CBRN ANSWERS & RATIONALES (2024)

SKIN INJURIES

QUESTION ONE: The correct answer is D.

Rationale: Because grease is oily and thick, it tends to trap heat, leading to a deeper burn. It may be hard to wipe away after exposure, and attempts to wipe it away may simply spread the oil and increase the size of the burn. Water and coffee are less viscous, and the heat can dissipate quicker when these substances come into contact with the skin, leading to less severe burns. Although steam can cause severe burns, it also evaporates more quickly than grease and tends to cause burns of less depth when compared to grease.

QUESTION TWO: The correct answer is A

Rationale: Chemicals may denature a cornea (especially alkali substances), leading to cataracts following a chemical burn to the eye. Color blindness and loss of pupillary accommodation are not related to chemical burns to the eye. Although severe chemical burns may cause retinal burns, retinal detachments are not commonly associated with this injury.

QUESTION THREE: The correct answer is C

Rationale: Respiratory tetany or paralysis of the diaphragm may both contribute to respiratory arrest following a severe electrical burn. Although a pneumothorax is not uncommon following an electrical burn, a hemothorax is not common. Atelectasis is more likely associated with acute respiratory distress syndrome as opposed to an electrical burn. Pulmonary contusions are more likely to be seen following chest trauma as opposed to an electrical burn.

QUESTION FOUR: The correct answer is C

Rationale: The ideal manner in which to thaw frostbitten tissue is to submerse it in water that is warmed to 37 – 39 C. Ideally, the water should continuously circulate (e.g., whirlpool). Pressure should not be applied to the area as this can exacerbate tissue injury and worsen long-term outcomes. Therefore, massaging the area or wrapping it in bulky material is not recommended. Frostbite should not be thawed using dry heat as the risk of secondary thermal burns is too great since the patient may not be able to sense if the temperature is appropriate or if the tissue is too close to the heat source.

QUESTION FIVE: The correct answer is A

An early symptom associated with necrotizing fasciitis is induration, warmth, and edema at the site of infection. The skin may also become discolored (red/purple or blue/gray) and shiny. Clusters of macules are not associated with this illness. This presentation is more common with rickettsial infections, rubella, or measles. Although blisters may appear at the site of necrotizing fasciitis, the blisters may be blood-filled as opposed to clear fluid. Although a blue/gray discoloration is associated with necrotizing fasciitis, this illness does not cause sloughing of the skin.

QUESTION SIX: The correct answer is B

Rationale: Sloughing epidermis may be removed (including in the surgical suite) in patients with Steven-Johnson syndrome (SJS). The area would then be covered with a biologic or synthetic dressing. This, however, is not required and does not need to be done urgently. Alternatively, the detached epidermis may be left intact, serving as a biologic dressing protecting the underlying dermis. Generally, only the epidermis layer sloughs, and the dermal layer remains intact. Therefore, removal of the dermal layer with an enzymatic agent is unnecessary. Although steroids may be used to treat patients with SJS, they will be administered systemically. Topical steroids are not therapeutic in the treatment of SJS.

ON SCENE MANAGEMENT

QUESTION SEVEN: The correct answer is D

Rationale: When carbon monoxide combines with hemoglobin (forming carboxyhemoglobin), that hemoglobin is prevented from carrying oxygen molecules. Oxyhemoglobin has a long half-life of several hours. Therefore, oxygen transport is reduced for lengthy periods of time. This can cause tissue hypoxia, which is reflected in elevated serum lactate levels. Tissue hypoxia drives a metabolic acidosis decreasing rather than increasing serum pH. The resulting hypoxia tends to cause tachypnea as opposed to reduced respiratory rates. Because carboxyhemoglobin has a similar color to oxyhemoglobin and the oxygen saturation probe is designed to pick up the color of oxyhemoglobin, it cannot differentiate these two, and oxygen saturation levels may be deceptively normal despite low serum oxygen levels.

QUESTION EIGHT: The correct answer is C

Rationale: The target pressure after resuscitation for burns is a mean arterial pressure above 65 mm Hg. A mean arterial pressure of 65 mm Hg is too low and indicates the need for further fluid resuscitation. Tachycardia is expected following a burn, even with adequate resuscitation. This is because of increased circulating catecholamines. A pulse between 100 and 130 BPM is expected. The target oxygen saturation is above 94%. Slight elevations in temperature are expected after a burn, and a temperature of 99.0F is not a concern.

QUESTION NINE: The correct answer is D

Rationale: The American Burn Association has developed the following recommendations for transfer to a burn center:

  1. Second-degree burns >10% of total body surface area (TBSA)

  2. Third-degree burns

  3. Burns that involve the face, hands, feet, genitalia, perineum, and major joints

  4. Chemical burns

  5. Electrical burns, including lightning injuries

  6. Any burn with concomitant trauma in which the burn injuries pose the greatest risk to the patient

  7. Inhalation injury

  8. Patients with pre-existing medical disorders that could complicate management, prolong recovery, or affect mortality

  9. Hospitals without qualified personnel or equipment for the care of critically burned children

  10. Burn injury in patients who will require special social, emotional, or long-term rehabilitative interventions.

Because this patient has an inhalation injury, he should be transferred to a burn center. The depth of the burn (partial thickness less than 10% of the body) does not require transfer to a burn center. The age of the patient is non-contributory in this scenario. The fact that the anterior thighs are burned does not influence the decision to transfer the patient to a burn center.

INITIAL MANAGEMENT

QUESTION TEN: The correct answer is D

Rationale: The majority of isotonic crystalloid solutions, such as normal saline, will extravasate from the intravascular to the extravascular bed shortly after administration. Approximately 70 – 80% will leave the vascular bed. This is the reason it requires so many crystalloids for fluid resuscitation.

QUESTION ELEVEN: The correct answer is B

Rationale: Electricity will almost always burn through the skin and travel through underlying muscles and nerves as it traverses the body. Because it occurs deep in the tissue, fluid will tend to accumulate deep in the tissue, and fasciotomies may required to release the pressure inside the deep fascial compartments. Because thermal burns occur on the surface, they are more likely to require escharotomies as opposed to fasciotomies. At times, full-thickness thermal burns may require fasciotomies, but this is rare. It is more likely fasciotomies will be required for electrical burns. Chemical burns are less likely to require either a fasciotomy or escharotomy, but escharotomies are far more likely in this scenario than a fasciotomy.

QUESTION TWELVE: The correct answer is D

Rationale: N-acetylcysteine (mucomyst) is given as a mucolytic in patients with an inhalation injury. It is believed to thin and mobilize secretions. Both nitric oxide and epoprostenol are pulmonary vasodilators used to improve ventilation-perfusion shunts. Inhaled heparin reduces inflammation and breaks up casts.

QUESTION THIRTEEN: The correct answer is A

Rationale: Surgical debridement is associated with significant blood loss, both during the procedure but also in the immediate postoperative period, and this complication should be monitored for and treated as it occurs. This may include the utilization of tourniquets, topical or injectable epinephrine, fibrin sealants, calcium-enriched alginate sheets, and compressive dressings. Neuropathic pain is associated with damage to the nerve fibers and occurs chronically. Surgical debridement is more likely to exacerbate background and breakthrough pain. Potassium imbalances are not associated with surgical debridement of burn wounds. Surgical debridement of burn wounds only removes the necrotic tissue on the surface and does not impact anatomical landmarks.

QUESTION FOURTEEN: The correct answer is D

Rationale: The use of silver nitrate has been reduced secondary to the side effects associated with it. These include staining of the skin and electrolyte imbalances such as hyponatremia and hypochloridemia. Changes in serum pH, hematocrit, and urinary output are not likely with the use of silver nitrate therefore, monitoring these parameters is not as important as monitoring the electrolyte panel.

QUESTION FIFTEEN: The correct answer is C

Rationale: Amnion is composed of the innermost layer of the amniotic sac. It is used as a temporary covering over burns, especially on the face, and is considered a skin substitute. It is a human product therefore, it is not a synthetic dressing. A xenograft is the temporary application of skin from a non-human species (frequently fish), and an autograft is the application of skin taken from a different site on the same patient.

WOUND MANAGEMENT

QUESTION SIXTEEN: The correct answer is A

Rationale: Bleeding is anticipated at the skin donor site in the postoperative period. Blood noted on dressings should be marked so the severity of bleeding can be monitored. Other parameters, such as hematocrit and lactate levels, should be monitored to ensure that the bleeding is not severe enough to cause hypovolemia. Although coagulopathies can occur post-burn, it is unlikely they will develop within hours of surgical removal of skin for grafting. Post-operative bleeding is a far more common cause. Dressings should be left intact over the site in the immediate post-operative period unless they become saturated with blood. It would be more advisable to re-enforce the dressing in the early post-operative period rather than remove it.

QUESTION SEVENTEEN: The correct answer is D

Rationale: The dressing over the site where a skin cell suspension has been applied should be left intact for six to eight days because the suspension is delicate, and removal of the dressing could disturb the underlying cells, reducing the success of graft take.

PAIN AND ANXIETY

QUESTION EIGHTEEN: The correct answer is D

Rationale: One complication of prolonged opioid use is opioid-induced hyperalgesia, where a patient receiving opioids may become more sensitive to painful stimuli. Using alternative analgesia and non-pharmacological pain interventions may decrease the incidence of this complication. Nociceptive pain is related to nerve damage within the burns and resulting scar tissue and is not related to prolonged opioid use. Scarring is related to numerous factors, including the timing of debridement, treatment options for burns, and the presence of absence of infection. Opioid use, however, does not impact scarring. Opioid use is not associated with liver failure.

QUESTION NINETEEN: The correct answer is B

Rationale: Virtual reality has been shown to be a very effective means for the treatment of anxiety. It can be used to elicit presence through multisensory features and body representation to reduce anxiety. Virtual reality is not used in the treatment of delirium and may actually precipitate delusions and other symptoms associated with this disorder. There is no therapeutic value in using virtual reality to assist with the acceptance of altered appearance or to assist the patient to return to their community after a burn.

ACUTE CARE

QUESTION TWENTY: The correct answer is D

Rationale: Multiple surgical procedures involve re-intubation with bacterial translocation, all of which increase the risk of ventilator assisted pneumonia (VAP). The correlation between intubation and VAP is well established. Allodynia, defined as a pain response to normally non-painful stimuli, is associated with poor pain control but is not associated with multiple surgical procedures. Keloid scarring is frequently genetic and is more likely to be seen in dark-skinned individuals but is not associated with multiple surgical procedures. (Multiple surgical procedures may increase the risk of scarring, especially hypertrophic scarring but not keloid scars). Heterotopic ossification (the formation of bone within soft tissues due to abnormal proliferation of osteogenic cells) is related to prolonged periods of immobility rather than multiple surgical procedures,

QUESTION TWENTY-ONE: The correct answer is B

Rationale: Hyponatremia is associated with acute kidney injury as the kidneys lose the ability to concentrate sodium. This results in hyponatremia. Effective treatment should, therefore, elevate serum sodium. Creatinine levels climb with acute kidney injury. Therefore, effective treatment should cause these levels to drop. Changes in prothrombin time are not typically associated with acute kidney injury. Therefore, an elevation in this lab value is not associated with effective treatment. The production of platelets is not impacted by acute kidney injury. Therefore, effective treatment does not tend to alter this lab result.

QUESTION TWENTY-TWO: The correct answer is B

Rationale: Because muscle utilizes glucose, muscle wasting will reduce muscle mass, reducing the utilization of glucose and is one of several causes of hyperglycemia in the patient with burns. The severity of scarring is dependent on factors such as the presence or absence of infection, the depth of the burn, and the type of treatment, amongst other factors. The severity of scarring is not, however, proportional to muscle wasting. Narcotic dependence is related to the length of time a patient receives narcotics coupled with intrinsic factors, including heredity, but is not proportional to muscle wasting. Hospital length of stay and muscle wasting are not proportional to one another.

QUESTION TWENTY-THREE: The correct answer is B

Rationale: Early wound excision and closure is associated with:

  • Reduced inflammatory response

  • Reduced stress hormones

  • Reduced metabolism

  • Reduced resting energy requirements

  • Reduced muscle catabolism.

For these reasons, it is the most important intervention for reducing the hypermetabolic response after a burn injury. While aggressive fluid resuscitation is essential for decreasing the effects of burn shock, it is not directly related to reducing the hypermetabolic response to burns. Enteral nutrition and normalization of serum glucose levels are both considered treatment modalities for the hypermetabolic response but do not reduce the hypermetabolic response after a burn injury (ideal enteral feedings after a burn injury are high in protein and carbohydrates as opposed to high in fat as well).

QUESTION TWENTY-FOUR: The correct answer is A

Rationale: Generally, the majority of antibiotics used in the burn unit are topical antibiotics applied directly to the burn wound. Prophylactic antibiotics are rarely used as prophylactic antibiotics are associated with secondary infections such as GI complications/diarrhea. Intravenous antibiotics, when used, are generally empiric and based on culture and sensitivity after initiation of infection (rather than prophylactic). Giving antibiotic agents to ensure coverage of various microbes or intravenously as soon as the excision of necrotic material is complete would both be prophylactic, which is generally avoided.

QUESTION TWENTY-FIVE: The correct answer is C

Rationale: One of the functions of the liver is the production of clotting factors. Liver failure reduces the production of clotting factors, which can either initiate coagulopathies or exacerbate existing coagulopathies. Failure of the renal system is more likely to cause electrolyte imbalances and altered fluid balance. Cardiac failure is more likely to cause pulmonary edema and hypotension. Pulmonary failure is more likely to cause hypoxemia and hypercarbia.

DISCHARGE AND LONG-TERM RECOVERY

QUESTION TWENTY-SIX: The correct answer is A

Rationale: One of the most reported complications following a burn injury is pruritis. The cause is multi-faceted and includes damaged oil glands, nerve damage, and trapped nerve endings in scars. Thermoregulation is altered after a burn, but the patient is more likely to experience cold or heat intolerance as opposed to hot flashes. Hot flashes are not a common complication after a burn. Although acute anxiety is common after a burn, the incidence of anxiety attacks is not more common when compared to pruritis. Patients tend to have hypermetabolism after a burn, which may make it difficult for them to sustain a healthy weight. But weight loss is more common than fluctuations in weight.

QUESTION TWENTY-SEVEN: The correct answer is A

Rationale: Patients who are adults at the time of a burn tend to experience greater sexual dysfunction than children and adolescents who are burned. Patients burned in childhood who grow up with scars report fewer complications associated with sexuality and body image. Reviews of patients burned during adolescence have shown those with disfiguring burn scars have similar thoughts, behaviors, feelings, and experiences to non-burned adolescents. The larger the body surface area burned, the higher the incidence of sexual dysfunction. There is no correlation between the presence of an intimate relationship at the time of the burn and the incidence of sexual dysfunction. Those who lack an intimate relationship at the time of the burn do not show greater sexual dysfunction compared to those who have an intimate relationship at the time of the burn. There is no correlation between the presence or absence of delirium and sexual dysfunction later on in the recovery.

QUESTION TWENTY-EIGHT: The correct answer is B

Rationale: Abnormal scarring is associated with:

  • prolonged healing times

  • prolonged inflammatory states

  • multiple surgical procedures

  • wound infections

  • extremes of age

  • darker skin pigmentation.

Wound infections are not directly associated with increases in anxiety. Hypermetabolism, as opposed to hypometabolism, is associated with burn injuries. Infections may contribute to worsening hypermetabolism but are not associated with hypometabolism. Fluid loss is not exacerbated by wound infections.

QUESTION TWENTY-NINE: The correct answer is C

Rationale: Post-burn syndactyly is associated with circumferential burns of the fingers in which the skin between the fingers grows together, causing them to be “webbed.” This can be prevented by splinting the fingers apart or by abduction to one another. Splinting them in adduction increases the risk of syndactyly. Splinting the hand in extension prevents a dorsal contracture (or claw hand) but does not prevent syndactyly. It is not appropriate to splint body parts in flexion after a burn, as this increases the risk of contractures.

QUESTION THIRTY: The correct answer is A

Rationale: A major goal of a burn camp is to create an environment where the patient with burns realizes they are not alone and that their experiences are likely felt by others. This, in turn, tends to increase an acceptance of the burn injury and resultant scarring to feel more confident. Although it would be ideal for the patient to verbalize a desire to attend burn camp again in the future, this is not the goal of burn camp. Burn camp is most likely to provide boosts to the patient’s emotional and cognitive status rather than their physical status. For this reason, reductions in pain and improved stamina are not the goals, nor are they the likely outcomes of attending burn camp.

PSYCHOSOCIAL SUPPORT AND PATIENT ADVOCACY

QUESTION THIRTY-ONE: The correct answer is C

Rationale: The onset of delirium in critically ill patients is recognized as a risk factor for increased mortality, and early recognition as well as intervention will help reduce mortality. Using a standardized tool, such as the CAM-ICU tool, to determine the presence of delirium will help identify patients with signs of delirium, allowing earlier interventions. The tool should be used once per shift for patients in the ICU, hourly measurements are unlikely to be necessary (even if the patient has changes in sensorium). There is no therapeutic value in using the tool one hour after the administration of narcotic analgesia. Although it is appropriate to use this tool as a measurement of the effectiveness of treatment for delirium, it has other uses, including screening for the onset of delirium before treatment or assessing the severity of delirium before treatment.

QUESTION THIRTY-TWO: The correct answer is B

Rationale: One of the first things that should occur when psychotherapy is initiated is goal setting, in other words, what will success look like? Goal setting is crucial for the management of depression to increase motivation and target behaviors that affect the patient’s mood. The therapy itself can then focus on the therapist and patient working together to meet the pre-established goals. Although anti-depressants are often used in conjunction with psychotherapy, they are independent of one another. Psychotherapy could be used in the absence of anti-depressants. It is difficult to determine the expected length of treatment, and this is unlikely to contribute to the success of the therapy. Therefore, this is not an early step in psychotherapy. Although parameters for disengaging after therapy are helpful, this is not necessarily an early step in treatment and would not be more important than setting goals for target behavior.

QUESTION THIRTY-THREE: The correct answer is C

Rationale: Lighting has been known to affect the circadian rhythm. Teaching interventions such as reducing lighting as bedtime nears, reducing blue light near bedtime, ensuring the room is dark during sleep hours, and being in well-lit areas during waking hours have all been known to improve sleep. Bedtime routines have an impact on sleep, but morning routines are less impactful when compared to lighting. The timing of bathing is unlikely to impact sleep hygiene and is not as impactful as ensuring appropriate lighting. It is important to discuss the need to reduce television near bedtime, a part of sleep hygiene, but the choice of programming is unlikely to impact sleep.

QUESTION THIRTY-FOUR: The correct answer is A

Rationale: Allowing loved ones to be involved in patient care allows them to feel involved and supported. In addition to this, they may be required to assist with dressing changes after discharge, so their presence may reinforce learning. Part of this process is teaching the family appropriate infection control practices to reduce the incidence of infection. The potential for increased psychological distress is present, so the family should be given the opportunity to consent to being present and should be given adequate preparation beforehand. (It is essential to give the patient the ability to consent as well). With appropriate preparation, the risk of psychological distress is minimized. There is no therapeutic value in waiting for the skin graft to take before allowing the family to be present for dressing changes.

PROFESSIONAL

QUESTION THIRTY-FIVE: The correct answer is D

Rationale: Numerous factors assist in a successful burn team, including:

  • Open and clear communication

  • Identifiable and reliable leadership

  • Shared goals and values

  • Willingness to listen and learn from one another

  • Problem-solving and conflict-resolution skills

Generally, leadership of the burn team is provided by the burn surgeon. Leadership should be based, however, on the most qualified individual rather than solely on the individual’s role. Psychiatry is often included as an ancillary member of the burn team rather than a core member. Including psychiatry as a core member may improve patient care but is unlikely to strengthen the burn team itself. Although a solid performance improvement plan is essential to ensure high-quality and safe care, it is unlikely to make the burn care team more successful.

QUESTION THIRTY-SIX: The correct answer is B

Rationale: Injuries with a low incidence indicate that the number of new injuries each year is low. Injuries with a high prevalence indicate that many people are alive in the community who have been affected by the particular mechanism of injury. If there are few new cases, yet many people alive who have been affected by the mechanism of injury, it indicates that people tend to survive the injury. If the injury were a major cause of death, prevalence would be much lower (and if it is a MAJOR cause of death, incidence would be higher). Understanding prevalence and incidence within a community does not provide information about surrounding communities, nor does it give any indication of the probability of success in the community. The probability of success of an injury prevention program is best determined by considering the public’s likely attitude toward the specific injury.

QUESTION THIRTY-SEVEN: The correct answer is B

Rationale: Key points to include in chemical burn prevention programs include:

  • the storage of cleaning supplies and chemicals in their protective containers

  • finding alternative products that don’t contain harsh chemicals

  • storing chemicals in a safe place, not accessible to children

  • Being aware of the safety risks associated with your products

  • Following all manufacturer-recommended safety instructions

  • Wearing appropriate protective equipment such as gloves, goggles, and face shield

Both acid and alkali burns require immediate decontamination followed by transport to medical care. The treatment does not differ in the pre-hospital field between these two. Therefore, there is no need to include differentiation in injury prevention programs. Neutralizing agents should not be employed in the first aid of chemical burns as some neutralizing agents may cause a reaction that can cause secondary thermal burns. Therefore, it is not important to include this in an injury prevention program. Because burns will increase in severity the longer the chemical is in contact with the skin; prompt decontamination should be encouraged rather than transporting prior to decontamination. It would be more appropriate to include instructions on appropriate decontamination in an injury prevention program.

QUESTION THIRTY-EIGHT: The correct answer is B

Rationale: Psychological first aid (PFA) aims to reduce stress symptoms and assist in a healthy recovery following a traumatic event, natural disaster, public health emergency, or even a personal crisis. It may be implemented following a disaster to help identify individuals who are having difficulty coping and assist them in finding resources. Mitigation is the prevention stage of disaster management, and preparedness assists an institution in ensuring resources are in place for a disaster. Because the disaster has not yet occurred, PFA would not be beneficial in these stages. The focus during the response stage of disaster management is to provide care and save lives. PFA does not serve these purposes.

SPECIAL POPULATIONS

QUESTION THIRTY-NINE: The correct answer is C

Rationale: As a patient ages, metabolism slows, therefore, the hypermetabolic response in the elderly will tend to be less severe than what is experienced in younger populations with higher metabolic rates.

QUESTION FORTY: The correct answer is B

Rationale: Cardiotocographic monitoring is a technique used to monitor fetal heartbeat and uterine contractions. Because fetal heart rate is an important assessment parameter in determining fetal health, it can be used to assess fetal response to a maternal burn. Although cardiotocographic monitoring may assess maternal contractions, it does not measure other important maternal parameters. Therefore, it is not useful in assessing potential maternal mortality or the maternal response to fluid resuscitation. Blood pressure and urinary output will be used to assess the maternal response to fluid resuscitation. Although fetal heart rate may be used to assess the fetal response to fluid resuscitation, cardiotocographic monitoring (including fetal heart rate) will not be useful in determining the amount of fluid needed to support the fetus.

QUESTION FORTY-ONE: The correct answer is B

Rationale: Patients with self-inflicted burn wounds, especially when showing signs of agitation, may have an underlying psychiatric condition and may pose a danger to themselves or others. Measures such as assigning a sitter, obtaining a psychiatric consult, or removing potentially harmful objects from the environment would meet this need. Ensuring the safety of the patient and care team constitutes a priority. Although debridement of the burn wounds is important, it would not be a higher priority than ensuring patient and care team safety. Aggressive fluid resuscitation is generally not indicated for wounds less than 20% of the body. There is nothing in this scenario to indicate this patient requires oxygen. Oxygen is generally reserved for oxygen saturation below 92 – 94% to reduce the incidence of oxygen toxicity.