Methods to Improve Success With the
GlideScope Video Laryngoscope
Darrell Nemec, CRNA, DNAP
Paul N. Austin, CRNA, PhD
Loraine S. Silvestro, PhD
Occasionally intubation of patients is difficult using a
video laryngoscope (GlideScope, Verathon Medical)
because of an inability to guide the endotracheal tube
to the glottis or pass the tube into the trachea despite
an adequate view of the glottis. We examined methods
to improve success when this difficulty occurs.
A literature search revealed 253 potential sources,
with 25 meeting search criteria: 7 randomized controlled trials, 4 descriptive studies, 8 case series, and 6
case reports. Findings from the randomized controlled
trials suggested that using a flexible-tipped endotracheal tube with a rigid stylet (GlideRite, Verathon
Medical) improved intubation success, whereas other
methods did not, such as using a forceps-guided
endotracheal tube exchanger. If a malleable stylet was
T
he video laryngoscope is used to facilitate
endotracheal intubation in cases of a suspected or unanticipated difficult airway.1
The GlideScope video laryngoscope (GSV;
Verathon Medical) was introduced in 2001
and provides direct visualization of the larynx in patients
with a potentially difficult airway. The GlideRite stylet
(GRS; Verathon Medical) is placed into the endotracheal
(ET) tube to help direct the ET tube through the glottic
opening.2,3 Despite the success of the GSV as an intubation device,4-8 there have been reports of problems,
including failure to successfully intubate patients.5
A high-grade Cormack and Lehane9 view due to excessive GSV advancement resulting in the camera being
close to the vocal cords can impede directing the ET tube
through the glottic opening. Problems due to excessive
GSV advancement include little room for the GSV and
the ET tube, decreased field of view, and distortion of
the anatomy, such as creating a sharp laryngeal angle
in relation to the trachea.10 Even when the GSV is not
advanced excessively, there can be problems in passing
the ET tube into the trachea.5 We examined methods of
facilitating the passage of the ET tube into the trachea
under these conditions.
Materials and Methods
•The Clinical Question. The PICO (population, intervention, comparison, outcome) question11 guiding the
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used, a 90° bend above the endotracheal tube cuff was
preferable to a 60° bend. Evidence from lower-level
sources suggested that several interventions were
helpful, including using a controllable stylet, a fiberoptic bronchoscope in conjunction with the GlideScope,
or an intubation guide, and twisting the endotracheal
tube to facilitate passage into the trachea. Providers
must consider the risks and benefits of any technique,
particularly if the device manufacturer does not recommend the technique. Further rigorous investigations
should be conducted examining methods to increase
success.
Keywords: Airway, anesthesia, complications, GlideScope, video laryngoscope, video laryngoscopy.
search for evidence was as follows: In patients undergoing video laryngoscopy with the GSV where there is
adequate visualization of the glottic opening, what additional maneuvers help improve intubation success?
•Search Strategy. A search was conducted using the
following search engines (2001 to 2014): PubMed, the
Cochrane Library, SUMSearch, the GSV operator and
service manual from Verathon Medical, and professional
and governmental websites. The authors examined the
reference lists of obtained sources for other potential
sources of evidence.
The following keywords and keyword strings were
used alone or in combination: difficult intubation, failed
intubation, GlideScope video laryngoscope, intubation failures with the GlideScope video laryngoscope, difficult intubation techniques using the GlideScope, Parker Flex-Tip
endotracheal tube, GlideScope-assisted fiberoptic intubation,
and trauma associated with the use of the GlideScope.
The following were the inclusion criteria: systematic
reviews, randomized controlled trials (RCTs), observational studies, cases series, and case reports involving
human subjects published in the English language, in
peer-reviewed journals in full-text form or on a professional specialty website addressing the PICO question.
Lower-level evidence such as observational studies, case
series, and case reports were included because of the
nature of the problem. Evidence where a video laryngoscope was used other than the GSV was considered
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because of the similarities between these devices. The
evidence was appraised and classified by level according to the method proposed by Melnyk and FineoutOverholt.12 The hierarchy of evidence described in this
method ranges from level I (systematic review or metaanalysis of randomized controlled trials) to level VII
(expert opinion).
Results
Two hundred fifty-two sources were found, and after
a review of the sources and removal of any duplicates,
25 met the inclusion criteria (Tables 1 and 2).13-37 All
the techniques described in Table 2 were reported to be
successful. There were 7 RCTs15,17-21,23 with a total of
750 subjects (ranging from 5821 to 19615 per study) and
4 descriptive studies13,14,16,22 totaling more than 1,029
subjects (from 16 to greater than 500 subjects in each
study); there also were 8 cases series24-31 (41 subjects,
ranging from 429,31 to 1328 per study with the number
not specified in 3 articles26,27,30) and 6 case reports.32-37
Five of the RCTs were conducted outside the United
States.15,17,18,20,23 All investigators randomly assigned
subjects to control or intervention groups,15,17-21,23 and
in 2 studies19,21 the authors used a randomized block
design to control for potential confounders such as
operator experience. There was at least partial blinding
of operators and observers in 5 of the studies,15,17,19-21
no blinding in 1 study,23 and the authors of the other
RCT18 did not comment on blinding. The sample size
in 5 of the studies was determined using a power analysis,15,17,20,21,23 in 1 study the sample size was described
as “appeared reasonable”,19 and the other RCT18 did not
comment on the method of sample size determination.
The subjects in the control and intervention groups
overall were comparable.15,17-21,23
All the subjects in 5 RCTs were assessed preoperatively as not being difficult to intubate (normal
airway),15,17,18,20,21 and most of the subjects in another
study19 were assessed as having a normal airway. A difficult airway was simulated in the final study by placing
a semirigid cervical collar on the subject and strapping
the subject’s head to the bed.23 Operators were described
as experienced,17,19,21 novice,20 and heterogenous,15 but
some authors18,23 did not indicate operator experience.
All subjects were intubated after induction of general anesthesia and administration of a muscle relaxant.15,17-21,23
Of the 4 descriptive studies,13,14,16,22 most described
the respective interventions as being effective.13,14,16 None
of the authors discussed blinding, and usually they did
not discuss sample size determination13,14,16; however,
the authors of 1 study22 performed a power analysis to
determine the required sample size. Subject airways were
assessed preoperatively as being normal,16 normal and
abnormal,13,14 or potentially difficult. Operator’s experience was most often not described.13,14,16 Subjects were
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intubated after induction of general anesthesia,13,16 or
the anesthetic technique was not described.14,22 All but 1
study lacked a control group.22
Of the 8 cases series,24-31 4 reports27-29,31 originated
from outside the United States. None of the authors discussed blinding and sample size determination. Subjects’
airways were assessed preoperatively as being normal and
abnormal25,26,31 or potentially difficult,28,29 and airway
status was not indicated in 3 sources.24,27,30 Operator’s
experience was often not described.25,26,28,29 The subjects
were intubated after induction of general anesthesia24,26,31
or sedation and administration of topical anesthetic to
the airway26,28; in 4 reports, the anesthetic technique was
not described.25,27,29,30 The authors of all the case series
reported that the interventions were effective, suggesting
the possibility of publication bias.24-31
All but 134 of the 6 case reports32-37 were from the
United States. Subjects’ airways were assessed preoperatively as normal35 or potentially difficult33,34,36,37 and
were not described in 1 source.32 Authors of 5 of the
reports33-37 stated they used the described intervention
after failure using a standard laryngoscope or GSV or
both, and the technique described was successful. Most
subjects were intubated after induction of general anesthesia and administration of a muscle relaxant.32,33,35-37
Authors of only 1 study described the operator’s experience.35 Interventions described included using alternatives to the GRS such as an intubation guide,32,37 using a
malleable stylet shaped to the GSV blade and rotating the
ET tube after passing below the glottic opening,35 GSVassisted fiberoptic bronchoscope intubation (FOBI),33,34
or GSV-assisted FOBI with the ET tube bevel facing
posteriorly.36
Discussion
•Stronger Evidence. The highest level of evidence was
from 7 RCTs.15,17-21,23 Below is a summary of these findings.
•Malleable Stylet With 90° Bend Formed 8 cm From
the Tip Compared With GlideRite Stylet. Using an ET tube
with an acute bend was proposed to improve intubation success by increasing the ability to advance the ET
tube through the glottic opening. Authors of 2 studies
compared using a malleable stylet with a 90° bend
formed 8 cm from the tip with the GRS.17,20 Operators
were described as expert17 or novice.20 Authors of these
studies17,20 reported a difference between the stylets in
outcomes, including time to intubation, ease of intubation, Cormack and Lehane grade view, number of attempts, and number of laryngeal manipulations. Some
authors reported that operators voiced more dissatisfaction when using the GRS.17
•Endotracheal Tube With a Malleable Tip Compared
With GlideRite Stylet. Investigators of 1 study compared
an ET tube with a malleable tip shaped into a “J” with
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the GRS.18 Avoiding the use of the GRS was proposed to
lessen the risk of airway injury. The only significant difference reported was the mean time to intubation favoring the GRS by 8 seconds. Intubation was unsuccessful
in 2 subjects, who subsequently were intubated using the
GRS. This study may have been underpowered.
•Endotracheal Tube Forward or Reverse Camber
Loaded on Malleable Stylet Compared With 60° or 90°
Bend. Investigators of 1 study compared an ET tube
loaded (forward or reverse camber; Figures 1 and 2) on
a malleable stylet with a 60° bend compared with an ET
tube loaded (forward or reverse camber) on a malleable
stylet with a 90° bend.15 The reverse camber loading was
proposed to overcome the problem of the tip of ET tube
hitting the anterior tracheal wall and the 90° bend to facilitate directing the ET tube through the glottic opening.
The camber had no impact on time to intubation. The
mean time to intubation was significantly less with use
of the malleable stylet with a 90° bend (47.1 seconds vs
54.4 seconds). The use of a stylet with a 90° bend also
resulted in significantly increased ease of intubation and
less use of external laryngeal manipulations. Evidence
found incidentally suggested using a jaw thrust, but not
laryngeal manipulations such as cricoid pressure, may
aid in directing the ET tube through the glottis.38
The other authors19 compared using a reverse camber
loaded (they termed it “reverse loaded”) ET tube on
a malleable stylet with a 60° or 90° bend. Fifty-one of
60 subjects were successfully intubated using the stylet
with 90° bend compared with 51 of 60 subjects successfully intubated using the stylet with 60° bend (odds ratio
10.41, P < .05). All subjects in the 60° bend group were
subsequently successfully intubated using a stylet with a
90° bend. They reported a greater ability in reaching the
glottic opening using the 90° bend.
•Flexible-Tip Compared With Standard Endotracheal
Tube (Both Loaded on GlideRite Stylet). Investigators21
compared an ET tube with a flexible tip (Parker FlexTip, Parker Medical) with a conventional ET tube with
both loaded on a GRS. This tube improved the ease of
intubation during suboptimal conditions, likely because
it incorporates a 37° bevel facing posteriorly and its tip
has the added flexibility to help it glide over the airway
structures (Figure 3). Using a randomized block design
to help control for operator experience, the authors reported a shorter mean time to intubation (defined as the
time from optimal glottic view via the GSV to the ET tube
passing through the glottis) with the flexible-tip ET tube
(8.2 vs 14.2 seconds, P < .005). Operators also reported
significantly greater ease of intubation with the flexibletip ET tube. The flexible tip may allow the ET tube to
better follow the contour of the trachea, especially when
the ET tube tip passes through the glottic opening but
encounters the anterior tracheal wall.
•Endotracheal Tube Exchanger Placed Into Trachea
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With the Aid of Vascular Forceps Compared With GlideRite
Stylet. There was no significant difference in intubating
the subject on the first attempt or the time to intubation
between the groups (stylet- or forceps-guided ET tube
exchanger).23 There was a higher incidence of postoperative sore throat with use of the GRS.23
•Weaker Evidence. The evidence from descriptive
studies13,14,16,22 or case series24-31 is weaker evidence.
Interventions examined included using the GSV in
combination with a fiberoptic bronchoscope,16,24,28 the
GSV22,25,26 or a similar device14 with a malleable stylet
rather than the GRS, a controllable stylet,27 or the GSV
with an intubation guide rather than the GRS.13,29-31 Case
reports32-37 represent even weaker evidence. Authors of
case reports employed alternatives to the GRS such as an
intubation guide,32,37 a malleable stylet with rotation of
the ET tube after passing it below the glottic opening,35
GSV-assisted FOBI,33,34 and GSV-assisted FOBI with ET
tube bevel facing posteriorly.36 Below is a summary of
these findings.
•Controllable Stylet. Authors from Japan reported
using a stylet with a controllable tip to help maneuver
the ET tube anteriorly to the glottic opening.27 The stylet
allowed the operator to direct the ET tube posteriorly to
help prevent the ET tube from impacting the anterior
airway structures as it passed through the glottic opening
into the trachea.
•GlideScope-Assisted Fiberoptic Bronchoscopic
Intubation. Authors of 3 studies16,24,28 reported success
using GSV-assisted FOBI. This technique was described
as a teaching tool when the patient is under general anesthesia,24 for awake intubation in difficult-to-intubate
situations,28 and in scenarios where the glottic view is adequate but there is difficulty in passing the ET tube into
the trachea.16 Authors of 3 case reports reported similar
findings.33,34,36 The controllable fiberoptic bronchoscope
allows its passage through the glottic opening into the
trachea. Unlike a styleted ET tube that can impact the
anterior tracheal wall, the fiberoptic bronchoscope can
be directed posteriorly, facilitating its placement into the
trachea. The ET tube can be passed over the fiberoptic
bronchoscope into the trachea. Orienting the ET tube
with the bevel facing posteriorly may further faciliate
passage of the ET tube.36 Figure 4 demonstrates the GSVassisted FOBI procedure using a manikin.
•GlideScope or Similar Device With Malleable Stylet
Rather Than GlideRite. Authors of a large retrospective
descriptive study suggested a higher success rate using
the GRS compared with a malleable stylet in an emergency department setting.22 Other authors reported success
using a malleable stylet.14,25
A J-shaped malleable stylet was used in 12 subjects
(2 with a suspected difficult airway).25 The investigators
reported that this stylet is more effective compared with
a stylet with a single 60° bend. The authors also recom-
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Evidence
type/level of
evidencea
40
N
“C”-shaped intubating
guideb
Intervention
Dupanović et
al,19 2010
RCT/level II
120
60
RCT/level II
Phua et al,18
2009
16
78
Descriptive study/
level VI
Greib et al,16
2007
196
Turkstra et al,17 RCT/level II
2007
RCT/level II
Jones et al,15
2007
ETT “reversed-loaded”
on MS with 60° bend vs
ETT “reversed-loaded”
on MS with 90° bend;
MS bent just above
cuff to the specified
angle against the natural
concave ETT curve
GRS vs ETT with
malleable distal tip in
“J” shapeg
GRS vs MS with 90°
bend formed 8 cm
from tip
Rigid video
laryngoscopee-assisted
FOI with patient under
general anesthesia
MS with 60° bend
(ETT loaded forward
or reverse camber)
vs MS with 90° bend
(ETT loaded forward or
reverse camber)
Descriptive study/ > 500 “Hockey stick”-shaped
Kramer and
MS
Osborn,14 2006 level VI
Falco-Molmeneu Descriptive study/
et al,13 2006
level VI
Evidence
source
Major findings
GSV used as primary intubation method and after failed
intubation with DL; twisting the ETT helps navigation
around laryngeal structures
Used electively; small diameter and memory allows
easier passage of guide into trachea
Comments
60° Bend
90° Bend
Intubation success 51/60
59/60
(subjects intubated ≤ 62 s)
Odds ratio for intubation success 10.41 (P < .03)
7 of 9 failures due to inability of 60° stylet to reach
glottic opening (all successfully intubated using 90°
stylet), 3 other failures due to TTI > 60 s
GRSMS
Median
42.7
39.9 (34.1-48.2)
TTI,f s (IQR)
(38.9-56.7)
Median
20 (12.0-33.0) 18 (9.5-29.5)
VAS ease of intubation,
mm (IQR)
Comments expressing 43
13
operator dissatisfaction, %
Only significant difference between groups was
comments expressing operator dissatisfaction (P = .005)
ETT with
malleable
GRS
distal tip
Mean TTI,h s (SD)
40 (10)
48 (20)
Successful intubations
30
28
> 1 intubation attempt
0
2
Only significant difference between groups was
mean TTI (P = .08)
Randomized block design attempting to control for
experience between operators, some blinding of
operator and observer; unknown method of sample
size determination; application of external laryngeal
maneuvers had an inverse effect on intubation success
Random assignment, unknown blinding; method of
sample size determination not described; 2 subjects
required conversion to GRS
Concealed random assignment, partial operator blinding,
full observer blinding; Other outcomes measured: CL
view, attempts, laryngeal manipulation, ETT advanced
from stylet by assistant
Operator rated procedure as easy in 15 of 16, fair in 1 Used electively; reported vital signs stable during
of 16 subjects
procedure
Angle of ETT bend had impact on TTI, but camber did not Less use of external laryngeal manipulations with 90°
60° Bend
90° Bend bend
Mean TTI,d s (SD)
54.4 (28.2) 47.1 (21.2)
Mean VAS score
27.3 (23.5) 16.4 (14.2)
ease of intubation,
mm (SD)
Significant difference in TTI, ease of intubation (P < .05)
Combination of techniques resulted in successful
intubation
TTI < 60 s in 38 of 40 subjects; in remaining 2 subjects,
modified guide allowed intubation in < 180 s
c
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GRS vs tube
exchangerk with
placement assisted
using vascular forceps
GRS vs MS
Conventional ETT vs
flexible-tip ETTi vs both
with GRS
GRS vs MS with 90°
bend formed 8 cm
from tip
ConventionalFlexible-tip
ETTETT
Mean TTI,j s (SE)
14.2 (1.1)
8.2 (1.1)
Mean number of
1.3 (1.2)
0.6 (1.2)
redirections (SE)
Mean VAS ease of 31.0 (4.0)
15.1 (4)
intubation, mm (SE)
ANCOVA with 2 covariates (CL view and muscle
paralysis)
Significant difference between groups for TTI (P = .005)
and mean VAS ease of intubation (P = .007)
GRSMS
No. of subjects
322
151
Intubation ultimately 93.5
78.1
successful, %
First-attempt success, %
82.9
67.5
Significant difference between groups in intubation
success and first-time success (P < .05)
Tube exchanger
with placement
assisted using
GRS vascular forceps
Intubation on first attempt, %93.2
94.4
Mean TTI, s (SD)l
67.8 (28.7) 66.1 (15.5)
No significant difference in intubation on first attempt
or mean TTI
MS with
GRS
90° bend
Median TTI,d s (SD)
60 (48-75)
61 (49-75)
Ease of intubation 1.5 (1-2)
1.0 (1-2)
(1 = easy, 5 = difficult; IQR)
No significant difference in TTI, ease of intubation,
glottic view, intubation attempts, use of external
laryngeal manipulation, or first-attempt success rate
Subjects randomized to groups; no blinding; sample size
determined using a power analysis; all subjects were
successfully intubated using the assigned technique
Incidence of oxygen desaturation less with GRS
Randomized block design, single-blinded observer;
sample size determined using a power analysis
Randomized design, operator mostly blinded and
observer blinded; sample size determined using a
power analysis
Abbreviations: ANCOVA, analysis of covariance; CL, Cormack and Lehane grade; DL, direct laryngoscopy; ETT, endotracheal tube; GRS, GlideRite rigid stylet; GSV, GlideScope video
laryngoscope; IQR, interquartile range; MS, malleable stylet, RCT, randomized clinical trial; TTI, time to intubation; VAS, visual analog scale.
a Evidence was appraised and classified by level using the method described by Melnyk and Fineout-Overholt.12
b Eschmann stylet was modified with a wire core, allowing it to maintain a preset shape.
c TTI not defined.
d From when GSV passed the lips to when end-tidal carbon dioxide (CO2) level was ≥ 30 mm Hg.
e DCI Video Laryngoscope (Karl Storz).
f From when GSV passed the teeth to when end-tidal CO level was ≥ 30 mm Hg.
2
g EndoFlex (Merlyn Associates).
h From insertion of GSV to appearance of trace end-tidal CO .
2
i Parker Flex-Tip (Parker Medical).
j From optimal glottic view via the GSV to ETT passing through the glottis.
k Sheridan T.T.X. (Teleflex).
l Insertion of GSV to 3 continuous end-tidal CO curves.
2
Table 1. Randomized Controlled Trials and Descriptive Studies Examining Methods to Increase Intubation Success During Use of the GlideScope Video Laryngoscope
RCT/level II
473
Retrospective
descriptive study/
level VI
Sakles and
Kalin,22 2012
Jeon et al,23
2013
58
RCT/level II
Radesic et al,21
2012
60
RCT/level II
Jones et al,20
2011
Evidence sourceaIntervention
Case series
Doyle,24 2004
GSV-assisted FOI (8 subjects)
Bader et al,25 2006
MS bent into a “J”-shape (12 subjects)
Dupanović et al,26 2006
MS bent above cuff to 90° (unable to determine sample size)
If intervention failed, coudé-tipped endotracheal introducer was inserted through
ETT into the trachea over the introducer
Hirabayashi,27 2006
Controllable styletb (unable to determine sample size)
28
Xue et al, 2006
GSV-assisted FOI (13 subjects)
Muallem and Baraka,29 2007
Curved pipe stylet and ETT introducerc (4 subjects)
Technique used electively
ETT can be rotated 90° so bevel faces posteriorly
Conklin et al,30 2010
Intubation guide with coudé tip (unable to determine sample size)
Ciccozzi et al,31 2013
Intubating introducerd (4 subjects)
Case reports
Heitz and Mastrando,32 2005
Coudé-tipped, gum elastic bougiee
33
Moore and Wong, 2007
GSV-assisted FOI
Vitin and Erdman,34 2007
GSV-assisted FOI
Walls et al,35 2010
MS shaped to the GSV blade, 180º clockwise rotation of ETT after passing through
glottis
Sharma et al,36 2010
GSV-assisted FOI with ETT bevel facing posteriorly
O’Mahony and Pagano,37 2013
Straight end of ETT introducerf in a “C” shape
Table 2. Case Series and Case Reports Describing Successful Intubation Methods During Use of the GlideScope
Video Laryngoscope
Abbreviations: ETT, endotracheal tube; FOI, fiberoptic intubation; GSV, GlideScope video laryngoscope; MS, malleable stylet.
a Evidence was appraised and classified by level using the method described by Melnyk and Fineout-Overholt.12
b StyletScope (Nihon Kohden Corp).
c Muallem ET Tube Introducer (VBM Medizintechnik).
d Frova Intubating Introducer (Cook Medical).
e Eschmann stylet modified with a wire core allowing it to maintain a preset shape.
f SunMed Endotracheal Tube Introducer (Azimuth Corp).
mended an additional 90° bend to the proximal end of
the ET tube because it may prevent the ET tube from
impacting the anterior tracheal wall.
Authors of a case series reported success using a malleable stylet with a 90° bend promixal to the cuff of the
ET tube.26 If this is not successful, they recommended
instead using an intubation guide, passing the coudé tip
of the guide into the trachea. The ET tube can then be
passed over the guide into the trachea. They, too, recommended an additional 90° bend to the proximal end of
the ET tube to help avoid impacting the anterior tracheal
wall. The exact number of subjects was not reported.
Other authors reported using a malleable stylet shaped
like a hockey stick to facilitate intubations in more than
500 awake and anesthetized subjects.14 They recommended twisting the ET tube to navigate around laryngeal structures and withdrawing the stylet during passage
through the glottic opening.
•GlideScope With Intubation Guide Rather Than
GlideRite. A malleable C-shaped ET tube introducer was
used instead of the GRS.13 The time to intubation was
less than 60 seconds in 38 of 40 subjects, and 2 subjects
were intubated in 180 seconds after modifying curvature
of the guide. A modified intubating guide was described
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in another case series involving 4 subjects.29 They also
oriented the ET tube so the bevel faced posteriorly,
aiding passage of the ET tube through the glottis into the
trachea. In 4 other subjects, an intubation guide was used
after failure using direct laryngoscopy and the GSV with
the GRS.31 Two case reports also described succesful use
of this technique.32,37 The narrow gauge and malleable
yet flexible nature of the intubating guides probably
facilitated passage into the trachea, and the ET tube was
then passed over the guide.
•Rotating Endotracheal Tube After Passing Below Glottic
Opening. A subject assessed as having a normal airway
was unable to be intubated with use of the GRS. A sharp
posterior tracheal angulation in relation to the larynx
was noted on GSV inspection. Successful intubation was
accomplished by rotating the ET tube 180° clockwise
after the ET tube loaded on a malleable stylet was passed
through the glottic opening.35 This must be done with
extreme care because of the risk of tracheal injury.
Conclusion
Despite an adequate glottic view, passage of the ET tube
into the trachea can be difficult. Reasons for this difficulty include not being able to maneuver the tip of the
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Figure 1. Endotracheal tube loaded onto a malleable
stylet forward camber. From top to bottom: stylet and
endotracheal tube, endotracheal tube loaded onto
stylet, endotracheal tube advanced off stylet. Note how
tip of endotracheal tube tends to advance anteriorly.
Figure 3. Parker Flex-Tip endotracheal tube.
Figure 2. Endotracheal tube loaded onto a malleable
style reverse camber, or “reverse loaded.” From top
to bottom: stylet and endotracheal tube, endotracheal
tube loaded onto stylet, endotracheal tube advanced
off stylet. Note how tip of endotracheal tube tends to
advance posteriorly.
ET tube through the glottic opening or the ET tube tip
impinging on airway structures, including the anterior
aspects of the larynx or trachea.31
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Findings from RCTs represent the highest level evidence. Findings from an RCT suggested that using a
flexible-tipped ET tube with the GRS may increase intubation success.21 Authors of 2 studies found no benefit of
using a malleable stylet with a 90° bend formed proximal
to the ET tube cuff.17,20 There was also no benefit of
“reverse camber” loading the ET tube onto the stylet.15,19
However, if using a malleable stylet, a 90° bend was preferable to a 60° bend regardless if the ET tube was loaded
forward camber or reverse camber.15,19 A malleable stylet
with a “J” bend was not found to be superior to the GRS
but this study may have been underpowered.18 Using an
ET tube exchanger with a vascular forceps did not result
in an increase in first attempt intubations or a decrease in
the time to intubation compared with the GRS.23
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than a conventional ET tube with the GRS.18
The generalizability of these findings must be viewed
with caution. Like any technique requiring psychomotor skill, an individual provider may be capable with a
particular technique because of experience using the
technique. Providers must consider the additional time
required to use these techniques. The risks and benefits
must be considered particularly if using a technique not
recommended by the device manufacturer. Cost and
personnel requirements must be considered such as the
additional expensive equipment and personnel required
for the GSV-FOBI technique.
Further rigorous investigations should be conducted
examining methods to increase success of intubation
using the GSV. Until then, providers should be aware
of methods that may increase success when encountering problems while using the GSV. These alternatives
should be practiced in a controlled setting before being
employed in an emergency situation.
REFERENCES
Figure 4. GlideScope-assisted fiberoptic
bronchoscopic intubation in a simulated setting.
A, GlideScope operator and fiberoptic bronchoscope operator.
B, Fiberoptic bronchoscope passed through endotracheal tube
and entering the glottic opening. C, Fiberoptic bronchoscope in
the trachea, with endotracheal tube passing over the fiberoptic
bronchoscope through the glottic opening and into the trachea.
Findings from lower-level evidence suggested a
number of alternatives to the GRS. Authors of a descriptive study,16 case series,24,28 and case reports33,34,36 suggested using a fiberoptic bronchoscope in conjunction
with the GSV increases intubation success. The fiberoptic
bronchoscope can be viewed via the GSV monitor and
the controls of the fiberoptic bronchoscope used to maneuver it to the glottic opening and into the trachea. This
combination of visualization and controllability reduce
trauma to delicate airway structures.36 Rotating the ET
tube after passing below the glottic opening35 and using
a controllable stylet could increase intubation success.27
Use of the fiberoptic bronchoscope with GSV has also
been described in a technical report.39
Descriptive studies,13 case series,29-31 and case
reports32,37 supported the use of an intubation guide. It
may be helpful to orient the ET tube bevel posteriorly
when one uses an intubation guide.29 There was no reported benefit of using a malleable tipped ET tube rather
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AUTHORS
Darrell Nemec, CRNA, DNAP, is a staff nurse anesthetist with the Edward
Hines Jr Veterans Affairs Hospital in Hines, Illinois. The author was a student in the Doctorate of Nurse Anesthesia Practice program at Texas Wesleyan University in Fort Worth, Texas, at the time this article was written.
Paul N. Austin, CRNA, PhD, is a professor in the Graduate Programs
of Nurse Anesthesia at Texas Wesleyan University.
Loraine S. Silvestro, PhD, is an associate professor of pharmacology in
the Graduate Programs of Nurse Anesthesia at Texas Wesleyan University.
DISCLOSURES
The authors have declared no financial relationships with any commercial
interest related to the content of this activity. The authors did not discuss
off-label use within the article.
ACKNOWLEDGMENTS
Dr Nemec would like the thank the following individuals at Edward
Hines Jr Veterans Affairs Hospital, Hines, Illinois, for their assistance: Fred
Luchetti, MD, Chief, Surgical Services; Usha Kolpe, MD; Molly Vadakara,
CRNA; Sabin Oana, MD; Reena Varkey, RN, Simulation Laboratory; Daniel Duverney, Medical Media Service; and the library staff.
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