Monday, May 3, 2021

Trauma and Burns Case File

Posted By: Medical Group - 5/03/2021 Post Author : Medical Group Post Date : Monday, May 3, 2021 Post Time : 5/03/2021
Trauma and Burns Case File
Eugene C. Toy, MD, Manuel Suarez, MD, FACCP, Terrence H. Liu, MD, MPH

Case 29
A 30-year-old man is admitted to the ICU. The patient is a fire fighter who was inside a burning building when the floor of the room collapsed, causing him to fall 3 floors into the basement. The patient was trapped under a large amount of  debris and was rescued after approximately 35 minutes. On examination at the scene, he had a pulse of 112 beats/minute, a blood pressure of 90/70 mm Hg, and bilateral thigh deformities with accompanying soft tissue swelling. He had burn  wounds involving the entire anterior chest and abdomen and circumferential burns involving both upper arms. The wounds on his legs appear to extend into the muscles. His GCS in the emergency center was 10, and the patient was intubated. His carboxyhemoglobin level was 27%. Dark, tea-colored urine returned after the insertion of the urinary catheter. A  CT scan  of the abdomen and pelvis  was done and revealed a laceration of the liver with minimal amount of free fluid in the abdomen. A fracture of the right iliac crest was also noted.

What are your priorities for this patient's care in the ICU?
How do you manage his fluid resuscitation?
What are the measures that you would take to prevent organ injuries that may develop as results of his burns? 


ANSWER TO CASE 29:

Trauma and Burns

Summary: This patient is a 30-year-old man with severe bums on his trunk and upper extremities in association with multiple other traumatic injuries. His presentation to the emergency department is consistent with shock and inhalation injury.
  • Priorities: Orotracheal intubation to secure the airway. Place the patient on 100% oxygen to minimize injuries from his carbon monoxide inhalation. Large bore secured intravenous access should be placed for ongoing fluid resuscitation and for central venous pressure monitoring. His thigh deformities likely indicate femur fractures that should be verified by x-rays, followed by reduction and stabilization. The bum wounds should be gently cleaned and covered with silver sulfadiazine and gauze dressing. 
  • Fluid resuscitation: Initial fluid resuscitation can begin using either the Parkland formula or the modified Brooke formula. Endpoint of resuscitation to follow include urine output >0.5 to 1.0 mL/kg/h and adequate central venous pressures. The initial fluid administration may need to be greater in this patient because of the other associated injuries (liver, pelvis, and long bones) and his myoglobinuria. Similarly, because of these potential bleeding sources, the patient's hemoglobin, hematocrit, coagulation profile, and platelet counts need to be closely monitored during the early resuscitation period. 
  • Measures to prevent organ injuries: Large bums produce cardiac depression from circulating systemic inflammatory mediators. Pulmonary injuries may result from direct bum effects or acute lung injury (ALI), and acute kidney injury may develop as the result of insufficient fluid resuscitation and myoglobin induced injuries. Primary prevention begins with timely and appropriate fluid resuscitation based on hemodynamic monitoring and responses to resuscitation (urine output, lactate, and base deficits). Early and timely wound management is also important in the prevention of distant organ dysfunction. For example, early burn wound excision has been demonstrated to produce fewer burn wound-associated septic complications and improved survival.

ANALYSIS

Objectives
  1. To learn the management of thermal injuries (inhalation injuries, infections, acute kidney injuries, pain management, metabolic and nutritional support).
  2. To learn to recognize and prioritize the care of bum patients with other associated injuries.

Considerations
This fire fighter suffered severe burn injuries as evident by the extent of his wounds, which involve the entire circumference of his trunk and upper extremities. Because he was trapped in a burning building for quite some time, he was exposed to the by-products of fire, mainly carbon monoxide and cyanide. Inhalation of these toxins along with direct heat and the steam of the flames can cause edema and severe damage to the airway. Hence, early intubation is warranted. The patient's carboxyhemoglobin of 27% is concerning and indicates significant carbon monoxide (CO) inhalation; COHgb levels of 30% are often associated with permanent central nervous system dysfunction, and COHgb levels greater than 60% commonly produce coma and death. Carbon monoxide has a 240-fold greater affinity for hemoglobin than oxygen; therefore, the half-life of CO in blood in room air is 250 minutes. The half-life of COHgb can be reduced to 40 to 60 minutes by placing the patient on 100% O2. This patient's history of having fallen several stories to the basement resulting in severe bony injuries and subsequent immobility are concerning for the occurrence of muscle degradation and rhabdomyolysis; therefore, precautions should be taken to identify and treat this potential complication. This patient's associated injuries of pelvic fracture, bilateral femur abnormalities, and a liver laceration are worrisome. This patient needs diagnostic studies to ensure that there is no active retroperitoneal bleeding (ie, angiography or CT angiography). Additionally, urgent orthopedic consultation is necessary for early skeletal stabilization. The grade of the liver laceration can be determined based on the CT findings, and serial hemoglobin and hematocrit levels can be helpful to determine if operative or angiographic interventions are needed.

Approach To:
Burns and Trauma

CLINICAL APPROACH

Management of Thermal Injuries
Burns are a major cause of trauma in the United States, as over 1 million cases occur annually. Burn injuries can be produced by heat, chemicals, electricity, or radiation, with thermal injuries being the most common. Thermal injuries are a significant cause of morbidity and mortality because of the profound inflammatory response generated both locally and systemically.

Skin Biology and Pathophysiology
The epidermis and dermis are 2 distinct layers which make up the skin. The epidermis is the outermost layer and has the unique responsibility of protecting the host from infection, fluid loss, and ultraviolet light. It is also the site of vitamin D absorption and provides much of our thermal regulation. It is derived from ectoderm and hence is capable of regeneration. In contrast, the dermis lies underneath the epidermis and provides the structural framework of skin. Collagen is the principal structural molecule found in this layer. It is the dermis that gives skin its durability and elasticity.

Burns can cause significant damage to the structure and function of the skin. Jackson's classification of the burn wound outlines the pathophysiology of  thermal injury. There are 3 zones of tissue injury resulting from a bum: the zone of coagulation, the zone of stasis, and the zone of hyperemia. The zone of coagulation is in the center and constitutes the most severely injured tissue. The cells in
this zone are coagulated and necrotic. The zone of stasis is immediately beyond the zone of coagulation and is characterized by ischemia and vasoconstriction. The zone of stasis is important as it oftentimes is initially viable but can progress to the zone of coagulation when exposed to severe edema and/or hypoperfusion (consequences of inappropriate initial fluid management). Beyond the zone of stasis is the zone of hyperemia. In this zone the tissue is viable but often involved in profound inflammatory changes from surrounding cells.

Clinical Assessment
A burn patient should be treated similar to any other trauma patient, meaning the initial assessment should focus on the patient's airway, breathing, and circulatory systems. Assessment of the extent of the burns and other major injuries should also take place at this time. Inspection of the airway includes evaluation of the mouth, nose, oropharynx, and trachea. Facial burns, cinched nose hairs, the presence of soot, foamy oral secretions, and mucosal edema should alarm the provider of possible inhalation injury, and early intubation should take place. Additionally, labored breathing with shallow breaths, use of accessory muscles, stridor, or diminished neurologic function also warrant intubation. A significant portion of initial deaths from fires occur secondary to hypoxia from oxygen deprivation or toxin inhalation.

Perhaps one of the biggest advances in managing severely burned patients is the use of early aggressive fluid resuscitation. The Parkland formula, named after the hospital in Dallas, Texas, is a guide to volume repletion. For adults with affected TBSA% > 15 or children with affected TBSA% > 10, it is recommended that supportive care, continued monitoring, and aggressive fluid resuscitation be given. The Parkland formula calculates the amount of volume that should be given in a 24-hour period by measuring the (affected TBSA%) x (4 mL of lactated Ringer solution) x (weight of the patient in kg) . Half of the calculated amount should be given in the first 8 hours following the injury, and the second half should be given in the subsequent 16 hours. This is only a guide for resuscitation and should be used in conjunction with other information (eg, urine output, central venous pressure, etc) to determine volume status. The modified Brooke formula is an alternative resuscitation approach using lactated Ringer solution at 2 mL/kg per% TBSA, with one-half of the fluid administered in the first 2 hours and the remaining half in the subsequent 16 hours; during second 24 hours, colloid is given at (0.3 to 0.5 mL/kg)/% TBSA burn + D5W to maintain urine output of at least 0.5 mL/kg/h.

Calculating TBSA can be tricky. Usually only second- and third-degree burns are included in estimating TBSA. Wallace rule of nines is a way of estimating the extent of burn injury in adults. The body is divided into sections and given a percentage (a fraction or multiple of 9) of body surface area. In this schema the anterior chest, posterior chest, abdomen, buttocks, unilateral anterior lower extremities, unilateral posterior extremities, circumferential unilateral arm, and circumferential head each equal 9%. The perineum equals 1 %. In total, the entire body is 100% (Figure 29-1 ).

patients burn size

Figure 29-1. Rule of nines to estimate patient's burn  size by dividing the body into regions in which the body total surf  ace area can  be calculated by multiples of nine. (Reproduced, with permission, from Brunicardi FC, Andersen DK,  Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. New York, NY: Mc Graw-Hill Education; 201 0. Figure  8-1.) 

The rule of nines does not apply to children as they are proportionately different from adults. Hence, an adaptation of the rule of nines estimates a larger surface area for the circumferential head and less for the extremities (Figure 29-1). In our patient, the calculated TBSA equals 36%.

Management of Burn Wounds
Determining the depth of the bum wound can provide some insight into the direction of management (see Figure 29-2). First-degree bums are superficial and only involve the epidermis. They appear erythematous in color and do not have any blisters. Healing usually occurs within a few days but can take up to 2 weeks. Treatment usually consists of applying a topical cream for symptom relief and serve as a barrier against infection.

Partial-thickness bums (formerly known as second-degree bums) extend beyond the epidermis and are further classified as superficial or deep. Superficial partial thickness bums are characterized by painful blisters that are usually pink in color. Topical agents such as silver sulfadiazine can be used for management of these bums, which usually heal within 2 weeks without much residual impairment and with

Layers of the skin

Figure 29-2. Layers of the skin showing depth of first-degree, second-degree, and third-degree burns. (Reproduced, with permission, from Doherty G M. Current Diagnosis &Treatment: Surgery. 13th ed, McGraw-Hill Education, 2010. Figure 14-1.)

minimal scarring. On the other hand, deep partial-thickness bums are dry, mottled, and variably painful. Silver sulfadiazine can also be used in their management; however, surgical excision and skin grafting may be necessary for wounds that do not heal within 3 weeks. Severe scarring, subsequent functional impairment, and contracture are associated with chronic deep partial-thickness bum wounds.

Third-degree burns are full-thickness bums, which involve the entire epidermis and dermis. Usually, these bums are painless as the nerve endings have also been damaged. These bums appear white or black with eschar formation. Spontaneous healing of these wounds can only take place by contraction, since the precursors for skin regeneration have been damaged. Similarly, deep partial-thickness bums have limited regenerative capacity, in which spontaneous regeneration is usually prolonged. Therefore, full-thickness and deep partial-thickness bums usually benefit from operative interventions with surgical excision and skin grafting for optimal functional outcomes. Early excision of devitalized tissue also reduces the local and systemic effects of inflammatory mediators.

Multiple Organ Dysfunction Syndrome After Burns
Due to the profound local and systemic inflammatory response from thermal injury, nearly every organ system has the potential to be compromised following a severe bum. In the immediate post-injury period, the neurologic, pulmonary, and cardiovascular systems are most commonly affected. Neurologically, bum victims can have a decline in their level of alertness for a number of reasons including hypoxia, inhalation of toxins, and associated traumatic head injuries. Supplemental oxygen should be given immediately. A low GCS warrants endotracheal intubation and mechanical ventilation. In patients who are alert, it is important to be aware that superficial and partial-thickness bums can cause excruciating pain and warrant careful and continuous dosing of analgesics.

A substantial percentage of patients who suffer severe bums have inhalation injury. Direct heat and steam can cause damage to the upper and lower airways and cause significant swelling leading to airway obstruction. Carbon monoxide and hydrogen cyanide are the byproducts of fires, and these toxins lead to inflammation and pulmonary edema that prevent adequate gas exchange. Hence, early intubation and mechanical ventilation should be considered. In the ICU, regular tracheobronchial care (ie, deep suctioning, therapeutic bronchoscopy, use of adjuvant pharmacologic agents such as bronchodilators or N-acetylcysteine ) should be provided.

Cardiovascular collapse following severe burn injury is usually caused by volume depletion from fluid loss after skin disruption and vasodilation from local and systemic inflammatory mediator releases. To combat hypovolemia, aggressive fluid resuscitation should be initiated in the emergency department and continued in the ICU. The Parkland formula provides an initial guideline for fluid resuscitation (4 mL of lactated Ringer solution X %TBSA X weight in kg with one-half given in the first 8 hours and the second half given in the subsequent 16 hours ) . In the ICU, continued measurements of urine output and central venous pressure should be used to determine the patient's response to fluid management. Often, the initial fluid resuscitation plans need to be adjusted to minimize the effects of under- or over-resuscitation.

One of the most devastating conditions associated with extensive burns is burn wound sepsis. Burn injuries disrupt the skin's protective barrier which, in turn, renders the host susceptible to burn wound infections. Severe thermal injuries induce a relative immunocompromised state which can lead to sepsis. Initially, burn wounds are sterile but quickly become colonized with indigenous skin flora such as Staphylococcus. The wounds can become subsequently colonized with gram-positive and gram negative organisms, as well as yeast from the host's oral-digestive flora and contaminants from health-care workers and the hospital environment. Pseudomonas auerogirwsa is a common organism found in bum wounds in many US hospitals. The application of digestive tract decontamination reduces hosts' GI tract colonization and has been shown to reduce the occurrence of burn wound sepsis in the ICU setting.

The metabolic demands are significantly increased after thermal injury. For severe burn patients ( >20% TBSA injured), early nutritional support is critical, with the nitrogen repletion and the maintenance of nitrogen balance being the most critical aspect of therapy. Early enteral nutritional support in this patient population is associated with improved maintenance of gastrointestinal tract, physiological and immunological functions, decreased burn wound sepsis, and decreased hospital length of stay. Nutritional goals should include a high protein diet with considerations for supplemental glutamine. Daily protein intake should be in the range of 1.5 to 2.0 g/kg/d. Avoidance of hyperglycemia is critical for minimizing infectious complications. Daily weight measurements with weekly assessment of pre-albumin levels are helpful for the determination of response and for guiding nutritional planning. Nutritional strategies are optimal when a multidisciplinary team approach is taken, including inputs from nutritionists.

MANAGING ASSOCIATED INJURIES
Burn victims often have associated traumatic injuries which can be life-threatening or compromise functional outcomes if not identified and treated in a timely manner. Burn victims should be treated as any other trauma patient. The initial assessment should begin with the ABCs of trauma but should be followed by a comprehensive secondary survey to identify other potential injuries. Radiographic imaging, such as, x-rays, CT scans, and ultrasound examinations are useful diagnostic tools.

Severe thermal injuries are often associated with immobility and subsequent muscle degradation. In addition to hypovolemia from capillary leak as a result of a profound systemic inflammatory response, the renal system can be affected secondary to rhabdomyolysis. Urine output measurements are important in the monitoring of volume status. Serial laboratory measurements of blood urinary nitrogen, creatinine, and CPK are useful in the management of rhabdomylosis and the prevention of acute kidney injuries.

LONG-TERM CONSEQUENCES
Should a patient survive a severe thermal injury, there are still several long-term consequences of bums. Psychiatric issues may develop as the result of prolonged hospitalization, multiple surgical procedures, severe skin scarring, contracture, and/ or impaired function. Long-term rehabilitation and counseling are important to improve functional recovery. Additionally, the severely injured bum patient has an increased risk of developing skin cancer. A Marjolin ulcer is a squamous cell carcinoma that arises from a bum scar. Any changes in a bum scar should prompt further investigation via tissue biopsy to rule out malignancy.

CLINICAL CASE CORRELATION
  • See also Case 4  (Hemodynamic Monitoring), Case 5 (Vasoactive Drugs), Case 8 (Airway Management), Case 28 (Blunt Trauma), and Case 33 (Multiorgan Dysfunction). 

COMPREHENSION QUESTIONS

29.1  A patient has deep partial bum wounds involving the entire anterior chest and abdomen, and circumferential bums involving both upper arms. His estimated weight is 75 kg. Based on the Parkland formula, how much IV fluid should he receive in the first 8 hours following his injury?
A. 2000-4000 mL LR
B. 4000-6000 mL LR
C. 8000-12,000 mL LR
D. 10,000-12,000 mL albumin
E. 4000-8000 mL albumin

29.2  A 45 -year-old woman suffered a thermal injury to her dominant arm 2 years ago. It took 6 months of aggressive wound care for the initial injury to heal. She presents to her physician with itching at the scar, which is irregularly bordered and has changed in shape over the past few months. Her PMD calls you to discuss the case since you cared for the patient in the ICU during her hospitalization. Which of the following is the best next step in management?
A. Observe the wound as it does not appear to be infected.
B. Prescribe an antibiotic as it may be infected.
C. Prescribe hydrocortisone cream which the patient should apply daily.
D. Take a tissue biopsy of the wound to rule out malignant transformation.
E. Refer the patient to a dermatologist.


ANSWERS TO QUESTIONS

29.1  B. This patient has burns to the anterior chest and abdomen and both arms, so the total body surface area involvement can be estimated at 18% (abdomen and chest) + 9% x 2 (both arms) = 36%. Based on the Parkland formula that provides 4 mL/kg x percent BSA, the calculation would be 4 X 75 X 36 = 10,800 mL over 24 hours. During the first 8 hours, half of the calculated volume will be given, which is approximately 5400 mL.

29.2  D. Patients with chronic wounds including burn scars are at risk of developing malignance transformation in the chronic wounds. Squamous cell carcinoma has been known to develop, and a history of shape change or growth would mandate tissue biopsy.


CLINICAL PEARLS

 A burn patient is a trauma patient. Therefore, initial assessment should begin with the ABCs of trauma with assessment of the severity of burn wounds and other traumatic injuries. 
 Every major organ system can be compromised following severe burns. 
 Early intubation, mechanical ventilation, aggressive fluid resuscitation, infection control, and enteral nutrition will reduce morbidity and mortality in the severely burned patient. 
 Tissue biopsy is necessary for all changes in burn wound scars to rule out malignancy. 

References

Chipp E, Milner C, Blackburn A. Sepsis in bums: a review of current practice and future therapies. Ann Plastic Surg. 2010;65: 228-236. 

Church D, Elsayed S, Reid 0, Winston B, Lindsay R. Bum Wound Infections. Clin Microbial Rev. 2006 Apr;19(2):403 -434. 

Enkhbaatar P, Traber DL. Pathophysiology of acute lung injury in combined bum and smoke inhalation injury. Clin Sci (Lond). 2004 Aug;l07(2):137-143. 

Evers L, Bhavsar D, Mailander P. The biology of bum injury. Experimental Dermatol. 2010;19:777-783.

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