Module 3
Complications of Managing the Airway
Complications with Intubation
MAINTENANCE OF THE ENDOTRACHEAL TUBE
Airway obstruction can occur at any
time during general anesthesia, particularly in prolonged
surgery or in patients with predisposing anatomic abnormalities.
Airway obstruction can result from diverse factors, including a
sharp bend or kink in the endotracheal tube or a tube that is
obstructed with mucus, blood, foreign bodies, or lubricant.
Reinforced wire tubes may be used to avoid kinking, and their
use is recommended in prolonged procedures, oral surgery or
during surgery associated with special positioning of the
patient. Nitrous oxide can cause expansion of gas bubbles
trapped in the walls of an endotracheal tube, leading to airway
obstruction.
The cuff of an endotracheal tube can also
cause airway obstruction. An over-inflated cuff may
compress the bevel of the endotracheal tube against the tracheal
wall, occluding its tip. The cuff may also herniate over
the tip of the endotracheal tube. When faced with any of
these problems, the best solution is to pass a suction catheter
or a fiberoptic bronchoscope down the lumen of the endotracheal
tube and attempt to clear it. If the endotracheal tube is
totally obstructed, passage of a stylet should be attempted.
Total obstruction that cannot be remedied quickly requires
removal of the endotracheal tube followed by reintubation.
A common and serious complication of endotracheal intubation is
disconnection of the endotracheal tube from the anesthesia
circuit. This was identified as the most common
critical incident in a study of anesthesia-related human errors
and equipment failures.30
Alarms to signal airway disconnection are included on all modern
anesthesia machines.
Leaks in an air delivery circuit
can cause hypoventilation and dilution of the inspired gases by
entry of room air into the system.
Lasers are frequently used in the
operating room to ablate benign and neoplastic tissues in the
airway. Laser fire is a very serious complication.
The use of special laser guarded or metal tubes is recommended,
and all inflammatory materials such as dentures and nasogastric
tubes should be removed. One of the most catastrophic
events associated with their use is an airway fire, which occurs
when the laser ignites the endotracheal tube. The heat and
fumes of the burning plastic may cause severe damage to the
airway. Treatment consists of immediately disconnecting
the circuit from the endotracheal tube and removing the burning
tube from the airway. The fire should be extinguished with
saline, and the patient should be supported by facemask
ventilation. The airway should be evaluated for damage
with bronchoscopy. Numerous precautions can reduce the risk of
an airway fire. If possible, placement of an endotracheal
tube may be avoided (ventilating laryngoscope, jet ventilation
system, intermittent apneic ventilation).31
Endotracheal tubes may be protected by wrapping them in
non-combustible tapes; alternatively, red rubber or metal
non-combustible endotracheal tubes may be used. Cuff
ignition can be minimized by filling the cuff with saline
solution instead of air. Nitrous oxide should not be used in
laser surgery because it supports combustion. It is
recommended that inert gases, such as helium or nitrogen, be
used instead of nitrous oxide, and that concentrations of oxygen
do not exceed 40%.
SPECIAL TECHNIQUES
Fiberoptic intubation is one of the
most common methods utilized in cases of anticipated difficult
intubation. Intubation with a fiberoptic bronchoscope
should not be attempted when the pharynx is filled with blood or
saliva, when inadequate space exists within the oral cavity, or
when time is critical and creating a surgical airway is the
priority. Relative contraindications include marked tissue
edema, distortion of the oropharyngeal anatomy, blood in the
airway, soft tissue traction, or a severe cervical flexion
deformity.
Potential complications associated with
the fiberoptic bronchoscope include bleeding, epistaxis
(especially if a nasal airway is attempted), laryngotracheal
trauma, laryngospasm, bronchospasm, and aspiration of blood,
saliva, or gastric contents. Another possible hazard is
associated with the practice of insufflating oxygen through the
suction channel. Subcutaneous emphysema of the pharynx, face,
and periorbital regions may occur in case of injury of the
pharyngeal mucosa.
The lighted stylet may be used to
facilitate intubation under both local and general anesthesia.
Sore throat, hoarseness, arytenoid subluxation and mucosal
damage are possible. Heat damage to the tracheal mucosa in
prolonged intubation is a potential risk with inappropriate
handling.
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