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.