance (46,47).
A histo ry of s leep apnea does not seem to be a pred ic tive sign of d if f icul t mask
venti lation (48). The ai rway in these patients may be improved by plac ing the head
in the sn if f ing posi tion (49).
The edentulous patient p resents the mos t common prob lem. There is loss of bone
of the alveolar ridge, causing a loss of dis tance between the po in ts where the mask
rests on the mandible and the nose. Furthermore, the buccinator muscle loses i ts
tone in these patien ts . The cheeks sag, creat ing gaps between them and the mask.
Alveolar process resorption resul ts in shrink ing a t the corners o f the mouth . Means
to improve mask f i t inc lude inserting an oral a irway, leaving the patient 's dentures
in p lace, packing the cheeks wi th gauze sponges , and insert ing the inferior margin
of the mask between the g ingiva of the mandible and the lower l ip (50,51).
Pat ients with fac ial deformit ies are part icularly challenging . Mask appl ication wi th
the nasa l project ion poin ted inferiorly has been used for children with certain facial
deformities (3) and fo r patients wi th acromegaly (10).
I f the mask is too smal l wi th an oral airway in place, the oral ai rway should be
removed and a nasal ai rway used. If a mask is too long, the mouth can be
elongated by inserting an oral ai rway.
I f mask venti lat ion is necessary for the patient who has a nasogastric tube in place,
there is usually a leak around the tube as i t ex i ts the side of the mask . This leak
can be improved by adding denture adhesive around the tube at the point where i t
ex its the mask (52).
Dead Space The face mask and its adaptor normally const itute the major part of the mechanical
dead space. Dead space may be decreased by increasing the pressure on the
mask, changing the volume of the cushion, us ing a smaller mask, ex tending the
separation between the insp iratory and expira tory channels close to or into the
mask, or blowing a jet of f resh gas into the mask. The leak induced wi th a poorly
f it ting face mask wi l l reduce the dead space o f the breathing system during
spontaneous venti la tion (53).
Mask Straps A mask strap (mask holder, inhaler re tainer, head strap, head harness, mask
harness, mask retainer, headband, head-res training strap) is used to ho ld the mask
f irmly on the face. Part icular care needs to be pa id to main taining the airway when
us ing a mask s trap because obstruc tion is more l ikely to go unrecognized than
when the mask is being he ld by the anesthesia provider's hand.
A typical mask strap (Fig . 16.8) consists of thin s tr ips arranged in a c i rc le wi th two
or four p rojec tions . The head res ts in the c irc le, and the straps attach around the
mask connector. The straps a t the jaw may tend to pull the jaw pos teriorly.
Crossing the two lower s traps under the chin may resul t in a better f it and
counteract the pul l f rom the upper straps so that there is less tendency for the
mask to creep up above the bridge of the nose (54). The best s trap applica tion is a
matte r of indiv idual pre ference and may be the best resul t of a tr ial -and-error
process (55).
Care must be taken tha t the s traps are no tighter than necessary to achieve a seal
in o rder to avoid pressure damage f rom the mask or the straps. They should be
released periodically and the mask moved sl igh tly. Gauze
P.449
sponges p laced between the straps and the skin wil l help to pro tec t the face f rom
excess ive pressure. Another r isk of using a mask strap is that i t wi l l take longer to
remove the mask if vomit ing or regurgitation occurs.
View Figure
Figure 16.8 Mask straps.
Advantages Using a face mask is associated with a lower incidence of sore th roat and requires
less anesthet ic depth than using a supraglottic device or a tracheal tube. Muscle
relaxants do not need to be used to tolerate the mask. The face mask may be the
most cost-eff ic ient method to manage the airway for short cases (56).
Disadvantages With a face mask, one or more of the anes thesia provider's hands are in continuous
use, and higher f resh gas flows are of ten needed. During remote anes thesia
(magnetic resonance imaging and computerized tomography scanning) ai rway
access is diff icul t. Compared with pat ients who are managed wi th a supraglo tt ic
ai rway device , pat ients who are managed wi th a face mask have more episodes of
oxygen desaturation, require more intraoperat ive airway manipulat ions, and present
more dif f icult ies in maintaining an ai rway (57,58). In spontaneously breathing
patients, the work of breathing is higher wi th a face mask than wi th a supraglo ttic
ai rway device or a trachea l tube (59). Using an a irway and/or cont inuous posi t ive
pressure wi l l reduce the work of breathing.
Complications Skin Problems Dermatit is may occur if the pat ient is al le rgic to the material f rom which the mask is
made (60). The pattern of the dermati tis follows the area of contact between the
mask and skin. Chemical or gas steri l ization of reusable masks can leave a residue
that can cause a sk in reac tion (61,62). Pressure nec ros is under the face mask has
been reported following prolonged mask app licat ion in the presence of hypotension
(1).
Nerve Injury Pressure f rom a mask or mask strap may resu lt in pressure inju ry to underlying
nerves. Forward jaw displacement may cause a s tretching nerve inju ry. Fortunately,
the sensory and motor dysfunct ions reported have been transient
(63,64,65,66,67,68). If excessive pressure on the face or extreme forward jaw
displacement must be exerted, tracheal intubation or a suprag lo tt ic ai rway dev ice
should be considered. The mask should be removed f rom the face periodically and
readjusted to make certa in that cont inuous pressure is not appl ied to one area.
Foreign Body Aspiration The diaphragm of an endoscopic mask may rupture during tracheal tube insert ion,
and a piece may be pushed into the pat ien t's tracheobronchial tree (69,70,71,72).
Other parts of a mask or mask strap may be aspira ted (73,74).
Gastric Inflation When posi tive pressure venti lat ion is used wi th a face mask, gases are likely to
enter the stomach (75,76). I t is recommended that inspiratory pressure be kept
below 20 cm H2O (75).
Eye Injury A corneal abrasion may be caused by a face mask inadvertently placed on an open
eye (77). Chemicals that enter the mask cushion during c leaning and disinfection
can be expelled from cracks in the cushion and come in to contact wi th the eye
when the mask is app lied to the face (78,79,80,81). Pressure on the medial ang les
of the eyes and supraorb ital margins may resul t in eyel id edema, chemos is of the
conjunctiva, pressure on the supraorb ital or supratrochlear nerve, cornea l inju ry,
and temporary blindness f rom central ret inal artery occlusion (82).
Mask Defects A mask wi th a plast ic membrane tha t occluded the connector has been reported
(83). Another mask had a metal
P.450
wi re st icking out of it (84). Incorrect assembly of a face mask has been reported
(85).
Cervical Spine Movement Most but not al l s tudies show tha t mask vent i lat ion moves the cerv ical spine more
than commonly used methods of tracheal intubat ion (86 ,87,88,89). This may be of
s ignif icance in the patient with an uns table cerv ica l spine injury.
Latex Allergy I f rubber is a component of a face mask, a serious reac tion can occur in the pat ient
wi th latex al lergy (90,91). This is discussed more fully in Chapter 15. Because of
the seriousness of this problem, non-latex masks are recommended wherever
possible.
Lack of Correlation between Arterial and End-tidal Carbon
Dioxide The dif fe rence between arte rial and end-tidal carbon dioxide levels is higher wi th
face mask venti lat ion than wi th a trachea l tube or supraglo tt ic device, particularly
wi th small tidal volumes (92).
Environmental Pollution Studies show that using a face mask is associated with greater operating room
pollut ion wi th anesthet ic gases and vapors than when a trachea l tube or
supraglo tt ic airway dev ice is used (93 ,94). Po llut ion can be reduced by using a
c lose active scavenging dev ice (95,96).
User Fatigue Holding a mask securely onto the face and at the same time main taining the correc t
jaw posi tion can be dif f icult and may resul t in operator fatigue. Fai lure to main tain
the correc t jaw posi tion may resul t in loss of ai rway patency or gas tric dis tention.
Jaw Pain Pos toperative jaw pain is more common af te r mask anesthesia than when a
supraglo tt ic airway dev ice is used (97).
Airways
Purpose A fundamental responsib il i ty of the anesthesia provider is to maintain a patent
ai rway. Unl ike other maneuvers to maintain a patent a irway, such as chin l if t , jaw
thrust, and tracheal intubation, cerv ical spine movement does not occur when an
ai rway is inserted (98).
Figure 16.9A shows the normal unobs tructed ai rway in a supine patient. The airway
passage has a rigid posterior wall , supported by the cerv ical vertebrae, and a
co llaps ib le anterio r wal l, consis ting of the tongue and epiglo tt is . Figure 16.9B
shows the most common cause of ai rway obstruc tion. Under anes thesia, the
muscles in the f loor of the mouth and pharynx support ing the tongue relax, and the
tongue and epiglottis fal l back into the pos terior pharynx, occluding the airway. The
purpose of an ai rway is to l i f t the tongue and epiglottis away f rom the posterio r
pharyngea l wal l and prevent them from obstructing the space above the larynx .
Using maneuvers such as dors if lex ion at the atlanto-occipi ta l jo in t and protrusion of
the mandible anteriorly may s ti l l be necessary to ensure a patent airway (99). An
oral or nasa l ai rway decreases the work of b reathing during spontaneous breathing
us ing a face mask (59).
View Figure
Figure 16.9 A: The normal airway. The tongue and other soft tissues are forward, allowing an unobstructed air passage. B: The obstructed airway. The tongue and epiglottis fall back to the posterior pharyngeal wall, occluding the airway. (Courtesy of V. Robideaux, M.D.)
Types Oropharyngeal Airways Figure 16.10 shows an oropharyngeal (oral) airway in place. The bi te portion is
between the teeth and lips , and the flange is outside the l ips . The pharyngeal end
rests between the posterio r wal l of the pharynx and the
P.451
base of the tongue and, by exert ing pressure along the base of the tongue, also
pulls the epig lo tt is forward .
View Figure
Figure 16.10 Oropharyngeal airway in place. The airway follows the curvature of the tongue, pulling it and the epiglottis away from the posterior pharyngeal wall and providing a channel for air passage. (Courtesy of V. Robideaux, M.D.)
In addi tion to helping to maintain an open ai rway, an oropharyngea l ai rway may be
used to prevent a pat ient f rom bi ting and occluding an oral tracheal tube, p rotect
the tongue f rom bi ting, fac il i tate oropharyngeal suct ioning, obta in a better mask f it ,
or p rov ide a pa thway for insert ing dev ices in to the esophagus or pharynx (100).
Oral ai rways have not been associated with an increased inc idence of sore throat
or o ther symptoms (101,102) or bacteremia (103).
Description An oropharyngeal ai rway (Fig. 16.11) may be made of elastomeric material o r
plast ic . I t has a f lange at the buccal end to prevent i t f rom moving deeper into the
mouth. The f lange may a lso serve as a means to f ix the ai rway in place. The bite
port ion is straigh t and f its between the teeth or gums. I t mus t be f i rm enough that
the pat ient cannot c lose the lumen by b it ing. The curved portion ex tends backward
to correspond to the shape of the tongue and palate.
View Figure
Figure 16.11 Oropharyngeal airway. All oral airways have a flange to prevent overinsertion, a straight bite block portion, and a curved section.
The American national s tandard (104) specif ies that the size of ora l ai rways be
designated by a number that is the length in centimeters (Fig. 16.11).
Specific Airways Guedel Airway The Guedel airway (Fig . 16.12) has a large f lange, a reinforced b ite portion, and a
tubular channel. Modif icat ions to a id f lex ib le f iberoptic intubation have been
described (105,106,107,108).
Berman Airway The Berman ai rway (Figs . 16.10, 16.11) has a center support and open sides. The
center support may have openings . There is a f lange at the buccal end. The s ide
opening can be opened wider to engage or disengage a tracheal tube.
Patil-Syracuse Endoscopic Airway The Patil-Syracuse endoscopic a irway was designed to aid f iberoptic intubat ion
(109). I t has late ral channels and a central groove on the l ingual surface to al low a
f iberscope wi th a tracheal tube to pass. A s lit in the dista l end allows the f iberscope
to be manipulated in the anteroposterio r di rec tion but
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l imi ts lateral movement (110). I t is made from aluminum. The ai rway must be
removed f rom the oropharynx before a tracheal tube can be advanced over the
f iberscope and into the g lott is .
View Figure
Figure 16.12 Guedel airways. The bite portions are color coded to provide easy identification of size. (Courtesy of Mercury Medical.)
View Figure
Figure 16.13 Williams airway intubators. (Courtesy of Mercury Medical.)
Williams Airway Intubator The Wi ll iams ai rway intubator was designed for b lind orotracheal intubations
(111,112,113). It can also be used to aid f iberopt ic intubat ions or as an oral airway
(114).
The airway, shown in Figure 16.13, is p lastic and avai lable in two s izes, #9 and
#10, which wi l l admit up to an 8.0 or 8.5 in ternal diameter (ID) t racheal tube,
respectively. The tracheal tube connector should be removed during intubation,
because i t wi l l not pass through the airway unless the a irway is modif ied (115). The
proximal half is cylindrical , whi le the distal half is open on its l ingual surface.
A comparison of the Wi ll iams airway intubator wi th the Ovassapian f iberoptic
intubat ing airway found that the Wil l iams airway intubator provided a better v iew of
the glott is in a s ignif icant number of patients (116).
Ovassapian Fiberoptic Intubating Airway The Ovas-sapian f iberoptic intubating a irway (F ig. 16.14) was designed to del iver a
f iberscope as c lose to the larynx as poss ib le (110). It has a f lat l ingual surface that
gradually widens at the distal end. At the bucca l end are two vert ical s idewalls .
Between the sidewalls is a pair of guide wal ls that curve toward each other. The
guide wa lls are f lex ible and permit the ai rway to be removed f rom around the
tracheal tube. The prox imal half is tubu lar so that i t can func tion as a bi te block .
The distal half is open pos teriorly. I t wi l l accommodate a tracheal tube up to 9 .0
mm ID. Placing a black l ine along the midd le of the ai rway helps to identify the
midline and fac il i tates advancing the f lex ib le endoscope (117,118,119).
View Figure
Figure 16.14 Ovassapian fiberoptic intubating airway. (Courtesy of A. Ovassapian, M.D.)
View Figure
Figure 16.15 Berman intubation pharyngeal airways.
A comparison of this ai rway with the Wi ll iams airway intubator and the Berman
intubat ing airway (see below) found tha t both other ai rways provided a good v iew o f
the glott is (116,120).
Berman Intubating/Pharyngeal Airway The Berman intubat ing/pharyngeal a irway (Berman II) (Fig. 16 .15) is tubular along
i ts en ti re length. I t is open on one s ide so that i t can be sp li t and removed from
around a tracheal tube. I t can be used as an oral airway or as an aid to f iberoptic
or b lind orotracheal intubation (121). When the f iberscope is in the a irway, the t ip
cannot be bent, l imi ting scope maneuverabil ity. Part ially wi thdrawing the ai rway wi l l
improve maneuverabil i ty (110).
One study found that the Berman ai rway offered an advantage over tongue
retraction for f iberoptic intubation (122). Comparison wi th the Ovassapian
intubat ing airway found that the Berman ai rway o ffers somewhat easier
v isualiza tion of the cords (120). However, if the tracheal tube impinges on the
ai rway, i t is more di ff icul t to complete the intubat ion wi th the Berman ai rway.
Manipu lat ing the Berman ai rway in place can lead to successful trachea l in tubat ion
(120).
Use Pharyngeal and laryngea l ref lexes should be depressed before an oral ai rway is
inserted to avoid cough ing or laryngospasm.
Selec ting the correc t size is important. Too smal l an a irway may cause the tongue
to k ink and fo rce part of
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i t agains t the roof of the mouth, causing obs truction. Too large an ai rway may
cause obs truct ion by displacing the epiglottis posterio rly and may traumatize the
larynx. The correc t s ize can be estimated by holding the ai rway next to the patien t's
mouth. The tip should rest cephalad to the angle of the mandible. The best c ri te ria
for proper s ize and posit ion are unobstructed gas exchange. I f the airway
repeated ly comes out of the mouth , it shou ld be removed and a smaller s ize tr ied.
View Figure
Figure 16.16 Insertion of oral airway. The airway is inserted 180° from the final resting position.
Wetting or lubricating the ai rway may fac il i tate insertion. The jaw is opened wi th
the lef t hand. The tee th or gums are separated by pressing the thumb against the
lower teeth or gum and the index or thi rd f inger against the upper teeth or gum.
One method to insert an ai rway is shown in Figure 16.16. The a irway is inserted
wi th i ts concave s ide fac ing the upper l ip . When the junct ion of the b ite portion and
the curved sect ion is near the inc isors, the ai rway is rotated 180° and s lipped
behind the tongue into the f inal posi tion. If res istance is met during insertion , it can
usual ly be overcome by a jaw thrust.
An al te rnate method of insert ion is shown in F igure 16.17. A tongue blade is used
to push forward and depress the tongue. The ai rway is inserted wi th the concave
s ide toward the tongue. As i t is advanced, it is ro tated to s lide around behind the
tongue.
I f the a irway has been used to faci l i ta te f iberoptic intubat ion, i t may be bette r to
remove the ai rway after the f iberscope has entered the trachea because the airway
might prevent the tracheal tube f rom passing into the trachea (123).
Bite Block A bi te block (gag, mouth prop, bi te protector) is placed between the molar teeth or
gums but not the inc isors (124). It is intended to prevent the teeth from bit ing on a
tracheal tube, supraglo tt ic a irway dev ice, f iberscope, or other device. Not on ly wi l l
i t protect these devices, but i t may also avoid dental in jury (125). A bi te block is
also used during elec troconvulsive therapy and in unconscious indiv iduals to
protect the tongue and lips. An oral ai rway should not be used for these purposes
(124,126,127). It is ineffec tive and may be harmful to the patient in this role
because a ll the power of the bi te is concentrated on the inc isors, which are not
designed for this pressure and are l iable to break or loosen. Because a bite block
does not extend in to the pharynx, it is usually less i rri ta ting than an oral ai rway.
View Figure
Figure 16.17 Alternative method of inserting an oral airway. A tongue blade is used to displace the tongue forward.
A varie ty of bite blocks have been developed (Figs. 16.18,16.19,16.20). Some have
a channel for gas to pass. Many have an a ttached string that can be p inned to the
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patient 's gown or taped to the sk in so that it can be easily retr ieved. The curved
port ion of an ora l ai rway can be removed, leaving the remaining port ion as a bi te
block (128,129). A gauze roll is soft and allows pressure to be distribu ted over
several teeth (127). A bi te b lock may be part of a device used to secure a tracheal
tube.
View Figure
Figure 16.18 Bite block. This is placed between the teeth or gums (preferably in the molar area) to prevent occlusion of a tracheal tube or damage to a fiberoptic endoscope or to keep the mouth open for suctioning.
View Figure
Figure 16.19 This bite block is designed to be placed between the molar teeth with the flat portion extending toward the side of the face. The flat portion is used to grip for insertion and removal. (Picture courtesy of Hudson RCI.)
A bi te block may become deformed so that it does not p revent bi t ing (130). A bi te
block may be aspira ted (130).
Nasopharyngeal Airways A nasopharyngeal airway (nasal ai rway, nasal trumpet) is shown in posi tion in
Figure 16.21. When fully inserted, the pharyngeal end should be below the base of
the tongue but above the epiglottis (131).
A nasal ai rway is be tter tole rated than an oral ai rway if the patient has intact ai rway
ref lexes. I t is p referable to use a nasal airway if the pat ien t's teeth are loose or in
poor condit ion or there is trauma or pathology of the oral cavi ty . It can be used
when the mouth cannot be opened.
View Figure
Figure 16.20 Oberto mouth prop, which is used for protecting the teeth during electroconvulsive therapy. (Courtesy of Rusch, Inc.)
View Figure
Figure 16.21 The nasopharyngeal airway in place. The airway passes through the nose and extends to just above the epiglottis. (Courtesy of V. Robideaux, M.D.)
Contraindicat ions to us ing a nasopharyngeal ai rway inc lude ant icoagula tion; a
basilar skul l f rac ture; pathology, seps is , or deformity of the nose or nasopharynx;
or a history of nosebleeds requ iring medical treatment. There is no ev idence that
nasal airways cause s ign if icant bacteremia (103,132).
Nasopharyngeal airways have been used during and after pharyngeal surgery
(133,134), in infan ts wi th Pierre Rob in syndrome (135), to app ly continuous posit ive
ai rway pressure (CPAP) (136), to fac i li tate suct ioning (137), as a guide for a
f iberscope (137), to treat s ingultus (hiccups), as a guide fo r a nasogastric tube
(138,139), to dilate the nasal passages in preparat ion for nasotrachea l intubation
(138) and as a means to main tain the airway and admin ister anes thesia during
denta l surgery (140).
A nasopharyngeal airway can be fi tted wi th a tracheal tube connector and used with
an anesthesia breathing sys tem (141,142,143,144,145,146,147,148). These dev ices
have been used to maintain vent i lation during oral fiberopt ic endoscopy (109) and
to admin is ter cont inuous posi tive pressure (136). Environmental gas contaminat ion
may be a problem with this techn ique (149).
Description A nasopharyngeal airway resembles a shortened tracheal tube wi th a f lange at the
outer end to prevent i t f rom completely pass ing into the naris . Some airways come
wi th a safety pin that can be inserted in to the flange or ai rway wa ll (150). The
f lange is movable on some models . The American standard (104) requ ires that the
s ize of a nasopharyngeal ai rway be designated by the inside diameter in
mi ll imeters.
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View Figure
Figure 16.22 Nasopharyngeal airways. The one on the right does not contain latex.
Specific Airways A varie ty of nasopharyngeal airways are ava ilable. Some are shown in Figure
16.22 .
Linder Nasopharyngeal Airway The Linder nasopharyngea l (bubble-tip) ai rway is shown in F igure 16.23. It is
plast ic with a large f lange (151,152). The distal end has no bevel . The ai rway is
suppl ied wi th an introducer, which has a balloon on its tip. The bal loon can be
inf lated and def lated by attaching a syringe to the one-way v alve at the other end of
the in troducer.
View Figure
Figure 16.23 Linder nasopharyngeal airway. (Courtesy of Polamedco, Inc.)
Before insert ion, the introducer is inserted into the ai rway unt i l the t ip of the
balloon is just pas t the end. Air is in jected unti l the bal loon t ip is inf lated to
approximately the outs ide diameter of the tube. The complete assembly is
lubricated and then inserted through the nos tri l . Af te r it is in p lace, the balloon is
deflated and the introducer removed.
Cuffed Nasopharyngeal Airway The cuffed nasopharyngea l (pharyngeal) airway is s imilar to a short cuffed tracheal
tube (147,148,153). I t is inserted through the nose into the pharynx, the cuff is
inf lated, and then is pulled back unt i l res is tance is fel t.
Binasal Airway The binasal a irway (F ig. 16.24) consists of two nasal ai rways jo ined together by an
adaptor fo r attachment to the breath ing system
(154,155,156,157,158,159,160,161). I t can be used to administer anesthesia or to
provide CPAP to babies.
Insertion The diameter of the nasa l ai rway should be the same as needed to insert a trachea l
tube (0 .5 to 1 mm smal le r than for an ora l tracheal tube).
View Figure
Figure 16.24 Binasal airway. (Courtesy of Rusch, Inc.)
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View Figure
Figure 16.25 Insertion of a nasal airway. A: Correct method. The airway is inserted perpendicularly, in line with the nasal passage. B: Incorrect method. The airway is being pushed away from the air passage and into the turbinates.
Before insert ion, the nasal ai rway should be lubricated thoroughly along i ts en ti re
length. Each side of the nose should be inspected for s ize, pa tency, and the
presence of polyps. A vasoconstric tor may be appl ied before insert ion to reduce
trauma.
The nasopharyngeal ai rway shou ld be inserted as shown in Figure 16.25A. The
ai rway is he ld wi th the bevel against the septum and gently advanced posterio rly
whi le being rotated back and fo rth. I f res is tance is encountered during insert ion ,
the other nostri l or a smal ler size ai rway should be used. F igure 16.25B shows an
incorrect method for insert ing the ai rway. The a irway is being pushed toward the
roof of the nose.
The airway may be adjus ted to fi t the pharynx by s liding i t in or out. If the tube is
inserted too deeply, laryngeal ref lexes may be stimu lated ; if too short, ai rway
obstruct ion wil l not be relieved. Al though the correct nasal airway length fo r a
patient correlates with s imple external measurements of the face and neck, s tudies
indicate a correlat ion only with the patient 's height (131).
Complications Airway Obstruction The t ip of an ai rway can press the epiglo tt is o r tongue against the pos terior
pharyngea l wal l and cover the laryngeal aperture (162,163). With a nasopharyngea l
ai rway, neck movement in rotat ion or anteropos teriorly may resul t in the lumen
becoming obstructed (164). The use of a fenestrated ai rway may overcome this
problem. The nasopharyngeal ai rway lumen may be compressed ins ide the nose
(131).
A foreign body can enter an airway and cause complete or partial obstruc tion
(165,166). In one case, the plast ic packaging became s tretched over the end of the
ai rway, causing obstruct ion (167).
I f a nasopharyngeal a irway perfo rates the re tropharyngeal space, the space may
expand and cause a irway obs truct ion (168).
Trauma Inju ry to the nose and posterior pharynx is a po tential compl ication of nasa l
ai rways. Epis taxis is usual ly self -l imit ing but can present a serious prob lem in some
patients. To control severe nasal and nasopharyngeal b leeding, an epis taxis a irway
(Fig . 16.26) can be used. Pharyngeal perforat ion and retropharyngeal abscess
formation can occur (168). The lip or tongue may be caught between the teeth and
an oral a irway.
Tissue Edema
Facial, neck , or tongue edema, either uni lateral or bilateral, can occur fol lowing
surgery, especially in the s i t ting pos ition, and can resul t in a irway obs truction
(169,170,171,172,173). Pressure f rom an oral ai rway may be a
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contribut ing factor. To prevent th is compl ica tion, the oral airway should not be lef t
in p lace fo r an extended period . A bite block should be used ins tead. Excess ive
head or neck flexion should be avoided, and the head and neck should be checked
f requently during long cases for edema or ecchymoses. Uvular edema possibly
caused by the uvula becoming entrapped between the hard pa late and an
oropharyngea l ai rway has been reported (174). Another patient developed
temporary deafness secondary to edema of the uvula and soft pala te following
prolonged nasopharyngeal ai rway use (175). Transien t sal ivary gland swel l ing may
occur wi th oral airway use (176,177).
View Figure
Figure 16.26 Epistaxis airway. This is inserted into the nose and inflated to provide local pressure on the bleeding site. It is available in several sizes. (Courtesy of Rusch, Inc.)
Ulceration and Necrosis Ulcerat ion of the nose or tongue can occur if an ai rway remains in place for a long
period of t ime (178).
Central Nervous System Trauma The use of a nasal ai rway in a patient wi th a basi lar skull f racture can resu lt in i ts
entering the anterior cranial fossa (179,180).
Dental Damage
Teeth can be damaged or avulsed if the patient bites down hard on an oral a irway
(181,182,183). An oral ai rway should be avo ided if there is ev idence of periodontal
disease, teeth weakened by caries or res torat ions, c rowns, f ixed partial dentures,
pronounced proclination (the front tee th having a forward inc l inat ion and
overlapp ing the lower f ront teeth), or isolated tee th. In these cases , the use of a
nasopharyngea l ai rway and/or a bi te block between the back teeth may be
preferable .
Laryngospasm and Coughing Inserting an ai rway before adequate anesthet ic depth is es tablished may cause
coughing or laryngospasm, especial ly if the ai rway contacts the epig lo tt is or voca l
cords .
Retention, Aspiration, or Swallowing Part or a ll of an ai rway may become disp laced into the pharynx, tracheobronchial
tree , or esophagus (184,185,186,187,188,189,190,191). Placing a safety pin
through the nasal ai rway f lange may prevent i t f rom sl ipping into the nose (192).
Devices Caught in Airway In one case, a cuff became detached when an esophageal s tethoscope was
removed f rom a pat ient wi th an oral airway in place (193). It was postulated that the
cuff became caught in the side grooves of the a irway. Another case was reported
where a fiberscope inadvertent ly traversed a fenes trated ora l ai rway, making i t
impossib le to pass a tracheal tube (194).
Equipment Failure An oral ai rway may fracture at the connection between the b ite portion and the
curved sect ion (195,196,197). A defect in the Wi l liams intubat ing airway that could
tear the tracheal tube cuff has been reported (198).
Latex Allergy I f an ai rway contains la tex , a severe react ion may occur i f the patien t is sensi t ive to
latex (90). Non-latex oral and nasal airways are readi ly identif ied and available.
Chapter 15 provides more details on latex al lergy.
Gastric Distention A nasopharyngeal airway that is too long may enter the esophagus wi th resu ltant
gastric d is ten tion (131).
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P.460
Questions For the fol lowing quest ions, answer
• i f A, B, and C are correct
• i f A and C are correct
• i f B and D are correct
• is D is correct
• i f A, B, C, and D are correct.
1. Complications associated with use of a face mask include
A. Movement of the cerv ical spine
B. Facial nerve injury
C. Chemical i rr itation o f the eyes
D. Sinus itis
View Answer2. Which maneuvers can be used to secure a patent airway?
A. Jaw thrust
B. Posterior protrusion of the mandible
C. Chin l if t
D. Posterior f lexion of the atlan to-occipital jo int
View Answer3. Airways developed to aid in fiberoptic intubation include
A. Patil-Syracuse
B. Wi ll iams
C. Ovassapian
D. Guedel a irway
View Answer4. Contraindications to nasal airways include A. Hemorrhagic disorders
B. Sepsis
C. Basilar skul l f racture
D. Se izure disorders
View Answer5. Which external measurements correlate with the proper length of a nasal airway? A. Tip of nose to 2 cm above the thyroid carti lage
B. The dis tance from the tip of the thumb to the t ip of the index f inger measured to
the hand and back
C. Tip of the earlobe to cricoid carti lage
D. The patien t's height
View Answer6. Complications associated with the use of oral airways include A. Swell ing of the tongue
B. Edema of the uvula
C. Ulcerat ion of the tongue
D. Swallowing of the ai rway
View Answer7. Predictors of difficult mask ventila tion include
A. High body mass index
B. Age over 65 years
C. History of snoring
D. History of s leep apnea
View Answer8. Techniques to improve mask fit in the edentulous patient include A. Packing the cheeks wi th gauze sponges
B. Not removing the dentures
C. Insert ing the infe rior margin of the mask between the gingiva of the mandib le
and the lower l ip
D. Us ing a nasal airway
View Answer