Chapter 34. Airway Management in Penetrating Neck Injury

A previously healthy 30-year-old man was shot at close range with a low-caliber handgun. A 911 call was placed immediately and paramedics were on the scene within 10 minutes. The victim was fully awake and cooperative. There was a single gunshot entrance wound in the midline at the level of the thyroid cartilage (Figure 34-1). The wound was about 5 mm in diameter and air was noted to be escaping from it. There was minimal bleeding. The patient complained of pain in the area of the anterior neck and the left scapula. He also complained of dyspnea and coughed up scant bloody sputum. He had no allergies, was on no medications, and was previously healthy.

Vital signs at the scene were: blood pressure (BP) 140/60 mm Hg, heart rate (HR) 90 beats per minute (bpm), respiratory rate (RR) 22 breaths per minute, oxygen saturation (SaO2) was 97%. Glasgow Coma Scale was 15. One IV was placed in each upper extremity and oxygen was administered by non-rebreathing facemask (NRFM). The patient was immobilized on a spine board and transported to the emergency department (ED). Transport time was 20 minutes.

On arrival in the ED the patient was awake and responded appropriately. Vital signs were: BP 140/90 mm Hg, HR 96 bpm, RR 20 breaths per minute, SaO2 was 98% on NRFM. He was hoarse, had scant hemoptysis, and complained of pain in the anterior neck and left scapular area. Air could again be appreciated escaping from the neck wound. There was minimal bleeding. Subcutaneous emphysema was palpable in the anterior neck but no hematoma was detected. No exit wound was identified. Air entry was decreased on auscultation of the left chest. The Glasgow Coma Scale was 15 and there were no neurologic deficits. The remainder of the examination was unremarkable.

34.2.1 How Common Is Penetrating Neck Injury?

Penetrating neck injury (PNI) has been reported to occur in 1% to 10% of all trauma patients1,2 and in 0.4% to 5% of major penetrating trauma victims.3 Not all PNIs involve vital structures. In a review of 26 reported series with a total of 4193 patients with PNI, there were 1285 vascular injuries (31%), 331 laryngotracheal injuries (8%), and 354 digestive (pharyngeal and esophageal) injuries (8.4%).4 Others have reported vascular injury in 13.3% to 37%2,5-7 of PNIs, aerodigestive tract injury in 6.3% to 18.5%,6-9 and esophageal injury in 0.9% to 8%.7,8,10,11 Pharyngoesophageal injury was reported by Thoma et al in 8.9% of PNIs.6

34.2.2 What Is the Mortality Associated with PNI?

The mortality associated with PNI has been reported in multiple series and reviews to be between 0% and 11%.1,4,5,7,12-22 A 2008 review reported that mortality rates from civilian PNIs was between 2% and 11%.23

Two series of patients with PNI have reported the mortality associated with vascular injury to be 0%6 and 2.2%.5 However, a mortality of 10% to 30% and approaching 50% has also been quoted for similar vascular injury.2,23 In a review of 11 series with a total of 1584 cases, Arsensio et al4 reported an average calculated mortality from penetrating carotid injury of 17%.

The mortality associated with penetrating laryngotracheal trauma has been reported to be 13.5%,24 3.5%,25 0%,6 and 11.5%.26 However, a mortality of 20%27 to 40%24 has also been quoted for penetrating laryngotracheal trauma.

The average calculated mortality for cervical esophageal wounds, most of which were penetrating, has been reported to be 10%.4 An increase in mortality has been observed with delayed diagnosis.2 A mortality associated with aerodigestive tract injury of 13% has also been reported.28

The mortality associated with PNI also varies with the mechanism of injury.21 The mortality associated with high-velocity bullet wounds is greater than that associated with low-velocity bullet wounds which is greater than that associated with stab wounds.21

34.2.3 Why Is Knowledge of the Anatomy of the Neck Important in PNI?

Penetrating injury to the aerodigestive tract, major vascular structures, or spinal cord in the neck can be life threatening.7 No other region of the body contains so many vital structures in such a confined space.7 Optimal evaluation and management of penetrating neck injury requires knowledge of the anatomy of the neck.29

The neck can be defined as that area located between the lower margin of the mandible and the superior nuchal line of the occipital bone superiorly, and the suprasternal notch and the upper border of the clavicles inferiorly.29 For the purpose of classification of penetrating neck injury, the neck has been divided into three anatomic zones7,29 (Figure 34-2). Although Monson and others30-33 have described the sternal notch as the boundary line between zones I and II, multiple other authors consider zone I to extend from the level of the clavicles and sternal notch to the cricoid cartilage1-3,5-7,22,27,29,34,35 and zone II to extend from the level of the cricoid cartilage to the angle of the mandible. Zone III extends from the angle of the mandible to the base of the skull. Although the three zones of the neck have been said to refer to the area anterior to the sternocleidomastoid muscles,7 posterior neck structures have also been included in this classification.7,29

The structures in zone I include the aortic arch, proximal carotid arteries, vertebral arteries, subclavian vessels, innominate vessels, apices of the lung, esophagus, trachea, brachial plexus, thoracic duct, and spinal cord (Figure 34-3). Important structures in zone II include the common, internal, and external carotids, the jugular veins, the larynx, the hypopharynx, and the proximal esophagus, as well as the spinal cord2,7,29 (Figure 34-4). Important structures in zone III include the distal cervical, petrous, and cavernous portions of the internal carotid arteries, the vertebral arteries, the external carotid arteries and their major branches, the jugular veins, the prevertebral venous plexus, the pharynx, the spinal cord, and the facial nerves2,7,29 (Figure 34-5).

The platysma, a thin superficial muscular sheet enclosed by the superficial fascia of the neck has often been cited as an important surgical landmark in the determination of whether a penetrating neck wound is superficial or deep.2,29 Penetration of the platysma raises the potential of injury to a vital structure, and has been used as an indication for neck exploration. Deep to platysma is the deep cervical fascia, which is subdivided into the investing, pretracheal, and prevertebral layers.2 The fascial compartments of the neck can limit external hemorrhage but when bleeding occurs within these closed compartments, airway compromise can be precipitated (Figure 34-6).

34.2.4 What Are Selective and Mandatory Neck Explorations?

Management of penetrating injury to zone I is complicated by difficult surgical exposure and difficult proximal control of bleeding vessels.2 Penetrating injury to zone III is similarly complicated by difficult surgical exposure and distal control of bleeding vessels.2 Operative intervention for injury in zones I and III has traditionally been selective, based on physical examination and radiologic findings.29

The surgical management of penetrating injury to zone II has been controversial. Some authors have advocated mandatory exploration for wounds that penetrate the platysma, whereas others recommend a more selective approach to surgical neck exploration due to high negative finding rates using the mandatory approach.5,7,11-16,18-21,29,36-42

Penetrating neck trauma most commonly occurs in zone II22 and requires emergency airway intervention in about one-third of cases.22 In a series of 223 patients with PNI, Demetriades et al reported zone II injury in 47%, zone I injury in 18%, and zone III injury in 19%. More than one zone was involved in 16%.5 Bell et al in a series of 120 patients reported 64% of PNI in zone II, 16% in zone I, and 20% in zone III.7

34.2.5 What Are the Mechanisms of PNI?

Forty-five percent of PNIs that penetrate the platysma have been reported to be caused by gunshot wounds (GSWs), 40% by stab wounds (SWs), and 4% by shotgun wounds (SGWs).1,5 In a series of 203 patients with PNI, Thoma et al reported GSWs in 20.7% and SWs in 78.3%,6 whereas Bell et al reported 25.8% GSWs and 52.5% SWs in a series of 120 patients.7

GSWs produce tissue destruction that is dependent on the kinetic energy of the projectile which is a function of the square of its velocity.29 The projectile produces a crush effect on tissue that it contacts and a stretch effect on tissue surrounding the missile path.43 High-velocity projectiles produce a greater blast effect and cause more extensive tissue destruction than low-velocity projectiles.44 However, the amount of damage produced depends on the interaction of the projectile and the specific tissue affected, in addition to its velocity.43 The site of the entry wound should be identified as well as the exit wound (if present), and consideration should be given to the path of the projectile.2 GSWs are more likely to cause vascular, aerodigestive, and neurologic injuries than are stab wounds (73% vs 31%).2,5 Transcervical GSWs (those that cross the midline) are also more likely to injure vital structures than GSWs that do not cross the midline.2,17 For this reason mandatory exploration of transcervical wounds has been recommended,45 although other authors have recommended a selective approach.17

34.3.1 What Are the Essential Elements of the Clinical Evaluation of PNI?

The initial evaluation of a PNI should follow the standard ABCs of resuscitation, followed by a systematic, rapid, and thorough secondary survey.2 The presence of an expanding or pulsatile hematoma, active bleeding, hemorrhagic shock unresponsive to IV fluids, airway compromise, extensive subcutaneous (SC) emphysema, absent upper extremity pulse, or air bubbling through the wound mandates urgent operative intervention2,7,22,29,46 and airway control.

In the hemodynamically stable patient without airway compromise, further diagnostic evaluation can be undertaken. The basis of this evaluation is the physical examination directed toward the identification of injury to the aerodigestive tract, the vasculature, and the nervous system.2

Physical signs indicative of vascular injury in addition to active bleeding, hemorrhagic shock, hematoma, or an absent upper extremity pulse noted earlier, include a carotid bruit or thrill, absent or decreased temporal or facial artery pulse, diminished ipsilateral radial pulse,2,7 or signs of air embolism.2 Abrupt onset of a stroke-type syndrome may herald vascular interruption, injury-induced thrombosis, or traumatic carotid or vertebral arterial dissection. Venous injury appears to be more common than arterial injury.4 Physical examination alone has been reported to be a reliable indicator of clinically significant vascular injury.7,46-49 In a retrospective review, Jarvik et al found no statistically significant difference between the sensitivities of clinical examination and angiography.49 In a review of 145 cases of PNI, Sekharan et al found that of the 114 patients without hard signs of vascular injury, only one required operative repair.50 Azuaje et al reported that physical examination alone had 93% sensitivity and 97% negative predictive value for vascular injury in a series of 216 patients.51 Similarly, Demetriades et al reported that none of 160 patients without clinical signs of vascular injury had serious vascular injury that required treatment.5 Thoma et al concluded that the absence of clinical signs and symptoms reasonably excluded vascular injury in their series of 203 patients.6

However, in a prospective study of 59 patients with a gunshot wound to the neck, Mohammed et al found physical examination alone to have a sensitivity of 57%, a specificity of 53%, a positive predictive value of 43%, and a negative predictive value of 67%.52 Ten patients without clinical signs of vascular injury in fact had vascular injury.52

Hematoma is the most common sign, followed by shock and external bleeding.7 Bleeding within the compartmentalized spaces of the neck can produce insidious displacement and distortion of the airway without external evidence. Airway obstruction can occur precipitously following a period of apparent quiescence, and airway control can be difficult.22 Any evidence of direct vascular injury to the neck has been said to be justification for intubation.22

The signs and symptoms of aerodigestive injury include hoarseness or dysphonia, stridor, subcutaneous emphysema or crepitance, dyspnea, dysphagia, hemoptysis, tenderness on palpation of the larynx, and air bubbling from the wound.2,7 Decreased breath sounds may be due to a hemothorax or pneumothorax.2 The only hard clinical sign of laryngotracheal injury is air escaping from the neck wound.8 Hoarseness is an indication of significant airway injury until proven otherwise.27 Subcutaneous emphysema is a suspicious finding that requires further investigation9 and violation of the aerodigestive tract must be assumed.53 Demetriades et al reported that subcutaneous emphysema (clinical or radiological) was almost always present in penetrating aerodigestive tract injuries8 and subcutaneous crepitus was the most common finding reported by Grewal et al in a series of 57 patients with penetrating laryngotracheal trauma.25 An absence of signs or symptoms suggestive of aerodigestive trauma has been found to reliably exclude injuries requiring surgical repair in a series of 152 patients.5 Emergency airway management has been required in 46% to 56% of patients with penetrating laryngotracheal injury.24,25,27

Esophageal injury due to penetrating neck trauma can be occult and difficult to diagnose on physical examination. Signs of esophageal trauma include dysphagia, odynophagia, hematemesis, SC crepitus, and retropharyngeal air on lateral neck radiograph.2

A thorough neurologic evaluation is necessary to detect or rule out penetrating injury to the central nervous system, cranial nerves, or peripheral nerves.2 Complete spinal cord transaction above C5 can lead to respiratory arrest, and injury below C5 can cause respiratory distress.2 Injury to cranial nerve (CN) VII is manifested by facial weakness, CN XI by an inability to shrug the shoulders, and injury to CN XII by deviation of the tongue.2 Injury to cervical nerve roots C5-C7 will manifest as sensory and motor deficit to the ipsilateral extremity.2 Interruption of blood flow in the carotid or vertebral arteries can cause ischemic stroke.2 The identification of spinal cord injury associated with PNI is important as immobilization has implications for airway management as well as physical examination.

It has been recommended that all patients with PNI be immobilized in a rigid cervical collar.54 However, there are no reports of unstable cervical spine injury in PNI due to stab wounds, and a GSW to the neck would need to fracture the cervical vertebrae in two columns to create an unstable fracture.55 The projectile would have to traverse the spinal cord to produce this injury and neurologic findings would be evident on physical examination55 in the conscious examinable patient.

In a study reported by Klein et al, 33 of 183 patients with GSWs to the neck had cervical spine injuries.56 However, only 1 of the 33 had a proven significant spinal injury with no neurologic findings on admission.56 The authors concluded that immobilization is essential for patients with GSWs to the neck until radiologic evaluation is complete.56 In a retrospective study by Medzon et al, 19 of 81 patients who had sustained a GSW to the head or neck had documented cervical spine fractures.57 However, of the 65 patients who were alert and without neurologic deficits, only 3 had a fracture, none of which were unstable.57 Sixteen of the 19 patients with fractures required acute airway management. The authors were reluctant to recommend removal of collar immobilization based on their data. However, they note that the likelihood of an unstable fracture in an alert and examinable patient without neurologic deficit is low.57 They went on to suggest that the decision to remove the collar or discontinue spinal precautions should be individualized, and when emergency airway control is required, it would be reasonable to remove obstructive devices to permit more expeditious treatment.57 In a retrospective review of 27 patients with PNI by Connell et al, 12 patients sustained a spinal cord injury, 1 due to a GSW and 11 from sharp weapons. Ten patients had obvious clinical evidence of spinal cord injury and two were in traumatic cardiac arrest. The authors concluded that fully conscious patients with isolated penetrating trauma and no neurologic deficit do not require spinal immobilization.58

Based on the available evidence, it appears unlikely that isolated PNI would produce an unstable cervical spine injury in the alert, examinable patient without a detectable neurologic deficit. Immobilization in this setting can interfere with airway management and can obscure findings on physical examination of the neck. In the presence of coincidental blunt trauma, an altered level of consciousness, or neurologic deficit, immobilization is indicated.

The patient presented here underwent cervical spine immobilization. He had the only hard clinical sign of laryngeal injury on clinical examination, air escaping from the entry wound in the anterior neck. There were no signs of vascular or neurologic injury.

34.4.1 What Airway Management Techniques Are Appropriate in PNI?

Airway management of the patient with penetrating neck trauma is intimidating and can be challenging even for the most skilled practitioners due to the coexistence of a potentially difficult airway and the need for rapid action.1,22,55 In addition, the rarity of PNI means that the experience of any one practitioner in the management of this injury can be limited.59 The need for airway control must be determined and the time available to achieve that control must be estimated. There must be a willingness to act quickly despite incomplete information as a delay in intervention can be hazardous,22 and there must be an ability to improvise and change plans under rapidly changing circumstances.27 Airway management decisions must be based on the patient's specific injuries, existing signs of airway compromise, the anticipated clinical course and risk of deterioration, the need for transport, and the patient's overall condition and level of cooperation, as well as planned diagnostic and therapeutic interventions.3,22 On examination, evidence of injury to an air-containing structure in the neck (SC emphysema, stridor, dysphagia, odynophagia, respiratory distress), vascular injury (hematoma, active bleeding, shock, palpable thrill, carotid bruit, absent or diminished pulses), and spinal cord injury (motor and sensory deficit) must be evaluated. The likelihood of difficult direct laryngoscopy must also be assessed. Emergency airway management may be necessary to secure a patent airway, in preparation for operative intervention, or as a part of airway evaluation in selective management of PNI.3 Emergency airway control is indicated in the presence of airway obstruction, respiratory failure, inability to protect the airway from aspiration, hemodynamic instability,3 and hard signs of vascular injury that mandate emergency surgical intervention.7,29 Edema, SC emphysema, or hematoma can produce sudden airway obstruction following a period of relative quiescence, and anatomic distortion can make intubation or a surgical airway more difficult to perform.22 The decision to observe a patient for impending airway compromise or to secure the airway to avoid a difficult intubation in the presence of anatomic distortion is a matter of clinical judgement.22,55 This decision must be based on the evidence on clinical examination of significant vascular, aerodigestive tract, and neurologic injury, and it must be recognized that if one choses to observe, airway obstruction may be sudden, complete, and irreversible. If there is evidence of injury to an air-containing structure in the neck (larynx, trachea, pharynx, esophagus), positive-pressure bag-mask-ventilation may be hazardous and can produce increased anatomic distortion and airway obstruction.2 Orotracheal intubation in the presence of laryngotracheal injury risks cannulation of a false passage, further disruption of damaged mucosa, and increased airway compromise.8,44,60 If there is evidence of significant vascular injury, airway management is indicated.22 A hematoma can expand in the deep tissue planes of the neck22 and airway compromise may proceed insidiously only to be followed by rapid and catastrophic deterioration.22

The timing, place, and method of airway control depend on the type of neck injury, the cardio-respiratory condition of the patient, the available resources, and the experience and skills of the resuscitation team.2,5

Several investigators have reported experience with airway management in PNI. Shearer et al reviewed the records of 107 patients who required an artificial airway from a series of 282 patients admitted with PNI.35 A surgical airway was the primary choice in 6%, RSI in 83%, awake bronchoscopic intubation in 7%, and blind nasal intubation in 4%. The success rates for these various techniques were: primary surgical, 100%; RSI, 98%; awake bronchoscopic, 100%; and blind nasal, 75%. Eight of the 107 patients had laryngotracheal injuries (8%) and 38 patients had vascular injuries (35.5%). RSI failed in two patients (2%) and a surgical airway was required. One blind nasal attempt failed (25%) and was followed by loss of the airway and death during attempted cricothyrotomy. Tracheotomy was performed as the primary airway in three of the eight patients with laryngotracheal injury. Of the nine patients who were hemodynamically unstable, five underwent a tracheotomy or cricothyrotomy in the ED. The authors concluded that airway control can be achieved in most patients with a penetrating neck injury by RSI or a surgical airway, and that a surgical airway should be strongly considered in patients who have wounds in proximity to the larynx who have stridor, dyspnea, hemoptysis, and SC emphysema.35

Mandavia et al conducted a retrospective study of ED intubations in patients presenting with PNI at a level I trauma unit over a 3-year period.61 During the study period, 748 patients with PNI were evaluated in the ED, of whom 82 (11%) required immediate airway management. Twenty-four of these 82 patients were excluded due to pre-hospital cardiac arrest or intubation. In the remaining 58 patients (45 GSWs, 12 SWs, 1 MVA), 39 underwent RSI with a 100% success rate. Thirty-three patients required one attempt, four patients required two attempts, and two required three attempts. Oxygen desaturation (<90%) occurred in two patients. Five unconscious patients were intubated orally without paralysis, and two underwent emergency tracheotomy. Flexible bronchoscopic intubation was attempted in 12 patients and was successful in 9. The three remaining patients were successfully intubated by RSI, although one patient required two attempts and experienced oxygen desaturation to 79%. Both patients who underwent emergency tracheotomy had GSWs and were unable to phonate properly. One of these patients had a laryngeal injury confirmed by endoscopic laryngoscopy prior to tracheotomy. Oral endotracheal intubation was the definitive technique in 47 of the 58 patients and was successful 100% of the time it was employed. The authors concluded that RSI was safe and effective in all of the cases in which it was attempted, and that practitioners with airway expertise should consider using RSI in the setting of PNI.61

Eggen and Jorden reviewed the charts of 114 patients with penetrating injury that breeched the platysma.30 The mechanism of injury was GSW in 59, SW in 39, shotgun wound (SGW) in 7, and miscellaneous in 9 patients. Sixty-nine patients required intubation, of whom 26 were intubated urgently. Urgent airway control was considered necessary in the presence of acute airway distress, airway compromise from blood or secretions, extensive SC emphysema, tracheal shift, or severe alteration of mental status. Eight of the 26 urgent intubations were initially unsuccessful, and six of these required an alternative technique. Four of these were failed oral intubation, three of whom were subsequently managed via the open wound, and one via a tracheotomy. Two of the six were failed nasotracheal intubations both of whom required emergency tracheotomy. Of the 26 patients who required urgent airway control, 9 required a tracheotomy and 5 of these patients had diffuse SC emphysema. Of the 98 patients with zone II injury, 22% required urgent airway control whereas all 3 patients with zone I injury and 5 of 13 (38%) with zone III injury required urgent airway control. The authors noted that a variety of approaches to airway management have been documented to be successful, and that no approach should be dismissed unless specific circumstances contraindicate it or make it technically impossible.30 It should be noted that these cases occurred and that this study was published at a time when RSI was not widely practiced by emergency physicians.

Bell et al performed a retrospective analysis of 134 patients with PNI, of whom sixty-five sustained wounds that violated the platysma.7 There were 31 patients with GSWs, 63 SWs, 13 flying glass injuries, and 15 who were impaled. Eight patients did not require airway management, except for the purpose of general anesthesia. Of the 59 patients who required emergency airway management, 48 were successfully intubated orally in the field. There were two failed intubations that required emergency tracheotomy on arrival, and seven additional tracheotomies were performed for airway compromise.7

Tallon et al performed a retrospective review of the airway management of PNI in a Canadian tertiary care center.62 Nineteen patients were identified over the 11-year period of the study. Three patients were not intubated. Of the remaining 16, 5 were intubated in the pre-hospital setting, 6 in the ED, and 5 in the OR. Eight patients were intubated awake and eight others underwent RSI. No adverse airway-related outcomes were identified in either group.62

Thoma et al performed a prospective observational study of 203 patients with PNI who presented to Groote Schuur Hospital in Cape Town between July 2004 and July 2005.6 Of these, 159 patients presented with stab wounds and 42 with low-velocity gunshot wounds. A vascular injury was identified in 27 patients, pharyngoesophageal injury in 18, and an upper airway injury in 8. Four patients had a laryngeal injury and four had tracheal injuries. Twenty-five patients required surgical intervention, and eight additional patients had endovascular procedures. Six patients underwent tracheotomy, four of whom had airway compromise associated with oropharyngeal injury. One of the patients with laryngeal injury required tracheotomy and one patient with a complete C4 spinal cord injury required long-term ventilation. Patients with airway compromise and hemodynamic stability were intubated either by oral endotracheal intubation or if that failed, emergency cricothyrotomy. However, there were no failed intubations requiring a surgical airway. The details of the technique of intubation were not provided.6

Grewal et al retrospectively analyzed the records of all patients admitted to a level I trauma center who required operative management for penetrating laryngotracheal injury over a 15-year period.25 Of the 57 patients with penetrating laryngotracheal injury, 32 had sustained GSWs and 25 had sustained SWs. Five patients were hemodynamically unstable on arrival. Emergency airway management was required in 32 of the 57 patients. Oral endotracheal intubation was performed in 14, cricothyrotomy in 3, and tracheotomy in 15. Eight of the emergency tracheotomies were performed in the ED. Forty-four patients underwent tracheotomy in the course of their resuscitation and management. The authors concluded that endotracheal intubation can be safely accomplished in selected patients with penetrating laryngotracheal injuries.25 They suggested that patients with minor to moderate laryngotracheal injury can be safely intubated whereas patients with major laryngeal injuries required individualized management. If the expertise required to perform tracheotomy in the emergency department is limited, then cricothyrotomy was felt to be the safest alternative.25

In a retrospective review of laryngotracheal trauma at two major hospitals between 1996 and 2004, Bhojani et al identified 52 patients who had sustained penetrating laryngotracheal injury.24 There were 26 GSWs and 24 SWs; 24 of the 52 patients required an emergency airway. Endotracheal intubation was performed in 20, tracheotomy in 3, and cricothyrotomy in 1. One patient, who was previously intubated, subsequently required emergency cricothyrotomy in the OR. Twelve of the patients who were intubated or who underwent cricothyrotomy required revision to tracheotomy. An additional seven patients required operative tracheotomy. The authors concluded that either routine intubation or a tracheotomy can be used to secure the airway.24

In a retrospective study of aerodigestive injuries of the neck, Vassiliu et al reviewed 1562 patients with neck trauma and identified 998 patients who had sustained penetrating injury.9 There were 432 GSWs and 524 SWs during the 5-year study period. Blunt trauma produced aerodigestive injury in 7 patients, GSWs in 44, and SWs in 25. Forty-two patients with other penetrating mechanisms did not sustain aerodigestive injury. Forty of the seventy-six patients with aerodigestive injury required an emergency airway in the ED, one of whom had sustained blunt trauma. Orotracheal intubation was successful in 28 patients. In nine patients orotracheal intubation failed, and a cricothyrotomy was performed. Flexible endoscopic intubation was performed in three patients. Of the 38 patients with laryngotracheal trauma, 20 required an emergency airway in the ED. Flexible endoscopic nasotracheal intubation was performed in one patient. Of the remaining patients, RSI failed in five and a cricothyrotomy was performed. The failure rate for RSI was 23% in the GSW group and 20% in the SW group. Twenty-five of 49 patients with isolated pharyngoesophageal injuries required an emergency airway, 16 due to airway compromise secondary to pharyngeal hematoma, and 9 due to shock. RSI was successful in 17 of these 25 patients. A flexible endoscopic intubation was performed in three patients and a cricothyrotomy in five. The authors concluded that RSI is the easiest technique in most cases of aerodigestive injury. However, in the presence of large hematomas, RSI can be difficult and potentially dangerous.9 If an RSI is undertaken, an experienced practitioner should be ready to perform a surgical airway, should the orotracheal intubation fail. In 22.5% of attempted RSI in this study, the airway was lost and a cricothyrotomy was necessary, highlighting the importance of the concept of a double set-up. The authors suggest that flexible endoscopic nasotracheal intubation is the safest approach provided that the patient has adequate cardiovascular stability.9

Bumpous et al performed a retrospective review of 16 patients with penetrating injury to the visceral compartment of the neck who were treated in a level I trauma center over an 8-year period.28 There were nine handgun injuries, one shotgun injury, five stab wounds, one razor slash, and two victims of penetrating trauma associated with a motor vehicle accident. Three patients sustained zone I injury, eleven zone II injury, and two patients, zone III injury. Eleven patients sustained tracheal injury, six esophageal injury, and five laryngeal injury. Multiple sites of aerodigestive tract injury occurred in 13 patients. Tracheotomy was required in 12 of the 16 patients.

Gussack et al reported a series of 117 patients with PNI of whom 8 had penetrating laryngotracheal injury.63 Of these eight patients with penetrating laryngotracheal injury, six underwent orotracheal intubation and two were intubated through the wound.63 Four of those who underwent orotracheal intubation subsequently required tracheotomy. Both patients intubated through the wound required tracheotomy. No untoward effect occurred related to the orotracheal intubation.63 The authors also reviewed an additional 392 cases of laryngotracheal trauma from 12 published series which included 123 cases of penetrating trauma. Seventy-three percent of the 392 cases required a tracheotomy. Gussack et al also reported a series of 12 patients with penetrating trauma to the laryngotracheal complex.59 The mechanism of injury was GSW in five patients and SW in seven. Nine of the patients with penetrating laryngotracheal injury required active airway control and were orally intubated. Three required an emergency tracheotomy, two with SWs and one patient with a GSW. No intubation failures were reported. The authors felt that intubation is the primary method of airway control, and is generally more expeditious than tracheotomy in the majority of patients. However, they went on to state that the operator should move quickly to tracheotomy if intubation is difficult.59 Cricothyrotomy was said to be relatively contraindicated if laryngeal trauma is suspected59 although it is not clear that this is an evidence based position.

There is no uniform agreement on the airway management method of choice in penetrating neck injury.3 Controversy persists and management varies from institution to institution.2 The method chosen must depend on the practitioner's expertise with the various approaches2 and, in general, the technique with which the practitioner is most comfortable is utilized.55 However, familiarly with multiple approaches to secure the airway is required as success with any single technique is not guaranteed,55 and back up plans must be in place should the primary technique fail.22 In most cases, an orotracheal intubation is the easiest and most appropriate technique.1,2 The use of rapid-sequence intubation in PNI was reported by Shearer et al with a success rate of 98%35 and by Mandavia et al with a success rate of 100%.61 Bell et al reported 2 failed and 48 successful oral intubations in PNI.7 However, Eggen and Jorden reported 8 out of 26 initially unsuccessful intubations in PNI, 4 of which were failed oral intubation.30 Gussack et al reported successful orotracheal intubation in penetrating laryngotracheal injury.59,63 However, Vassiliu et al reported a failure rate of 22.5% with RSI in penetrating aerodigestive injury.9 Rapid-sequence intubation can be difficult and potentially dangerous in the presence of PNI and should only be undertaken if judged likely to be successful and the personnel and equipment necessary to establish a surgical airway must be immediately available should the intubation fail (ie, a double set-up).

Awake flexible endoscopic intubation has been advocated as the safest method for most patients with PNI and should be considered in all cooperative patients with suspected airway injury.3 However, this technique may only be feasible in stable patients who are not in severe respiratory distress, and is usually not possible in combative patients or when immediate airway control is required.3,8 The nasal route may require less patient cooperation. The flexible endoscopic technique has the advantage that airway injuries may be identified and the endotracheal tube can be passed distal to the injury. The flexible bronchoscope can also be used to perform the intubation as part of a rapid-sequence intubation technique.8 This variation of technique may be useful in combative patients who otherwise do not have predictors of difficult intubation.8 In the moribund or apneic patient, or in the presence of massive upper airway bleeding, awake orotracheal intubation may be the most expeditious approach.8

If an airway must be immediately established and endotracheal intubation fails, then cricothyrotomy is indicated.9,22,44,60 Conversion to tracheotomy can be performed as soon as the clinical situation permits.44 Cricothyrotomy has also been considered to be contraindicated if the exact location of the airway injury is unknown3 and tracheotomy had been advocated in this setting.3 In the presence of laryngotracheal injury, if uncertainty exists about the difficulty or safety of intubation, an awake tracheotomy under local anesthesia can be performed under controlled conditions if the patient's condition permits.2,44,60 However, an awake tracheotomy requires patient cooperation and the difficulties associated with the performance of a surgical airway in the presence of anatomic distortion in a restless hypoxic patient cannot be overemphasized.8 In extreme circumstances in which a surgical airway is immediately required, most practitioners would consider a cricothyrotomy to be the procedure of choice.30,39 and emergency tracheotomy is not considered an appropriate method to establish an emergency definitive airway.27 Blind nasal intubation has been reported in the management of PNI with a success rate of 90%.64 However, most authors agree that blind intubation techniques should not be used in PNI because of the risk of producing further injury and complete airway obstruction.3

34.4.2 How Was the Patient's Airway Managed?

The patient developed increasing respiratory distress following arrival in the ED. A surgeon, an anesthesiologist, and an emergency physician were at the bedside. Options for airway management were discussed. No bronchoscope was immediately available. The degree of respiratory distress rapidly increased and awake tracheotomy was not considered to be feasible. A rapid-sequence intubation (RSI) was initiated. The necessary equipment was opened and the surgeon was ready to perform a surgical airway should intubation fail.

On direct laryngoscopy a Grade 3 (epiglottis only) view was obtained with a #4 MacIntosh blade. The Eschmann tracheal introducer (bougie) was successfully passed on the first attempt and an 8.0-mm ID endotracheal tube (ETT) easily passed into the trachea over the bougie. Edema of the pharynx and larynx was noted. Endotracheal tube position was confirmed by colorimetric carbon dioxide analysis.

34.5.1 What Investigations Are Appropriate in the Stable Patient with PNI?

Patients who do not have airway compromise and who are hemodynamically stable should undergo further diagnostic evaluation based on the findings on physical examination.7 The evaluation and management of PNI must also be tailored to the diagnostic capabilities in the individual institution and the experience and availability of personnel.2 Stable patients who have suspected aerodigestive injury on examination require further investigation. Cervical spine and chest x-rays can be done as part of the initial trauma resuscitation. Flexible endoscopy is the investigation of choice for suspected laryngotracheal trauma.8 Direct laryngoscopy may also be used in the evaluation of laryngeal trauma.53,60 The diagnostic imaging procedure of choice in the evaluation of suspected laryngeal injury is high-resolution CT scanning, which provides the most complete radiologic assessment of the larynx.60,65 However, CT scanning cannot be recommended as a replacement for triple endoscopy (pharyngolaryngoscopy, esophagoscopy, and bronchoscopy) in PNI65 and controversy exists with regard to the utility of CT scanning in the evaluation of laryngeal injury.44 The pharynx and cervical esophagus can be evaluated by endoscopy or contrast swallow studies or both modalities.8 Rigid esophagoscopy may be more reliable than flexible esophagoscopy or esophagraphy for the diagnosis of cervical esophageal injury.8 Catheter angiography continues to be the gold standard for the evaluation of suspected vascular injury and has well-documented efficacy.7,66-69 However, Rivers et al in a retrospective study concluded that the angiogram result did not alter management in zone II penetrating neck injuries.70 Furthermore angiography is invasive and has an associated complication rate of 0.16% to 2.0%.70 In a study of 223 patients with PNI, 176 underwent angiography.5 Abnormalities were detected in 34 patients, of whom 14 required treatment of the vascular lesion.5

Helical and multislice CT angiography (CTA) has emerged as a fast and minimally invasive study for the evaluation of PNI.7 This technology permits accurate evaluation of vascular and extravascular soft tissue and bone in less than 2 to 3 minutes and is readily available in most trauma centers.7 Signs of vascular, aerodigestive, neurologic, and bony injury are well demonstrated by CTA.7 Mazolewski et al, in a prospective study of zone II PNI, determined the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT angiography for significant injury to be 100%, 91%, 75%, and 100%, respectively.71 Inaba et al in a prospective study of PNI reported that multidetector CT angiography (MCTA) achieved 100% sensitivity and 93.5% specificity in detecting all vascular and aerodigestive injuries.72 Helical CTA (HCTA) has been compared to conventional angiography for the diagnosis of arterial injuries of the neck in several studies, and a sensitivity and specificity for HCTA as high as 90% to 100% has been reported.7,71,73-75 In 2002, Munera et al reported a sensitivity of 100% and specificity of 98.6% in the evaluation of arterial injury in PNI.76

Color flow Doppler imaging and duplex ultrasonography have also been used in the evaluation of penetrating neck injury.2,8,55

X-rays of the cervical spine and chest revealed surgical emphysema in the neck, a left upper lung field opacity compatible with contusion or hemothorax, and a bullet fragment over the left scapula.

Following intubation the patient was taken to the CT scanner sedated and paralyzed. An enhanced CT scan revealed no vascular injury in the neck. Extensive surgical emphysema was present but no airway injury was identified.

34.5.2 What Is the Appropriate Disposition of the Patient with PNI?

Unstable patients are taken urgently to the OR. Stable patients without airway compromise undergo evaluation as directed by the physical examination. If a significant injury is identified, surgical management is undertaken as indicated. If no signs or symptoms of significant injury are present, and no injury is identified on further investigation, then observation is appropriate.

The patient was taken to the OR for neck exploration. In the OR, a rigid pharyngolaryngoscopy, flexible bronchoscopy, and flexible esophagoscopy were performed. No penetrating injury was identified although the cephaled trachea could not be examined due to presence of the ETT. Edema of the pharynx and larynx was again noted. On neck exploration penetrating injury to the trachea at the third and fourth tracheal rings was identified and repaired, and a tracheotomy was performed. The projectile tract was followed to the level of the cervical spine. Soft tissue disruption was noted in the tracheoesophageal groove and raised the likelihood of recurrent laryngeal nerve injury.

Nasopharyngoscopy was performed on postoperative day 2 and confirmed vocal cord palsy. The patient was decannulated on postoperative day 3.

On follow-up examination 1 month postoperatively, the patient had no shortness of breath but was still hoarse. Endoscopy revealed a persistently paralyzed vocal cord and minimal narrowing at the site of the tracheal injury.

Optimal management of PNI requires knowledge of the anatomy of the neck, an understanding of the mechanism of injury, careful clinical examination, and investigation as directed by the physical examination. Management of the traumatized airway can prove to be the ultimate test of a practitioner's technical skills27 and clinical judgment.