Emergency Escharotomy

Escharotomy is the surgical division of the nonviable eschar, the tough, inelastic mass of burnt tissue that results from full-thickness circumferential and near-circumferential skin burns. The eschar, by virtue of its inelasticity, gives rise to the burn-induced compartment syndrome. This is caused by the accumulation of extracellular and extravascular fluid within confined anatomic spaces of the extremities or digits. The excessive fluid causes the intracompartmental pressures to increase, resulting in collapse of the contained vascular and lymphatic structures and, hence, loss of tissue viability. The capillary closure pressure of 30 mm Hg, also measured as the compartment pressure, is accepted as that which requires intervention to prevent tissue death.

The circumferential eschar over the torso can lead to significant compromise of chest wall excursions and can hinder ventilation. Abdominal compartment syndrome with visceral hypoperfusion is associated with severe burns of the abdomen and torso. (A literature review by Strang et al found the prevalence of abdominal compartment syndrome in severely burned patients to be 4.1-16.6%, with the mean mortality rate for this condition in these patients to be 74.8%. ^[1] ) Similarly, airway patency and venous return may be compromised by circumferential burns involving the neck.

Escharotomy allows the cutaneous envelope to become more compliant. Hence, the underlying tissues have an increased available volume to expand into, preventing further tissue injury or functional compromise (see image below). ^[2] For more information on burn treatment, see the Medscape Drugs & Diseases article Burn Rehabilitation and Reconstruction.

Escharotomy to release the chest wall and allow for ventilation of the patient.

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Escharotomy is considered an emergent procedure in burn treatment protocols. However, it rarely needs to be performed in the emergency department at the time of initial presentation of the severely burned patient. Advanced ventilation methods allow the patient to be stabilized to allow for expeditious transfer to the intensive care unit or the surgical suite, where the procedure can be performed under more controlled circumstances. ^{[3, 4]} For more information, see Medscape Drugs & Diseases article Burn Resuscitation and Early Management.

Indications for emergency escharotomy are the presence of a circumferential eschar with one of the following:

1. Impending or established vascular compromise of the extremities or digits

2. Impending or established respiratory compromise due to circumferential torso burns ^[5]

Severely burned extremities should be elevated and range of motion exercises performed every 15-30 minutes as tolerated by the patient. This can help to minimize tissue edema and elevated tissue pressures.

Neurovascular integrity should similarly be monitored frequently and in a scheduled manner. Capillary refilling time, Doppler signals, pulse oximetry, and sensation distal to the burned area should be checked every hour. ^[6] Limb deep compartment pressures should be checked initially to establish a baseline. Subsequently, any increase in capillary refill time, decrease in Doppler signal, or change in sensation should lead to rechecking the compartment pressures. Compartment pressures greater than 30 mm Hg should be treated by immediate decompression via escharotomy and fasciotomy, if needed. ^{[7, 8]} A decision-making algorithm is shown in the image below.

Decision-making algorithm for escharotomy in severely burned extremities.

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Patients who have established irreversible gangrene of the extremity or digit in association with a circumferential or near-circumferential eschar would not likely benefit from an escharotomy. This scenario is likely to be encountered in patients who have been managed nonoperatively for a prolonged period of time, during which the neurovascular status of the extremity involved was not monitored adequately. In this group of patients, the risks and potential complications of performing an escharotomy are to be weighed carefully against the benefits.

See the list below:

• In the severely burned patient who is obtunded and intubated, no anesthesia is required because the eschar is nonviable tissue with complete destruction of nerve endings. ^[9]

• Patients who are awake or conscious require sedation and, occasionally, general anesthesia, to allow the procedure to be completed adequately. For more information, see Procedural Sedation.

See the list below:

• Sterile drapes

• Povidone-iodine solution

• Electrocautery: Escharotomy can result in substantial blood loss; hence, it should be performed using electrocautery and in a controlled environment such as the operating room or the intensive care unit.

• Dressing materials

See the list below:

• Position the patient supine.

• Maintain the ability to move the patient into lateral positions to allow circumferential access to the extremity or torso, as needed.

See the list below:

• Clean the proposed surgical site with povidone-iodine solution and drape with sterile drapes.

• Use electrocautery to create incisions in the eschar up to the level of the subcutaneous fat.

• Severely burned limbs may require performance of fasciotomy concomitantly with the escharotomy.

  • This may be determined preoperatively by measurement of compartment pressures greater than 30 mm Hg.

  • Compartment pressures can be obtained intraoperatively after completion of the escharotomy. If elevation of pressure above 30 mm Hg is persistent, a fasciotomy should be performed.

• Carry the incision of the eschar down through to the level of the subcutaneous fat. An immediate release in tissue pressure is experienced as a discernible popping sensation.

• Carry the incisions approximately 1 cm proximal and distal to the extent of the burn.

• Areas overlying joints have densely adherent skin, and the incisions should extend across joints to allow for decompression of neurovascular structures. Take care to avoid damage to the neurovascular bundles that run superficially and near joints. ^[7]

• Make escharotomy incisions for the chest, neck, and limbs as shown in the diagram below.

  Diagrammatic representation of escharotomy incisions over the chest, neck, and limbs.

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• Make escharotomy incisions for the digits as shown in the diagram below.

  Diagrammatic representation of escharotomy incisions over the digits.

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• Bleeding from escharotomy incisions should be controlled by use of the electrocautery.

• The resulting wounds are a potential source of infection and should be treated, as the burn wound, with application of topical antimicrobial and dressings.

• Adequacy of the escharotomy can be tested after completion by checking capillary filling pressures, using a handheld Doppler, and by checking compartment pressures. ^[10]

  • Improvement in flow and decrease in compartment pressures indicate that the procedure is adequate.

  • Persistent low Doppler signals or elevated compartment pressures indicate inadequate release of tissue pressure and a need for additional escharotomy incisions and, possibly, the addition of fasciotomy.

See the list below:

• Escharotomy incisions for the limbs should be carried to the level of the thenar and hypothenar eminences for the upper extremity and to the level of the great toe medially and the little toe laterally for the lower extremity.

• Limb escharotomy incisions run in close proximity to superficial veins, and these veins should be identified and preserved, if possible. If the escharotomy incision transects these veins, adequate hemostasis should be ensured using electrocautery or ligation.

• Digital escharotomy should be performed by a practitioner with experience in hand surgery for burns whenever possible. The locations of the incisions for decompression are near the digital neurovascular bundles, and injury to these can lead to profound and permanent loss of function.

Complications of inadequate decompression ^[11] or of not performing an escharotomy when indicated are severe. ^[12] They include the following:

• Muscle necrosis

• Nerve injury

• Gangrene resulting in amputation of the limb or digits

• Respiratory compromise due to inadequate ventilation as a result of compressive effect of chest and upper torso burns

• Abdominal compartment syndrome with visceral hypoperfusion as a result of abdominal wall and upper torso burns ^[13]

• Systemic complications of inadequate decompression including myoglobinuria, renal failure, hyperkalemia, and metabolic acidosis

Complications of an escharotomy are as follows:

• Excessive blood loss

• Inadvertent fasciotomy: This results in exposure of the underlying viable tissue, which can become desiccated.

• Incision/injury to the underlying healthy tissue including neurovascular structures, especially in the extremities and digits

• Bacteremia: Underlying tissue may be infected, and the manipulation can result in bacteremia and septic shock. If underlying infection is suspected, the escharotomy should be performed under antibiotic coverage.

• Infection of the open escharotomy wounds: These wounds are treated with the same degree of care (with dressings and application of antimicrobial agents) as the burns wounds. These wounds also contribute to the ongoing insensate fluid losses in a manner similar to the burns wounds.

A retrospective study by Schulze et al indicated that full-thickness and electrical burns are risk factors for the amputation of fingers even after successful escharotomies of the digits, in patients who suffer hand burns. ^[14]

A study by Markowska et al indicated that surgical smoke produced by an electric knife during escharotomy and necrectomy in burn surgery contains complex toxic hydrocarbon derivatives. The investigators determined that overall, as much as 17.65% of the compounds evaluated in the smoke consisted of benzene and its derivatives, with almost 25% of the volatile organic compounds assessed consisting of alkanes and alcohols, along with their derivatives. ^[15]

A study by Fischer et al of patients with deep circumferential burns of the upper extremities indicated that in specific individuals—ie, those whose burns are no more than 12 hours old, are not dry burns requiring presoaking, are not associated with compartment syndrome, and are not the result of blast or electrical injuries for which fasciotomy or carpal tunnel release is needed—enzymatic débridement can render escharotomy unnecessary. ^[16]

A Swiss study, by Grünherz et al, found that although early enzymatic débridement is an effective means of eschar removal in circumferential burns, escharotomy tended to be used for more severe and widespread burns at the burn center of the University Hospital Zurich. The investigators reported that the use of NexoBrid (which contains proteolytic enzymes) “for preventive decompression in circumferential deep partial-thickness and full-thickness burns” had increased at the hospital. Nonetheless, patients who underwent NexoBrid débridement had a mean burn total body surface area (TBSA) of 31.3%, compared with 47.2% for patients who underwent escharotomy. Moreover, statistically, the number of patients with third-degree burns who were treated with escharotomy was significantly higher than in the NexoBrid cohort, with the mean abbreviated burn severity index scores being 9.1 (escharotomy group) versus 6.2 (NexoBrid group). Although the mortality rate in the escharotomy cohort was 36.4%, versus 10.3% in the NexoBrid patients, the investigators attributed this to the high TBSA of the burns in the escharotomy group. ^[17]