Airway obstruction by extrinsic tracheal compression during spinal surgery under prone position -A case report-.

Abstract

Tracheal compression by vascular anomalies in adults is uncommon and most related reports are of children. A 79-year-old woman without any respiratory history underwent a lumbar spine surgery under general anesthesia. She suddenly developed airway obstruction after a position change from supine to prone. A fiberoptic bronchoscopy showed the obstruction of endotracheal tube. The obstruction was relieved after we changed the depth of endotracheal tube and supported the patient's neck with a cotton roll. The surgery ended without any other event and the patient recovered safely. A computed tomography revealed the rightward tracheal deviation and tortuous innominate artery contact with trachea. The patient didn't manifest any respiratory related symptoms during postoperative period, and she was discharged without any treatment.

Full text

Page 1

Korean J Anesthesiol 2010 December 59(Suppl): S45-S48
DOI: 10.4097/kjae.2010.59.S.S45
Case Report
Copyright ⓒ Korean Society of Anesthesiologists, 2010
www.ekja.org
Tracheal compression by vascular anomalies in adults is uncommon and most related reports are of children. A
79-year-old woman without any respiratory history underwent a lumbar spine surgery under general anesthesia.
She suddenly developed airway obstruction after a position change from supine to prone. A fiberoptic bronchoscopy
showed the obstruction of endotracheal tube. The obstruction was relieved after we changed the depth of
endotracheal tube and supported the patient’s neck with a cotton roll. The surgery ended without any other event
and the patient recovered safely. A computed tomography revealed the rightward tracheal deviation and tortuous
innominate artery contact with trachea. The patient didn’t manifest any respiratory related symptoms during
postoperative period, and she was discharged without any treatment. (Korean J Anesthesiol 2010; 59: S45-S48)
Key Words: Fiberoptic bronchoscopy, Prone position, Tracheal compression, Vascular anomaly.
Airway obstruction by extrinsic tracheal compression
during spinal surgery under prone position
-A case report-
Rak Min Choi, Jin Sun Yoon, Jae Hoon Noh, Kyoung Oh Kang, Sang Wook Ryu, Hee Jung Jun, and
Sam Soon Cho
Department of Anesthesiology and Pain Medicine, Seoul Veterans Hospital, Seoul, Korea
Received: March 10, 2010. Revised: 1st, March 20, 2010; 2nd, April 5, 2010. Accepted: April 14, 2010.
Corresponding author: Jin Sun Yoon, M.D., Department of Anesthesiology and Pain Medicine, Seoul Veterans Hospital, 6-2, Dunchon-dong,
Gangdong-gu, Seoul 134-060, Korea. Tel: 82-2-2225-1417, Fax: 82-2-2225-1416, E-mail: medisun74@naver.com
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium,
provided the original work is properly cited.
CC
Airway can be compressed by vascular malformations such as
innominate artery anomaly or right aortic arch. As such vascular
malformation occurs mainly in inherent, it is usually detected
right after birth or in infants but rare in adults [1,2]. When an
infant or a child experiences repeatedly respiratory problems
with an unknown origin, such as upper airway obstruction,
wheezing and stridor, dysphasia, or obstructive apnea, or when
an adult has a history of the above symptoms that have been
repeated, it is likely that the patient’s airway is mechanically
obstructed. Especially a special attention should be paid to
the type of vascular anomalies and a possibility of having
heart disease or any intrinsic tracheobronchial tree lesion as
anesthesia varies according to them. Authors report a case with
literature review where a patient with an unknown vascular
malformation has a sudden respiratory problem after changing
a position from supine to prone for a lumbar spine surgery.
The patient could finish the operation safely after adjusting
the depth of an endotracheal tube by confirming obstruction
of the tube under fiberoptic bronchoscopy and supporting the
patient’s neck with a cotton roll.

Page 2

S46www.ekja.org
Tracheal compression during spinal surgery
Vol. 59, Suppl, December 2010
Case Report
A 79-year-old female patient with weight of 58 kg and height
of 156 cm visited the hospital for lumbar pain accompanied
by referred pain in the left hip and the rear thigh. She was
diagnosed as spinal retrolisthesis and stenosis at L 4-5.
She admitted to the hospital for discectomy and partial
laminectomy. She had no special past history but a thyroid
isthmectomy to remove thyroid nodule in 2005. She was normal
in a blood test, a chest X-ray, and a thyroid function test but had
RBBB in ECG. In a pulmonary function test, forced vital capacity
(FVC) was 1.42 L (72.3% of an expected value), forced expiratory
volume at 1 second (FEV1) 1.13 L (71.1% of an expected
value), and FEV1/FVC 79.4%; which were mild restrictive
patterns. However, arterial blood gas analysis was normal. In
physical examination, we could find a 3 cm sized scar from the
isthmectomy, 2 cm above the sternal notch and her breathing
sound was normal at both lungs. In addition, she did not appeal
any symptom related to a respiratory system. Thus, the lumbar
surgery was proceeded as scheduled.
Patient did not receive any preanesthetic medication and she
inhaled 100% oxygen sufficiently after standard monitoring
with ECG, non-invasive blood pressure monitor and a pulse
oximetry. General anesthesia was induced with lidocaine 40
mg and propofol 80 mg, and rocuronium 40 mg was injected for
muscle relaxation after eyelid reflex disappeared. An armored
endotracheal tube of 7.0 mm was inserted and fixed at 21 cm.
Breathing sounds at both lung fields were normal. Ventilator
was adjusted at 550 ml of tidal volume and 10 times per minute
of the respiratory rate. Peak airway pressure was 18 mmHg.
Anesthesia was maintained with sevoflurane 1.5-2.0 vol% in a
50% of oxygen-nitrous oxide balance. End tidal carbon dioxide
tension was maintained at 30-35 mmHg. To monitor invasive
blood pressure, a 20 G catheter was introduced into the right
radial artery and a foley catheter was inserted. For a surgery, the
patient changed her position from supine to prone. We check
her airway was adequately maintained and her breathing sound
normal. Then surgeon began disinfecting around the operation
site. While arranging her head on a head rest, the peak airway
pressure surged into 35 to 40 mmHg, the tidal volume reduced
to 50 to 100 ml, and her breathing sounds were rarely heard
from both lung fields. The endotracheal tube was fixed at 21
cm as same at the supine position. There was resistance when
we tried to insert a suction tube to suck up the endotracheal
tube into which the suction tube could not move. We observed
the endotracheal tube with a flexible fiberoptic bronchoscopy
and reddish soft tissue was almost obstructing the tube (Fig. 1).
Although we moved the tube back up to 19 cm while observing
it with the bronchoscopy, the airway obstruction continued.
When we moved it further up to 23 cm again, the obstruction
reduced a little bit. As we pushed the front neck lightly
with hand, the obstruction was almost eliminated but not
completely. Thus we decided to change the patient’s position
to supine. We laid down the patient on the back and inspected
carefully her neck and chest areas. The skin right up the part
where the right clavicle and the sternum meet together was
somewhat protruded, and the pulse was felt behind the clavicle
with hands. When we observed it in the supine position with the
bronchoscopy, the internal lumen was maintained at the depth
of 23 cm of the endotracheal tube. The tube was located above
the carina and it was not one lung ventilation. At this time, the
tidal volume was 500 ml and the peak airway pressure was 18
mmHg at the respiratory rate of 12 times per minute. Position
change to prone allowed ventilation but not as good as in the
supine position. Supporting the patient’s neck with a cotton
roll helped to keep the tidal volume at 500 ml, the peak airway
pressure at 22 mmHg and normal breathing sounds. After
confirming with the fiberoptic bronchoscopy that the airway
was obtained and the tip of the tube is located above the carina,
the operation was continued. There was no airway obstruction
during the operation after that. The operation was completed
without any special problem. After we confirmed that the
patient was recovered with consciousness and spontaneous
breathing, the endotracheal tube was removed. The patient was
moved to a ward as she had no problem in recovery. Computed
tomography on the neck and the chest showed that the trachea
was deviated to the downward right side from the thoracic inlet
at which a tortuous innominate artery contact with the trachea
Fig. 1. Bronchoscopic findings of endo-
tracheal tube. (A) Endotracheal tube
fixed at 21 cm is near totally obstructed
by soft tissue under prone position. (B)
Tracheal lumen is maintained under
prone position. The tube is fixed at 23
cm and the patient’s neck is supported
by a cotton roll. (C) Tracheal lumen is
intact under supine position. The tube
is fixed at 23 cm.

Page 3

S47www.ekja.org
Korean J Anesthesiol
Choi, et al.
(Fig. 2). Beneath the subcutaneous layer of the right clavicle,
the distal innominate artery was met the trachea as twisted.
In the computed tomography measurement, the innominate
artery contact with the trachea in the depth of 19.6 cm to 21.3
cm along the trachea from the upper central incisor. When
we checked the chest X-ray backward, which was taken at the
preoperative examination, it was normal without lesion in lung
parenchyma but the trachea was deviated to the right side from
the thoracic inlet. As the patient has had no subjective symptom
related to vascular problems, she did not take any action against
it. The patient was discharged after being noticed that she needs
to talk about the history to an anesthesiologist in case of general
anesthesia in the future.
Discussion
Vascular malformation that obstructs the airway occurs
relatively commonly in infants and children. In a serious case, it
can be corrected by operation in the age of infants or children.
Thus, it is rarely found in an adult. In general, it companies
with symptoms like respiratory difficulty in exercise, repeated
pneumonia, bronchitis, continued stridor in the upper airway,
and dysphasia when the vessel compresses the esophagus
together. It is often misdiagnosed as asthma in adults [3]. If
the innominate artery originates in the distal aortic arch, the
artery should turn around the front of the trachea when going
to the right upper quadrant to reach to the right thracic apex.
When the artery is big and tight, it gives more pressure on the
trachea [4]. However, there is a dispute on the classification of
the anterior tracheal compression by innominate artery into
one of vascular malformation that causes airway obstruction
[5]. In the past, there were excessive diagnoses and treatment
of innominate artery compression and tracheomalacia
was regarded as a major cause of pathophysiology rather
than external pressure [6]. In addition, most normal infants
had compression on anterior tracheal without respiratory
symptoms when the innominate artery came across the trachea
in radiologic examinations [7].
It is relatively easy to assess whether the innominate
artery compresses the trachea or not. In a simple chest
posteroanterior X-ray view, there is no special problem.
Meanwhile the lower part of the trachea is narrow and a finger
pressed trace is found in the tracheal anterior wall in the lateral
view, the posterior wall is right and well arranged [8]. Moreover
the simple X-ray helps us to distinguish whether the narrow
trachea is caused by underdevelopment of tracheal cartilage by
vascular malformations or by simple external compression. If it
is caused by external compression, the narrow part is relatively
constantly kept as narrow from the beginning to the end of a
respiratory period. If the tracheal cartilage matters, a tracheal
diameter increases in inspiration and decreases in expiration.
Computed tomography is useful to indentify the range of the
narrowed area and the degree of obstruction, a change of a
tracheal diameter and a location of the tracheal cartilage defect.
As the magnetic resonance imaging is non-invasive and shows
blood vessels, the heart, tracheobronchial tree, both systemic
circulation system and the pulmonary circulation system,
recently it is selected as a primary test of all types of vascular
compression syndromes [9]. A structure of the tracheobronchial
tree can be observed with a bronchoscopy. It makes possible
to assess functional factors of airway obstruction or intrinsic
lesion such as tracheomalacia, tracheal stenosis, total tracheal
cartilage ring, tracheal variation, as well as to know the
location of an endotracheal tube in general anesthesia. We can
determine the proper size and the depth of the endotracheal
tube by evaluating the location and length of the compressed
area and the degree of obstruction.
In anesthesia of a patient with airway obstruction by vascular
compressions, it is helpful not to use muscle relaxants while
keeping self-respiration for maintaining the airway [1].
Fig. 2. Neck computed tomography
shows rightward tracheal deviation
(wide arrow) and tortuous innominate
artery (narrow arrow) contact with
trachea at right supraclavicular area
beneath subcutaneous layer (A), and at
thoracic inlet level (B).

Page 4

S48www.ekja.org
Tracheal compression during spinal surgery
Vol. 59, Suppl, December 2010
Although some forced expiration can prevent airway from
being obstructed during the exhalation, excessive efforts during
expiration or respiration in an unstable patient can aggravate
tracheal obstruction in the dynamic intrathoracic cavity and
further increase turbulent flow around the obstructed area.
Thus, it is important to understand a cause, a degree and a
location of the damaged airway. When the trachea became
too much narrow, the endotracheal tube should be located
neighboring the lesion passing the narrow part to prevent
the formation of edema or granulation tissue due to the tube.
It is safe to insert a stent using a rigid bronchoscope or an
endotracheal tube to obtain proper ventilation in a patient with
serious tracheal collapse.
In the case of the study, we considered correlation with a
thyroid isthmectomy at the very beginning because the patient
has a history of the operation. However, the operation scar
at 2 cm upward from the sternal notch was distant from the
area where the right clavicle and the sternum meet, at which
pulse is felt. In addition, as the isthmectomy is to remove
isthmus only while preserving the both thyroid lobes, it is too
minimal invasive to cause complications such as adhesion
or hematoma. Although the tracheal cartilage defect could
not be completely excluded, tracheomalacia or cartilage
defect was not considered as a cause because the patient had
no complaint on the respiratory system. Airway obstruction
by external compression is not common in adults whose
trachea is completely matured. However, there is a case that
adult male patient had severe tracheal obstruction due to the
pseudomeningocele after induction of general anesthesia. Thus
we assumed that the airway obstruction in our patient was
caused by external compression by blood vessels [10]. In this
case, the blood vessel does not encircle the trachea like a ring
and the innominate artery is branched in the normal location
of aortic arch. Although the innominate artery is tortuous
and goes in a bended shape, it does not compress the trachea
directly and the patient has had no respiratory symptom.
Therefore it is reasonable to see the innominate artery as
normal variation rather than malformation. When the patient
changed the position into prone, the chest was compressed and
thus innominate artery contact with the trachea compressed
the trachea. As the endotracheal tube was inserted toward the
carina, the tip of the tube might pass the compressed area and
maintain the endotracheal lumen. In addition, we guess that the
cotton roll supporting the patient’s neck in the prone position
pushed the trachea backward and released the anterior tracheal
compression by the tortuous artery at the thoracic inlet level
to some extent. As the patient was old and had no respiratory
problem for a life, we discharged her without special treatment.
Also, we recommended her to talk about the anesthesia-related
history to an anesthesiologist in the future if it is necessary to
intubate an endotracheal tube with general anesthesia because
the tortuous innominate artery and the rightward deviated
trachea can cause the tube obstruction again.
As the airway obstruction by vascular malformations is rarely
found, it can be misdiagnosed as a respiratory disease such as
asthma when only respiratory symptoms occur. Anesthesioloists
should understand mechanical features of airway obstruction
by vascular malformations in advance when conducting general
anesthesia for a patient who has a respiratory symptom due to
unidentified airway obstruction in order to make a diagnosis
and treatment in a more accurate and rapid manner.
References
1. Kussman BD, Geva T, McGowan FX. Cardiovascular causes of
airway compression. Paediatr Anaesth 2004; 14: 60-74.
2. Bose S, Hurst TS, Cockcroft DW. Right-sided aortic arch presenting
as refractory intraoperative and postoperative wheezing. Chest
1991; 99: 1308-10.
3. Hardin RE, Brevetti GR, Sanusi M, Bhaskaran D, Burack JH,
Genovesi MH, et al. Treatment of symptomatic vascular rings in the
elderly. Tex Heart Inst J 2005; 32: 411-5.
4. Myer CM 3rd, Wiatrak BJ, Cotton RT, Bove KE, Bailey WW.
Innominate artery compression of the trachea: current concepts.
Laryngoscope 1989; 99: 1030-4.
5. McLaren CA, Elliott MJ, Roebuck DJ. Vascular compression of the
airway in children. Paediatr Respir Rev 2008; 9: 85-94.
6. Mahboubi S, Gheyi V. MR imaging of airway obstruction in infants
and children. Int J Pediatr Otorhinolaryngol 2001; 57: 219-27.
7. Strife JL, Baumel AS, Dunbar JS. Tracheal compression by the
innominate artery in infancy and childhood. Radiology 1981; 139:
73-5.
8. Gross RE. Arterial malformations which cause compression of the
trachea or esophagus. Circulation 1955; 11: 124-34.
9. van Son JA, Julsrud PR, Hagler DJ, Sim EK, Puga FJ, Schaff HV, et
al. Imaging strategies for vascular rings. Ann Thorac Surg 1994; 57:
604-10.
10. Blank RS, Waldrop CS, Balestrieri PJ. Pseudomeningocele: an unusual
cause of intraoperative tracheal compression and expiratory
obstruction. Anesth Analg 2008; 107: 226-8.