SECURING AN EMERGENT
AIRWAY
Maintenance of a patent airway is a primary supportive and resuscitative maneuver, and every physician should be able to insert an oropharyngeal or nasopharyngeal airway, pass an endotracheal tube, and perform an emergency tracheotomy or cricothyrotomy. There are many causes of acute upper airway obstruction, including decreased pharyngeal muscle tone after loss of consciousness; acute inflammatory or infectious processes such as angioedema, epiglottitis, or Ludwig angina; and obstructing tumors or masses of the pharynx and larynx. Inhalation burns, laryngeal trauma, and foreign body aspiration can also lead to acute airway obstruction. Depending on the specific cause and severity of the airway compromise, different maneuvers and techniques may be implemented to secure an emergent airway.
Loss of consciousness is associated with relaxation of
the pharyngeal musculature, causing the tongue to fall back and occlude the
oropharynx. Simple repositioning with the neck extended and the mandible
brought forward helps open the airway. If this fails, an oropharyngeal or
nasopharyngeal airway can be used to reestablish the airway and allow for
appropriate resuscitation measures to continue. For sustained ventilatory
support, endotracheal intubation is required. The endotracheal tube may be
introduced by the oropharyngeal or nasopharyngeal route. Oropharyngeal
intubation is preferred, but nasopharyngeal intubation may be necessary in
cases of posttraumatic cervical spine instability, impaired ability to open the
mouth (trismus), or obstructing pathology affecting the tongue and floor of the
mouth.
Whenever possible, endotracheal intubation is the
procedure of choice for securing and maintaining a compromised airway.
Unfortunately, this may not be feasible outside the hospital setting, and there
will be times when endotracheal intubation fails despite multiple attempts in
even the most experienced hands. In these situations, a surgical airway must be
established, either by tracheotomy or cricothyrotomy. With the exception of
young children and obese patients with poor anatomic landmarks, cricothyrotomy
is preferred over tracheotomy in the emergent setting. Cricothyrotomy is
performed by palpating the cricothyroid space in the midline of the neck and
making a vertical incision through the overlying skin and soft tissue. A
transverse stab incision is then made through the cricothyroid membrane with
the point of the blade directed inferiorly to avoid laryngeal injury. A small
endotracheal tube or any available tubular object is then inserted into the
airway.
Cricothyrotomy carries the risk of permanent damage to
the larynx and should be performed only in extreme emergencies when all other
methods of providing an artificial airway have been exhausted. Serious bleeding
may occur, and life-threatening subcutaneous emphysema has been reported. There
is also the potential for adverse long-term sequelae, such as subglottic
stenosis. For this reason, the cricothyrotomy should be converted to a formal
tracheostomy by an experienced surgeon in the operating room after the patient
has been stabilized. After the underlying condition or injury that caused the
airway obstruction has been resolved and mechanical ventilation is no longer required,
flexible fiberoptic laryngoscopy should be performed to assess the status of the
upper airway before removing the tracheostomy tube.
Several temporizing measures have been described in an attempt to provide additional time to secure the airway without having to resort to emergent tracheotomy or cricothyrotomy. One example is “needle cricothyrotomy,” in which a large-bore angiocatheter needle is used to cannulate the airway and deliver supplemental oxygen to the lungs. This technique carries the risk of inadvertently introducing air into the sub- cutaneous tissues of the neck, further complicating an already difficult situation. Ultimately, the potential morbidity and complications associated with emergent tracheotomy or cricothyrotomy are preferable to the anoxic brain injury or death that will occur if the airway is not secured.
