General Flashcards
An otherwise healthy 30-year-old woman is diagnosed with dermatofibrosarcoma
protuberans (DFSP) of the upper back. A wide excision is performed, and a local flap is
used to reconstruct her back. On follow-up evaluation, CT scan shows multiple
pulmonary metastases. Which of the following is the most appropriate next step in
management?
A ) Chemotherapy
B ) Hormone therapy
C ) Immunotherapy
D ) Radiation therapy
E ) Surgical excision
The correct response is Option A.
The most appropriate next step in management is chemotherapy. Patients with
inoperable, recurrent, or metastatic disease may benefit from imatinib which is a
tyrosine kinase inhibitor and acts as a molecularly targeted drug. It acts by inhibiting the platelet-derived growth factor receptor tyrosine kinase. Dermatofibrosarcoma
protuberans (DFSP) is characterized by chromosomal rearrangements resulting in the
production of platelet-derived growth factor B, eventually leading to autocrine growth
stimulation of DFSP. Imatinib functions as an inhibitor of platelet-derived growth factor
receptors, thus blocking this autocrine stimulation. Therefore, imatinib can be used as
an adjuvant therapy for cases in which obtaining sufficient surgical margins is
impossible. Neoadjuvant imatinib has also been used for locally advanced primary
tumors.
Radiation therapy may improve local control and reduce the risk of recurrence
postoperatively in patients with DFSP. There is no described role of it in pulmonary
metastases. Resection of the multiple lesions in the lung, and hormonal or immune
therapy are not recommended for metastatic DFSP.
2019
A 75-year-old woman with a history of right mastectomy and irradiation therapy presents
with a sarcoma that requires radical resection and partial sternectomy. A photograph is
shown. A pedicled flap is planned to repair the defect. Which of the following arteries
supplies the most appropriate flap in this situation?
(picture - midline defect upper chest)
A ) Deep inferior epigastric
B ) Internal mammary
C ) Lateral thoracic
D ) Thoracoacromial
E ) Thoracodorsal
The correct response is Option E.
The most appropriate pedicled flap for this particular defect is a latissimus flap, shown in
the photograph, supplied by the thoracodorsal artery. The latissimus flap is a Mathes/Nahai
type V flap that can be transferred on its dominant pedicle (thoracodorsal artery) or on multiple segmental paraspinal perforators. The internal mammary artery terminates as the
superior epigastric artery, which would provide blood supply for a superiorly based vertical
rectus flap. The rectus flap is a Mathes/Nahai type III flap, with two dominant
pedicles. However, this pedicle is not available because of the radical resection and prior
irradiation. The lateral thoracic artery is one of two dominant pedicles supplying the
serratus anterior muscle (Mathes/Nahai type III). This flap is an option, but it would not
provide enough bulk necessary for the defect in this situation. The deep inferior epigastric
artery (DIEA) supplies the DIEA perforator flap, which would be an option as a free tissue
transfer but not as a pedicle flap for this situation.
2019
A 45-year-old woman who underwent Achilles tendon repair through a posterior midline
incision 3 weeks ago develops a postoperative wound infection and subsequent skin
necrosis. Physical examination shows a 3 x 3-cm wound directly overlying the Achilles
tendon in the absence of peritenon. A fasciocutaneous propeller flap from the medial leg is designed to cover this defect. The septal perforators to this flap run between which of
the following structures?
A ) Flexor hallucis longus and gastrocnemius
B ) Gastrocnemius and soleus
C ) Peroneus longus and peroneus brevis
D ) Soleus and flexor digitorum longus
E ) Tibialis anterior and extensor digitorum longus
The correct response is Option D.
This defect may be reconstructed with a posterior tibial artery perforator propeller
flap. These vessels emerge between the flexor digitorum longus and the soleus muscle. In
one anatomic study, there were three clusters of perforators: 4 to 9 cm, 13 to 18 cm, and 21
to 26 cm from the intermalleolar line. The peroneal artery perforators often arise through
the posterior peroneal septum, and the anterior tibial artery perforators are often found
between the extensor digitorum longus and the peroneus longus or between the tibialis
anterior and the extensor digitorum longus.
When considering dislocations of the thumb carpometacarpal (CMC) joint, which of the
following is most correct regarding which vector of dislocation would occur with injury to
the stabilizing ligament?
Injured Ligament Vector of Dislocation
A ) Dorsal intercarpal radial
B ) Dorsoradial dorsal
C ) Intermetacarpal ulnar
D ) Radiocarpal dorsal
The correct answer is B.
The CMCJ is very important for hand function and plays a key role in pinch and grasp. The
increased range of motion inherent to the thumb CMCJ is attributed to the anatomy of the joint. The biconcave saddle shaped articular surface of the CMCJ also provides some inherent stability.
Motion allowed by the joint includes flexion, extension, adduction, abduction, circumduction.
Stabilizing ligaments and joint capsule further reinforce the joint, thus thumb CMCJ dislocations are rare injuries. These injuries account for less than 1% of hand injuries.
There are five major stabilizing ligaments to the CMCJ: anterior (volar) oblique, ulnar collateral,
intermetacarpal, dorsoradial, and dorsal (posterior) oblique. These ligaments are critical stabilizers during motion. The volar oblique ligament and dorsoradial ligaments are considered to be the most
important resistive forces in dislocation in cadaver studies. Reports of traumatic thumb CMCJ dislocation have been in a dorsal vector. The volar oblique ligament was originally thought to be the critical resistive ligament; however, recent literature has supported the dorsal complex (includes the dorsoradial and posterior oblique ligaments) are the most critical for restraint of the joint, thus are injured in dorsal dislocations. Timely recognition is important for these injuries as
immediate reduction and casting or splinting for 4 to 6 weeks may be adequate to prevent
recurrence. However, these injuries are often missed on radiologic examination or may be
persistently unstable. Closed reduction and Kirschner wire fixation may be adequate for treatment in persistently unstable injuries. Some authors advocate for open reduction and ligament reconstruction. Delayed treatment especially beyond three weeks will likely require open reduction
and ligament reconstruction. These injuries are often missed on x-ray examination as they can be subtle especially in the setting of more obvious trauma. Inadequate treatment puts these patients at
increased risk for subsequent posttraumatic osteoarthritis given the joint malalignment.
The radiocarpal and dorsal intercarpal ligaments are wrist stabilizer not thumb CMCJ stabilizers.
2019
A 51-year-old farmer is brought to the emergency department after sustaining extensive burns in a fertilizer explosion. Examination shows white phosphorus embedded in his
burn wounds. In addition to burn resuscitation and examination of the wounds under
ultraviolet light, application of which of the following is the most appropriate next step in
management?
A ) Calcium gluconate
B ) Mafenide (Sulfamylon)
C ) Mineral oil
D ) Polyethylene glycol
E ) Saline irrigation
The correct response is Option E.
White phosphorus is sustained in both military and civilian circumstances. It is commonly
found in fireworks, fertilizers, and pesticide. It is extremely volatile and can ignite
spontaneously upon exposure to air. Additionally, phosphoric acids form during combustion
and further injure tissues.
Treatment mainstays include:
1. Immediate debridement of visible debris
2. Copious irrigation
3. Keep the area wet and covered with saline-soaked gauze
4. Cardiac monitoring and electrolyte evaluation.
Profound hypocalcemia, hyperphosphatemia, and sudden death have been associated with
this injury.
Calcium gluconate gel is used in the management of hydrofluoric acid burns. Polyethylene
glycol is used in the management of phenol and cresol burns. Mineral oil is used to isolate
potassium, sodium, and magnesium from water, with which they react explosively.
Mafenide (Sulfamylon) has no role in the immediate management of white phosphorus
burns.
A 48-year-old woman undergoes excision of a 3-cm recurrent keloid of the presternal
chest. Immediate reconstruction with a collagen-glycosaminoglycan scaffold dermal
regeneration template is performed, followed by thin (0.008-in) epidermal autografting
21 days later. After it has healed completely, punch biopsy is performed. The absence
of which of the following histologic features is most likely to indicate regenerated skin in
this patient?
A ) Capillary loops at the dermal-epidermal junction
B ) Elastic fibers
C ) Hair follicles
D ) Neovascularization
E ) Rete ridges
The correct response is Option C.
Regenerated skin is clearly quite different histologically from scar and, in fact, shares many
characteristics with normal physiologic skin. Regenerated skin shows mechanical
competence, vascularization, and heat and cold sensitivity. Furthermore, the dermal
epidermal junction shows formation of rete ridges and capillary loops. Regenerated skin
displays elastic fibers and increased collagen fiber density in the reticular dermis, and it
often exhibits nerve fiber regeneration as well. Regenerated skin, even when resurfaced
with a split-thickness skin graft, however, does not have the dermal appendages such as hair
follicles and sweat glands, that are present throughout normal skin.
An 80-year-old man sustains an extravasation injury to the dorsum of the arm
secondary to administration of a dopamine infusion. Which of the following findings is
an indication for a surgical intervention in this patient?
A ) Blanching of the skin
B ) Blistering
C ) Erythema
D ) Induration
E ) Persistent pain
The correct response is Option E.
The indications for surgery in an extravasation injury include full-thickness skin necrosis,
chronic ulceration, and persistent pain. Whereas blistering indicates a partial-thickness skin
loss, it is alone not an indication for surgery. Erythema, induration, and poor capillary refill
(blanching) are signs of extravasation injury but are not indications for an operative
intervention.
A 56-year-old man is scheduled to undergo excision of a lower extremity melanoma
during regional anesthesia. Current medications include lisinopril and occasional
motrin. He does not smoke cigarettes. Which of the following factors increases the risk
of postoperative nausea and vomiting in this patient?
A ) Age over 50 years
B ) Male gender
C ) Nonsmoking status
D ) Use of anti-inflammatory medications
E ) Use of local anesthetic
The correct response is Option C.
Risk factors for postoperative nausea and vomiting fall into four categories: patient-related, anesthesia-related, surgery-related, and other factors.
Patient-related predictors are: female sex, non-smoking status, history of postoperative nausea
and vomiting/motion sickness, genetics, age of 50 years or younger, and obesity (BMI greater
than 30 kg/m2).
Anesthesia-related predictors are: postoperative opioids, inhalational anesthetics, and nitrous
oxide.
Surgery-related predictors are: surgery duration and surgery type.
Other factors including high patient anxiety and postoperative pain.
2019
A 45-year-old man is scheduled to undergo abdominal wall reconstruction after being involved in a major motor vehicle collision that resulted in multiple intra-abdominal injuries 1 year ago. He underwent trauma laparotomy, which resulted in an open abdomen and a prolonged hospital course. Skin grafting of the bowel was performed, and the patient has since been living with a large ventral hernia. Preoperative injection of botulinum toxin type A into the lateral abdominal wall will most likely result in which of the following?
A) Decreased incidence of wound healing complications
B) Decreased length of hospital stay
C) Increased infection rate
D) Increased likelihood of primary fascial closure
E) Prolonged ventilator dependence
Correct answer is D
Prehabilitation of the abdominal wall through botulinum toxin type A (BTA) injections into the lateral abdominal wall musculature of patients with large ventral hernias and loss of domain has been demonstrated in multiple studies and meta-analyses to increase the likelihood of primary fascial closure. Advocates for its use have used varying types of BTA, doses, number of injections, and timing of injections, but results have consistently shown that its use has decreased the number of patients requiring bridging of the repair. Based on the mechanism and peak effect of BTA, studies using the injections at the time of repair have been less effective than their use 2 to 4 weeks prior to the planned operation. Radiologic assessment of the patients at the time of injection and immediately prior to surgery have demonstrated a lengthening of the lateral abdominal wall musculature and decrease in the width of the midline hernia. This lengthening and relaxation results in the decreased excursion distance and improved compliance of the abdominal wall, thus allowing for increased numbers of primary fascial closures with or without component separation. Larger scale studies are needed to determine other benefits of its use in this population. There are mixed results related to improved pain control, with some studies reporting a reduction in oral morphine equivalents, while others show no statistical difference. Improvement in complication rates such as hospital stay and recurrence are not consistent across studies. The use of tissue expanders and progressive preoperative pneumoperitoneum have also shown promise as adjuncts to abdominal wall reconstruction. These have been used alone and in conjunction with BTA injections with improved results regarding achieving primary fascial closure. Since these are more invasive procedures, they do carry unique risks (tissue expander infection/extrusion, intra-abdominal organ injury) that need to be factored into the operative plan. The use of prehabilitation with BTA has not been shown to decrease length of hospital stay or incidence of wound breakdown, nor has it been shown to prolong ventilator dependence or increase infection rate.
2024
A 66-year-old woman develops mediastinitis 3 weeks after undergoing single-vessel coronary artery bypass grafting using a left internal mammary artery to left anterior descending coronary artery bypass. History includes diabetes mellitus and stage 3 chronic kidney disease. Following serial debridement and removal of all hardware, repair of the resultant sternal wound is planned. A photograph is shown. Use of which of the following flaps is CONTRAINDICATED in this patient?
A) Left pectoralis major advancement
B) Left pectoralis major turnover
C) Omental
D) Right pectoralis major advancement
E) Right rectus abdominis
-pic shows large chest wound-
The correct response is Option B.
Mediastinitis, along with purulent material from the mediastinum, constitutes a deep sternal wound infection. It is a potentially life-threatening complication following cardiac surgery involving a sternotomy. Surgical management includes drainage of purulent material, debridement of devitalized tissue, appropriate antibiotic therapy, and removal of contaminated foreign material such as sternal wires. The resultant defect can present reconstructive challenges, and proper flap selection is critical.
A pectoralis major muscle turnover flap is based on the perforators arising from the internal mammary vessels. In this patient, the left internal mammary regional pedicle is unavailable since it has been redirected to the coronary circulation as part of the patient’s initial surgery. Therefore, a left pectoralis major turnover flap is contraindicated.
The pedicle for a right pectoralis major advancement flap is the right thoracoacromial artery. The pedicle for a right rectus abdominis flap is the right superior epigastric artery. The pedicle for an omental flap is the right omental artery via the right gastroepiploic artery. The pedicle for a left pectoralis major advancement flap is the left thoracoacromial artery. None of these pedicles has been disrupted by a previous surgery. Therefore, these others would be reasonable flap options for the obliteration of dead space and soft-tissue coverage of the defect.
2024
A 1-day-old male newborn is evaluated because of an omphalocele. Which of the following embryologic processes is most likely responsible for this anomaly?
A) Incomplete closure of umbilical ring fascia
B) Patent processus vaginalis
C) Persistence of physiologic midgut herniation
D) Pleuroperitoneal fold defect
E) Rupture of amnion along the umbilical cord
C
Abdominal wall defects occur in up to 1 in 2000 live births. The two most common are omphalocele and gastroschisis. In an omphalocele, the abdominal wall defect is in the central abdomen in the umbilical region, and the intestinal contents are covered with a membrane. In gastroschisis, the defect is to the right of the umbilicus and intestinal contents are not covered by a membrane. There is no clear consensus about the exact etiology of these abdominal wall defects. Omphalocele is thought to be caused by failure of intestines to return to the abdominal cavity. During gestational week 6, the intestines herniate into the umbilical cord because of rapid intestinal elongation. They return to the abdominal cavity at 10 weeks. Failure of this return results in an omphalocele. One of the most widely accepted theories about the pathogenesis of gastroschisis is that it occurs because of rupture of the amniotic membrane along the right side of the umbilical cord. This allows evisceration through the abdominal wall defect.
Incomplete closure of the fascia of the umbilical ring leads to infantile umbilical hernias; most of these close spontaneously. The processus vaginalis is a protrusion of the peritoneum into the scrotum. Failure of obliteration results in hydroceles or inguinal hernias. The pleuroperitoneal folds separate the pleural and abdominal cavities. Failure of fusion of these folds results in congenital diaphragmatic hernias.
2024
A 39-year-old woman presents for ostomy takedown and repair of an upper midline incisional hernia. Separation of components by transversus abdominis release is planned. Which of the following best describes the plane of dissection lateral to the semilunar line?
A) Between the external oblique muscle and internal oblique muscle
B) Between the neurovascular bundles and the semilunar line
C) Between the rectus abdominis muscles and transversalis fascia
D) Between the transversus abdominis muscle and internal oblique muscle
E) Between the transversus abdominis muscle and transversalis fascia
E
The transversus abdominis release technique involves incision of the transversus abdominis muscle medial to the neurovascular bundles. Dissection continues between the transversus abdominis muscle and the transversalis fascia above the arcuate line and between the transversus abdominis and the peritoneum beneath the arcuate line.
The plane between the external oblique and internal oblique muscles is the plane for an anterior component separation.
The plane between the rectus abdominis muscles and transversalis fascia describes the retrorectus plane, which is medial to the semilunar line.
The plane between the transversus abdominis and the internal oblique muscles is the plane for anesthetic infiltration for transversus abdominis plane blocks. This plane contains neurovascular bundles and would risk denervation of the rectus abdominis muscles.
Dissecting between the neurovascular bundles and the semilunar line would also risk denervation of the rectus abdominis muscles.
2024
A 3-day-old female newborn is evaluated in the neonatal intensive care unit because of a myelomeningocele. Physical examination shows an intact 5 × 4-cm sac in the lower lumbar area with evidence of clear fluid drainage. The primary reason for early operative repair in this patient is to decrease which of the following?
A) Need for cerebrospinal fluid shunt placement
B) Need for future surgeries
C) Risk for bacterial meningitis
D) Risk for permanent motor damage
C
Failure of the neural tube to close during the fourth week of gestation results in a myelomeningocele. There is exposure of the spinal canal and neural elements, allowing for cerebrospinal fluid leakage and risk for infection. The primary indication for early intervention is to prevent bacterial meningitis. Initial care involves keeping the sac sterile and hydrated. Many of these patients have hydrocephalus and will require a shunt to decrease intracranial pressure and cerebrospinal fluid leakage. Further workup for cardiac, urologic, orthopedic, and other neurologic abnormalities is required, with many of these patients requiring multiple future surgeries. Early intervention has not been shown to improve the return of motor function but may improve bladder function.
After stabilization of other medical conditions, some authors have proposed placement of a temporary split-thickness skin graft until definitive repair is undertaken. Definitive correction will require repair of the dura to prevent further cerebrospinal fluid leakage, followed by placement of a well-vascularized layer of tissue between the dura and skin repair. Various flaps have been used for providing vascularized coverage of the dura. These include paraspinous fascia turnover flaps, paraspinous muscle advancement flaps, local/regional fasciocutaneous flaps, gluteal advancement flaps, and latissimus turnover flaps. The vascularized layer will prevent contact with cutaneous bacteria and subsequent meningitis if either the dural or skin repairs fail.
2024
A 60-year-old man undergoes coronary artery bypass grafting of the left anterior descending coronary artery with the left internal mammary artery as the conduit. One month later, he presents with a defect in the lower sternum by the xiphoid. He undergoes debridement and negative pressure wound therapy. The most appropriate flap for closure of this patient’s wound is supplied by which of the following?
A) Left deep inferior epigastric artery
B) Left internal mammary artery perforators
C) Left transverse cervical artery
D) Right gastroepiploic artery
E) Right thoracoacromial artery
D
The omentum has dual major pedicle blood supply through the right gastroepiploic and left gastroepiploic arteries. It provides bulk and can adequately cover lower sternal defects. Typically, skin grafting may be required over the omentum. The pectoralis major muscle flap can be used as an advancement flap (thoracoacromial artery pedicle) or as a turnover flap based on the internal mammary perforators. A pectoralis major muscle turnover flap can potentially reach a lower sternal defect, whereas that can be challenging for a pectoralis advancement flap. The thoracoacromial artery is the pedicle for the pectoralis major muscle advancement flap. It would be difficult for the pectoralis major muscle advancement flap to reach a lower sternal defect. A vertical rectus abdominis muscle flap can be used, particularly for lower sternal defects, but it is based on the superior epigastric artery, not the inferior epigastric artery, when it is pedicled for chest reconstruction. A left pectoralis major muscle turnover flap would reach the lower sternal defect. However, it is based on the internal mammary artery perforators and cannot be used in this patient because of his history using the left internal mammary artery for coronary artery bypass. The transverse cervical artery supplies the trapezius muscle and supraclavicular flap. Neither flap would reach the lower sternal defect.
2024
A 45-year-old man is evaluated because of a history of open abdomen following a motor vehicle collision 2 years ago. At the time of the original injury, the fascia was closed with absorbable mesh, and ultimately a split-thickness skin graft was used to close the wound. The patient is otherwise healthy and does not smoke cigarettes. BMI is 29 kg/m2. Physical examination shows a large reducible ventral hernia with a fascial defect about 15 cm in its widest dimension. Which of the following techniques is most likely to result in the lowest risk for hernia recurrence in this patient?
A) Bridged mesh repair only
B) Component separation and bridged mesh repair
C) Component separation and primary closure of fascia
D) Component separation, primary fascial closure, and retrorectus mesh placement
D
Performing a definitive hernia repair at the time of explantation for mesh infection would be best suited via the use of a xenograft biologic mesh and placement in the sublay position without a bridge. This patient has a Grade 4 hernia based on the Ventral Hernia Working Group classification system. In Grade 4 hernias, permanent synthetic mesh is currently thought to be contraindicated because of the high infection rate and need for explantation. Based on the classification system, Grade 1 hernias are those with low risk for complications and no history of infection, Grade 2 hernias have comorbidities that increase the risk for complication, Grade 3 hernias have discontinuity of their gastrointestinal tract or a history of wound infection, and Grade 4 hernias have a mesh infection. There is debate as to the contraindication of synthetic mesh in Grade 2 and 3 hernias, and different studies have demonstrated superior outcomes with synthetic and biologic mesh. While human-derived mesh continues to be widely used in breast reconstruction, early experience in abdominal wall reconstruction demonstrated a lack of durability and high hernia recurrence rate. As a result, the use of human biologics was replaced by xenograft biologics in the form of porcine, bovine, or ovine-derived products with better outcomes. There have been multiple studies looking at the position of the mesh and the long-term outcomes. Bridged repairs, where the mesh is placed in a gap between the edges of the soft tissue, carry a much higher hernia recurrence rate when compared with other repairs. The sublay or underlay position where the mesh is placed in the abdomen, preperitoneal space, or retrorectus space has a more favorable hernia-free survival comparatively. Performing this type of repair in someone with a history of major abdominal injury often requires the use of bilateral component separation to approximate the abdominal wall over the mesh to prevent the need for bridging.
2024
Which of the following immunologic responses is most likely to be seen in a 50-year-old woman who has sustained a 50% total body surface area (TBSA) burn in a house fire?
(A) Augmented B lymphocyte function
(B) Decreased fibronectin levels
(C) Decreased quantity of suppressor T lymphocytes
(D) Increased complement activation
(E) Increased production of IgG and IgM antibodies
The correct response is Option B.
Immunologic responses anticipated in this 50-year-old woman who has sustained a 50% TBSA burn include decreased levels of fibronectin, diminished complement activation, and decreased production of immunoglobulin antibodies. Patients who sustain burn injuries enter into an immunocompromised state, in which the ability to perform the functions of phagocytosis and pathogen elimination are severely limited, resulting in an inability to produce fibronectin. In addition, there is a generalized depression of the cellular immune response, including a decrease in the quantity and function of both B and T lymphocytes; however, the number of suppressor T lymphocytes is actually increased following acute thermal injury.
Which of the following physiologic mechanisms is increased during the first 24 hours following thermal burn injury?
(A) Cardiac output
(B) Central venous pressure
(C) Circulating erythrocyte volume
(D) Circulating glucose concentration
(E) Plasma volume
The correct response is Option D.
The circulating glucose concentration is increased during the first 24 hours following thermal burn injury. The affected patient develops glucose intolerance due to the release of catecholamines from the burn site. Because of this, glucose should not added to the fluids given intravenously for acute resuscitation.
Following burn injury, the release of myocardial depressants diminishes cardiac output. Cardiac output is decreased to 40% to 60% of normal as a result of decreased plasma volume and increased systemic vascular resistance. Cardiac output then returns to normal but is not increased. The aforementioned decrease in plasma volume, which occurs in part from a capillary leak, subsequently leads to a decrease in central venous pressure. In addition, there is a decrease in circulating erythrocyte volume, due in part to a direct destruction of erythrocytes by the injured tissue.
A 25-year-old man is evaluated in the emergency department 3 hours after sustaining first-degree burns to 5% of his total body surface area and second-degree burns to 80% of his total body surface area. He weighs 176.4 lb (80 kg). Using the Parkland formula, which of the following is the most appropriate initial hourly rate for fluid administration in this patient?
A) 800 mL/h
B) 1600 mL/h
C) 1700 mL/h
D) 2560 mL/h
E) 2720 mL/h
The correct response is Option D.
The Parkland formula is 4 mL per percent total body surface area with second-degree or higher burns, multiplied by the patient’s body weight in kilograms, starting from the time of the burn (25,600 mL for this patient) to be given over the first 24 hours. Starting from the time of the burn injury, half of the total fluid should be given in the first 8 hours, and the other half should be given in the next 16 hours. The first-degree burn does not enter in the calculation. In some centers, the Parkland formula is no longer used to avoid over-resuscitation with crystalloid.
For this particular patient, a total of 25,600 mL (4 x 80 x 80) should be given in the first 24 hours after the burn. Since the patient arrived 3 hours after injury, the first half should be given over a period of 5 hours, at an initial rate of 2560 mL/h (12,800 / 5).
2024
A 33-year-old man is admitted to the burn unit after sustaining superficial partial-thickness burns involving 28% of total body surface area. The burns are cleaned, and topical therapy is initiated with silver nitrate-soaked dressings secondary to sulfonamide allergy. Which of the following effects is most likely?
A) Effective tissue penetration
B) Hyponatremia
C) Metabolic acidosis
D) Neutropenia
E) Pain on application
B
Because of the skins important function as a microbial barrier, prevention of infection after burn injury is still one of the most difficult challenges in caring for burn patients. The development of effective topical antimicrobial agents has significantly decreased the incidence of invasive burn wound infection and sepsis. Topical therapy should be started after the initial wound debridement. The three most common topical antimicrobial agents are silver sulfadiazine, silver nitrate, and mafenide acetate.
Silver nitrate is typically delivered as a 0.5% solution as a wet dressing. Silver nitrate has excellent antibacterial properties and is effective for most Staphylococcus species and most gram-negative aerobes, including Pseudomonas. This agent is typically used when there is a history of sulfonamide allergy or when sensitivity to the other agents has developed. A common use of silver nitrate is in the setting of toxic epidermal necrolysis. Application is painless, but tissue penetration is poor. Concentrations above 5% are cytotoxic to normal tissues. Because leaching of sodium, potassium, and calcium is common, this effect should be anticipated and replaced appropriately.
Painful application is associated with mafenide acetate. Mafenide acetate is delivered as suspension in a water-soluble base. As a result of its solubility, it has excellent tissue penetration and is often used in heavily contaminated wounds with thick eschar. Due to excellent cartilage penetration, it is also the agent of choice for ear burns. Mafenide acetate is highly effective against gram-negative organisms. Other side effects include hypersensitivity reactions (7% of patients) and inhibition of carbonic anhydrase with a resultant hyperchloremic metabolic acidosis.
Silver sulfadiazine is the most common topical antimicrobial agent used. It has intermediate tissue penetration secondary to its limited water solubility. This agent has a good antibacterial spectrum, a low incidence of development of resistant organisms, and is applied painlessly. Transient leukopenia is a common side effect of silver sulfadiazine. This condition is self-limited and does not appear to increase mortality in burn patients.
Switching to a different topical agent for a few days will allow the white blood cell count to return to normal.
2024
A 14-year-old girl sustained a burn contracture at the elbow that is limiting her range of motion. Reconstruction using a Z-plasty technique is planned to revise and lengthen the scar. A Z-plasty with a 60-degree angle will create which of the following percent increases in length?
A) 25%
B) 50%
C) 75%
D) 100%
E) 150%
C
Per the table below, different Z-plasty angles will produce different increases in length.
Z-plasty angle Gain in length (%)
30-30° 25
45-45° 50
60-60° 75
75-75° 100
90-90° 125
2024
