Previous reviews have addressed airway management of trauma patients without a detailed description of management of the traumatized airway. This clinical commentary focuses on the approach to patients with upper airway trauma.
Airway injury is a major cause of early death in trauma.1,2 The incidence of traumatic airway injuries is low, although it is recently increasing.3,4 In contrast, mortality due to traumatic airway injuries is high, in part, because of associated injuries to other organs, which are present in about one half of the cases of blunt or penetrating airway trauma.1,2 Patients with a significant injury severity (scored on a scale of 0 to 75,5 which accounts for the most severely traumatized body systems) have a higher predicted mortality. In a retrospective review of 12,187 civilian patients treated at a regional trauma center in Toronto from 1989 to 2005, 36 patients (0.3%) had blunt airway trauma (injury severity score, 33; mortality, 36%) and 68 patients (0.6%) had penetrating airway trauma (injury severity score, 24; mortality, 16%).1 Among 24 deaths, airway injury was the primary cause in 10 patients. Twelve patients had thoracic airway injury, 9 of whom died. In another study including 44,684 trauma patients from Texas between 1996 and 2003,2 there were 19 patients (12 died) with blunt trauma and 52 patients (7 expired) with penetrating laryngeal–tracheal trauma. Traumatic airway injury is rare (incidence < 1%); thus, assessment and management are not well characterized because physicians rarely treat such cases.
Previous reviews of trauma care have addressed airway management, usually without a detailed discussion of management of patients with a traumatized airway.1,2,6–11 This clinical commentary will thus review the approach to patients with airway trauma, particularly with injuries to the facial compartments (i.e., maxillary and mandibular regions) and to the neck and glottis region. Care of patients with lower airway trauma, which represents thoracic trauma, will not be addressed in this review.
Anatomy of Trauma to the Airway
Airway injuries can be divided into three types: maxillofacial, neck, and laryngeal injury.
Blunt or penetrating trauma to the face can affect the maxillary/mandibular or mid-facial region and extend intracranially12–14 (table 1). Maxillofacial trauma can result in life-threatening airway and hemorrhage problems and lead to significant ocular, nasal, and jaw dysfunction. Bleeding may complicate airway management. Swallowing of blood clears the airway and is facilitated with the patient in the sitting position. However, gastric distension from swallowing of blood may increase the likelihood of regurgitation and aspiration. Venous bleeding can be controlled by packing and fracture reduction. Patients may not be able to control their own airway due to brisk arterial hemorrhage. Arterial bleeding may require angiographic embolization or may be resolved with surgical intervention.
In bilateral (bucket handle) or comminuted parasymphyseal mandibular fractures, the tongue is no longer anchored anteriorly. This leads to posterior displacement of tongue and periglottic soft tissue, causing airway obstruction. However, this airway obstruction can be reduced by upright positioning, although a known or suspected spinal cord injury could be worsened with upright positioning. Finally, a condylar fracture fragment might be displaced through the roof of the glenoid fossa to the middle cranial fossa, thus preventing mouth opening.
Mid-facial injury can cause unilateral or bilateral Le Fort I, II, and III, and associated fractures (fig. 1). Le Fort II and III fractures may be associated with a fractured skull base and leakage of cerebrospinal fluid (CSF). The cribriform plate and sphenoid sinus may be damaged in patients with nasoorbito-ethmoid fractures, Le Fort II and III fractures, or panfacial fractures. Mid-face fractures are generally associated with head and cervical spine (C-spine) injuries, whereas zygomatic and orbital fractures are associated with eye injury.15
Basilar skull fractures may involve the temporal, occipital, sphenoid, and ethmoid bones. They may lead to “raccoon eyes,” i.e., periorbital ecchymosis; Battle’s sign, i.e., retroauricular ecchymosis; CSF rhinorrhea; and cranial nerve palsy.
Penetrating and blunt neck trauma may involve almost every major vital structure including respiratory, vascular, digestive, endocrine, and neurologic organs.17 Findings consistent with major injury to the neck are listed in table 2. After penetrating trauma, arterial injury was reported in 12 to 13% of the cases, whereas the incidence of venous injury was found in 18 to 20% of the patients. Early deaths are generally caused by asphyxia from airway compromise or arterial hypotension from hemorrhagic shock.18
Dividing the neck into three zones (fig. 2) helps with the differential diagnosis of penetrating injuries and determination of airway management, hemorrhage control, and surgical approach.19 The airway may be compressed and obstructed by tissue disruption, edema, and hematoma, which may progress after admission of the patient to the hospital.19 Neck wounds should not be probed or explored in the emergency department due to the risk of dislodging a thrombus that would cause an uncontrollable hemorrhage.17 C-spine injury may cause retropharyngeal hematoma leading to airway compression and difficult laryngoscopy, even in the absence of externally visible changes.20 C-spine injury above C4 to C5 may cause laryngeal edema, apnea due to loss of diaphragmatic innervation, and neurogenic shock due to decreased sympathetic tone. This complicates the management of the associated airway trauma. C-spine injury may occur in conjunction with face, neck, and head trauma, especially in patients with blunt trauma and Glasgow Coma Scale score ≤ 8. Finally, a digestive tract injury should be suspected in the presence of dysphagia, retropharyngeal air, or pneumomediastinum.17
The signs, symptoms, and bronchoscopic and computed tomographic (CT) findings of laryngotracheal trauma22 are presented in table 3. Signs and symptoms may not correlate with the severity of injury. Associated injuries include those to skull base, cranium, neck, C-spine, esophagus, and pharynx. Cervicothoracic vascular injuries are present in one quarter of the patients.2 Blunt trauma to the larynx usually involves the trachea. Some patients with blunt injury to the anterior neck may initially appear to have a normal airway but may develop airway compromise over several hours due to an increase in laryngeal disruption, edema, and hematoma. Time from injury—to include prehospital transport—as opposed to time since admission should be a consideration in the decision to intubate or to observe the patient. Other patients may have self-limiting injuries, not requiring tracheal intubation or laryngeal surgery.22 Tracheal compromise by compression or direct injury should be suspected if there is airway obstruction, stridor, or trauma to the neck, sternum, or clavicle.8–11,23
Laryngeal–tracheal separation may occur. Insertion of an endotracheal tube (ETT) may also cause separation of a trachea tenuously held to the larynx. Sudden deceleration causing flexion–extension of the neck can lead to shearing, primarily at the cricoid and carina as they are anchored to adjacent structures (fig. 3). Blunt trauma may crush the trachea against the vertebral bodies, transecting tracheal rings and the cricoid cartilage, causing a “clothesline” injury. A transected cervical trachea may retract into the mediastinum and will need to be surgically extracted. Other causes of blunt airway trauma are steering wheel or bicycle handlebar injury and hanging. Finally, an increased intrathoracic pressure due to chest compression against a closed glottis can tear the posterior membranous trachea.
In the United States, prehospital trauma care is usually provided by the Emergency Medical System staffed primarily by emergency medical technicians and paramedics.6 In some countries, physicians lead prehospital care.24 The choice between temporizing at the scene versus definitive airway and other prehospital interventions is guided by triage, availability of expertise and equipment in the pre-hospital versus hospital settings, and travel time to the hospital. In many areas, statewide and region-specific guidelines exist that specify protocols for prehospital personnel (http://www.miemss.org/home/ems-providers, accessed October 28, 2015). Airway management is impacted by associated injuries to other organs and the condition of the patient. If oxygenation and ventilation can be maintained, prehospital establishment of a definitive airway may not be required and may potentially be detrimental.7,25,26 Care of injuries to other organs and management of hemorrhage is limited in the prehospital setting, even in the presence of a physician. Hence, a noncritical airway intervention should not delay transport to the hospital.
If prehospital expertise and equipment is comparable to that in the hospital, if there are prehospital personnel who are trained and experienced in airway management, or if the travel time to the hospital is long, definitive airway management may be performed as soon as indicated. Hence, depending on the urgency and facilities, a traumatized airway that needs securing may be controlled in the field, during transport, in the hospital trauma bay, or in the operating room. Allotment of resources for prehospital care may be proportionately higher in settings with long travel time to the hospital. For example, in the Toronto study, 31% of the airways were secured at the scene or en route, 21% at an outside hospital, 16% in the emergency department of the regional trauma center, and 29% in the operating room.1
Evaluation of the Traumatized Airway
Protective gear may be necessary for care providers. Airway trauma may not be readily apparent, and its evaluation requires a high level of suspicion for airway disruption and compression. Airway examination should be as complete as possible but may be limited by lack of time and patient cooperation, neck immobilization, and injury in and around the airway. History and physical examination should help determine mechanism of injury, extent of associated injuries, degree of shock, and previous interventions (table 4). Excessive bleeding in and around the airway or a rapidly expanding hematoma (e.g., neck area with compromised airway) may be due to anticoagulant medication. Currently, it is difficult to reverse the effect of some newer anticoagulants, thus increasing the risk.
When the airway compromise is due to tissue disruption, edema and hematoma may worsen over time. Thus, the airway should be reevaluated frequently, at least for several hours. Significant findings associated with maxillofacial, neck, and laryngotracheal trauma are bleeding, bruising, hematoma, disruption of bony and soft tissues, edema, air leak, and subcutaneous emphysema and are summarized in tables 1 to 3.1 Inspiratory stridor suggests impending loss of airway. Ability to speak and answer simple questions indicates a patent airway, enough respiratory effort to generate voice, and enough blood pressure to perfuse the brain.22
If time permits, a history and physical examination should be performed in every patient whenever feasible, before the initiation of anesthetic care and airway management. However, the Advanced Trauma Life Support Manual27 espouses three underlying concepts: (1) treat the greatest threat to life first, (2) the lack of a definitive diagnosis should never impede the application of an indicated treatment, and (3) a detailed history is not essential to begin the evaluation of a patient with acute injuries.27 Evaluation of the traumatized airway and adjoining structures may use direct laryngoscopy (DL), videolaryngoscopy (VL), fiberoptic bronchoscopy (FOB), or ultrasonic imaging, with or without sedation and topical anesthesia. Radiographic evaluation including CT and magnetic resonance imaging can be performed if intubation is not emergent or once the airway has been secured. Imaging provides comprehensive information about airway and surrounding structures and is especially suitable for evaluating the risk of airway compression.
There is a paucity of evidence regarding the management of patients with traumatized airway. Initially, 100% oxygen is administered, the airway is cleared of material (e.g., dentures, loose teeth, tissue, blood, and vomitus), and basic maneuvers are done: suction, chin lift, jaw thrust, oral airway, and bag-mask ventilation may all be necessary. A supraglottic airway may be cautiously utilized to enhance airway patency in obtunded patients, especially in the field. If a cervical injury is suspected, all maneuvers must be performed with due caution (e.g., manual in-line immobilization, cervical collar). Nasal airways should be avoided if there is a possibility of basilar skull or nasal fracture. If a large vessel has been injured, supine or Trendelenburg position will minimize the risk of air embolism. In patients with facial fractures, positive-pressure face mask ventilation may displace the facial bone fragments, worsen airway obstruction, and aggravate subcutaneous emphysema, pneumoencephalus, pneumomediastinum, and pneumothorax. In some instances, the face mask will improve the situation because it serves as a “splint” to stabilize facial fractures that have resulted in unwanted motion of facial structures. Laryngeal injuries may be extended by cricoid pressure, rigid laryngoscopy, intubating stylets, blind techniques, and even by the ETT. This may result in avulsion of mucous membranes and creation of a pseudolumen or a false passage.
A certain percentage of patients with limited airway injury do not require intubation.1,2 In one study,2 a definitive airway was emergently required in approximately 50% of the penetrating trauma cases and 80% of blunt trauma cases. In another study,1 about a third of the intubations were performed in the operating room, indicating that they were not emergent. Thus, conservative management is suitable for stable patients without airway compromise. If intubation is not performed, the patient should be frequently reassessed.
Indications for urgently securing the airway include severe trauma, cardiac arrest, shock, respiratory distress, hypoxia, severe agitation, and inability to protect the airway, i.e., low Glasgow Coma Scale score (≤ 8) and altered mental status. Esophageal injury is present in up to 10% of patients with laryngotracheal trauma, especially penetrating trauma.2 Patients with esophageal injury should be intubated urgently. Early airway control should also be considered in cases of hematoma that may expand in or around airway, and injury due to chemical, biological, or inhalational agents, including smoke and burns that cause mucosal edema. A surgical airway is indicated in the hypoxic or hypotensive patient who cannot be orally intubated.
Various techniques of intubation including DL, VL, and FOB are suitable. Spontaneous ventilation is desirable in difficult airway situations in cooperative patients and can be facilitated by topical anesthesia, judicious sedation, patient cooperation, and removal of vomitus, blood, and debris. Rapid sequence induction (RSI) and intubation utilizing manual in-line axial stabilization of the head and neck (if indicated) is the alternative.1 RSI can be successfully used in patients with penetrating neck trauma.19 Indeed, in a study of 12,187 civilian trauma patients, RSI was used in 70% of the patients with airway trauma.1
Intubation during spontaneous ventilation in an awake or a sedated patient avoids positive-pressure ventilation, affords more time for intubation before oxygen desaturation (if adequate preoxygenation has occurred), and allows more complete inspection of the airway. In cooperative patients, it may be safer if unknown airway disruption exists or if intubation is difficult. RSI is usually faster and more suitable for uncooperative or hemodynamically unstable patients with major injuries to other organs. The equipment and personnel to perform RSI is generally more readily available in all locations. The choice between primary surgical airway, awake/spontaneous breathing intubation, RSI, and watchful waiting without intubation is a clinical decision that depends on patient’s condition, clinical setting, type and severity of airway and systemic injuries, and available personnel, equipment, and expertise. VL may be combined with FOB or an airway exchange catheter.28 VL can guide the FOB by visualizing the larynx and the tip of the FOB.28 VL with a channeled blade requires less pharyngeal retraction than that with a nonchanneled blade and may be preferable in the setting of airway trauma.28 FOB is suitable in the presence of coexisting difficult mask ventilation as well as difficult intubation, encountered in facial trauma and other situations. Its flexibility may be desirable for nasal intubation and in the presence of airway or C-spine trauma. FOB is preferable if airway access is limited as during intubation in the prone or lateral position or in the presence of neurosurgical fixation with a surgical halo device. The use of FOB is limited by blood, mucous, and inability to displace debris.
Inability to intubate necessitates a surgical airway and is supported by both the American Society of Anesthesiologists Difficult Airway Algorithm modified for trauma 2014 and the American Society of Anesthesiologists Taskforce on Management of the Difficult Airway.29,30 Hence, all necessary airway equipment and personnel should be immediately available.
Mandibular and zygomatic arch injuries can cause trismus that may resolve with neuromuscular blockade. Condylar fractures may limit jaw opening because of actual mechanical blockage produced by displacement of a bony fragment. Surgical intervention may be required to dislodge the fragment (table 1). Conversely, bilateral mandibular fractures may ease laryngoscopic retraction. Mid-face fractures with a compromised airway may require a surgical airway, which also facilitates surgical access to the face. Alternatively, with submental intubation, the ETT exits from an incision in the floor of mouth (fig. 4). Avulsed permanent teeth should be replanted as soon as possible after intubation.
Nasal intubation is rarely performed acutely because of the risk of basilar skull injury. In the presence of a fractured skull base, nasal cannula and delivery of high-flow oxygen via FOB increase the risk of intracranial infection. Nasal intubation is primarily used for nonemergent oral and maxillofacial surgery. Nasal intubation using FOB is suitable if the fracture does not cross the midline and the cribriform plate is intact on CT imaging. In cases of frontobasal fractures with CSF fistula, nasal intubation has not been found to be associated with meningitis.31
Neck Trauma with Extrinsic Airway Compression
Airway manipulation might dislodge a hematoma and thus increase bleeding and/or tissue edema. Surgical release of the overlying tissue may reduce compression but may increase bleeding. RSI minimizes the risk of expansion of a hematoma due to coughing and bucking but may worsen airway obstruction. Intubation during spontaneous ventilation is also suitable. A surgical airway may be urgently required should RSI be unsuccessful.
If the airway injury is large or subglottic, a surgical airway may be the best initial approach. In some patients, it may be possible to insert an ETT through the wound.1 Alternatively, FOB may be used to pass the ETT distal to the site of disruption while avoiding further injury. Spontaneous ventilation is desirable. Conventional DL is risky in the presence of partial separation or avulsions of larynx and trachea.22
There is a lack of evidence-based approach regarding the best practice for airway management in patients with a traumatized airway. General recommendations for the management of the traumatized airway are summarized in table 5. Airway trauma may not be readily apparent, and its evaluation requires a high level of suspicion for airway disruption and compression. For patients with facial trauma, control of the airway may be significantly impacted by edema, bleeding, inability to clear secretions, loss of bony support, and difficulty with face mask ventilation. With the airway compression from neck swelling or hematoma, intubation attempts can further compromise the airway due to expanding hematoma. For patients with airway disruption, the goal is to pass the tube across the injured area without disrupting it or to insert the airway distal to the injury using a surgical approach.
If airway injury is extensive, a surgical airway distal to the site of injury may be the best initial approach. Alternatively, if orotracheal intubation is chosen, spontaneous ventilation may be maintained or RSI may be performed. RSI is a common approach. Thus, some of the patients intubated may subsequently require tracheostomy. A stable patient with limited injuries may not require intubation but should be watched carefully for at least several hours.
Because of a paucity of evidence-based data, the choice between these approaches and the techniques utilized is a clinical decision depending on the patient’s condition, clinical setting, injuries to airway and other organs, and available personnel, expertise, and equipment. Inability to obtain a definitive airway is always an absolute indication for an emergency cricothyroidotomy or surgical tracheostomy.
This study was supported by the Department of Anesthesiology, Alameda Health System, Oakland, California; Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland; Metrohealth Medical Center, Case Western Reserve University, Cleveland, Ohio; and University of Alabama at Birmingham, Birmingham, Alabama.
The authors declare no competing interests.