B. Full Stomach. A full stomach is a background condition in acute trauma. (Urgency of securing the airway often does not permit adequate time for pharmacologic measures to reduce gastric volume and acidity.) After locating the cricothyroid membrane and denitrogenating the lungs, a rapid sequence induction may be used to permit securing the airway with direct laryngoscopy or, if necessary, with immediate cricothyroidotomy.

C. Head, Open-Eye, and Contained Major Vessel Injuries

1. These patients require deep anesthesia and profound muscle relaxation before airway manipulation (helps prevent hypertension, coughing, and bucking and thereby minimizes intracranial, intraocular, or intravascular pressure elevation, which can result in herniation of the brain, extrusion of eye contents, or dislodgment of a hemostatic clot from an injured vessel).

2. The preferred anesthetic sequence in patients who are not hemodynamically compromised includes preoxygenation and opioid loading followed by relatively large doses of an intravenous (IV) anesthetic and muscle relaxant (prevent fasciculations produced by succinylcholine).

II. CERVICAL SPINE INJURY. Overall, 2% to 4% of blunt trauma patients have cervical spine (C-spine) injuries (most often motor vehicle accidents), of which 7% to 15% are unstable.

A. Initial Evaluation. Accurate and timely evaluation is important because 2% to 10% of patients with blunt trauma–induced C-spine injury develop new or worsening neurologic deficits after admission.

1. Clearance of the neck at the earliest possible time after airway management should be performed to minimize the complications associated with the collar such as pressure ulceration, intracranial pressure (ICP) elevation in head-injured patients, compromised central venous access, and airway management challenges if reintubation is needed.

2. Routine computed tomography (CT) in addition to clinical evaluation is recommended to rule out C-spine injury in major trauma victims.

3. The Canadian C-spine rule for radiography after trauma is a tool designed to identify low-risk patients (Fig. 52-2).

B. Airway Management. Almost all airway maneuvers, including jaw thrust, chin lift, head tilt, and oral airway placement, result in some degree of C-spine movement. To secure the airway with direct laryngoscopy, manual in-line stabilization (MILS) of the neck is the standard care of these patients in the acute stage. A hard cervical collar alone, which is routinely placed, does not provide absolute protection, especially for rotational movements of the neck.

1. MILS is best accomplished by having two operators in addition to the physician who is actually managing the airway. The first operator stabilizes and aligns the head in neutral position without applying cephalad traction, and the second stabilizes both shoulders by holding them against the table or stretcher.

FIGURE 52-2. Canadian cervical spine (C-spine) rule designed to diagnose C-spine injury and identify patients who require further radiographic (computed tomography) evaluation. (Adapted with permission from Stiell IG et al: The Canadian C-Spine rule versus the NEXUS low-risk criteria in patients with trauma.) CT = computed tomography; ED = emergency room; MVA = motor vehicle accident.

2. In the presence of MILS, the glottic view may be suboptimal in 10% to 15% of patients during direct laryngoscopy because of limitation of neck extension.

a. The more the restriction of the glottic view during direct laryngoscopy, the greater the pressure on the tongue, the spine, and the unstable segment with potential displacement of the unstable fragment.

b. During various phases of direct laryngoscopy and intubation, the pressures exerted on the tongue and indirectly to the spine are greater with MILS than without MILS. Nevertheless, it cannot be concluded airway management without MILS is associated with a favorable spinal cord outcome. However, it is reasonable to allow some relaxation of the MILS to improve the glottic view when visualization of the larynx is restricted.

III. DIRECT AIRWAY INJURIES. Direct airway damage can occur anywhere between the nasopharynx and the bronchi.

A. Maxillofacial Injuries. In addition to soft tissue edema of the pharynx and peripharyngeal hematoma, blood or debris in the oropharynx may be responsible for partial or complete airway obstruction in the acute stage of these injuries.

1. Serious airway compromise may develop within a few hours in up to 50% of patients with major penetrating facial injuries or multiple trauma as a result of progressive inflammation or edema resulting from liberal administration of fluids.

2. Fracture-induced encroachment on the airway or limitation of mandibular movement, pain, and trismus may limit mouth opening. (Fentanyl in titrated doses of up to 2–4 μg/kg over a period of 10–20 minutes may produce an improvement in the patient’s ability to open the mouth if mechanical limitation is not present.)

3. Most patients with isolated facial injuries do not require emergency tracheal intubation. Surgery may be delayed for as long as 1 week with no adverse effect on the repair. Alternatively, tracheostomy may be indicated as an emergency procedure.

B. Cervical Airway Injuries. Clinical signs such as air escape, hemoptysis, and coughing are present in almost all patients with penetrating injuries, facilitating the diagnosis. In contrast, the patient with major blunt laryngotracheal damage may asymptomatic or not recognized because suggestive signs and symptoms are missed in the initial evaluation (hoarseness, muffled voice, dyspnea, stridor, dysphagia)

1. A CT scan of the neck provides valuable information and should be performed before any airway intervention in all stable patients.

2. Laryngeal damage precludes cricothyroidotomy. Tracheostomy should be performed with extreme caution because up to 70% of patients with blunt laryngeal injuries may have an associated C-spine injury.

C. Thoracic Airway Injuries. Blunt injury usually involves the posterior membranous portion of the trachea and the mainstem bronchi, usually within approximately 3 cm of the carina.

1. In patients intubated without the suspicion of a tracheal injury, difficulty in obtaining a seal around the endotracheal tube or the presence on a chest radiograph of a large radiolucent area in the trachea corresponding to the cuff suggests a perforated airway.

2. Anesthetics, and especially muscle relaxants, may produce irreversible obstruction, presumably because of relaxation of structures that maintain the airway patent in the awake patient. Airway loss may also occur during attempts at awake intubation.

IV. MANAGEMENT OF BREATHING ABNORMALITIES. Of the several causes that may alter respiration after trauma, tension pneumothorax, flail chest, and open pneumothorax are life threatening.

A. Although cyanosis, tachypnea, hypotension, neck vein distention, tracheal deviation, and diminished breath sounds on the affected side are the classic signs of tension pneumothorax, neck vein distention may be absent in hypovolemic patients, and tracheal deviation may be difficult to appreciate.

1. The definitive diagnosis is made by CT scanning.

2. In hypoxemic and hypotensive patients, immediate insertion of a 14-gauge angiocatheter through the fourth intercostal space in the midaxillary line or, at times, through the second intercostal space at the midclavicular line is essential. (There is no time for radiologic confirmation in this setting.)

B. A flail chest results from fractures of more than two sites of at least three adjacent ribs or rib fractures with associated costochondral separation or sternal fracture.

1. It often develops over a 3- to 6-hour period, causing gradual deterioration of the chest radiograph and arterial blood gases (ABGs).

2. Effective pain relief by itself can improve respiratory function and often avoid the need for mechanical ventilation (continuous epidural analgesia).

3. Ventilation with low tidal volumes (6–8 mL/kg) and moderate positive end-expiratory pressure (PEEP) producing low inspiratory alveolar or plateau pressures appears to be the best pattern to prevent deterioration of hemodynamics and decrease the likelihood of acute respiratory distress syndrome (ARDS).

4. Systemic air embolism occurs mainly after penetrating lung trauma and blast injuries or less frequently after blunt thoracic trauma that produces lacerations of both distal air passages and pulmonary veins. (Positive-pressure ventilation after tracheal intubation may then result in entrainment of air into the systemic circulation.)

a. Respiratory maneuvers that minimize or prevent air entry into the systemic circulation include isolating and collapsing the lacerated lung by means of a double-lumen tube or ventilation with the lowest possible tidal volumes via a single-lumen tube.

b. Transesophageal echocardiography (TEE) of the left side of the heart may permit visualization of air bubbles and their disappearance with therapeutic maneuvers.

V. MANAGEMENT OF SHOCK. Hemorrhage is the most common cause of traumatic hypotension and shock and is, after head injury, the second most common cause of death after trauma (Table 52-1).

A. Patients with significant intra-abdominal fluid recognized with these tests and hemodynamic instability require immediate surgical intervention.

B. Those who are suspected to have occult abdominal bleeding based on a high-risk mechanism of injury but who are hemodynamically stable must undergo further evaluation with CT.

C. Clinical assessment using hemodynamic data is based on a few relatively insensitive and nonspecific clinical signs. (Tachycardia as an index of hypovolemia may be absent in up to 30% of hypotensive trauma patients because of increased vagal tone.)

1. Although traditional vital signs are relatively unreliable for recognizing life-threatening shock, heart rate, systemic blood pressure, pulse pressure, respiratory rate, urine output, and mental status are still used as early clinical indicators of the severity of hemorrhagic shock (Table 52-2).

2. The response to initial fluid resuscitation in the form of lactated Ringer’s solution (LRS) or normal saline solution of about 2 L or 20 mL/kg in children over a period of 15 to 30 minutes may permit estimation of the severity of hemorrhage (Table 52-3).

D. Crystalloids are used in the vast majority of trauma centers for initial resuscitation. (There is no difference in the mortality rate between patients receiving crystalloids and those receiving colloids.) Hydroxyethyl starch solutions (maximum, 20 mL/kg) should probably be given priority over albumin solutions. (Possible deleterious effects of colloids have mostly been associated with albumin.)

TABLE 52-1 GUIDELINES FOR MANAGEMENT OF TRAUMATIC SHOCK

BP = blood pressure; ED = emergency department.

Reproduced with permission from American College of Surgeons, Committee on Trauma. Shock, Advanced Trauma Life Support Student Course Manual. Edited by the American College of Surgeons, 8th ed. Chicago: American College of Surgeons; 2008:55–71.

^*For a 70-kg male patient based on initial presentation.

^†The 3:1 rule is based on empiric observation that most patients require 300 mL of balanced electrolyte solution for each 100 mL of blood loss. Without other clinical and monitoring parameters, this guideline may result in excessive or inadequate fluid resuscitation.

Adapted with permission from American College of Surgeons, Committee on Trauma: Shock, Advanced Trauma Life Support Student Course Manual. Edited by the American College of Surgeons, 8th ed. Chicago: American College of Surgeons; 2008:55–71.

TABLE 52-2 ADVANCED TRAUMA LIFE SUPPORT CLASSIFICATION OF HEMORRHAGIC SHOCK*

*For a 70-kg male patient based on initial presentation.

E. Some of the proven markers of organ perfusion can be used during early management to set the goals of resuscitation. Of these, the base deficit and blood lactate level are the most useful and practical tools during all phases of shock, including the earliest.

1. Base deficit is considered a better prognostic marker than the arterial pH. (Normalization of the base deficit is one of the end points of resuscitation.)

2. Elevation of the blood lactate level is less specific than base deficit as a marker of tissue hypoxia. Nevertheless, in most trauma victims, an elevated lactate level correlates with other signs of hypoperfusion, rendering it an important marker of dysoxia and an end point of resuscitation.

TABLE 52-3 RESPONSE TO INITIAL FLUID ADMINISTRATION*

^*2,000 mL of isotonic solution in adults; 20 mL/kg bolus of lactated Ringer’s solution in children.

F. Measurement of hemoglobin (Hgb) or hematocrit (Hct) helps in managing bleeding trauma patients. However, decision making based on a single Hct value may lead to erroneous management decisions. (Trauma patients, if not treated with adequate crystalloids or colloids, or those receiving packed red blood cell [PRBC] transfusion, can maintain a normal Hct despite ongoing bleeding.)

1. Serial Hct measurements and consideration of the type and amount of fluid received may be useful in deciding the timing and amount of transfusion.

2. The recommended target Hgb concentration in all phases of management is 7 to 9 g/dL, including brain-injured patients in whom tissue oxygenation is most relevant. This concern should not preclude timely and adequate administration of blood products.

FIGURE 52-3. Schematic representation of the “bloody vicious cycle” or “lethal triad.” Trauma-induced hemorrhage causes acidosis, hypothermia, and coagulopathy. Acidosis and hypothermia produce factor and platelet dysfunction, enhancing coagulopathy, which in turn causes increased bleeding. The cycle continues until death ensues unless effective treatment by timely control of bleeding and correction of acidosis, hypothermia, and coagulopathy is instituted.

G. One of the principal goals during early management of a hemorrhaging trauma victim is to avoid the development of the so called “vicious cycle” or “lethal triad” consisting of acidosis, hypothermia, and coagulopathy (Fig. 52-3).

1. Both acidosis and hypothermia are major factors in the induction of coagulopathy.

2. Bleeding and intravascular coagulation further augment coagulopathy via loss or consumption of damaged or depleted platelets and coagulation factors.

3. The practice of administering large volumes of crystalloids, colloids, and PRBCs with no hemostatic components for initial resuscitation is considered to be the major factor in the development of often lethal coagulopathy.

4. Rapid establishment of venous access with large-bore cannulae placed in peripheral veins that drain both above and below the diaphragm is essential for adequate fluid resuscitation in a patient who is severely injured. (Ultrasound guidance may facilitate cannulation of the internal jugular vein.)

VI. EARLY MANAGEMENT OF SPECIFIC INJURIES

A. Head Injury. Approximately 40% of deaths from trauma are caused by head injury, and even a moderate brain injury may increase the mortality rate of patients with other injuries. Of all the possible secondary insults to the injured brain, decreased oxygen delivery as a result of hypotension and hypoxia has the greatest detrimental impact.

1. Diagnosis. If consciousness remains depressed despite ventilation and fluid replacement, a head injury is assumed to be present, and the patient is managed accordingly.

a. Every effort should be made to support the blood pressure with fluids and vasopressors (preferably phenylephrine, which does not constrict cerebral vessels).

b. A baseline neurologic examination should be performed after initial resuscitation but before any sedative or muscle relaxant agents are administered and should be repeated at frequent intervals because the patient’s condition may change rapidly (Table 52-4).

c. Dilatation and sluggish response of the pupil is a sign of compression of the oculomotor nerve by the medial portion of the temporal lobe (uncus). A maximally dilated and unresponsive “blown” pupil suggests uncal herniation under the falx cerebri.

d. CT scanning is used for the diagnosis of most acute head injuries (midline shift, distortion of the ventricles and cisterns, effacement of the sulci in the uninjured hemisphere, and the presence of a hematoma at any location in the cranial vault). Patients in severe coma (Glasgow Coma Scale [GCS] score <8) have a 40% likelihood of an intracranial hematoma.

2. Management. The most important therapeutic maneuvers in these patients are aimed at normalizing ICP, cerebral perfusion pressure (CPP), and oxygen delivery. Primary therapy includes normalization of the systemic blood pressure (mean blood pressure >80 mm Hg) and maintaining the PaO₂ >95, the ICP <20 to 25 mm Hg, and the CPP at 50 to 70 mm Hg.

a. The patient is kept at 30 degrees of head elevation; sedation and paralysis are given as necessary; and cerebrospinal fluid is drained through a ventriculostomy catheter, if available.

TABLE 52-4 TWO-LEVEL INITIAL EVALUATION OF CONSCIOUSNESS