CBRN ANSWERS & RATIONALES (2023)

PATHOPHYSIOLOGY

QUESTION ONE: The correct answer is A

Rationale: If all elements are equal (e.g., temperature, object, length of exposure), then the depth of the burn will be dependent on the thickness of the skin involved. The thinner the skin, the deeper the burn will be. Areas of the body such as the lips and the eyelids have very thin skin and are susceptible to deeper burns. The skin on the buttocks, backs of the legs, and palms of the hand are thicker than the skin on the lips and will have less burn depth (if all other factors are equal.)

QUESTION TWO: The correct answer is B

Rationale: The more organs that demonstrate failure in multi-organ dysfunction syndrome (MODS), the higher mortality climbs. The patient’s urinary output may indicate the onset of acute kidney injury in MODS but is not directly related to mortality from this syndrome. Aggressive fluid resuscitation, especially shortly after a burn, may reduce the incidence of MODS, but once MODS has commenced, mortality is not dependent on the degree of fluid resuscitation. There is no association between mortality and the onset of MODS.

QUESTION THREE: The correct answer is C

Rationale: Dislodgement of the endotracheal tube can be catastrophic because progressive airway edema after a burn may prevent the re-introduction of the tube. Therefore, ensuring the endotracheal tube is adequately secured following intubation is important to ensure an adequate airway after significant burns. Administering nebulized heparin is meant to treat inhalation injuries as opposed to assisting with ensuring an adequate airway. Facilitating escharotomies for circumferential burns of the torso is meant to improve respiratory effort by reducing pressure on the chest. It does not facilitate the maintenance of the airway. Keeping the head of the bed elevated AFTER intubation has no therapeutic value in maintaining the airway.

QUESTION FOUR: The correct answer is B

Rationale: Phosgene gas is known to cause pulmonary edema which would be noted by auscultating breath sounds. Phosgene gas is not known to affect hemoglobin, pupil reactivity, or the electrocardiogram.

INITIAL MANAGEMENT

QUESTION FIVE: The correct answer is C

When calculating utilizing the Lund and Browder chart, superficial burns are excluded (but partial thickness and full thickness burns are included).

QUESTION SIX: The correct answer is C

Rationale: The Ivy index is used to determine the maximum amount of fluid a patient should receive in a 24-hour period. It is determined by multiplying the patient’s weight in kilograms by 250 mg.

QUESTION SEVEN: The correct answer is D

Rationale: Nitrous oxide reduces the pulmonary-artery pressure and increases arterial oxygenation by improving the matching of ventilation with perfusion, without producing systemic vasodilation in patients with ARDS. Nitrous oxide has no therapeutic effect in treating pain, ICU narcosis, or hypovolemic shock.

QUESTION EIGHT: The correct answer is A

Rationale: The ABCs of trauma should be utilized when caring for patients with burns. When utilizing the ABCs of trauma, the airway is always the highest priority (after controlling any uncontrolled bleeding when appropriate). One step in airway protection for traumatically injured patients is to protect the cervical spine, therefore that is a higher priority when compared to initiating intravenous lines (“C” on the ABCs), covering the patient with sheets (“E” on the ABCs) and application of oxygen (“B” on the ABCs).

ACUTE CARE

QUESTION NINE: The correct answer is D

Rationale: HFPV is a pressure-limited, time-cycled mode of ventilation that delivers small volume breaths at a high frequency percussing the inside of the lungs. This will help loosen airway secretions while providing adequate gas exchange in the lower airways. Although pressure support ventilation, volume assist control ventilation, and continuous positive airway pressure may be utilized, these modes of ventilation do not provide the percussive advantages of HFPV, making HFPV the desired mode of ventilation for patients with inhalation injuries.

QUESTION TEN: The correct answer is A

Rationale: Although inotropic medication and vasopressors may be used to treat hypotension in the patient with burns, these medications should only be delivered if the fluid volume is optimized. If there is any indication of fluid deficits, then fluids should be utilized rather than positive inotropes or vasopressors. Dobutamine does not have an impact on the patient’s white blood cell count, so reviewing this parameter will not affect the initiation of Dobutamine. There is no need to reduce a patient’s maintenance pain medication dose or to reduce the peak end-expiratory pressure on the mechanical ventilator before imitating Dobutamine.

QUESTION ELEVEN: The correct answer is B

Rationale: Contractures following a burn can become so severe that they may cause dislocations and subluxations of joints near the area of the contracture. Proper positioning can reduce the severity of or even the incidence of contractures, thus reducing the risk of subluxations in nearby joints. Proper positioning does not reduce anxiety (in fact, it may be uncomfortable or painful for the patient and increase anxiety). Keloids are genetic and are not reduced by proper positioning. Adequate fluid resuscitation and ensuring good blood pressure will help reduce the extension of the zone of stasis, but proper positioning is unlikely to have this impact.

QUESTION TWELVE: The correct answer is C

Rationale: signs of feeding intolerance include nausea and vomiting. If these develop, feedings may need to be reduced or even stopped temporarily. Post-pyloric feeding tubes reduce the incidence of this complication. Nausea is not associated with hyperglycemia, a fluid volume deficit, or excessive protein in the feeding.

QUESTION THIRTEEN: The correct answer is B

Rationale: When positioning joints, they should be maintained in the opposite position of a potential contracture. For the elbow, that would mean maintaining the arm in full extension. Contractures of the arms cause flexion of the elbow joint, therefore caring for the patient with the elbows flexed would not be therapeutic.

PROFESSIONAL PRACTICE

QUESTION FOURTEEN: The correct answer is A

Rationale: One purpose of equity is to ensure patients have what they need in and out of treatment settings to effectively benefit from best practices in treatment. This includes ensuring that all patients have access to healthcare, and this can be facilitated by increasing access to healthcare. Building a rehabilitation center in an area that is economically disadvantaged increases access. Other things that might be done include increasing home care in economically disadvantaged areas or providing free transportation when community members have difficulty accessing healthcare. Encouraging a diverse workforce better embodies diversity and inclusion. Holding focus groups al better encompasses both diversity and inclusion. Ensuring all populations are served equally is an example of equality, which is different from equity. Because there are inequities in the provision of healthcare, equality is not always the goal. There are times when underserviced communities may have different needs than other communities.

QUESTION FIFTEEN: 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 to find resources. Mitigation is the prevention stage of disaster management and preparedness assists an institution to ensure 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.

WOUND MANAGEMENT

QUESTION SIXTEEN: The correct answer is B

Rationale: Appropriate wound care after application of an enzymatic wound debridement agent is to cover the area with a polyurethane film dressing which is then left undisturbed for four hours. At that time, the dressing is removed and a compressive, saline-soaked dressing is applied. The saline-soaked dressing is changed every two hours for the next 24 hours.

QUESTION SEVENTEEN: The correct answer is C

Rationale: In the inosculation phase of graft take, severed vessels within the skin graft connect into the capillary bed of the wound. This causes the graft to change from pale to pink in color and is a positive sign that the graft will take. Ideally, this will occur within four days of the graft but must take place within four days of the graft to ensure graft take. Blistering should never be present under a graft. This will most certainly result in graft failure. A decrease in hyperemia surrounding a graft does not indicate that inosculation has occurred. The graft grows into the surrounding skin long after the graft take. This may not occur for several weeks after inosculation.

QUESTION EIGHTEEN: The correct answer is A

Rationale: CEA involves growing sheets of the patient’s own skin in a lab and transplanting them back onto a debrided, healthy wound bed. Therefore, skin must be procured before the CEA may be placed. A CEA is secured to the wound with sutures or staples, not with a wound adhesive. A platelet transfusion is not required before the placement of a CEA. Mechanical or chemical abrasion is not required before placement of a CEA.

QUESTION NINETEEN: The correct answer is C

Rationale: Generally, superficial partial thickness burns heal within 2 – 3 weeks and do not require grafting. This can be affected by factors such as age, health of the patient, and size of the wound.

PAIN, AGITATION, AND DELIRIUM

QUESTION TWENTY: The correct answer is D

Rationale: Opioid-induced hyperalgesia is an increase in nociceptive sensitivity due to frequent opioid use. This condition may cause an increase in the patient’s pain when opioids are administered. Treatment focuses on reducing the use of opioids through increased utilization of non-opioid alternatives. Methadone is an opioid and increasing the use of opioids will not effectively treat this condition. Similarly, changing to different opioids does not reduce the use of opioids overall and is not considered an effective treatment. Patient-controlled analgesia utilizes opioids so this is not an effective alternative.

QUESTION TWENTY-ONE: The correct answer is A

Rationale: Potential side effects of Dexmedetomidine include hypotension (rather than an increase in mean arterial pressure) and bradycardia. Alpha-adrenergic agonists may be administered to counter these effects. Dexmedetomidine is not associated with elevated blood urea nitrogen and does not reduce the effectiveness of opioids. In fact, Dexmedetomidine may actually enhance pain control in patients receiving opioids due to the synergistic effects of these two medications.

AMBULATORY AND RECONSTRUCTION

QUESTION TWENTY-TWO: The correct answer is D

Rationale: Autologous skin grafting involves harvesting, processing, and injecting fat cells into an area with a soft tissue defect. This procedure aids in the regeneration of dermal and subcutaneous tissue due to the presence of stem cells and adipose tissue. This in turn may reduce neuropathic pain by releasing nerve entrapments and covering nerve endings. Autologous fat grafting does not reduce the incidence of pruritis. Pharmacology and moisturizers are more effective for the treatment of this complication. Fat grafting does not increase sweating. Keloids occur despite autologous fat grafting.

QUESTION TWENTY-THREE: The correct answer is A

Rationale: Tricyclic antidepressants have some antihistamine H1-blocking activity and may be useful in treating Pruritus even when conventional antihistamines have failed. Tricyclic antidepressants have no therapeutic value in managing amenorrhea or insulin resistance. Although tricyclic antidepressants may reduce neuropathic pain, they are not useful in managing procedural pain.

PSYCHOSOCIAL SUPPORT AND ADVOCACY

QUESTION TWENTY-FOUR: The correct answer is B

Rationale: Although an acute stress disorder can occur at any point following an injury, it is most likely to be acute shortly after the injury secondary to the fact that the patient is undergoing numerous changes all at once such as dealing with the injury event itself, adapting to hospitalization, experiencing loss and fear for survival. Acute stress disorder may also tend to appear near the time of discharge when the patient faces the uncertainty of returning to life outside of the hospital, although the stress experienced at the time of discharge tends to be less acute than the stress experienced shortly after the injury. If acute stress disorder remains acute at 28 days following the injury, it is defined as post-traumatic stress disorder. Although surgical debridement and skin grafting may create stress, the stress experience at this time tends to be less acute compared to the stress experienced shortly after the injury.

QUESTION TWENTY-FIVE: The correct answer is A

Rationale: A major goal in attending a burn camp is to allow burn survivors to interact with others and learn that they are not facing their challenges alone. This is meant to improve the attendee’s self-esteem. The purpose of the burn camp is not to manage a patient’s pain or improve their activity tolerance. Although it would be desirable for the child to return to the camp in the future, this is not the purpose of the camp.

SPECIAL POPULATIONS

QUESTION TWENTY-SIX: 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 TWENTY-SEVEN: The correct answer is B

Rationale: Following thawing, tissue can easily be injured and must be treated gently. This includes applying antimicrobial cream, applying loose dressings, splinting the area, and elevating it. Tissue that has been thawed following frostbite becomes edematous and is prone to compartment syndrome, therefore, compressive dressings should not be used. Furthermore, the tissue is easily damaged following thawing, therefore compressive dressings should not be used. The tissue should not be left exposed as it is prone to both infection and further damage. There is no therapeutic value in placing warm packs over the area following thawing.

QUESTION TWENTY-EIGHT: The correct answer is D

Rationale: It is not uncommon for patients with erythema multiforme to develop ulcerations of the mucosa, including the mucosa of the mouth and gastrointestinal tract. This can result in a reluctance to take nutrition orally requiring enteral nutrition. Hypoglycemia, paralytic ileus, and hypermetabolism are not associated with this condition.

QUESTION TWENTY-NINE: The correct answer is C

Rationale: symptoms such as muscle cramping and tremors are associated with opioid withdrawal. Effective treatment should result in relaxation of the muscles relieving those symptoms. Opioid withdrawal causes tachycardia and hypertension, so an increase in pulse and blood pressure would not be associated with effective treatment. Opioid withdrawal causes dilated pupils, therefore an increase in pupil size is not associated with effective treatment.