54: Trauma

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CHAPTER 54 Trauma

James Duke, MD, MBA

1 Review conditions that predispose trauma patients to increased anesthetic risk

A depressed level of consciousness may lead to hypoventilation, loss of protective airway reflexes, inappropriate behavior, and decreased ability to examine and interview the patient. Full stomachs increase the risk of pulmonary aspiration of gastric contents. Because of blood loss, hypothermia, alcohol and drug intoxication, and organ injury, these patients are prone to altered responsiveness to anesthetic agents.

2 Outline the initial management of an unconscious, hypotensive patient

The ABCs (airway, breathing, and circulation) are essential. Unconscious patients require rapid and definitive airway control. The trachea should be intubated in a rapid-sequence fashion. Establish numerous large-gauge sites of intravenous access, using either short 14- or 16-G catheters peripherally or 9 Fr introducers into the central circulation. Quickly bolus the patient with at least 2 L of balanced crystalloid solution. Failure to respond indicates a need for blood. If crossmatched blood is unavailable, transfuse O-negative or type-specific red blood cells. If more than 2 units of O-negative red bloods cells is given, continue administering O-negative blood. Establish an arterial catheter for continuous monitoring and blood analysis (arterial blood gases, hematocrit, platelet count, coagulation profiles, and blood chemistries).

3 What is the significance of Glasgow Coma Scale (GCS) score of 8?

The GCS is an assessment for patients with head injury. The final score is the sum of scores for best eye opening, best motor and best verbal responses; scores range from 3 to 15. Generally, the GCS for severe head injury is 9 or less; for moderate injury, 9–12; and for minor injury, 12 and higher. A patient with a GCS of 8 is sufficiently depressed that endotracheal intubation is indicated (see Table 54-1).

TABLE 54-1 Glasgow Coma Scale*

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4 Describe the changes in vital signs associated with progressive blood loss

See Table 54-2.

TABLE 54-2 Changes in Vital Signs with Progressive Blood Loss

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5 What is the initial therapy for hypovolemic shock?

Initially replace estimated blood losses with balanced crystalloid solutions. The volume administered is three or four times the estimated blood loss. Continued hemodynamic instability suggests that blood transfusion is necessary, although other causes of hypotension such as head injury, hemothorax, tension pneumothorax, or pericardial tamponade should be considered. Patients who have lost more than 25% or 30% of their blood volume may likely require transfusion with packed red blood cells.

6 Why is rapid-sequence induction preferred for airway management in trauma patients?

Rapid-sequence induction is used because trauma patients are at risk for pulmonary aspiration of gastric contents and it minimizes the time between loss of consciousness and airway protection with a cuffed endotracheal tube (ETT). The usual rapid-sequence induction begins with preoxygenation with 100% oxygen. A cardiostable induction agent (ketamine or etomidate) in reduced doses is chosen in the unstable patient. The moribund patient may require only paralysis. A rapid-acting relaxant, usually succinylcholine (SCh), is chosen. Before induction, pressure is applied firmly over the cricoid ring (Sellick maneuver) to prevent regurgitation of gastric contents. The patient is intubated as soon as adequate muscle relaxation is achieved (usually around 45 to 60 seconds). The presence of end-tidal CO2 is confirmed, and breath sounds are assessed before release of cricoid pressure.

7 How does an uncleared cervical spine modify the approach to the airway?

Patients requiring emergent surgical procedures do not have time to have their cervical spines evaluated fully. There is no airway management technique that results in no cervical motion. However, there is no documentation of iatrogenic neurologic injury in patients with cervical fractures when cervical spine precautions are used. These precautions include an appropriately sized Philadelphia collar, sand bags placed on each side of the head and neck, and the patient resting on a hard board with the forehead taped and secured to it.

Alternative airway management techniques in the traumatized patient include rapid-sequence induction with in-line stabilization, use of the Bullard laryngoscope, blind nasal intubation, and fiber-optic bronchoscopic-assisted ventilation. A Glidescope is a laryngscope with a camera lens on its tip and is very useful when a patient’s neck must be maintained in a neutral position. An unstable or uncooperative patient likely would receive a rapid-sequence induction.

When a cervical fracture or cervical spinal cord injury (SCI) is documented, most anesthesiologists choose fiber-optic intubation facilitated by some form of topical anesthesia to the airway and sedation, titrated to effect, keeping in mind the patient’s other injuries and hemodynamic status. This allows postintubation assessment of neurologic status before induction of unconsciousness. It would not be advisable to ablate all protective airway reflexes in a patient with a full stomach.

8 Which induction agents are best for trauma patients?

Far more important than the particular drug is the dose given because most induction agents produce hypotension through loss of sympathetic tone. Ketamine may be the best agent in the hypovolemic patient because its sympathetic stimulation supports the blood pressure; it should be recognized that on occasion its direct myocardial depressant effects may result in hypotension. It is contraindicated in patients with increased intracranial pressure because it increases cerebral blood flow. Etomidate may be used in some trauma patients because of its minimal effect on hemodynamic variables; however, it will decrease sympathetic tone in patients probably relying on enhanced autonomic tone to maintain cardiac output; thus reductions in usual doses are appropriate. It also depresses adrenal function, although the impact of one dose is unclear.

9 Why are trauma patients hypothermic?

Hypothermia results from the same events as in any surgical patient, including loss of hypothalamic regulation, peripheral vasodilation, and exposure within a cold environment. However, trauma patients are often hypothermic on arrival to the hospital because of environmental exposure, are often not well covered during their diagnostic period, and may be receiving unwarmed intravenous fluids and blood. Hypothermia also contributes to coagulopathy. The following strategies are recommended:

image Warm the room before arrival.
image Warm all fluids and blood products.
image Use convective air-warming blankets and cover all nonprepped exposed skin surfaces.
image Warming of gases is not particularly useful because the heat content of gas is negligible.

10 What is meant by damage control surgery?

Damage control is the principle of performing the minimum necessary interventions to save life and limb, leaving further reconstructive procedures to a later time, after the patient has obtained hemodynamic stability.

From a historical view, patients would present with life-threatening injuries (e.g., high-grade liver lacerations) and undergo heroic surgical procedures with massive blood loss. As a consequence of the aggressive surgical efforts, the patients would become hypothermic, acidotic, and coagulopathic (the lethal triad) and often succumb to these complications.

In the present day the same patient might be submitted to an abbreviated damage control procedure. For a liver laceration the injured surface of the liver is packed with surgical sponges to temporize bleeding while the anesthesia team concentrates on resuscitation. Once stabilized, the patient’s abdominal cavity is covered with a sterile dressing, and the resuscitative efforts continue in the intensive care unit. Perhaps only the next day when the patient has stabilized is he or she returned to the operating room and re-explored and further procedures undertaken as indicated. The damage control philosophy has been embraced by other surgical disciplines as well, particularly orthopedics.

11 How have damage control concepts been applied in orthopedic injuries?

Many patients with femur or pelvic fractures have multisystem injuries and are hemodynamically unstable. Pulmonary contusions can be problematic in these patients because reaming of the femoral canal for intramedullary nailing can shower the lungs with fat emboli at a vulnerable period, propagating an inflammatory reaction that may lead to increased morbidity (e.g., adult respiratory distress syndrome, prolonged intensive care stays and hospitalizations, and increased ventilator days) and mortality. Rather than perform definitive surgery at the time of injury, damage control is practiced by using temporary external fixation as a bridge until the patients are better able to tolerate internal fixation.

12 What is the universal theory of the compartment syndrome?

Increased pressure within any semi-rigid anatomic structure will increase to the point at which perfusion is diminished by the increasing pressure. This can apply to the cranium, thorax, pericardium, abdomen, and extremities. Failure to recognize and rapidly treat any compartment syndrome results in increased morbidity and may result in death.

13 How does cardiac tamponade present? What is Beck’s triad? How should anesthesia be managed in a patient with tamponade?

Cardiac tamponade may arise from either blunt or penetrating trauma. When bleeding into the pericardial space increases pericardial pressures, cardiac filling is impaired. Positive-pressure ventilation further decreases venous return and may greatly exacerbate the reduction in cardiac output. Stroke volume decreases, and tachycardia compensates for a time to increase cardiac output. Beck’s triad consists of hypotension, distant heart sounds, and distended neck veins, the classic signs associated with cardiac tamponade, although neck vein distention may not be observed because of hypovolemia. Electrical alternans, in which the major electrocardiogram (ECG) axis is constantly changing, may be noted. This is because the heart floats freely in the expanded pericardium.

A patient with tamponade is at risk for cardiovascular collapse with anesthetic induction. Because of this, it may be wise to drain the pericardium using local anesthesia at the operative site (a subxiphoid pericardial window) before general anesthetic induction.

14 What is the significance, clinical presentation, and treatment of a tension pneumothorax?

Patients may sustain a pneumothorax in association with trauma such as rib fractures, stab wounds, and central line placement. If the pleural cavity does not communicate with the ambient environment, air may accumulate between the chest wall and lung and may expand quickly with positive-pressure ventilation. Eventually a tension pneumothorax decreases venous return to the thorax and causes torsion of mediastinal vessels, leading to cardiovascular collapse.

The chest may rise unevenly with inspiration, breath sounds become unequal, the hemothorax is tympanitic to percussion, and the trachea may shift away from the affected side. Neck veins may become distended if the patient is normovolemic. Airway pressures rise.

The immediate treatment is the placement of a large-bore needle through the chest wall in the second intercostal space in the midclavicular line. A rush of air confirms the diagnosis. The needle should be left in place until a tube thoracostomy is performed. Tension pneumothorax is a clinical diagnosis; do not delay treatment for radiologic confirmation of this life-threatening condition. Nitrous oxide should not be used in trauma patients because it quickly diffuses into any air-filled cavity such as a pneumothorax.

15 What is the abdominal compartment syndrome?

A victim of polytrauma experiencing hypotension, oliguria, and respiratory failure manifesting as increasing airway pressures and decreasing oxygenation may have abdominal compartment syndrome (ACS). ACS is often noted after massive fluid and blood resuscitations, and the patient may be coagulopathic. Diagnosis is by clinical suspicion and confirmed by measuring bladder pressure (>25 cm H2O is suspicious). Treatment involves fluid resuscitation and abdominal decompression. The increased intra-abdominal pressures also increase intrathoracic pressures, and “normal” central pressures may actually be associated with hypovolemia. Thus it is usually wise to always respond to hypotension with a fluid bolus. However, excessive fluid administration may increase bowel edema, delaying later closure of the abdomen. Refractory intracranial pressure may be caused by ACS and improve with decompression.

16 What challenges do spinal cord–injured patients pose?

Airway management has been discussed briefly. The technique of choice depends on the urgency of the situation but might be direct laryngoscopy with in-line stabilization, intubation using a Bullard laryngoscope, or fiberoptic intubation. When moved, patients should be log-rolled; that is, rolled and moved with care to maintain the neck in a neutral position.

Some degree of neurogenic shock should be expected with injuries above the T6 level. However, hypotension in cord-injured patients is most likely caused by other injures. Catecholamine surges may produce pulmonary vascular damage, resulting in neurogenic pulmonary edema. There may be some element of myocardial dysfunction. If moderate fluid resuscitation does not result in hemodynamic improvement, central venous catheterization for monitoring may be required. Spinal cord injuries cephalad to midthoracic levels interrupt sympathetic cardioaccelerator fibers, resulting in bradycardia. If accompanied by hypotension, administration of atropine is indicated. Occasionally infusion of vasopressors such as phenylephrine is needed to support blood pressure. Anesthetic agents should be titrated carefully since drug-associated cardiovascular depression cannot be compensated for by increases in sympathetic tone. Doses of 30% to 50% of normal are likely to be sufficient. SCh may be administered in the first 24-hour period after cord injury but not thereafter to avoid the potential for life-threatening hyperkalemia.

Corticosteroids have been administered to cord-injured patients, although this remains controversial; universal application in this setting is dwindling. Corticosteroids are not without their own risks, including immunosuppression, hyperglycemia, and delayed wound healing.

Sympathetic tone eventually returns after injury, and sympathetic responses to stimuli distal to the injury may be exaggerated. Despite a loss of sensation, any surgical procedure or distention of a hollow viscus below the injury may produce life-threatening hypertension, termed autonomic hyperreflexia. Exaggerated reactions manifest as the patient moves into the period of spastic paralysis (4 to 8 weeks after injury) and beyond. The more distal the stimulus, the more exaggerated the reaction. Urologic procedures or fecal disimpaction, common procedures in chronic cord patients, are examples. All procedures on chronic cord-injured patients require some anesthetic to prevent or attenuate autonomic hyperreflexia. Neuraxial and inhalational anesthetics are usually satisfactory, although occasionally vasodilators such as nitroprusside are necessary to control hypertension.

17 Should succinylcholine be used in patients with spinal cord injury?

Within 48 to 72 hours after acute SCI, the denervated muscles respond with proliferation of extrajunctional acetylcholine receptors along the muscle cell membrane. When SCh is administered in the presence of extrajunctional receptors, a large release of potassium into the circulation results in ventricular fibrillation and cardiac arrest. Prior administration of a nondepolarizing muscle relaxant does not reliably decrease the potassium release associated with administration of SCh in patients with SCI. Ch should be avoided in patients with SCI.

18 Describe the presentation of a myocardial contusion

Blunt chest trauma may cause cardiac contusion. Associated injuries include sternal fractures, rib fractures, and pulmonary contusion. Dysrhythmias are common, the most common being sinus tachycardia with nonspecific ST segment changes. Conduction blocks and ventricular rhythms may also be observed. Patients may also sustain injury to valves or papillary muscles and sustain thrombosis to coronary arteries, most commonly the right coronary artery (presenting with ischemic changes in inferior ECG leads). The absence of dysrhythmias for 24 hours is reassuring. Pump failure is an ominous finding. Cardiac enzymes add little to the evaluation of a patient suspected of having a contusion. Echocardiography is perhaps the most useful test and in the presence of contusion reveals segmental wall motion defects. Urgent surgery need not be delayed in the presence of contusion, although the threshold for invasive monitoring is lower. Myocardial contusion is predominantly a clinical diagnosis.

KEY POINTS: Trauma image

1. The initial management of a trauma patient requires attention to the ABCs: airway, breathing, and circulation. Ensuring numerous large-gauge intravenous sites for resuscitation is a priority.
2. Precipitous cardiovascular collapse may be caused by cardiac tamponade, tension pneumothorax, or air embolism.
3. Unstable, hemorrhaging patients should receive O-negative, type-specific, or crossmatched blood if still unstable after resuscitation with 2 L of balanced crystalloid solution.
4. Transfusions of over 5 units of red blood cells require administration of plasma or platelets to address dilutional coagulopathy. In the setting of massive transfusion, it is the current practice to transfuse 1 unit of plasma with each unit of packed red blood cells. (See Chapter 6.)
5. The triad of hypothermia, acidosis, and coagulopathy is highly lethal; in this scenario damage-control surgical principles should be considered.

19 Describe the management of a pregnant trauma patient

The usual concerns for pregnant women apply. Because of airway edema and large breasts, airway management may be difficult, and these patients are at risk for pulmonary aspiration. The gravid uterus may render the patient hypotensive, especially if there has been blood loss. Patients should be positioned with left uterine displacement. Pregnancy is also a vasodilated state, confounding interpretation of vital signs. Probably because of the effects of progesterone, pregnant women have increased sensitivity to sedatives and local anesthetics. Pregnant women have dilutional anemia, confounding interpretation of the hematocrit. Consult an obstetrician concerning fetal viability. Seat belts may produce uterine rupture. If fetal distress occurs, an emergency cesarean section may be required, depending on fetal age. Aggressive resuscitation of the maternal circulation will improve the fetal circumstances. After surgery the patient may experience premature labor that may be masked by the administration of opioids for surgical pain. Monitoring uterine contractions and fetal heart tones is necessary.

20 Review concerns for the elderly trauma patient

Elderly patients may have significant, life-threatening injuries despite seemingly trivial mechanisms of injury. They have diminished organ reserves and numerous comorbidities. They are on numerous medications that may have led to the injury (e.g., benzodiazepines and other psychotropic medications) or may render them prone to bleeding (e.g., antiplatelet drugs, warfarin). They may easily lose airway protective reflexes, rendering them prone to aspiration, and have blunted cardiovascular reflexes as well. Elderly patients have increased mortality rates when compared to younger cohorts.

21 How might a bronchial or tracheal tear present? What are alternatives for managing ventilation during operative repair?

Large airway injuries usually occur within 2.5 cm of the carina and are usually immediately recognizable; distal bronchial injuries are more difficult to identify. Physical features that may be associated with these injuries include respiratory distress, subcutaneous or mediastinal air, hemoptysis, pneumothorax, and persistent large air leak after tube thoracostomy.

Any injury near the carina is likely to require lung isolation and single-lung ventilation. A single-lumen ETT might be inserted into the uninvolved main stem bronchus. Other options include inserting a double-lumen ETT or using a bronchial blocker. A fiber-optic bronchoscope is invaluable for any option chosen.

22 How is air embolism diagnosed and managed?

Penetrating lung injuries may result in systemic air entrainment via bronchovenous or alveolocapillary fistulas. Increased airway pressures associated with loss of pulmonary compliance and reduced venous pressure increase the likelihood of air embolism. Frothy, sanguineous secretions emanating from injured lung surfaces should make one wary of systemic air embolization. Air may be observed within coronary arteries. Systemic air embolism should be suspected whenever unexpected signs of central nervous system or myocardial ischemia and precipitous cardiovascular collapse occur in the appropriate clinical context. When treating patients at risk, minimize inspiratory airway pressure, avoid positive end-expiratory pressure, and administer small tidal volumes.

SUGGESTED READINGS

1. Bonatti H., Calland J.F. Trauma. Emerg Med Clin North Am. 2008;26:625-648.

2. Cereda M., Weiss Y.G., Deutschman C.S. The critically ill injured patient. Anesthesiol Clin. 2007;25:13-21.

3. Holcomb J.B., Jenkins D., Rhee P., et al. Damage control resuscitation: directly addressing the early coagulopathy of trauma. J Trauma. 2007;62:307-310.

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