Chapter 39 Trauma, Bioterrorism, and Natural Disasters
Acute management of trauma patients
1. Trauma is the most common cause of death in what age group?
2. What resources are available at hospitals specializing in trauma (e.g., “level 1” trauma centers)?
3. In reference to traumatic injuries, what is “The Golden Hour”?
4. What are the management priorities when caring for a trauma patient?
5. What is ATLS? What is its relevance to all trauma providers?
6. What are the “ABCDEs” of trauma?
7. A motor vehicle accident victim arrives with an endotracheal tube in situ, a blood pressure of 80/60, heart rate 120, and an obvious right ankle deformity with exposed bone. What is the first step in management of this patient?
8. List the indications for endotracheal intubation after life-threatening trauma.
9. Prior to the arrival of a trauma patient, what should providers do to prepare for possible endotracheal intubation?
10. What intravenous medications are most commonly used to intubate the trachea in severely injured patients?
11. In the context of traumatic brain injury, what is a plateau wave?
12. How should a trauma patient’s head be positioned for asleep endotracheal intubation if the stability of the cervical spine is unknown?
13. In the event of airway obstruction and an inability to perform endotracheal intubation, how should the airway be secured?
14. How is shock defined in trauma care? What blood pressure and heart rate values are consistent with shock?
15. What are the most sensitive and specific markers of shock in trauma patients?
16. Into what three anatomic spaces can a trauma patient massively hemorrhage? How would identification of orthopedic injuries limit internal bleeding?
17. What degree of chest tube output requires operative intervention?
18. What does persistent hematuria in a trauma patient indicate?
19. What is the treatment for hypovolemic shock following injury?
20. What is the definition of massive transfusion? What is the significance of blood product ratios in massive transfusion?
21. What is the Glasgow Coma Scale (GCS) and how is it used to evaluate a trauma patient? What GCS score is considered “severe”? Why do patients with severe traumatic brain injury (TBI) require endotracheal intubation, even if protecting their airway?
22. What secondary insults should be avoided in patients with traumatic brain injury?
23. At what intracranial pressure (ICP) is treatment frequently recommended? Name some methods used to treat an increased ICP.
24. What osmotic diuretic is commonly used to decrease an elevated ICP?
25. Why should glucose-containing intravenous solutions be avoided in patients with traumatic brain injury?
26. Should corticosteroids be administered to a patient with traumatic brain injury and signs of an elevated ICP?
27. When should hyperventilation be performed to decrease ICP? What is the danger of excessive hyperventilation?
28. When does a trauma patient require cervical spine stabilization at the time of initial assessment? How do trauma providers “clear” a patient’s cervical spine?
29. How is the “E” of the “ABCDEs” addressed in the initial evaluation of a trauma patient?
30. How does the initial evaluation of a burn injury patient differ from other trauma patients?
31. What are some indications for endotracheal intubation in the trauma patient with a burn injury? What is the danger of delaying endotracheal intubation in a patient with suspected inhalational injury?
32. How is the percentage of body surface area burned estimated in an adult?
33. Why should burn patients be initially placed on 100% oxygen, regardless of pulse oximetry reading?
34. Why do burn patients require larger than typical amounts of fluid resuscitation? What volume of intravenous fluid should be initially ordered?
35. What type of fluid should be used to resuscitate burn patients? Why do burn patients often receive a different volume over the first 24 hours than that initially calculated?
36. How should providers evaluate a patient with a suspected closed-head injury?
Emergency surgery for trauma
38. How does the time since a patient’s last meal affect the initial airway management of a trauma patient?
39. How does the maintenance of general anesthesia differ in emergency trauma surgery compared to elective outpatient surgery?
40. How can movement during surgery be prevented if a trauma patient is too unstable to tolerate high levels of general anesthetic agents?
41. What are the basic principles of intraoperative fluid management for trauma patients needing emergency surgery?
42. What diagnostic tests are used to guide intraoperative fluid therapy?
43. What preparations are needed prior to surgical opening of the peritoneum in an exploratory laparotomy for abdominal injuries?
44. What injuries might result from trauma to the abdomen? How is the diagnosis of intraabdominal hemorrhage made in a trauma patient?
45. What is “damage control” surgery and how does it benefit trauma patients?
46. What is the treatment for a hypotensive motorcycle accident victim with pelvic instability on examination and presumed pelvic bleeding?
47. What is the definition of abdominal compartment syndrome?
Mass casualty disasters
48. What types of mass casualty disasters are possible? What are intentional disasters?
49. How long should hospitals be prepared to manage mass casualty disasters before state and national resources arrive?
50. What roles do anesthesia providers play during mass casualty events?
51. What are the goals of mass casualty triage? How are patients classified? What is an “expectant” mass casualty patient?
52. Where does decontamination of mass casualty patients occur?
53. What are the advantages of ketamine, when compared to other anesthetic agents, in facilitating surgical procedures during mass casualty scenarios?
54. What are the risks of neuraxial blockade in mass casualty patients?
Chemical and biologic terrorism
58. What are “category A” agents, with respect to bioterrorism?
59. The appearance of five young patients in the emergency department with low-grade fever and myalgias for several days, who all now present with severe substernal chest pain and severe hypoxemia, should raise suspicions of exposure to what bioterrorism agent? What finding on chest radiograph would support this diagnosis? What else should be done for these patients and exposed individuals?
60. How do the cutaneous manifestations of smallpox and varicella zoster differ?
61. How long is aerosolized plague viable if released in weaponized form? How is a patient with pneumonic plague managed?
62. A group of travelers were exposed to an unknown vapor during a terrorist attack. Twelve hours later, several of those exposed experience difficulty breathing and progressive weakness, with decreased salivation and urinary retention. What category A bioterrorism agent is the most likely cause of these symptoms? What treatment is available, and what precautions should a care provider take? How would the presumed agent differ if those exposed had increased salivation and urinary incontinence?
64. What is the treatment for Sarin-exposed individuals? How does pretreatment with pyridostigmine provide protection from nerve gas exposure?
Answers*
Acute management of trauma patients
1. Trauma is the leading cause of death among those younger than 45 years old. An estimated 5 million people worldwide die each year from injuries. (681)
2. Specialized trauma centers maintain the staff, space, and supplies required to provide immediate trauma care. This includes a number of different physician specialties (emergency medicine, trauma surgery, anesthesiology, neurosurgery, diagnostic and interventional radiology, orthopedic surgery), nursing staff, dedicated patient care areas in the emergency department, operating rooms, intensive care unit (ICU), immediate diagnostic resources, and a blood bank. In the United States, a hospital designated as a level 1 trauma center must be able to provide such services on an immediate basis 24 hours a day. (681)
3. “The Golden Hour” refers to the first hour after a patient sustains major injuries. Most trauma-related deaths occur during this first hour, usually as a result of uncontrolled hemorrhage. Early recognition and treatment of shock is therefore a major priority in acute trauma care. (681)
4. The immediate priorities in acute management of trauma patients are to keep the patient alive, identify life-threatening injuries, stop any ongoing bleeding, and provide definitive treatment as early as possible. (681)
5. ATLS is the acronym for the Advanced Trauma Life Support course that is administered worldwide through the American College of Surgery’s Committee on Trauma. ATLS is important to trauma providers because it provides a standardized algorithm that can be universally applied to all trauma patients, regardless of a provider’s background or available resources. While trauma providers may vary from the basic ATLS algorithm based on availability of certain resources, knowledge of ATLS is useful to all trauma providers because it establishes a baseline for trauma management and a universal language (e.g., primary survey, secondary survey, ABCDEs) that providers all share. (682)
6. The “ABCDEs” of trauma refers to the appropriate sequence of priorities in trauma management: Airway, Breathing, Circulation, Disability (neurologic status), Exposure/Environment. Providers must immediately assess the ABCDEs, in sequence, when initially evaluating a trauma patient. Compromise at any step should be corrected before moving on to the next. (681-685, Table 42-1)
7. Acute management of any trauma patient must begin with confirmation of a patent airway, therefore the first step in managing this patient is to confirm proper position of the endotracheal tube (ETT). Capnography, auscultation of bilateral breath sounds, pulse oximetry, direct laryngoscopy, arterial blood gases, and fiber-optic bronchoscopy are all commonly used to confirm that an “in situ” ETT is, in fact, in the trachea. (682)
8. Indications for endotracheal intubation after life-threatening trauma include inadequate airway protection, impending loss of airway (e.g., inhalational injury, expanding neck hematoma), laryngeal or tracheal injury, inadequate ventilation or oxygenation, severe head injury, and need for surgery under general anesthesia. (682, Table 42-2)
9. Management of a trauma patient should include prior preparation of functioning suction, oxygen delivery devices (oxygen source, breathing circuit, ventilator), airway equipment (face mask, oral/nasal airways, intubation equipment), pharmaceuticals (for intubation of the trachea and management of hemodynamics), intravenous access with fluids and tubing, monitors, and personal protective equipment. Assistants to help with cervical spine and aspiration precautions should be designated, as well as equipment and personnel needed for a surgical airway if endotracheal intubation cannot be performed. (682-683, Table 42-3)
10. Etomidate or ketamine are most often used as the intravenous induction agent for severely injured patients, given the risk of hypovolemic shock and hemodynamic instability with induction. Propofol can be used for induction of stable patients without signs of shock. Succinylcholine is the most commonly used neuromuscular blocking agent to quickly provide optimal conditions for rapid sequence intubation of the trachea. Succinylcholine can be safely used in trauma and burn patients within the first 24 hours after injury, provided no other contraindications exist. (682-683)
11. A plateau wave is an abrupt and sustained increase in intracranial pressure that can occur in patients with traumatic brain injury, often in response to painful stimulation. This severe intracranial hypertension can last for 20 minutes before resolving, often dropping rapidly to a level lower than the previous baseline. (683, Figure 42-1)
12. If a patient’s cervical spine stability is unknown and the airway must be secured, asleep endotracheal intubation should proceed with the patient’s head stabilized in the neutral position on a flat, rigid surface. Such manual, in-line stabilization should be performed by an assistant whose goal during intubation is to prevent atlanto-occipital extension during direct laryngoscopy. (683-684, Table 42-3)
13. Inability to mask ventilate or intubate the trachea necessitates immediate invasive intervention such as emergency cricothyrotomy or tracheotomy. (683)
14. Shock is defined as inadequate perfusion to vital organs. Low, normal, and high blood pressure and heart rate can be seen in patients with shock. Compensatory mechanisms and other factors, such as pain and agitation, allow patients with shock to maintain normal or even elevated blood pressure and/or heart rate. Decompensated hypovolemic shock, or late shock, will lead to profound hypotension and tachycardia. Spinal shock is characterized by hypotension and bradycardia. Clinicians should therefore maintain a high level of suspicion for shock in patients with severe injuries, regardless of a normal blood pressure and heart rate. (683)
15. Abnormal base deficit and lactate are the best independent markers of shock after trauma. The degree of base deficit also correlates with the severity of shock, volume deficit, morbidity, and nonsurvival. One or both markers should be checked in all trauma patients with risk of shock. (683)
16. Massive hemorrhage can occur into the thoracic, abdominal, or pelvic cavities. Estimated blood loss must therefore take into account both visible hemorrhage (at the injury scene and hospital) and potential hemorrhage into one of these three cavities. Significant blood volume can also be lost into the thigh with certain femoral injuries. Identification of pelvic injuries or femur fractures, with subsequent placement of pelvic binders or long bone splints, helps to limit hemorrhage into the pelvis and thigh, respectively. (683)
17. Operative intervention is required if more than 1500 mL of blood comes out at the time of thoracostomy tube placement, or 200 mL per hour thereafter. This degree of chest tube output suggests active intrathoracic hemorrhage and is defined as a massive hemothorax. Massive hemothorax should also be assumed, until proven otherwise, in any patient with a penetrating thoracic injury that is hemodynamically unstable. (683)
18. Persistence of hematuria in a trauma patient may be an indication of bladder injury or injury to the genitourinary system. (683)
19. The primary treatment of hypovolemic shock is to stop any active bleeding. Delays in identification and control of hemorrhage can be deadly and should therefore be avoided. Fluid resuscitation is the mainstay of supportive therapy for patients with hypovolemic shock after injury. Warmed isotonic crystalloid can be used initially for volume resuscitation, but patients with persistent shock should be given blood products to maintain minimum perfusion pressures until hemorrhage is controlled. Vasopressors may be helpful in patients not responding to fluid therapy or to induce higher blood pressure for spinal cord or cerebral perfusion. (683-684)
20. Massive transfusion is traditionally defined as: greater than or equal to 10 units of blood transfused in 24 hours, equivalent to the replacement of one blood volume in an average size patient. The unit ratios of blood products transfused may affect the likelihood of hemorrhage control and survival in injured patients requiring massive transfusion. During a massive transfusion, many trauma centers use blood product ratios to help providers administer fluids that more closely replace the functions of a patient’s lost blood. (684)
21. The GCS is used during the initial assessment of a trauma patient to rapidly evaluate neurologic status. The GCS is calculated by assigning points based on a patient’s eye opening (1 to 4), verbal response (1 to 5), and motor response (1 to 6) to compute a total score between 3 (worse) to 15 (best). The GCS can then be used to categorize the severity of traumatic brain injury (TBI). A GCS score of 8 or less is classified as “severe” TBI. Patients with severe TBI have a high likelihood of intracranial hypertension, possibly with midline shift or brain herniation. Endotracheal intubation and control of ventilation is therefore needed to quickly diagnose and treat any life-threatening intracranial hemorrhage. (684, Table 42-4)
22. Hypotension, hypoxia, hyperthermia, and sustained intracranial hypertension should be avoided in traumatic brain injury patients, as these secondary insults are associated with worse outcomes in brain-injured patients. Hyperglycemia is also neurotoxic in models of brain injury and should be avoided. (684)
23. Treatment of an elevated ICP is frequently recommended when the pressure exceeds 20 mm Hg for a sustained period of time. There are several methods by which elevations in ICP can be treated. These include positioning of the head up and neutral, hyperosmolar therapy, osmotic and loop diuretics, cerebrospinal fluid drainage, and the administration of drugs such as barbiturates that decrease both cerebral blood flow and cerebral metabolism. (684)
24. Mannitol is the osmotic diuretic that is most frequently administered to decrease ICP. Osmotic diuretics decrease ICP by drawing water out of tissues and into the intravascular space. Osmotic diuretics do so by transiently increasing the osmolarity of plasma. The dose of mannitol that is administered is 0.25 to 1.4 g/kg over 15 to 30 minutes. (684)
25. Glucose-containing intravenous solutions should be avoided in traumatic brain injury patients because of the potential for hyperglycemia and hypotonicity, both of which can be neurotoxic. (684)
26. Though corticosteroids are often administered to patients with an elevated ICP, they are most effective in decreasing focal cerebral edema such as that which develops after brain tumor resection. Steroids have no demonstrated benefit in traumatic brain injury patients, increase the risk of hyperglycemia, and should not be given routinely to TBI patients. (684)
27. Deliberate hyperventilation should only be instituted if there is ongoing or imminent brain herniation and rescue measures are needed prior to decompressive craniectomy. Prolonged hyperventilation (PaCO2 25 to 30 mm Hg) is associated with worse outcomes in TBI patients. Excessive hyperventilation in adults (<25 mm Hg) and children (<20 mm Hg) creates even greater potential for cerebral ischemia, as cerebral blood flow decreases in response to alkalosis. (684)
28. All trauma patients with a loss of consciousness, an unclear history, or a mechanism of injury suggestive of neck injury should be placed in a rigid cervical spine collar at the time of initial assessment, if not already done. Mechanisms of injury with a higher likelihood of cervical spine injury include: front-end motor vehicle accident without a seat belt, head-first fall, and blunt maxillofacial trauma. “Clearing” the cervical spine (i.e., declaring that cervical spine stabilization is no longer necessary) occurs when a patient reliably denies pain with neck palpation and neck movement. This should not be done if the patient has a distracting injury or altered mental status. If physical examination is unreliable, computed tomography and MRI are commonly used to diagnose cervical spine fractures and ligamentous injuries. (683-685)
29. The final component of the “ABCDEs” of trauma assessment is Exposure/Environment. This begins with the removal of all clothing and prehospital dressings, a practice that allows for a complete examination of the entire body to ensure that no injuries are missed. Contaminated and cold clothing are also removed at the same time, transitioning to a safer and warmer environment for the patient. Once examined, a hypothermic patient should be rewarmed with blankets, forced air blankets, and warmed intravenous fluids. (685)
30. Special considerations for a burn injured patient include the administration of 100% oxygen regardless of airway examination due to risk of carbon monoxide poisoning, calculation of total body surface area burned, and assessment for signs of inhalational injury (e.g., singed nasal hair, voice changes, carbonaceous sputum). (682, 685)
31. For the burn injury patient arriving to a trauma center, a history of closed space fire or explosion, and the presence of facial burns, singed nasal hair or eyebrows, and/or carbonaceous sputum are all risk factors for significant inhalational injury and need for endotracheal intubation. Stridor, hoarseness, or visualized periglottic swelling/soot are signs of imminent loss of airway and indications for immediate endotracheal intubation. Patients with inhalational injury can rapidly develop facial and glottic edema that completely obstructs the airway, making oral intubation of the trachea difficult or impossible. (685)
32. A patient’s percentage of body surface area (BSA) burned is estimated using the “rule of nines”: (685)
| Head and neck region: | 9% |
| Upper extremities: | 18% (left and right: each 9%) |
| Lower extremity: | 36% (front and back: each 9%) |
| Torso: | 18% (front and back: each 9%) |
| Perineal area | 1% |
| Total: | 100% |
33. Burn injury victims may have suffered from smoke inhalation injury with associated carbon monoxide inhalation, particularly if the patient had been exposed to smoke in a closed space. Carbon monoxide has a binding affinity for hemoglobin that is about 200 times greater than that of oxygen. The presence of high carbon monoxide levels therefore creates a functional anemia by reducing the oxygen content and delivery of a patient’s hemoglobin, despite the presence of a normal PaO2. In addition, the binding of carbon monoxide to hemoglobin shifts the oxyhemoglobin dissociation curve to the right, making the remaining oxygen bind more tightly to hemoglobin and decreasing the ability of hemoglobin to unload oxygen at the tissues. A pulse oximeter will have normal readings despite carbon monoxide toxicity. Carbon monoxide toxicity should be treated with the administration of 100% oxygen. A high PaO2 will lead to the removal of carbon monoxide from hemoglobin with greater rapidity. (685)
34. The burn injury patient often requires large volumes of fluid for volume resuscitation after his or her injury secondary to huge volume shifts into burned tissue, increased vascular permeability, evaporative losses, and increased metabolism. The Consensus formula (traditionally known as the Parkland formula) is used to calculate the initial rate of fluid administration. Lactated Ringer solution should be given at 4 mL/kg in the first 24 hours for every 1% of the patient’s body surface area that is burned, with one half of the calculated volume administered in the first 8 hours after injury. The remaining half should be administered in the subsequent 16 hours, though the fluid rate should be continually adjusted to maintain adequate organ perfusion. (685)
35. Warmed isotonic solution such as lactated Ringer solution should be used for fluid resuscitation in burn patients. Colloids have no demonstrated advantage over crystalloid and may actually worsen outcomes. While the Consensus formula is used to determine the initial fluid requirements of burn patients, the fluid rate is typically adjusted continuously, based on a urine output goal of 0.5 mL/kg/hr, to avoid overresuscitation or underresuscitation of patients. (685)
36. Patients suspected of having a closed-head injury can be evaluated by history, physical examination, and radiologic studies. The hallmark clinical sign of a closed-head injury is loss of consciousness. A GCS score should be calculated based on eye opening and verbal and motor responses. A noncontrast computed tomographic scan of the head should be performed as early as possible to assess for intracranial hypertension or a need for emergent operative intervention. Midline shift, brain herniation, skull fractures, and any intracranial bleeding can be quickly assessed with computed tomography. (684, Table 42-4)
37. A plateau wave in the ICP wave tracing refers to an abrupt increase in the ICP observed during continuous monitoring. This can occur following painful stimuli even in an otherwise unresponsive patient. The plateau wave is usually sustained for 10 to 20 minutes, followed by a rapid decrease in the ICP. The presence of plateau waves on an ICP wave tracing may indicate that the intracranial compliance is low. Some providers administer opioids and/or lidocaine to blunt this effect, though the efficacy of such measures is unclear. (683, Figure 42-1)
Emergency surgery for trauma
38. In general, rapid sequence intubation of the trachea should be performed for all emergency trauma procedures, so the time since a patient’s last meal has no impact on airway management. Because gastrointestinal motility decreases following trauma, providers assume that all trauma patients have full stomachs and are at risk for the aspiration of gastric contents. Rapid sequence intubation of the trachea reduces this risk by minimizing the time between loss of airway reflexes and placement of a secure airway. (682, 686, Table 42-3)
39. In emergency surgery for trauma, the risks of preexisting hypovolemia, massive hemorrhage, and hemodynamic instability are higher; therefore general anesthesia is maintained with lower than usual doses of inhaled volatile anesthetics or benzodiazepines to optimize hemodynamic stability. Ketamine can also be used for this purpose. Nitrous oxide is generally avoided in patients with a potential for pneumothorax or for abdominal procedures. (682-683, 686)
40. If a trauma patient is unable to tolerate high levels of general anesthetics, neuromuscular blocking drugs are needed to prevent skeletal muscle movement and facilitate the surgical procedure. Small doses of a benzodiazepine or scopolamine can be used under these circumstances in an attempt to prevent recall. Under these critical conditions, patients may experience some recall of the intraoperative events, making it important for the anesthesiologist to communicate with the patient during and after the procedure. (686)
41. Intraoperative fluid management for trauma patients follows the same principles as the initial management of the acute trauma patient, with the goals of maintaining adequate circulating volume while optimizing conditions for hemorrhage control. Fluid resuscitation may be initiated with isotonic crystalloid solutions, with early transition to blood products and permissive hypotension if hemorrhaging is uncontrolled. Hypothermia, coagulopathy, and severe acidosis should be actively prevented and corrected. Rapid fluid infusion, fluid warmers, and autotransfusion systems should be used if appropriate and available. (683-684, 686, Table 42-5)
42. Arterial blood gases, hematocrit and platelet count, coagulation tests, and electrolytes are followed regularly to assess the progress of resuscitation and surgery. Invasive monitoring, such as arterial pressure variability, central venous pressure, and echocardiography, is also commonly used to guide therapy. Use of newer technologies such as thromboelastography and central venous oxygen saturation can also provide real-time measurements of coagulopathy and shock, respectively. (683-684, 686, Table 42-5)
43. Opening of any anatomic compartment containing recent blood loss can remove external pressure on injured vessels and precipitate uncontrolled hemorrhage. Opening of the peritoneum in a patient with recent intraabdominal hemorrhage should not occur until the preparations have been made for adequate large-bore intravenous access, monitoring, fluid products, and vasoactive medications. Surgical equipment such as vascular clamps and wound packing supplies should also be immediately available. The same principles apply to opening of the dura during craniotomies, opening of the pleura during thoracotomies, etc. (686)
44. Injuries that may be sustained in abdominal trauma include soft tissue contusions or avulsions, rupture of visceral organs, or laceration of the spleen or liver. Injury to the spleen or liver can result in significant hemorrhage. The diagnosis of intraabdominal hemorrhage is made by FAST (focused assessment with sonography in trauma) examination, peritoneal lavage, and/or computed tomography. (683, 686)
45. “Damage control” surgery for trauma patients refers to the practice of focusing the initial surgical intervention on hemorrhage control and abbreviated surgery, with a plan to delay extensive examination and definitive repair of all injuries until after the patient is fully resuscitated and stabilized in the ICU. This practice allows for shorter operating and general anesthesia time initially, achieves hemorrhage control and shock reversal sooner, and reduces the risk of developing acidosis, coagulopathy, and hypothermia. (686)
46. After establishing that the airway and breathing are stable, the pelvic ring should be initially closed with a pelvic binder device, followed by angioembolization of pelvic vessels in the interventional radiology suite. If interventional radiology services are not available, extraperitoneal packing can be performed to achieve hemorrhage control, with external fixation of the pelvis performed once the patient is fully resuscitated and hemodynamically stable. (687)
47. Abdominal compartment syndrome is defined as an intra abdominal pressure greater than 20 mm Hg with associated organ dysfunction. Trauma patients with abdominal injury and/or large volume resuscitation should be closely monitored for abdominal compartment syndrome. (687)
Mass casualty disasters
48. Mass casualty disasters are events that require more resources than the local community can provide. Disasters can be natural (e.g., floods and earthquakes), unintentional (e.g., industrial or multivehicle accidents), or intentional. Intentional disasters are acts of terrorism or warfare, and can be explosive, nuclear, biologic, or chemical disasters. (687, Table 42-6)
49. Additional resources are unlikely to arrive for at least 24 to 72 hours after a disaster, so hospitals should have enough resources within the local community to respond for this period of time. Community emergency preparedness plans should be in place and coordinated among local health care providers, law enforcement agencies, fire and rescue services, and local governments. (687-688, Table 42-8)
50. In the event of a mass casualty disaster, anesthesia providers may be required to fulfill many roles including assistance with triage, stabilization of patients in the emergency department, resuscitation and life support in the intensive care unit, as well as intraoperative patient management. Like all clinicians, anesthesia providers should also be able to fulfill their duties within the local emergency response plan, recognize and report any suspected cases of mass casualty events, and be familiar with available exposure prophylaxis. (687, Table 42-9)
51. The goals of patient triage in mass casualty events are to quickly prioritize injuries based on severity of injury and likelihood to survive, so that limited resources can be used to achieve the greatest population benefit. This concept of population-based resource allocation can be difficult for providers used to utilizing every possible resource for each patient under their care. While multiple mass casualty triage systems exist, nearly all divide patients into groups requiring immediate, delayed, minimal, or no treatment. “Expectant” patients are those who are expected to die of their injuries, even if life-saving surgery were attempted. Expectant patients are separated from the main patient flow and placed in a quiet area with an emphasis on analgesia and comfort. (688-689, Table 42-10)
52. Decontamination of mass casualty patients is typically performed at the scene before transportation. Hospitals set up a secure area outside of the main hospital area to complete decontamination and triage of patients. Out-of-hospital decontamination reduces ongoing exposure injuries and minimizes the risk of secondary exposure to health care providers and other patients. (689)
53. Mass casualty events create situations where patients outnumber resources, including airway equipment and ventilators. Maintaining spontaneous ventilation and hemodynamic stability can therefore be critical in such patients. Ketamine is a useful and commonly used anesthetic agent in such scenarios—including prehospital procedures such as limb amputation—because it provides analgesia and hypnosis with minimal depression of respiratory or cardiovascular function. (689)
54. Neuraxial blockade (i.e., epidural or spinal anesthesia) is generally avoided in mass casualty patients due to the risk of severe hypotension due to hypovolemia and underlying injury. Coagulopathy and need for immobilization are also common reasons to avoid neuraxial blockade for emergency trauma surgery. (690)
Nuclear exposure
55. Transmission of radioactive material from victim to health care provider is low, so standard trauma protocols should be followed during the initial evaluation of a nuclear exposed trauma patient, progressing from “A” through “D”: airway, breathing, circulation, disability (neurologic status). Decontamination is then performed as part of the assessment and treatment of “E,” or exposure. (690)
56. As part of the exposure assessment, nuclear disaster victims are externally decontaminated by removing all clothing and rinsing the skin with warm soapy water. Once stabilized and externally decontaminated, internal decontamination is performed with methods such as gastric lavage, emetics, laxatives, and diuretics, as well as copious irrigation of any open wounds. These measures are necessary to prevent continued injury from retained nuclear material. (690)
57. Acute radiation syndrome is characterized by thrombocytopenia, granulocytopenia, nausea, and vomiting. Once stabilized, the patient should be monitored continuously for such signs. Prevention involves minimizing the duration of exposure through both external and internal decontamination. Medications can be given to facilitate renal excretion and chelation. Potassium iodide can also be given within the first 24 hours to prevent radiation-induced thyroid abnormalities. (690)
Chemical and biologic terrorism
58. Category A bioterrorism agents, as classified by the United States Centers for Disease Control and Prevention, are agents thought to be mass-engineered by terrorist groups, easily disseminated or transmitted to victims, have a high mortality rate, and/or create public panic if released. Examples of category A agents are anthrax, smallpox, and Ebola virus. (691, Table 42-12)
59. Any clustering of unusual illness should be treated as victims of bioterrorism until proven otherwise. In this case, the history of flulike symptoms followed by chest pain and profound respiratory distress suggests inhalational anthrax. Shock and meningitis may also be present. A widened mediastinum, due to mediastinal adenopathy, can be seen on chest radiograph of inhalational anthrax patients. When profound dyspnea develops, death can ensue within 2 days; therefore treatment and supportive measures should be instituted immediately (e.g., antibiotic therapy, endotracheal intubation, and mechanical ventilation). Either ciprofloxacin or doxycycline can be used to effectively treat weaponized anthrax. Although inhalational anthrax presents little to no risk of secondary spread from patients with established infection, such patients should initially be isolated and health care officials should be notified. Prophylaxis for exposed individuals can be done with either a fluoroquinolone alone for 60 days or a vaccination plus a fluoroquinolone for 30 days. (691-692, Table 42-13 through Table 42-16, Figure 42-2)
60. Smallpox produces cutaneous lesions 72 to 96 hours after a fever, whereas patients with varicella zoster infection, or “chickenpox,” develop their rash at the same time as a fever. In addition, smallpox lesions appear all at once and will therefore all be at the same stage. In contrast, chickenpox lesions appear at different times, so physical examination reveals lesions with different stages of lesion development (papules, vesicles, pustules, scabs). (692)
61. Aerosolized plague (Yersinia pestis) is viable for approximately 60 minutes. If an individual develops pneumonic plague, management includes strict isolation and exposure precautions because pneumonic plague is highly contagious. Early antibiotic treatment is also critical, as the mortality of untreated individuals approaches 100%. Streptomycin, gentamicin, tetracycline, and chloramphenicol are all effective therapies for plague. (692, Table 42-18)
62. Clostridium botulinum toxin is a category A agent that causes skeletal muscle weakness between 12 to 36 hours after ingestion or inhalation of the toxin. Botulism results from inhibition of acetylcholine release, and can be treated with trivalent antitoxin. Endotracheal intubation and mechanical ventilation may also be required. The toxin is not contagious, however, therefore health care providers do not need to follow any additional special precautions. While botulism leads to decreased salivation, ileus, and urinary retention, nerve agents (e.g., sarin) are acetylcholinesterase inhibitors and cause cholinergic effects in addition to skeletal muscle weakness. (691, 693-696, Table 42-12, Table 42-20, Table 42-22)
63. Nerve agents are military-grade chemicals that act, similar to organophosphate pesticides, by inhibiting acetylcholinesterase and produce cholinergic effects including muscle fasciculations, weakness, incontinence, and hypersecretion. They are typically lipophilic clear liquids that vaporize at room temperature and are absorbed through the skin, mucous membranes, lungs, or gastrointestinal tract. (695)
64. Sarin is a potent nerve agent that has been used recently in chemical terrorist attacks. It is also referred to by the two-letter NATO military code “GB.” Like other nerve agents, exposure to sarin should be treated with atropine (2 to 6 mg IM) and pralidoxime (600 to 1800 mg IM), with atropine redosed every 5 to 10 minutes until secretions begin to decrease. Pyridostigmine is a medication that reversibly binds to AChE. Administration of pyridostigmine 30 minutes before exposure therefore provides protection by occupying the binding sites that the nerve agents target. It then dissociates from the AChE enzyme after the exposure risk has passed. (695-696, Table 42-22)
