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\begin{document}

\title{A comfortable and unconscious intubation by the combination of
intermittent sevoflurane inhalation and the modified spray-as-you-go
technique for a patient with severe postburn mentosternal contracture}



\author[1]{Zhi Wang}%
\author[1]{Yong Yang}%
\author[1]{Yang Chen}%
\author[1]{Bin Yi}%
\author[1]{Kai Lu}%
\author[2]{Bing Chen}%
\affil[1]{Southwest Hospital, Army Military Medical University}%
\affil[2]{The Second Affiliated Hospital of Chongqing Medical University}%


\vspace{-1em}



  
  \date{June 09, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Airway management of patients with difficult airways is a challenge to
the anesthesiologists and awake tracheal intubation is the recommended
strategy. A safe, comfortable, unconscious, and satisfied intubation
with spontaneous breathing keeping was achieved by intermittent
sevoflurane inhalation and the modified spray-as-you-go technique for
airway topicalization and intubation.%
\end{abstract}%



\sloppy


\textbf{A comfortable and unconscious intubation by the combination of
intermittent sevoflurane inhalation and the modified spray-as-you-go
technique for a patient with severe postburn mentosternal contracture}

Zhi Wang\textsuperscript{1}, Yong Yang\textsuperscript{1}, Yang
Chen\textsuperscript{1}, Bin Yi\textsuperscript{1}, Kaizhi
Lu\textsuperscript{1}, Bing Chen\textsuperscript{2}

\textsuperscript{1}Department of Anesthesia, Southwest Hospital, Army
Military Medical University, Chongqing 400038, China

\textsuperscript{2}Department of Anesthesia, The Second Affiliated
Hospital of Chongqing Medical University, Chongqing 400010, China

\textbf{Corresponding author:}Bing Chen
(E-mail:\emph{chenbing2050@163.com}), Department of Anesthesia, The
Second Affiliated Hospital of Chongqing Medical University, Chongqing
400010, China, or Yong Yang (E-mail:\emph{yabg183@163.com}), Department
of Anesthesia, Southwest Hospital, Army Military Medical University,
Chongqing 400038, China.

\textbf{Author contributions}

ZW, YY, and BC: study conception and design, acquisition, analysis, and
interpretation of data, drafting and revising the article; YC, BY, KL:
revising the article. All authors read and approved the final manuscript
and agreed to be accountable for all aspects of the work.

\textbf{Key Clinical Message}

A safe and comfortable intubation with spontaneous breathing keeping was
achieved in a patient with severe postburn mentosternal contracture and
refused to accept awake intubation, which can be expanded to other
patients with difficult airway.

\textbf{Abstract}

Airway management of patients with difficult airways is a challenge to
the anesthesiologists and awake tracheal intubation is the recommended
strategy. A safe, comfortable, unconscious, and satisfied intubation
with spontaneous breathing keeping was achieved by intermittent
sevoflurane inhalation and the modified spray-as-you-go technique for
airway topicalization and intubation.

\textbf{Key words:} Awake intubation, difficult airway, sevoflurane,
spray-as-you-go.

\textbf{Introduction}

Airway management of patients with postburn mentosternal contracture is
a challenge to the anesthesiologists {[}1, 2{]}. Awake tracheal
intubation (ATI) has been recommended as the gold standard in airway
management for anticipated difficult airway {[}3{]}. However, ATI needs
patients' cooperation and may leave a discomfort and nociceptive recall
to patients, which leads to the rejection of ATI in the next surgery. We
described a patient with severe post-burn contracture refused ATI due to
the unsuccessful experience before, a comfortable and unconscious
endotracheal intubation with spontaneous breathing keeping was achieved
by the combination of intermittent sevoflurane inhalation and the
modified spray-as-you-go (SAYGO) technique using flexible bronchoscopy.

\textbf{Case Presentation}

A 33-year-old woman, with severe postburn mentosternal contracture and
cicatricial carcinoma, presented for skin grafting surgery in our
hospital. The burn occurred when she was 4-year-old. She underwent two
reconstructive procedures at 7 and 14 years in local medical centers.
Due to the pain caused by the expansion of cicatricial carcinoma,
affecting eating and speaking, she had tried several medical centers for
treatment in the past year, but failed for unsuccessful ATI. In
preoperative physical examination, severe scar contractures and a great
tumor of approximately 15 cm\selectlanguage{ngerman}×12 cm were observed on the lower lip, neck,
and anterior chest (Fig. 1a and 1b); the chin, chest, and bilateral
armpits fused together; the cervicomental and mentosternal angles
completely obliterated; the anterior neck structures, including the
larynx, the trachea, and the carotid arteries, were unidentifiable or
impalpable. Mouth opening was limited (15 mm) and Mallampati test was
unavailable. The left nostril was obstructive for stenosis, but the
right nostril breathing was smooth. Preoperative X-rays and a computed
tomography scan (data not shown) revealed distortion of the upper airway
and no stenosis of the trachea. It was difficult to perform face mask
ventilation because of the nearly fixed neck and regressed mandible.
Meanwhile, conventional laryngoscopic intubation, laryngeal mask airway,
lightwand, or a GlideScope\selectlanguage{english}\textsuperscript{} Video laryngoscope were
thought to be impossible. Moreover, surgical tracheostomy under local
anesthesia {[}4{]} was not the preferred strategy for the existence of
tumor on neck. Furthermore, the patient rejected ATI for discomfort and
nociceptive recall before. Therefore, orotracheal or right nasotracheal
fiberoptic intubation with sedation seems the last remaining strategy.
Here we used intermittent sevoflurane inhalation for short sedation and
modified SAYGO technique using flexible bronchoscopy for airway
topicalization and nasotracheal intubation.

A written anesthetic consent was taken with explanation focused on the
risks of difficult airway. Atropine 0.5 mg was intramuscular injected to
reduce secretion before transferring to the operating room. The patient
was monitored and preoxygenated once she arrived in the operation room.
Vital signs were stable. A pillow and some folded sheets were stuffed
between the patient back and the operating bed to make her feel
comfortable. Intravenous midazolam 2 mg and sufentanil 5 \selectlanguage{greek}μ\selectlanguage{english}g were given.
Nasal passage was anesthetized by pledgets with 2\% lidocaine and 0.25\%
phenylephrine. Sevoflurane 2\% with a flow rate of 4 L/min with 100\%
O\textsubscript{2}, was administered via an oxygen mask connected to the
Y-piece of the ventilator circuit. The concentration of sevoflurane was
gradually increased to 4\% {[}5{]} and stopped when the bispectral index
reached 55-60 within 3 minutes, then airway reassessment and
topicalization were achieved by the modified SAYGO technique {[}6-8{]}.
An epidural catheter (Fig. 2), with an outer diameter of 3.8 mm, was
fixed and 1.5 cm longer was applied at the end of the fiberscope (MDH
A10; Zhuhai~Mindhao~Medical~Technology~Co.,~Ltd., ShenZhen, China).
Topicalization was achieved by spraying 2\% lidocaine (7 ml) via the
catheter onto the posterior nasal canal, pharyngeal cavity, epiglottis,
glottis, and tracheal (Fig. 3). Meanwhile, supplemental oxygen 10 L/min
was delivered by a hose (Fig. 2a) through the mouth to avoid hypoxemia.
When lidocaine worked, about 5 minutes later, sevoflurane was inhaled
again until the bispectral index reached 55-60. Then, a Parker Flex-Tip\selectlanguage{ngerman}®
tube with an inner diameter of 6.0 mm (Lead Medical Instrument Co.,
Ltd., Guangzhou, China), which was heated by 40 \selectlanguage{english} and lubricated in
advance, was successfully and smoothly inserted into the trachea from
the direction of flexible bronchoscopy (Fig. 1c). No stress reactions,
including cough, hypertension, tachycardia, arrhythmia, hypoxia, and
bronchospasm, and no intubation related complications, such as airway
trauma, airway obstruction, and bleeding, were occurred during
intubation. Importantly, the patient was very satisfied with this
experience after emergence.

\textbf{Discussion}

General recommendations for difficult airway management are awake
fiberoptic intubation, awake video laryngoscope, laryngeal mask airway
as an intubating conduit, lightwand, oral or nasal blind intubation,
retrograde intubation, invasive airway access, and ECMO which is left as
the last method {[}9{]}. In this case, due to the severe contractures
and microstomia, direct visualization of the pharynx and larynx by video
laryngoscope seemed impossible. Laryngeal mask airway was not considered
because size \# 3 or 4 for a female adult is too large to pass through
her mouth. Orotracheal intubation with lightwand was excluded on the
reason that neck scars cannot be illuminated. Retrograde intubation and
tracheostomy were also excluded for the reason that anterior neck
structures, including the larynx, trachea, and carotid arteries, are
unidentifiable and impalpable. For the distortion of the upper airway
and uncertainty of success, oral or nasal blind intubation was not the
preferred choice. Due to a good safety and success profile, awake
fiberoptic intubation is a preferred choice of anticipated difficult
tracheal intubation {[}3{]}. However, ATI may give patients significant
discomfort and nociceptive recall {[}10-12{]} or be perceived as
potentially dangerous when causing a pronounced sympathetic response
{[}13{]}. Furthermore, due to the several failures of awake intubation
in other medical centers, the patient refused to accept it again.
Therefore, fiberoptic intubation with precise~sedation, analgesia, and
without inhibition of spontaneous ventilation and cardiovascular
function seems an ideal choice.

At present, many sedative drugs, such as midazolam, dexmedetomidine,
propofol, sevoflurane, can be selected. A low dose of midazolam produces
a direct amnesia effect. Dexmedetomidine provides a good sedative effect
in awake conditions, but the sedation needs to be carefully titrated as
excessive sedation can lead to hypoventilation and bradycardia, or
inadequate sedation leads to discomfort, anxiety and excessive
sympathetic discharge. Moreover, dexmedetomidine may cause nociceptive
recall {[}8, 14{]}. Compared with propofol intravenous anesthesia,
sevoflurane inhalational has less effect on respiratory depression
{[}13{]}. Moreover, sevoflurane can be quickly washed out. Thus, it is
more controllable than other intravenous drugs. In this case, midazolam
2 mg, sufentanil 5 \selectlanguage{greek}μ\selectlanguage{english}g, and intermittent sevoflurane inhalation were
administrated to provide precise sedation and analgesia. Meanwhile, an
oral hose was connected to a high flow of oxygen to prevent hypoxia.
However, sedation should not be used as a substitute for inadequate
airway topicalization {[}3{]}.

To sufficiently anesthetize the upper airway and suppress the gag,
swallow and cough reflexes, a perfect topicalization is essential. There
are many ways of airway topicalization, such as nebulization with
lidocaine, nerve block, thyrocricocentesis spraying, and the SAYGO
technique {[}2{]}. However, research indicated that atomization of local
anesthetics had a potential possibility of higher stress responses and
poisoning {[}15{]}. Due to anatomical structure changes, nerve block and
thyrocricocentesis were impossible for such kind of patients. Compared
with the classical SAYGO technique that lidocaine sprayed directly via
the working channel of the fiberscope, the modified SAYGO technique,
which lidocaine sprayed via an epidural catheter inserted through the
working channel of the fiberscope, controls the dosage of local
anesthetics more accurately and does a better anesthesia effect,
therefore usually used in patients with difficult airway {[}6-8{]}.
However, the epidural catheter does not match with all fiberscopes.
Here, we directly fastened the epidural catheter at the end of the
fiberscope. Moreover, this SAYGO technique can evaluate the airway
passage directly, which increases the safety of intubation. Thus, it
seemed a better choice in this case.

Furthermore, once the local anesthetics worked, the patient was sedated
by sevoflurane inhalation again, then intubated by the guidance of
flexible bronchoscopy. Taken together, using intermittent sevoflurane
inhalation and the modified SAYGO technique, a safe, comfortable,
unconscious, and satisfied intubation with spontaneous breathing keeping
was achieved in a postburn patient with severe difficult airway and
unwillingness to accept ATI. Moreover, this strategy is not limit to
postburn patients with difficult airway.

\textbf{Conclusion}

This case demonstrated the combination of intermittent sevoflurane
inhalation and the modified SAYGO technique could provide a safe,
comfortable, unconscious, and satisfied airway management with
spontaneous breathing keeping for patients with anticipated difficult
airway, such as severe postburn mentosternal scar contracture, and/or
unwillingness to accept ATI.

\textbf{Data Availability}

No data were used during the study.

\textbf{Conflicts of Interest}

None

\textbf{Funding Statement}

This work is supported by the Kuanren Talents Program of the Second
Affiliated Hospital of Chongqing Medical University.

\textbf{References}

1. Caruso TJ, Janik LS, Fuzaylov G. Airway management of recovered
pediatric patients with severe head and neck burns: a review. Paediatr
Anaesth. 2012;22(5):462-8.

2. Prakash S, Mullick P. Airway management in patients with burn
contractures of the neck. Burns. 2015;41(8):1627-35.

3. Ahmad I, El-Boghdadly K, Bhagrath R, Hodzovic I, McNarry AF, Mir F,
O'Sullivan EP, Patel A, Stacey M, Vaughan D. Difficult Airway Society
guidelines for awake tracheal intubation (ATI) in adults. Anaesthesia.
2020;75(4):509-28.

4. Park CD, Lee HK, Yim JY, Kang IH. Anesthetic management for a patient
with severe mento-sternal contracture: difficult airway and scarce
venous access -A case report. Korean J Anesthesiol. 2013;64(1):61-4.

5. Smith CE, Fallon WF, Jr. Sevoflurane mask anesthesia for urgent
tracheostomy in an uncooperative trauma patient with a difficult airway.
Can J Anaesth. 2000;47(3):242-5.

6. Siddiqui N, Arzola C, Friedman Z, Guerina L, You-Ten KE. Ultrasound
Improves Cricothyrotomy Success in Cadavers with Poorly Defined Neck
Anatomy: A Randomized Control Trial. Anesthesiology.
2015;123(5):1033-41.

7. Rosenstock CV, Thogersen B, Afshari A, Christensen AL, Eriksen C,
Gatke MR. Awake fiberoptic or awake video laryngoscopic tracheal
intubation in patients with anticipated difficult airway management: a
randomized clinical trial. Anesthesiology. 2012;116(6):1210-6.

8. Liu HH, Zhou T, Wei JQ, Ma WH. Comparison between remifentanil and
dexmedetomidine for sedation during modified awake fiberoptic
intubation. Exp Ther Med. 2015;9(4):1259-64.

9. Apfelbaum JL, Hagberg CA, Caplan RA, Blitt CD, Connis RT, Nickinovich
DG, Benumof JL, Berry FA, Bode RH, Cheney FW, Guidry OF, Ovassapian A.
Practice guidelines for management of the difficult airway: an updated
report by the American Society of Anesthesiologists Task Force on
Management of the Difficult Airway. Anesthesiology. 2013;118(2):251-70.

10. Law JA, Morris IR, Brousseau PA, de la Ronde S, Milne AD. The
incidence, success rate, and complications of awake tracheal intubation
in 1,554 patients over 12 years: an historical cohort study. Can J
Anaesth. 2015;62(7):736-44.

11. Fiadjoe JE, Nishisaki A, Jagannathan N, Hunyady AI, Greenberg RS,
Reynolds PI, Matuszczak ME, Rehman MA, Polaner DM, Szmuk P, Nadkarni VM,
McGowan FX, Jr., Litman RS, Kovatsis PG. Airway management complications
in children with difficult tracheal intubation from the Pediatric
Difficult Intubation (PeDI) registry: a prospective cohort analysis.
Lancet Respir Med. 2016;4(1):37-48.

12. Joseph TT, Gal JS, DeMaria S, Jr., Lin HM, Levine AI, Hyman JB. A
Retrospective Study of Success, Failure, and Time Needed to Perform
Awake Intubation. Anesthesiology. 2016;125(1):105-14.

13. Xue FS, Yuan YJ, Wang Q, Liu JH, Liao X. Comments on ''Propofol
versus sevoflurane for fiberoptic intubation under spontaneous breathing
anesthesia in patients difficult to intubate''. Minerva Anestesiol.
2011;77(4):470-1; author reply 472-3.

14. Cattano D, Lam NC, Ferrario L, Seitan C, Vahdat K, Wilcox DW,
Hagberg CA. Dexmedetomidine versus Remifentanil for Sedation during
Awake Fiberoptic Intubation. Anesthesiol Res Pract. 2012;2012:753107.

15. Gupta B, Kohli S, Farooque K, Jalwal G, Gupta D, Sinha S,
Chandralekha. Topical airway anesthesia for awake fiberoptic intubation:
Comparison between airway nerve blocks and nebulized lignocaine by
ultrasonic nebulizer. 1. Caruso TJ, Janik LS, Fuzaylov G. Airway
management of recovered pediatric patients with severe head and neck
burns: a review. Paediatr Anaesth 2012; 22: 462-8.

2. Prakash S, Mullick P. Airway management in patients with burn
contractures of the neck. Burns 2015; 41: 1627-35.

3. Ahmad I, El-Boghdadly K, Bhagrath R, Hodzovic I, McNarry AF, Mir F,
O'Sullivan EP, Patel A, Stacey M, Vaughan D. Difficult Airway Society
guidelines for awake tracheal intubation (ATI) in adults.
Anaesthesia.2020 04 ;75(4):509-528.

4. Park CD, Lee HK, Yim JY, Kang IH. Anesthetic management for a patient
with severe mento-sternal contracture: difficult airway and scarce
venous access -A case report. Korean J Anesthesiol 2013; 64: 61-4.

5. Smith CE, Fallon WF, Jr. Sevoflurane mask anesthesia for urgent
tracheostomy in an uncooperative trauma patient with a difficult airway.
Can J Anaesth 2000; 47: 242-5.

6. Siddiqui N, Arzola C, Friedman Z, Guerina L, You-Ten KE. Ultrasound
Improves Cricothyrotomy Success in Cadavers with Poorly Defined Neck
Anatomy: A Randomized Control Trial. Anesthesiology 2015; 123: 1033-41.

7. Rosenstock CV, Thogersen B, Afshari A, Christensen AL, Eriksen C,
Gatke MR. Awake fiberoptic or awake video laryngoscopic tracheal
intubation in patients with anticipated difficult airway management: a
randomized clinical trial. Anesthesiology 2012; 116: 1210-6.

8. Liu HH, Zhou T, Wei JQ, Ma WH. Comparison between remifentanil and
dexmedetomidine for sedation during modified awake fiberoptic
intubation. Exp Ther Med 2015; 9: 1259-64.

9. Apfelbaum JL, Hagberg CA, Caplan RA, Blitt CD, Connis RT, Nickinovich
DG, Benumof JL, Berry FA, Bode RH, Cheney FW, Guidry OF, Ovassapian A.
Practice guidelines for management of the difficult airway: an updated
report by the American Society of Anesthesiologists Task Force on
Management of the Difficult Airway. Anesthesiology 2013; 118: 251-70.

10. Law JA, Morris IR, Brousseau PA, de la Ronde S, Milne AD. The
incidence, success rate, and complications of awake tracheal intubation
in 1,554 patients over 12 years: an historical cohort study. Can J
Anaesth 2015; 62: 736-44.

11. Fiadjoe JE, Nishisaki A, Jagannathan N, Hunyady AI, Greenberg RS,
Reynolds PI, Matuszczak ME, Rehman MA, Polaner DM, Szmuk P, Nadkarni VM,
McGowan FX, Jr., Litman RS, Kovatsis PG. Airway management complications
in children with difficult tracheal intubation from the Pediatric
Difficult Intubation (PeDI) registry: a prospective cohort analysis.
Lancet Respir Med 2016; 4: 37-48.

12. Joseph TT, Gal JS, DeMaria S, Jr., Lin HM, Levine AI, Hyman JB. A
Retrospective Study of Success, Failure, and Time Needed to Perform
Awake Intubation. Anesthesiology 2016; 125: 105-14.

13. Xue FS, Yuan YJ, Wang Q, Liu JH, Liao X. Comments on ''Propofol
versus sevoflurane for fiberoptic intubation under spontaneous breathing
anesthesia in patients difficult to intubate''. Minerva Anestesiol 2011;
77: 470-1; author reply 72-3.

14. Cattano D, Lam NC, Ferrario L, Seitan C, Vahdat K, Wilcox DW,
Hagberg CA. Dexmedetomidine versus Remifentanil for Sedation during
Awake Fiberoptic Intubation. Anesthesiol Res Pract 2012; 2012: 753107.

15. Gupta B, Kohli S, Farooque K, Jalwal G, Gupta D, Sinha S,
Chandralekha. Topical airway anesthesia for awake fiberoptic intubation:
Comparison between airway nerve blocks and nebulized lignocaine by
ultrasonic nebulizer. Saudi J Anaesth. 2014;8(Suppl 1):S15-9.

Fig. 1. The face, neck, and chest appearance of a 33-year-old woman with
severe postburn mentosternal contracture. Views on the front (a) and
lateral (b) showed obvious contractures and a large carcinoma on the
face, neck, and chest, and a small oral opening. (c) Intubated state
after skin grafting surgery.

Fig. 2. The modified spray-as-you-go technique. (a) An epidural catheter
was fixed at the end of the fiberscope. Supplemental oxygen was
delivered via a tube through the mouth to avoid hypoxemia. Views on the
lateral (b) and top (c) showed the local anesthetic was sprayed out from
the epidural catheter.

Fig. 3. Images showed the anesthesiologist sprayed 2\% lidocaine via an
epidural catheter onto the patient's airway mucosa. (a) Posterior nasal
canal, (b) left pharyngeal recess, (c) epiglottis, (d) right pharyngeal
recess, (e) supraglottis, (f) subglottis and trachea.\selectlanguage{english}
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