Highlights of the American Academy of Emergency Medicine (AAEM)
Highlights of the American Academy of Emergency Medicine (AAEM)
The 12th Annual Scientific Assembly of the American Academy of Emergency Medicine (AAEM) brought together well over 500 attendees to review the most relevant clinical advances in emergency medicine during the past year. In keeping with the tradition of previous Scientific Assemblies, the conference once again presented top educators in Emergency Medicine covering cutting-edge topics.
Col. Lee Cancio, MD, Surgeon and Clinical Trials Program Manager of the Trauma Division at the US Army Institute of Surgical Research, Brooke Army Medical Center, San Antonio, Texas, presented an interesting discussion on burn management, with a special emphasis on burn mass-casualty scenarios relating to his recent military experience in Iraq.
He described the different phases of resuscitation of burn patients. Clearly, the phases overlap increasingly because excision and grafting often begin on the immediate post-burn day. The ABCs (airway, breathing, circulation) are applied with special attention to the physiology of burn patients. In addition, because of a burn patient's risk for hypothermia and insensitive fluid losses, particular attention to fluid management and temperature control are paramount. Cancio recommends prophylactically intubating patients with burns greater than 40% of total body surface area, obvious inhalational injury, or deep facial burns to minimize the risk of loss of airway due to facial edema.
Inhalation injury can involve injury at 3 different levels: above the vocal cords, below the vocal cords, or in the lung tissue. Pitfalls to be aware of when treating these patients include hypoxia and hypercarbia due to inhalational injury that can lead to ventilator-induced lung injury (acute respiratory distress syndrome [ARDS]). He advocates "gentle" mechanical ventilation, keeping peak inspiratory pressures less than 40 cm H2O, FiO2 less than 60% along with pH greater than 7.2, SaO2 greater than 90%, and permissive hypercapnia and frequent use of bronchodilators to limit bronchospasm.
Cancio described the importance of differentiating burn shock from other forms of shock in terms of pathophysiology and time of onset. In cases of burn shock, increased capillary permeability, hydrostatic pressure, and colloid oncotic pressure contribute to loss of plasma volume from the microvasculature into the interstitium, leading to hypovolemic shock and edema formation. This usually occurs within 48 hours following the initial burn. In addition, decreased myocardial contractility and increased afterload also occur. This combination of events reduces cardiac output, which makes it necessary to correct the volume problem gradually.
To correct this volume problem, Cancio recommends against the use of a "bolus," using a modified "Brooke Army" formula at 2 cc/kg/% burn in adults with adjustments to achieve a urinary output of 30-50 cc/hr. Urine output, mental status, and resolution of base deficit are regarded as his indicators of ongoing resuscitation. He noted that examining the character of the peripheral pulses, and monitoring pulse and blood pressure are important as well. In a patient with a normal mental status, palpable peripheral pulses, and measurable blood pressure, Cancio recommends initially giving 1 L/hour of lactated Ringers solution. He then calculates burn size and using the formula, updates his fluid orders. An exception to this recommendation is the patient who presents with profound hypotension, has preexisting signs of dehydration, or when there has been a delay in resuscitation. In this situation a rapid infusion is used to restore palpable radial pulses and mentation.
Cancio then reviewed care of burns for civilians as well as mass-casualty situations that may occur too far from a burn center for immediate transport. For civilians who are burned and can be rapidly transported to a burn center (less than 24 hours), he states that there is no need for application of creams, debridement, or prophylactic antibiotics. The goal is to keep the burns dry, warm, and clean, covering the burns with a dry sheet. In a mass-casualty scenario, patient transfer to a burn center is often delayed sometimes for days, so application of creams and prophylactic antibiotics is not unreasonable. The generous use of pain medication to debride burned tissue and perform dressing changes is essential.
Silver sulfadiazine (Silvadene) cream or mafenide acetate (Sulfamylon) cream should be applied as a thick layer as opposed to a lotion. He recommends application of a layer up to 1/16th to 1/8th of an inch. Silver sulfadiazine is often less painful and may costs less, but gram-negative organisms may have some resistance to this cream. Mafenide acetate, on the other hand, penetrates eschar and cartilage more effectively, has excellent gram-negative coverage including Pseudomonas, but can be quite painful on application to partial-thickness burns.
As an alternative to silver sulfadiazine cream or mafenide acetate cream, Silverlon and Acticoat have emerged for the treatment of burns. The principal mechanisms of action for these products are the same as those for silver sulfadiazine, with slow release of silver ions from a sheet-like material along with an antimicrobial effect.
Cancio discussed the management of burn wound cellulitis as well as burn wound sepsis. In burn wound cellulitis, there is usually more than 2 cm of erythema surrounding the burn wound edges. The causative organism is usually Staphylococcus aureus or streptococci bacteria. In addition, a low-grade fever may develop. The treatment is penicillin, vancomycin, or a first-generation cephalosporin.
Burn-wound sepsis was the leading cause of death before the introduction of topical antimicrobial agents. It is rarely seen in the West today. However, sepsis or septic shock due to Pseudomonas or other gram-negative organisms can constitute a life-threatening emergency. The presence of skin-color changes including dark red, brown, or black discoloration of the eschar makes the diagnosis of burn wound sepsis more likely. A biopsy specimen of the burn wound may reveal bacteria in the subcutaneous fat. Treatment is with an IV aminoglycoside, and antipseudomonal semisynthetic penicillin, along with application of mafenide acetate cream and excision of the burn down to the fascia.
The 12th Annual Scientific Assembly of the American Academy of Emergency Medicine (AAEM) brought together well over 500 attendees to review the most relevant clinical advances in emergency medicine during the past year. In keeping with the tradition of previous Scientific Assemblies, the conference once again presented top educators in Emergency Medicine covering cutting-edge topics.
Burn Management
Col. Lee Cancio, MD, Surgeon and Clinical Trials Program Manager of the Trauma Division at the US Army Institute of Surgical Research, Brooke Army Medical Center, San Antonio, Texas, presented an interesting discussion on burn management, with a special emphasis on burn mass-casualty scenarios relating to his recent military experience in Iraq.
He described the different phases of resuscitation of burn patients. Clearly, the phases overlap increasingly because excision and grafting often begin on the immediate post-burn day. The ABCs (airway, breathing, circulation) are applied with special attention to the physiology of burn patients. In addition, because of a burn patient's risk for hypothermia and insensitive fluid losses, particular attention to fluid management and temperature control are paramount. Cancio recommends prophylactically intubating patients with burns greater than 40% of total body surface area, obvious inhalational injury, or deep facial burns to minimize the risk of loss of airway due to facial edema.
Inhalation injury can involve injury at 3 different levels: above the vocal cords, below the vocal cords, or in the lung tissue. Pitfalls to be aware of when treating these patients include hypoxia and hypercarbia due to inhalational injury that can lead to ventilator-induced lung injury (acute respiratory distress syndrome [ARDS]). He advocates "gentle" mechanical ventilation, keeping peak inspiratory pressures less than 40 cm H2O, FiO2 less than 60% along with pH greater than 7.2, SaO2 greater than 90%, and permissive hypercapnia and frequent use of bronchodilators to limit bronchospasm.
Cancio described the importance of differentiating burn shock from other forms of shock in terms of pathophysiology and time of onset. In cases of burn shock, increased capillary permeability, hydrostatic pressure, and colloid oncotic pressure contribute to loss of plasma volume from the microvasculature into the interstitium, leading to hypovolemic shock and edema formation. This usually occurs within 48 hours following the initial burn. In addition, decreased myocardial contractility and increased afterload also occur. This combination of events reduces cardiac output, which makes it necessary to correct the volume problem gradually.
To correct this volume problem, Cancio recommends against the use of a "bolus," using a modified "Brooke Army" formula at 2 cc/kg/% burn in adults with adjustments to achieve a urinary output of 30-50 cc/hr. Urine output, mental status, and resolution of base deficit are regarded as his indicators of ongoing resuscitation. He noted that examining the character of the peripheral pulses, and monitoring pulse and blood pressure are important as well. In a patient with a normal mental status, palpable peripheral pulses, and measurable blood pressure, Cancio recommends initially giving 1 L/hour of lactated Ringers solution. He then calculates burn size and using the formula, updates his fluid orders. An exception to this recommendation is the patient who presents with profound hypotension, has preexisting signs of dehydration, or when there has been a delay in resuscitation. In this situation a rapid infusion is used to restore palpable radial pulses and mentation.
Cancio then reviewed care of burns for civilians as well as mass-casualty situations that may occur too far from a burn center for immediate transport. For civilians who are burned and can be rapidly transported to a burn center (less than 24 hours), he states that there is no need for application of creams, debridement, or prophylactic antibiotics. The goal is to keep the burns dry, warm, and clean, covering the burns with a dry sheet. In a mass-casualty scenario, patient transfer to a burn center is often delayed sometimes for days, so application of creams and prophylactic antibiotics is not unreasonable. The generous use of pain medication to debride burned tissue and perform dressing changes is essential.
Silver sulfadiazine (Silvadene) cream or mafenide acetate (Sulfamylon) cream should be applied as a thick layer as opposed to a lotion. He recommends application of a layer up to 1/16th to 1/8th of an inch. Silver sulfadiazine is often less painful and may costs less, but gram-negative organisms may have some resistance to this cream. Mafenide acetate, on the other hand, penetrates eschar and cartilage more effectively, has excellent gram-negative coverage including Pseudomonas, but can be quite painful on application to partial-thickness burns.
As an alternative to silver sulfadiazine cream or mafenide acetate cream, Silverlon and Acticoat have emerged for the treatment of burns. The principal mechanisms of action for these products are the same as those for silver sulfadiazine, with slow release of silver ions from a sheet-like material along with an antimicrobial effect.
Cancio discussed the management of burn wound cellulitis as well as burn wound sepsis. In burn wound cellulitis, there is usually more than 2 cm of erythema surrounding the burn wound edges. The causative organism is usually Staphylococcus aureus or streptococci bacteria. In addition, a low-grade fever may develop. The treatment is penicillin, vancomycin, or a first-generation cephalosporin.
Burn-wound sepsis was the leading cause of death before the introduction of topical antimicrobial agents. It is rarely seen in the West today. However, sepsis or septic shock due to Pseudomonas or other gram-negative organisms can constitute a life-threatening emergency. The presence of skin-color changes including dark red, brown, or black discoloration of the eschar makes the diagnosis of burn wound sepsis more likely. A biopsy specimen of the burn wound may reveal bacteria in the subcutaneous fat. Treatment is with an IV aminoglycoside, and antipseudomonal semisynthetic penicillin, along with application of mafenide acetate cream and excision of the burn down to the fascia.
Source...