Module 3
Complications of Managing the Airway
Complications with Intubation
ENDOTRACHEAL INTUBATION (con't)
Numerous investigators have reported
vocal cord paralysis after intubation with no other obvious
source of injury. Paralysis may be unilateral (hoarseness)
or bilateral (respiratory obstruction). The most likely
source of injury is an endotracheal tube cuff, malpositioned in
the subglottic larynx that presses on the recurrent laryngeal
nerve. Permanent voice change after intubation because of
external laryngeal nerve trauma occurs in up to 3% of patients
undergoing surgery in sites other than the head or neck.
However, vocal cord paralysis after intubation is usually
temporary. Its incidence may be decreased by avoiding
over-inflation of the endotracheal tube cuff and by placing the
endotracheal tube at least 15 mm below the vocal cords.
Vocal cord paralysis may also have a central origin.
Eroded vocal cords may adhere together, eventually forming
synechiae. Surgical correction is usually necessary.
Tracheobronchial trauma has various
causes. Injury may result from an over-inflated
endotracheal tube cuff, inadequate tube size, malpositioned tube
tip, laryngoscope, stylet, tube exchanger or related equipment.
Predisposing factors include anatomic difficulties, blind or
hurried intubation, inadequate positioning, poor visualization,
or— most commonly—inexperience on the part of the intubator.
Edema after extubation limits the lumen diameter and increases
airway resistance. Small children are most susceptible to
this problem; almost 4% of children 1–3 years of age develop
croup following endotracheal intubation. Tracheal
rupture, especially after emergency intubation, has been
reported, as well as a bronchial rupture secondary to use of an
endotracheal tube exchanger.21
Endotracheal tube cuffs inflated to a
pressure greater than that of the capillary perfusion may
devitalize the tracheal mucosa, leading to ulceration, necrosis,
and loss of structural integrity. Ulceration will occur at
even lower pressures in hypotensive patients. The need for
increasing cuff volumes to maintain a seal is an ominous sign of
tracheomalacia. The various nerves in this region of the
neck are also at risk. Erosion of the endotracheal tube
into the paratracheal nerves may result in dysphonia,
hoarseness, and laryngeal incompetence. Tracheomalacia
results from erosion confined to the tracheal cartilages.
It is imperative that the anesthesiologist inflate the cuff of
the endotracheal tube only as much as is necessary to ensure an
adequate airway seal. If using nitrous oxide during a
lengthy surgical procedure, the pressure in the endotracheal
tube cuff should be checked by a cuff pressure control device.
The cuff pressure should not exceed 25 cmH2O.
The incidence of granulomas has been
reported to range from 1:80022
to 1:20 00023.
Several months after prolonged endotracheal intubation, tracheal
stenosis and fibrosis may occur, typically at the site of
an inflated cuff, sometimes at the location of the endotracheal
tube tip. Dilation of the stenosis is curative if the
stenosis is caught in its early stages. However, surgical
correction may be necessary once the tracheal lumen has been
reduced to 4–5 mm.
Supraglottic complications induced by
long-term intubation may be prevented by early tracheostomy.
There is no evidence about the ideal time for tracheostomy in
longterm ventilated patients.
Barotrauma, inducing
pneumomediastinum or tension pneumothorax, results from
high-pressure distention of intrapulmonary structures.
High-flow insufflation techniques are most often associated with
barotrauma. Such problems are common in microlaryngeal
surgery in which jet ventilation is used.
Laryngoscopy and cuffed supraglottic
airway devices may cause periodical or permanent nerve injury.
Transient weakness, numbness, or paralysis of the tongue can
occur after laryngoscopy, presumably because of pressure on the
laryngeal and hypoglossal nerves. Damage of the internal
branch of the superior laryngeal nerve during difficult
intubation leading to anesthesia of the upper surface of the
larynx may occur. Transient palsies may occur when an LMA
device is used because it affects the hypoglossal and lingual
nerves. The authors personally observed five cases of
hyposmia following uncomplicated nasotracheal intubation for
head and neck surgery, and one case of anosmia despite
the use of preformed, warmed and lubricated nasotracheal tubes.
The hyposmias completely recovered in 3–6 months, whereas the
anosmia became permanent.
Airway management techniques such as chin
lift, jaw thrust and direct laryngoscopy transmit movement to
the cervical spine and may induce cervical spine injury.
Attempts to hyperextend the necks of patients with ankylosing
spondylitis may result in cervical fractures and quadriplegia.
Special attention should be given to patients with C1 or C2
fractures because any degree of extension might compromise
spinal cord function.
Several conditions—such as Down syndrome,
Arnold-Chiari malformation and rheumatoid arthritis—are
associated with atlantoaxial instability. Also, elderly
patients and those with pathological fragility—such as
connective tissue disorders, lytic bone tumors and
osteoporosis—should be intubated with caution. Awake
fiberoptic intubation should be considered in all cases where
time is not crucial.
Corneal abrasions are the most common
eye complications that occur during general anesthesia.
They are primarily caused by a facemask being placed on an open
eye or by the eyelids not being completely closed during
anesthesia. Prevention consists of vigilance on the part
of the anesthesiologist and application of adhesive tape over
the closed eyelids, especially during head and neck surgery.
Although these injuries typically heal within 24 hours, they are
usually painful and can lead to corneal ulceration. An
immediate ophthalmologic consultation is recommended. In
the presence of a penetrating eye injury, an increase in
intraocular pressure should be avoided by adequate anesthesia.
Temporomandibular joint injury (TMJ)
is a rare but serious complication. Rupture of the lateral
ligament is possible. TMJ injuries are caused by
increasing force during laryngoscopy to optimize the view of the
glottis. As a result, limited mouth opening, pain in the
joint, lateral deviation of the mandible (in case of unilateral
luxation), protrusion of the mandible, and lockjaw may occur.
Most of the cases of TMJ injury have not been associated with
difficult airway management.24
In the ASA closed claims database, only 17% of the claims had
documented pre-existing TMJ disorders, such as pain.25
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