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Congenital High Airway Obstruction Syndrome and Airway Reconstruction
An Evolving Paradigm
Christopher J. Hartnick, MD;
Michael Rutter, MD;
Florian Lang, MD;
J. Paul Willging, MD;
Robin T. Cotton, MD
Arch Otolaryngol Head Neck Surg. 2002;128:567-570.
ABSTRACT
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Objectives To refine the classic definition of, and provide a working definition
for, congenital high airway obstruction syndrome (CHAOS) and to discuss the
various aspects of long-term airway reconstruction, including the range of
laryngeal anomalies and the various techniques for reconstruction.
Design Retrospective chart review.
Patients Four children (age range, 2-8 years) with CHAOS who presented to a single
tertiary care children's hospital for pediatric airway reconstruction between
1995 and 2000.
Conclusions To date, CHAOS remains poorly described in the otolaryngologic literature.
We propose the following working definition for pediatric cases of CHAOS:
any neonate who needs a surgical airway within 1 hour of birth owing to high
upper airway (ie, glottic, subglottic, or upper tracheal) obstruction and
who cannot be tracheally intubated other than through a persistent tracheoesophageal
fistula. Therefore, CHAOS has 3 possible presentations: (1) complete laryngeal
atresia without an esophageal fistula, (2) complete laryngeal atresia with
a tracheoesophageal fistula, and (3) near-complete high upper airway obstruction.
Management of the airway, particularly in regard to long-term reconstruction,
in children with CHAOS is complex and challenging.
INTRODUCTION
CONGENITAL HIGH airway obstruction syndrome (CHAOS) was defined by Hedrick
et al1 in 1994 as upper airway obstruction
that is diagnosed in utero by ultrasound, with concomitant findings of large
echogenic lungs, flattened or inverted diaphragms, dilated airways distal
to the obstruction, and fetal ascites or hydrops. Of the 4 children with CHAOS
who were described by Hedrick and colleagues, none survived past childbirth.
Since 1994, there have been several reports of in utero diagnosis of CHAOS,
with survival enabled by means of the EXIT (ex utero intrapartum treatment)
procedure.2 The EXIT procedure was originally
designed to treat children with large cervical masses (eg, hemangiomas and
teratomas) that were diagnosed in utero and that produced airway obstruction.3-4 Of key importance to this type of procedure
is the multidisciplinary involvement of the obstetrician, anesthesiologist,
otolaryngologist, pediatric surgeon, and neonatologist.
The hallmark findings of CHAOS that were described by Hedrick and coworkers
are found consistently only when prenatal ultrasonography is performed and,
importantly, only when there is complete high upper airway obstruction with
no tracheoesophageal connection. The findings relate to the described pathogenesis
of the syndrome, whereby the fluid produced by fetal lung tissue has no means
of being excreted into the amniotic fluid owing to the upper airway obstruction.1 The lungs therefore expand and produce the flattening
of the diaphragm and the hyperechogenic lung fields that are seen on ultrasound.
If the lung fields expand to the point of producing esophageal compression,
polyhydramnios may occur as a result of impaired swallowing of amniotic fluid.
The fundamental pathophysiology of CHAOS is altered when there is either
an incomplete upper airway obstruction or a tracheoesophageal fistula (TEF),
as the fetal lung fluid now has a way to flow from the pulmonary system, and
the lung fields therefore do not expand outward. In utero ultrasound may therefore
not diagnose the impending danger due to the upper airway obstruction. Survival
in such cases therefore depends on the degree of upper airway obstruction,
the ability to tracheally intubate the child through the TEF, or the ability
to perform an emergent tracheostomy. Also, regardless of whether the diagnosis
was made in utero, management of the survivor's upper airway obstruction is
a challenging surgical process. The following 4 cases represent the spectrum
of clinical CHAOS and the various modalities used for pediatric airway reconstruction.
To our knowledge, this article presents the first description in the otolaryngologic
literature of CHAOS and its long-term manifestations.
REPORT OF CASES
CASE 1
A 6-year-old boy was born at an outside institution with complete laryngeal
atresia and a TEF. He was intubated emergently through the fistula, and a
tracheostomy was subsequently performed. The TEF was then repaired at a later
date. Other pertinent findings included an imperforate anus, microgastria,
an atrial septal defect, and a ventricular septal defect. At the time of presentation
to the Children's Hospital Medical Center, Cincinnati, Ohio, laryngoscopy
and bronchoscopy revealed a complete atretic plate extending from the glottis,
where there were no discernible vocal folds to the superior extent of the
tracheal stoma site (Figure 1).
Intraoperative evaluation of the airway revealed a cordlike atretic cricoid
cartilage and an upper tracheal segment with a flattened posterior cricoid
plate (Figure 2). A partial cricotracheal
resection with thyrotracheal anastomosis was performed using a T tube for
stenting purposes. The T tube has since been removed, and the patient is undergoing
plugging and proceeding toward decannulation (Figure 3).
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Figure 1. Preoperative endoscopy showing
complete laryngeal atresia.
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Figure 2. Intraoperative view with a Penrose
drain elevating narrow cordlike upper tracheal/subglottic stenosis that extends
from the tracheal stoma site to the glottis.
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Figure 3. Postoperative view at the time
of T tube removal.
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CASE 2
A 7-year-old boy was born with stridor and in immediate airway distress
requiring emergent tracheotomy. Laryngoscopy and bronchoscopy revealed a tight
grade III Myer-Cotton subglottic stenosis with posterior glottic extension.
He underwent a tracheostomy immediately after birth. Other physical findings
included pectus excavatum. The patient was referred to Children's Hospital
Medical Center for evaluation at the age of 3 years, at which point the laryngeal
findings were confirmed (Figure 4).
No vocal folds could be identified. The patient first underwent a laryngofissure
with placement of a No. 6 Albouker above-stoma stent and subsequently underwent
a double-stage anterior costal cartilage laryngotracheal reconstruction. His
airway currently has a 4.5 endotracheal tube with a 15-cm water leak; he is
currently undergoing a plugging trial and moving toward decannulation (Figure 5).
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Figure 4. Preoperative view showing tight
grade III Myer-Cotton subglottic stenosis with narrow posterior subglottic
and posterior glottic lumen.
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Figure 5. Postoperative view 1 month after
T tube removal.
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CASE 3
A 1-year-old Venezuelan boy underwent a tracheostomy at birth for laryngeal
atresia. Other diagnoses included pectus excavatum, renal ptosis, and pulmonary
hypoplasia. He was referred to Children's Hospital Medical Center, where laryngoscopy
and bronchoscopy revealed a tight grade III subglottic stenosis with congenital
lateral and posterior shelves. As the patient had a persistent oxygen requirement,
the decision was made to perform airway reconstruction, with the goal of achieving
a safe airway with delayed decannulation. Therefore, a double-stage posterior
costal cartilage laryngotracheal reconstruction was performed, with placement
of a No. 6 Albouker above-stoma stent. When the stent was removed, the patient
had a widely patent airway. He has returned to Venezuela. The plan is to reevaluate
his oxygen requirement in 1 year and to consider decannulation at that point.
CASE 4
A 12-year-old boy underwent an emergent tracheostomy at birth for complete
laryngeal atresia. Other findings included bilateral inguinal hernias and
prune-belly syndrome. When he was 8 years old, he was seen and evaluated at
Children's Hospital Medical Center, where brochoscopy revealed a complete
laryngeal atresia with subglottic and upper tracheal extension (Figure 6). His operative course has been complicated: he has undergone
a 4-quadrant split laryngotracheal reconstruction, placement of a T tube,
and a cricotracheal resection with thyrotracheal anastomosis, and he recently
underwent a tracheal homograft placement.
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Figure 6. Preoperative endoscopy showing
complete laryngeal atresia.
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COMMENT
The classic definition of CHAOS as described by Hedrick et al1 relies on in utero ultrasound for diagnosis and provides
a distinct survival advantage to the neonates who are affected because it
allows the proper interventional team to be assembled and prepared at the
time of delivery. Nevertheless, even given a timely diagnosis and proper management,
there have been only a handful of children who have survived. The possibility
for survival becomes more dire when ultrasound evaluation is either not performed
or nonrevealing. As noted above, the classic findings of CHAOS have been described
only in the context of complete upper airway obstruction with no connection
to the esophagus. Reports of children born with complete laryngeal atresia
with a TEF and without the classic findings of CHAOS have been noted anecdotally
by one senior surgeon (R.T.C., oral communication, May 10, 2001). As has been
noted elsewhere, temporary ventilation through this TEF can be lifesaving.5 In any case, when there has been no prenatal diagnosis,
survival depends upon emergent airway management. The final common pathology
is the same: a life-threatening airway obstruction that requires emergent
operative intervention. The 4 cases reported herein represent examples of
fortunate survivors. The airway management for these children was 2-fold:
(1) emergent airway intervention and (2) delayed reconstruction.
As children with complete or near complete laryngeal atresia present
with similar symptoms at birth and require a similar treatment course, both
immediately and with regard to airway reconstruction, we propose to amend
the classic definition of CHAOS to include the various types of high airway
obstruction that may be encountered. The amended definition would include
any neonate who needs a surgical airway within 1 hour of birth owing to high
upper airway (ie, glottic, subglottic, or upper tracheal) obstruction and
who cannot be tracheally intubated other than through a persistent TEF. Therefore,
CHAOS has 3 possible presentations: (1) complete laryngeal atresia without
an esophageal fistula, (2) complete laryngeal atresia with a TEF, and (3)
near-complete high upper airway obstruction. One subset of children who are
described by this condition would be identifiable on prenatal ultrasound;
the others would not. Children with congenital obstructing masses occluding
the airway are excluded from this definition of CHAOS, as they may share a
similar common scenario in terms of acute management, but the long-term management
of their airway is quite different.
The treatment of children with CHAOS can be divided into immediate and
long-term care. As has been noted above, emergent airway management at the
time of delivery is enhanced if there has been prenatal diagnosis. A proper
team can be assembled, and an EXIT procedure can be planned and carried out.
Unfortunately, however, the diagnosis is not always made in utero. Emergent
airway management then consists of either tracheoesophageal intubation or
emergent tracheostomy. Airway reconstruction is delayed until the child is
stabilized and has been allowed to grow.
To our knowledge, there have no reports of subsequent airway reconstructions
in children with CHAOS who have survived the perinatal period to date, possibly
because there are so few survivors. Pediatric airway reconstruction in this
population is challenging. An accurate baseline assessment must be made regarding
the child's baseline medical status and comorbid problems, in particular any
cardiopulmonary or neurological problems that might preclude decannulation.
A careful endoscopy with both flexible and rigid equipment is necessary to
assess the mobility of the vocal cords and the degree and length of stenoses.
Immobile vocal cords may predispose to an increased risk of postoperative
decannulation, and a fiberoptic endoscopic evaluation of swallowing is invaluable
in providing information about the child's ability to protect his or her airway
or the likelihood of aspiration. Pediatric airway reconstructive surgery should
be delayed in the child who is believed to be at risk for aspiration, as opening
the glottic and subglottic airway will only increase the likelihood of chronic
aspiration and may spur the development of chronic lung disease. Over the
past year, 1 child has been evaluated at Children's Hospital Medical Center
who was diagnosed with CHAOS in utero, underwent a successful EXIT procedure,
and was under consideration for airway surgery. The patient was believed to
be highly likely to have severe aspiration after surgery, and the reconstructive
surgery was delayed.
There are a variety of options for surgical reconstruction, including
the use of a T tube, cartilage graft reconstruction, cricotracheal resection,
and tracheal homografting, and the approach should be individually tailored
for each case. The diversity of the possible surgical techniques reflects
the diversity that makes up our working definition of CHAOS. Although the
final common pathway may produce similar symptoms, the degree of airway obstruction
may be near complete or complete, and may involve one discrete level of the
airway or may extend from the glottis to the subglottis to the upper trachea.
On the other hand, eventual decannulation is a possibility for children with
CHAOS, and the families involved should be counseled accordingly.
AUTHOR INFORMATION
Accepted for publication August 29, 2001.
Corresponding author and reprints: Christopher J. Hartnick, MD, Department
of Otolaryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary,
243 Charles St, Boston, MA 02114 (e-mail: christopher_hartnick{at}meei.harvard.edu).
From the Department of Otolaryngology, Harvard Medical School and Massachusetts
Eye and Ear Infirmary, Boston (Dr Hartnick); the Department of Pediatric Otolaryngology,
Children's Hospital Medical Center, Cincinnati, Ohio (Drs Rutter, Willging,
and Cotton); and the Otorhinolaryngology Service, Centre Hospitalier Universitaire,
Lausanne, Switzerland (Dr Lang).
REFERENCES
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1. Hedrick MH, Ferro MM, Filly RA, Flake AW, Harrison MR, Adzick NS. Congenital high airway obstruction syndrome (CHAOS): a potential for
perinatal intervention. J Pediatr Surg. 1994;29:271-274.
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2. DeCou JM, Jones DC, Jacobs HD, Touloukian RJ. Successful ex utero intrapartum treatment (EXIT) procedure for congenital
high airway obstruction syndrome (CHAOS) owing to laryngeal atresia. J Pediatr Surg. 1998;33:1563-1565.
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3. Catalano PJ, Urken ML, Alvarez M, et al. New approach to the management of airway obstruction in "high risk"
neonates. Arch Otolaryngol Head Neck Surg. 1992;118:306-309.
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